Brain Metastases

Brain Metastases Francois G. Kamar, M.D.,1 and Jerome B. Posner, M.D.1

ABSTRACT

Downloaded by: Memorial Sloan Kettering Cancer Center. Copyrighted material.

Approximately 10% of patients with cancer develop brain metastases. Some evidence indicates that as techniques for treating systemic tumors improve, the incidence of brain metastases, sequestered as they are behind the blood–brain barrier, is increasing. Although usually appearing late in the course of the disease, a brain metastasis may cause the initial symptoms, before the primary cancer has been identified. The diagnostic and therapeutic approach depends on the number and location of brain lesions and the stage of the cancer. Patients with brain metastases are rarely cured. However, appropriate treatment can improve both the quality and duration of the patient’s life. Treatment must be directed not only at the brain metastasis (definitive care), but also at a multitude of other symptoms that plague patients with brain metastases (supportive care). Judicious selection of pharmacologic agents and nonpharmacologic techniques can effectively treat many serious symptoms in patients with brain metastases, but injudicious selection of pharmacologic agents may have side effects and make the patient’s quality of life worse. The authors review some aspects of both definitive and supportive care with particular attention to the side effects of some commonly used pharmacologic agents. KEYWORDS: Brain metastasis, supportive care, corticosteroids, seizures, venous thromboembolism

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ld autopsy data suggest that about 10% of patients with cancer develop brain metastases at some time during the course of the disease1; two-thirds of these patients have had neurologic symptoms during life.2 Once a brain metastasis has developed, survival is usually short. However, early identification and aggressive treatment can often ameliorate symptoms and increase both the duration and quality of survival. The treatment of brain metastases has three major components. The first is treatment of the lesion itself (definitive therapy). The second is management of symptoms related to the brain metastasis or the primary cancer (supportive care). Finally, increasing evidence suggests that for some tumors, prophylactic irradiation

of the brain prevents development of brain metastases (see below). Definitive treatment of a metastasis includes surgery, radiation therapy (either focal or whole-brain), chemotherapy, and increasingly, targeted small molecule therapy.2,3 Most of these therapies are administered by neurosurgeons, radiation oncologists, or medical oncologists. Supportive care often is or should be handled by a neurologist. Prophylactic cranial irradiation may prevent metastases in selected patients with cancer. This review briefly describes some aspects of the epidemiology, diagnosis, and treatment of brain metastases most of which are widely known and the subject of many monographs and reviews3–6; emphasis is placed

1 Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, New York. Address for correspondence and reprint requests: Jerome B. Posner, M.D., Department of Neurology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (e-mail: [email protected]). Neurologic Complications of Cancer; Guest Editor, Josep Dalmau,

M.D., Ph.D. Semin Neurol 2010;30:217–235. Copyright # 2010 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662. DOI: http://dx.doi.org/10.1055/s-0030-1255225. ISSN 0271-8235.

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on supportive care of brain metastases, an area that is the subject of only a few reviews.4,7,8 The approaches suggested here are our opinions based on evidence where documented, and on experience where not documented.

EPIDEMIOLOGY OF BRAIN METASTASES The exact incidence of brain metastases is unknown and varies substantially depending on the primary site of the cancer (Table 1); lung and breast cancers are common causes of brain metastases, whereas prostate and ovarian cancers, although common tumors, are uncommon causes of brain metastases. Because of difficulties in ascertainment, these figures probably underestimate true incidence. The incidence also varies by the histologic subtype. For example, small-cell lung cancer (SCLC) is more likely to metastasize to the brain than non-small cell lung cancer (NSCLC); among NSCLC, adenocarcinoma more commonly metastasizes to the brain than squamous carcinoma. Among patients with breast cancer, those overexpressing HER-2 are more likely to develop brain metastases than those with triple negative (estrogen receptor, progesterone receptor, HER-2) cancers. Once in the brain, there is some evidence that different histologic subtypes vary in their behavior. For example, a recent report suggests that triple negative breast cancers disrupt the blood–brain barrier as characterized by expression of Glut1 and BCRP in cerebral vessels more than do HER-2 positive cancers.11 However, there is no clear evidence that gadolinium enhancement (one manifestation of blood–brain barrier disruption) differs with the histologic subtype of metastasis. There is substantial evidence that the incidence of brain metastases is increasing. A population-based study of patients admitted to a Swedish hospital describes a doubling of admissions for brain metastases between 1987 and 2006.12 Despite all the above differences, there appears to be no significant difference in the outcome once a patient has developed a brain metastasis. In the Swedish study, the overall survival was 2.7 months.12 Even in patients with the best prognosis (good performance status, con-

Table 1 Incidence of Brain Metastases from Two Studies # (%) of Metastases9

# (%) Metastases10

Lung

11,763/59,038 (19.9%)

156/938 (16.3%)

Breast Renal

2,635/51,898 (5.1%) 467/7205 (6.5%)

42/802 (5.0%) 12/114 (9.8%)

Primary Tumor

Melanoma

566/8229 (6.8%)

12/150 (7.4%)

Colorectal

779/42,817 (1.8%)

10/720 (1.2%)

trolled systemic disease, age less than 65) the median survival is only 7 months.13 Nevertheless, there are some long-term survivors,14 and in most patients who are treated there is some improvement in quality of life.13 With the increasing incidence and poor prognosis, there is a major need for improvements in treatments both to control the metastases and improve the patient’s quality of life. We address these issues below.

DIAGNOSIS AND TREATMENT OF BRAIN METASTASES When a patient presents with neurologic signs and symptoms that the physician believes may be related to structural disease of the brain, a magnetic resonance image (MRI) both with and without contrast should be the first step in diagnosis; in the appropriate clinical setting, the presence of one or more contrast-enhancing lesions establishes the diagnosis. However, not all contrast-enhancing lesions are metastases. In one biopsy study, 5 of 51 patients with cancer and a single contrast-enhancing brain lesion were discovered not to have a brain metastasis.15 If there is any question concerning the diagnosis, a biopsy should be considered. In a patient not known to have cancer, biopsy may not only identify a metastasis, but may suggest the primary source.16 Current evidence suggests that a small, ambiguous lesion(s) (less than 1cm) can, even if it is a metastasis, be followed closely without compromising the effectiveness of subsequent therapy17; larger lesions require immediate diagnosis and treatment. The treatment of a patient with one or more brain metastases depends on several factors: 1. The number and size of metastases: Single and sometimes two or three lesions are amenable to focal therapy (e.g., surgery or stereotactic radiosurgery), whereas multiple metastases are usually treated with whole-brain radiation therapy. Metastases larger than 3 cm are not good candidates for radiosurgery. A single large metastasis may require surgery to relieve symptoms, even when the patient has other smaller metastases. 2. Age, performance status, clinical symptoms, and extent of disease: Patients younger than age 65 with good performance status, and those with controlled or no extracranial lesions fare best. Those with poor performance status fare worst and the remainder are in between. A recursive partitioning analysis (RPA)13 has been devised based on pretreatment prognostic characteristics and treatmentrelated variables to decide appropriateness of treatment based on likelihood of survival. Even for those patients with the best prognosis (RPA class I), the median survival is only 7 months. Nevertheless,


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most patients respond initially to treatment and there are some long-term survivors. As individual variability is so great, almost all patients with brain metastases should be treated. 3. Histology, including radiosensitivity and chemosensitivity of the primary tumor: Different histologies of tumors arising from the same organ differ in their likelihood to metastasize to the brain and their treatment. For example, SCLC has a propensity for early spread to the brain causing multiple metastases that are often responsive to chemotherapy; therefore, surgical resection, even of a single brain metastasis, is rarely considered. Conversely, a single brain metastasis occurring synchronously with NSCLC is usually treated surgically. 4. Site of metastasis: Basal ganglia metastases are not amenable to surgical removal but do respond to radiosurgery. Cerebellar metastases, if removed surgically, risk the development of subsequent leptomeningeal tumor.18 The multiplicity of factors indicated above emphasize that each patient is different and therefore treatment must be individualized. Fig. 1 suggests an approach to treatment taking these factors into consideration. In a patient not known to have cancer, a single contrast-enhancing lesion in a surgically accessible area should probably be removed. Prior to the surgery, the patient is likely to undergo a computerized tomography (CT) scan of the chest, abdomen, and pelvis and/or a

whole-body fluorodeoxyglucose positron emission tomography (PET) scan. However, if the MRI suggests a primary brain tumor, one can proceed to craniotomy without additional diagnostic tests. Unless a systemic cancer threatening imminent death is encountered, surgical extirpation of the single lesion is probably the best therapeutic approach6,19 to establish the diagnosis. Surgery rules out a primary tumor or an abscess, usually relieves neurologic symptoms, and improves the likelihood that subsequent treatment will be effective. If the lesion is not surgically accessible, and the workup has not identified a primary cancer, a stereotactic needle biopsy will establish the diagnosis. If the biopsy reveals a brain metastasis, radiosurgery should be considered.20 If a patient without a known cancer has two or three contrast-enhancing lesions, metastatic disease becomes a more likely diagnosis. If scanning of the body by CT or PET identifies a tumor, tissue is best procured from one of the systemic organs. The physician then assumes that the lesions in the brain have the same histologic characteristics unless the brain MRI gives him reason to believe otherwise. Surgical removal of two or three lesions is sometimes performed, but radiosurgery, with or without whole brain radiation therapy, is the better treatment. Some radiation oncologists have advocated radiosurgery for as many as seven lesions in the brain.21 If there are more than three lesions in the brain and CT or PET does not reveal a primary cancer, stereotactic needle biopsy of the brain lesions should establish the diagnosis. Immunohistochemistry may help identify the primary site, but the physician must recognize that in

Figure 1 A suggested approach to the treatment of metastatic brain tumors. SRS, stereotactic radiosurgery; WBRT, wholebrain radiation therapy.

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patients with brain metastases from an unknown primary source, the primary may not be identified even at autopsy.22 The treatment of multiple brain metastases is whole brain-radiation therapy generally delivered as 10 treatments of 300 cGy each. In patients who are known to have cancer, the treatment will depend, in part, on the stage of the cancer. If the patient has a reasonable performance status and a reasonable predicted survival, single lesions should be removed, giving the patient the best chance for a good neurologic quality of life. If there are two or three lesions that have the characteristic appearance of brain metastases (rim enhancing, spherically shaped lesions) there is no reason to do a biopsy. Radiosurgery is probably the treatment of choice. Whether wholebrain radiation therapy should follow radiosurgery (or surgery) is controversial. One must weigh the benefits (decreased recurrence and decreased likelihood of other brain metastases developing, without an increase in survival)23 against the risks of radiation-induced cognitive deficits.24 If the patient is followed carefully, we believe that one can wait for the appearance of other lesions before delivering whole-brain radiation therapy. For multiple lesions, whole-brain radiation therapy should be delivered promptly. An exception to this approach exists in patients with more than one lesion who are relatively asymptomatic and who are about to undergo chemotherapy for the treatment of their primary disease. Chemotherapy is often as effective in treating enhancing brain metastases as it is in treating the primary tumor or systemic metastases; thus, it is reasonable to try chemotherapy before deciding on radiation.5 Because there are so many variables both in the brain lesion and in the systemic lesion(s), the general rules given above may not apply to every patient. Each patient must be considered as an individual, with attention being given not only to the number, but also the site of the brain metastases as well as the stage of the patient’s cancer and performance status. Prevention of the development of metastases is an expanding field. Prophylactic cranial irradiation is the accepted treatment for patients with limited stage SCLC and has shown promise in trials in extensive SCLC, NSCLC, and breast cancer.25,26 Neurocognitive side effects are a concern.26

SUPPORTIVE CARE OF THE PATIENT WITH BRAIN METASTASES Table 2 lists some aspects of supportive care that should be addressed in a patient with a brain metastasis. Many physicians confronted with a patient suspected of having a brain tumor (either metastatic or primary) almost reflexively begin supportive care treatment immediately. Prescriptions are given for dexamethasone 16

Table 2 Supportive Care of Patients with Brain Metastasis Problem

Agent

Brain edema

Corticosteroids

Seizures

Anticonvulsants

Venous thromboembolism

Anticoagulants

GI problems Anorexia/cachexia

Megestrol, cannabinoids, etc.

Nausea/vomiting GI bleeding/perforation

Antiemetics H-2 blockers, protein pump inhibitors Misoprostol, sucralfate

Constipation

Laxatives

Cognitive/behavior problems Depression

SSRIs, tricyclics

Fatigue

Methylphenidate

Pain

Modafinil Opioids, anticonvulsants, antidepressants Corticosteroids

Delirium Infection

Haloperidol Antibiotics (prophylactic?)

GI, gastrointestinal; SSRIs, selective serotonin reuptake inhibitors.

mg a day (even in patients with minimal brain edema), phenytoin 300 or 400 mg a day (despite the evidence that valproate with or without levetiracetam is probably better treatment27,28), a histamine-2 receptor blocker (H2 blocker) or proton pump inhibitor to prevent gastrointestinal (GI) bleeding, and sometimes trimethoprim/sulfamethoxazole for prophylaxis of pneumocystis pneumonia. If the patient has a known cancer, these agents are added to several other drugs, including cytotoxic agents. Because most patients with brain metastases are older, the patient may be taking a variety of drugs for illnesses unrelated to cancer, such as hypertension, hypercholesterolemia, or diabetes.29 All of these medications have side effects and many have interactions that interfere with treatment of the primary cancer. Therefore, the physician should carefully consider each drug prescribed to decide whether that particular drug is necessary or even desirable. The paragraphs below describe what we believe to be the indications and contraindications for some of the drugs given in a supportive care setting.

Brain Edema Brain metastases, with few exceptions (metastatic lymphoma and melanoma that often infiltrate along blood vessels), tend to occur as discrete masses that push aside rather than infiltrate normal brain. However, because they cause disruption of the blood–brain barrier, metastases are often surrounded by considerable edema, often more symptomatic than the tumor itself. The edema is


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vasogenic and results from disruption of the blood–brain barrier within the tumor and in peritumoral areas,30,31 the latter probably from vasoactive factors (e.g., vascular endothelial growth factor31) secreted by tumor cells to produce angiogenesis. Brain edema is treated with corticosteroids.4,32 Inhibitors of vascular endothelial growth factor (e.g., bevacizumab33 and corticotropin-releasing factor34) may in the future prove effective in minimizing the dose of corticosteroids required. Most physicians prescribe 16 mg of dexamethasone a day, although other corticosteroids (e.g., prednisone) may work as well. Because dexamethasone is long-acting, it need not be given more than twice a day; however, because of its long duration of action, every other day application does not prevent steroid side effects. Brain edema in and of itself does not require treatment; only symptomatic brain edema needs to be treated. Furthermore, the dose required is not known. Some symptomatic patients respond to 4 to 8 mg a day,32 others require doses as high as 100 mg a day.35 In patients with symptomatic brain edema, we usually begin with 16 mg a day tapering the dose to tolerance at a rate of 2 mg every 4 or 5 days. If 16 mg are ineffective in 48 to 72 hours, the dose can be doubled each 48 to 72 hours until there is maximal response. A comprehensive review of the role of steroids in the management of brain metastases has appeared recently.32 Although corticosteroids have other salutary effects in patients with advanced cancer such as prevention of nausea and vomiting, increased appetite, relief of pain, and prevention of some hypersensitivity symptoms to radiation therapy and chemotherapy,36 if a patient is not symptomatic from the brain edema, steroids are not required (curiously, dexamethasone, overused in patients with brain metastases is often underused as an antiemetic37). Even when symptomatic, corticosteroids are contraindicated when primary central nervous system lymphoma (PCNSL) is a

serious diagnostic consideration as their use may prevent establishing a histologic diagnosis. Asymptomatic patients about to undergo whole brain radiation should be given 16 mg of dexamethasone for at least 48 hours before the radiation is begun. Corticosteroids are probably unnecessary for radiosurgery of small, asymptomatic lesions with little or no edema. For lesions larger than 2 cm, it is probably wise to give prophylactic corticosteroids (4 to 8 mg). The mechanism of action of corticosteroids on edema and increased intracranial pressure is not fully understood. The drug appears to stabilize the blood– brain barrier decreasing the transfer constant of watersoluble agents and perhaps proteins into the brain, allowing the edema to resolve over time on its own.4 Patients often respond with neurologic improvement within hours after the corticosteroids are given, even though there is no change in the amount of edema seen on CT or MR scans until much later.32 The reason for not routinely prescribing corticosteroids is that these drugs may have unwanted side effects (Table 3). Reconstitution of the disrupted blood–brain barrier may prevent the entry of a water-soluble chemotherapeutic agent that might have otherwise been effective in treating a brain metastasis. In addition, some or all of the side effects noted in Table 3 may diminish the patient’s quality of life. All patients should be warned that the drug causes insomnia, in part a direct effect of the drug on the brain, and in part because corticosteroids induce urinary frequency at night often requiring the patient to get up hourly. Hypnotic agents may reduce the insomnia. Patients should also be warned that they may develop tremor. Essential tremor is substantially worsened by corticosteroids to the point that some patients previously unaware of tremor may become symptomatic. Corticosteroids increase the appetite, which may be salutary in a patient concerned

Table 3 Some Side Effects of Corticosteroids Common but Usually Mild

Nonneurologic but Serious

Neurologic (Common)

Neurologic (Uncommon)

Insomnia

Osteoporosis

Myopathy

Psychosis

Urinary frequency

Osteonecrosis (hip)

Behavioral alterations

Delirium

Increased appetite

GI bleeding

Hallucinations (high-dose)

Seizures

Abdominal bloating

Bowel perforation

Hiccups

Memory loss

Moon facies Visual blurring

Diabetes Opportunistic infections

Tremor Brain atrophy

Acne Edema

(Pneumocystis) Glaucoma

Lipomatosis

Kaposi sarcoma

Genital burning (IV push)

Pancreatitis

Candidiasis GI, gastrointestinal; IV, intravenous.

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about anorexia, but the weight gain is fat, not muscle, and the fat is redistributed to the face and abdomen where it often produces an unsightly change in the patient’s physiognomy. Curiously, despite often developing a voracious appetite, the patients frequently complain of feeling ‘‘bloated.’’ Almost all patients who are on steroids for more than a few weeks develop steroid myopathy characterized by weakness of neck flexors and muscles of shoulder and pelvic girdle. The first symptom is usually difficulty getting off the toilet seat without using one’s hands and later difficulty climbing stairs. The myopathy almost never prevents walking. Because the respiratory muscles are involved, the myopathy may compromise respiratory function.38 Corticosteroids have also been implicated as a cause of critical illness myopathy.39 The mechanisms of steroid myopathy are multifactorial40,41 involving both decreased protein synthesis and increased protein degradation. Although a variety of agents, such as growth factors, creatine, and amino acids have been proposed40 either to prevent or treat steroid myopathy, there is no effective treatment other than discontinuing the steroids, after which most patients recover. Patients should be encouraged to be as active as they can because exercise may be helpful in ameliorating weakness. A second site of steroid damage is bone. Steroids cause osteoporosis both by promoting bone resorption and by inhibiting bone formation.42 Patients taking steroids for a long period can be prescribed vitamin D and calcium or bisphosphonates.42 Because it takes a long time for osteoporosis to develop and survival from metastatic brain tumors is usually short, osteoporosis is rarely a major clinical problem. However, a second bone disease, avascular necrosis of the hip (rarely of other joints), may occur within weeks of starting corticosteroids, even at standard doses, although usually its onset is delayed for many months to a few years. Bisphosphonates may be useful for prevention and treatment, but many patients require surgery.43 As indicated by the frequent prescription of H2 blockers or proton pump inhibitors, GI bleeding is a concern of most physicians although the evidence that corticosteroids alone (in the absence of nonsteroidal antiinflammatory agents, aspirin, or other risk factors for ulceration) cause significant GI bleeding is weak.44,45 Corticosteroids, even in high doses and in short courses, rarely are the cause of GI bleeding.46 Agents used for prophylaxis may have undesirable side effects or complications. H2 blockers and proton pump inhibitors increase the gastric pH, potentially leading to bacterial colonization and aspiration pneumonia. H2 blockers are also associated with encephalopathy in the elderly and thrombocytopenia in the critically ill. Accordingly, we do not recommend gastric protection unless the patient develops upper GI symptoms or there is significant

evidence of bleeding. Perforation of the GI tract from corticosteroids is a more serious and often missed complication.47,48 Corticosteroids may cause diabetes in a previously nondiabetic patient. Because both hyperglycemia and corticosteroids themselves may be toxic to neurons, blood glucose levels should be monitored and treated.49,50 One important effect of corticosteroids is suppression of inflammation and immunity. This effect, salutary in treating some diseases, may render patients susceptible to opportunistic infections including Pneumocystis carinii pneumonia.51 Most cases occur in patients with primary brain tumors because most patients with brain metastases require steroids for only several weeks. Thus, we do not recommend starting prophylaxis with trimethoprim/sulfamethoxazole or other drugs unless it is clear that the patient is going to be on steroids for an extended period (e.g., more than 8 weeks). The agent should be continued for a month after the steroids have been discontinued. Most patients who begin corticosteroids note changes in behavior. Patients often describe themselves as being ‘‘wired’’ and relatives indicate that they are hyperactive and sometimes irritable. However, severe behavioral change is rare52,53; it is less common with synthetic steroids and is reported to be even less common with dexamethasone than other synthetic steroids. The psychosis can be affective (manic or less commonly depressive), schizophrenic-like or delirium. Withdrawal can also cause behavioral change, usually depression.53,54 The treatment is either to withdraw the corticosteroids if possible, or if not, to use appropriate antipsychotic agents. A steroid psychosis occurring during a course of corticosteroids does not predict recurrence of the psychosis during another course of corticosteroids.

Seizures In one series of 470 patients with brain metastases, seizures occurred either at presentation or during the course of the illness in 113 (27%).55 The likelihood of seizures was highest with melanoma (67%), but lung (48%), breast (32%), and unknown primary tumors (55%) were also common causes. The seizures may be focal or generalized. If generalized, they have a focal onset, although the focal discharge may be asymptomatic. When patients have seizures, anticonvulsants should be prescribed, but care must be taken in choosing an anticonvulsant, both because the drugs themselves have side effects and because many have interactions with chemotherapeutic agents. Vecht and colleagues,56 and more recently Yap and colleagues,57 have reviewed these interactions (Table 4). In addition to the interactions listed in the Table, there is a suggestion that


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Table 4 Interactions between Antiepileptic Drugs (AED) and Cytotoxic Drugs (CTD) CTD that Decrease AED Concentration

CTD that Increase AED Concentration

CTD Whose Concentrations Are Lowered by AED

Phenytoin

Nitrosourea

5-FU

Busulfan

Cisplatin

UFT

Vincristine

Etoposide

Tegafur

Vinca

Carmustine

Tamoxifen

Taxanes

Dacarbazine

Dexamethasone

Methotrexate

Doxorubicin Carboplatin

Capecitabine

Paclitaxel Docetaxel

Vinca

Topotecan

Methotrexate

Irinotecan

Bleomycin

Tamoxifen 9-aminocamptothecin

Dexamethasone

Ixabepilone

Cytarabine

Procarbazine

?Sorafenib

Exemestane

?Sunitinib

Erlotinib Gefitinib

CTD Whose Toxicity Is Increased by AED


AED

Letrozole Sorafenib Sunitinib Temsirolimus Toremifene Etoposide Teniposide Cyclophosphamide Corticosteroids Dacarbazine Dexamethasone Anastrozole Carbamazepine

Cisplatin

Vincristine

Adriamycin

Methotrexate Taxanes Paclitaxel Etoposide 9-aminocamptothecin Erlotinib Teniposide Letrozole Procarbazine Sorafenib Ixabepilone Exemestane Gefitinib Irinotecan Sunitinib Tamoxifen, Temsirolimus Toremifene Vinca Anastrozole Doxorubicin

Valproic acid

Methotrexate

Sorafenib

Nitrosoureas

Cisplatin

Cisplatin

Adriamycin

Etoposide ?Ixabepilone


2010

Table 4 (Continued ) AED

CTD that Decrease AED Concentration

CTD that Increase AED Concentration

Phenobarbital

CTD Whose Concentrations Are Lowered by AED

CTD Whose Toxicity Is Increased by AED

Thiotepa Nitrosoureas Doxorubicin Erlotinib Exemestane Gefitinib Ixabepilone Letrozole Procarbazine Sunitinib Tamoxifen, Temsirolimus Toremifene Vinca Vincristine Methotrexate Paclitaxel Taxanes 9-aminocamptothecin Irinotecan Teniposide Procarbazine Corticosteroids Prednisone Anastrozole Cyclophosphamide 56

Modified from Vecht et al and Yap et al. 5-FU, fluorouracil; UFT, uracil and ftorafur.

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interactions between antiepileptic drugs that are histone deacetylase inhibitors (carbamazepine, topiramate, valproic acid, and metabolites of levetiracetam) may interact with the chemotherapeutic agent vorinostat to cause thrombocytopenia.57 Most of the old-line treatments for seizures, including carbamazepine, phenytoin, phenobarbital, and the newer anticonvulsant, oxcarbazepine, induce P450 enzymes in the liver and may lead to increased metabolism of chemotherapeutic agents that are metabolized by the same enzymes. Conversely, the chemotherapeutic agents may increase anticonvulsant metabolism and thus lower levels. If possible, it is best to avoid these drugs in patients with known systemic cancer who are being treated with chemotherapy. Valproate, gabapentin, lamotrigine, topiramate, levetiracetam, and zonisamide are drugs that do not induce enzymes and should be chosen for a patient with a known brain metastasis who has a seizure. Most patients with brain metastases who had seizures benefitted from the use of anticonvulsants and a significant percentage (>60% in one small series58) became seizure-free. If patients do not have seizures they do not need anticonvulsants.59 There is evidence that prophylactic anticonvulsants do not prevent seizures from develop-

ing, even when the drugs are within the therapeutic range.60 Because prophylactic anticonvulsants are ineffective as prophylaxis, and because all of the agents have the potential for producing cognitive dysfunction and other serious side effects (e.g., Stevens-Johnson syndrome61), they should not be prescribed unless the patient has had or is having seizures. Most neurosurgeons insist that patients about to undergo craniotomy receive prophylactic anticonvulsants, but there is no unequivocal evidence that they prevent postoperative seizures. A few studies suggest a decrease in the incidence of postoperative seizures with prophylactic anticonvulsants,62 but other studies show no such decrease.63 If anticonvulsants are prescribed for craniotomy, they should be discontinued 1 to 2 weeks postoperatively. If the patient has seizures and is on anticonvulsants, drug levels should be monitored but the physician should treat the patient, not the drug level. Many patients tolerate levels of drug in the so-called toxic range without evident side effects and with good seizure control. Such patients should not have their levels adjusted into the so-called therapeutic range unless there is clear evidence of toxicity. Other patients have seizure control at levels well below the therapeutic


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range and their drug dose should not be increased simply to treat the blood level. The kinetics of some of the anticonvulsants, particularly phenytoin is not zero-order, and thus, a small increase in the dose of drug may catapult a patient from the mid-range of the therapeutic range into the toxic range with associated clinical toxicity. In patients with seizures, we recommend beginning treatment with levetiracetam and if necessary adding valproate. Others have recommended beginning with valproate and if necessary adding levetiracetam.64

Deep Venous Thrombosis Patients with brain metastases have a substantial increased risk for venous thromboembolism (VTE).65 Almost all patients with cancer are hypercoagulable and thus susceptible to this complication. Most patients with brain metastases have had prior chemotherapy and/or hormonal therapy for the primary cancer, rendering them even more hypercoagulable.66 Craniotomy for the treatment of a brain metastasis increases the likelihood of developing a deep vein thrombosis (DVT) either in the immediate postoperative period or after discharge from the hospital67; the incidence of a clinically evident VTE is as high as 20%.68 How craniotomy increases the risk of thromboembolism is not entirely clear, but the brain is rich in thromboplastin and other clotting agents that may be released by the surgery. The risk of DVT occurs not only in patients who have a weak or paralyzed leg or are bedridden after surgery, but also in those who are fully ambulatory the day following surgery and have no weakness in their extremities. Compression stockings and pneumatic boots decrease the incidence of postoperative DVT but do not abolish it; the addition of heparin or low-molecular-weight heparin on the first postoperative day markedly decreases the incidence of VTE without significant risk of intracranial hemorrhage.69 Goldhaber and colleagues have presented a multimodality approach including graded compression stockings, pneumatic boots, and low-molecular-weight heparin (LMWH) beginning the morning after surgery.69,70 Oral agents, including direct factor IIa inhibitors (dabigatran71) and direct factor Xa inhibitors (rivaroxaban, apixaban72,73), do not need laboratory monitoring and show comparable efficacy and safety profile to LMWHs and warfarin in orthopedic surgery patients. Their role in patients with brain metastases is as yet undefined. Heparins seem to treat cancer-associated hypercoagulability more effectively than warfarin,74 only in part because of difficulty maintaining effective anticoagulant levels with warfarin. Patients with brain metastases, especially those with paralysis or after craniotomy, are at high risk of VTE.75 The diagnosis of VTE is based on specific tests such as ultrasound Doppler of the lower extremities,

spiral CT scan of the chest, or ventilation and perfusion scan of the lungs. Most recently, the D-dimer assays have been used as a screening test in patients suspected of having VTE75; in one study the negative predictive value was 89%.75 In patients with brain metastases, VTE may be treated either prophylactically or therapeutically. We routinely give LMWH to hospitalized patients with brain metastases. For those undergoing craniotomy we recommend a protocol similar to that of Goldhaber and colleagues,69 LMWH beginning the day after surgery, usually after a postoperative scan has shown no evidence of a hematoma, along with perioperative graduated compression stockings and sequential pneumatic compression boots. This protocol substantially reduces the incidence of VTE without increasing the risk of clinically significant bleeding. Perioperative anticoagulation with low-dose heparin or LMWH seems safe. Treatment of established VTE in patients with brain metastases does not differ from that of patients without cancer, except that LMWH may be superior to and safer than warfarin.70 Bleeding into a metastasis is not a major risk.76 Some advocate the placement of vena cava filters instead of anticoagulation to prevent possible intracranial bleeding. In our experience, the complication rate of filters is high and many patients may still require anticoagulants.77,78 Our approach to the treatment of venous thromboembolic events is presented in Fig. 2.

Gastrointestinal Problems ANOREXIA/CACHEXIA

Weight loss, with or without anorexia, is a common symptom in cancer patients.79 Table 5 lists some of the factors responsible for weight loss in patients with a brain metastasis. Most of these factors are not specific to the lesion in the brain, but case reports clearly describe anorexia and cachexia as presenting symptoms of primary brain tumors80 and metastatic tumors.81 In some cases (e.g., dysphagia), weight loss may be a direct result of an appropriately located brain metastasis. Anorexia is a common symptom in patients with cancer. Clinical evidence suggests that patients who are anorexic and lose weight have a worse prognosis than those who do not suffer weight loss. Anorexia can occur in patients with cancer and brain metastasis, as an isolated symptom,82 can be a manifestation of taste or smell dysfunction, xerostomia, dysphagia, nausea and vomiting, or food aversion. Taste and smell dysfunction is common in patients with cancer, particularly those receiving chemotherapy,83 and after whole-brain radiation therapy for brain metastasis. Chemotherapeutic agents are directed at rapidly dividing cells. Taste receptors turn over about

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Figure 2 The Memorial Sloan-Kettering Cancer Center approach to treatment of deep vein thrombosis. LMWH, lowmolecular-weight heparin.

every 10 days and olfactory receptors about every 30 days. Corticosteroids may also alter taste even when they increase, rather than decrease, appetite.84 Because taste is carried by three different paired cranial nerves (facial, Table 5 Factors Causing Weight Loss in Patients with Cancer Brain metastasis Anorexia Taste and smell dysfunction Xerostomia Dysphagia Nausea and vomiting Food aversion Cancer cachexia syndrome

glossopharyngeal, and vagus), neither brain metastasis nor leptomeningeal disease are likely to substantially alter taste. However, brain metastases have caused reversible anosmia from direct olfactory system involvement.85 Olfactory sensations during the course of brain irradiation occur when high-energy photons produce ozone that stimulates the olfactory mucosa. The patient experiences an unpleasant odor.86 Xerostomia results when radiation therapy to the head and neck damages salivary glands.87 Dry mouth is unpleasant in and of itself but also decreases taste and appetite. Dysphagia can be caused by brain metastases affecting the brainstem or by leptomeningeal tumor affecting lower cranial nerves. Food aversion generally is a result of a conditioned reflex in which particular foods are associated with exposure to nauseating events such as chemotherapy.88


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The cancer cachexia syndrome is believed to be mediated by substances secreted either by the tumor or the immune system, including cytokines, ectopic hormones with catabolic consequences, and peptides.89 Examples include tumor necrosis factor-a, interleukin1b, interleukin-6, ciliary neurotropic factor, and the proteolysis-inducing factor. Symptoms include not only anorexia and cachexia, but also nausea, early satiety, fatigue, and decreased performance status often lumped together and referred to as the ‘‘systemic immunemetabolic syndrome.’’90 The treatment of cachexia or anorexia depends on the cause. For example, excessive secretion of parathyroid hormone-related protein causes hypercalcemia, which in turn causes anorexia and nausea. Antiparathyroid hormone-related protein antibodies reverse the cachexia associated with increased production of parathyroid hormone-related protein.91 Food intake can sometimes be increased by providing small frequent meals and nutritional supplements. Bland foods are often better than highly seasoned foods. Megestrol acetate, medroxyprogesterone, and corticosteroids are often effective in relieving cancer anorexia and sometimes increase body weight.92 A long list of other drugs, including cannabinoids, thalidomide, testosterone, melatonin, omega-3 fish oils, and psychotropic drugs occasionally are effective, but often have unacceptable side effects.92 NAUSEA/VOMITING

Vomiting, with or without nausea, can be the first symptom of a brain metastasis, usually in the posterior fossa. Characteristically, the vomiting occurs shortly after awakening and frequently before breakfast. There may be little or no preceding nausea and the vomiting may be quite violent (projectile vomiting). Patients known to

have cancer involving abdominal structures undergo an extensive workup of the GI tract before either desperation, or the presence of early morning headaches, leads to imaging of the brain. In patients with brain metastases, vomiting is more often a result of the treatment than of the disease. Radiation therapy delivered to the brain in high doses and without corticosteroid coverage can result in nausea and vomiting, but rarely in patients receiving standard radiation therapy fractions (180 to 300 cGy) along with corticosteroids (8 to 16 mg). Corticosteroids are essential in preventing acute side effects of radiation in patients receiving whole-brain radiation in doses of 300 cGy or more, but probably not required in those receiving focal brain radiation in 180 to 200 cGy fractions. Cytotoxic drugs, such as cisplatin, promote the release of 5-hydroxytriptamine (5-HT) from enterochromaffin (EC) cells in the intestinal mucosa.93,94 The released agent stimulates vagal receptors that in turn simulate the vomiting center near the area postrema of the brainstem, inducing a vomiting reflex. The area postrema lacks a blood–brain barrier so that circulating emetogenic agents can stimulate it directly.94 The goal in preventing and treating nausea and vomiting in patients receiving cytotoxic therapy is to choose an antiemetic best suited to block the drug receptor stimulated by the agent. Several classes of antiemetics are being used currently (Table 6).95 The most widely used are serotonin antagonists that act through specific binding to the 5-HT3A and 5-HT3B receptor complexes. They are particularly effective against platinum-induced nausea and vomiting, but their effectiveness may vary depending on polymorphisms in the 5-HT3B receptor gene.96 Dexamethasone is a useful drug, perhaps because it decreases transfer of noxious agents into the brain.97 The chemoreceptor trigger zone in the brainstem also contains receptors for dopamine, acetylcholine, and opioids all of which have

Table 6 Treatment of Nausea and Vomiting in Cancer Patients Beneficial

5HT3 antagonists for the control of chemotherapy-related nausea and vomiting Dexamethasone for the control of chemotherapy-related nausea and vomiting

5HT3 antagonists plus corticosteroids for the control of radiotherapy-related

Aprepitant for the control of nausea and vomiting in people with cancer (enhances

Haloperidol for the control of nausea and vomiting in people with cancer

Metoclopramide for the control of chemotherapy-related nausea and vomiting

Phenothiazines for the control of nausea and vomiting in people with cancer Venting gastrostomy for the control of nausea and vomiting in people with cancer

Trade-off between benefits and harms

Cannabinoids for the control of chemotherapy-related nausea and vomiting

Unknown effectiveness

5HT3 antagonists for the control of radiotherapy-related nausea and vomiting

Antihistamines for the control of nausea and vomiting in people with cancer

Antimuscarinics for the control of nausea and vomiting in people with cancer

Antipsychotics (atypical) for the control of nausea and vomiting in people with cancer

Benzodiazepines for the control of chemotherapy-related nausea and vomiting

Likely to be beneficial

nausea and vomiting—New effects of a conventional antiemetic regimen)

Data from Keeley.

95

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emetogenic properties. The National Comprehensive Cancer Network has published updated (2010) cancer guidelines for emesis control with algorithms describing the best approach (www.NCCN.org). Guidelines for cancer-related fatigue and cancer pain are also available at this site. CONSTIPATION

Constipation affects about one-third of patients with cancer regardless of whether they take opioids or not. Constipation is the third most common symptom affecting cancer patients referred to a palliative care service. It ranks below pain (64%) and anorexia (34%) and is equal in frequency to dyspnea (32%).98 In one series, constipation affected 52% of 992 patients with advanced cancer.99 Up to 90% of patients taking an opioid require laxatives. Opioid analgesics are the most common cause of constipation in cancer patients, exacerbating other causes such as dehydration, low fiber diet, and immobility. Other medications, including anticholinergics, antihistamines, antidepressant and chemotherapeutic agents, such as the taxanes or the mitotic spindle poisons, either cause or exacerbate constipation. Constipation is a distressing symptom and if not recognized and treated, can result in a myriad of other symptoms, including bowel obstruction, impaction, nausea, vomiting, abdominal pain, anorexia, and bowel perforation.47 Bowel obstruction from direct tumoral extension or carcinomatosis and bowel compression, or pseudo-obstruction (Ogilvie syndrome), should be recognized as part of the differential diagnosis and if present or suspected, treated appropriately. The diagnosis of constipation is usually selfevident.100 However, some patients with a poor appetite have fewer bowel movements than usual but are not constipated. Conversely, overflow diarrhea can be associated with fecal impaction. In general, patients are considered constipated if the frequency of bowel movements does not satisfy them, if they feel they have not completely evacuated, or if the consistency of the stool is hard and painful. Prophylaxis combining a stool softener (docusate sodium) and a laxative101 is better than treatment; however, if that fails, other laxatives can be tried. Some patients require enemas or manual disimpaction. An opioid antagonist, methylnaltrexone, which is unable to cross the blood–brain barrier, was designed to allow reversal of the narcotic-induced constipation without inducing the opiate withdrawal.102

Cognition/Behavior/Emotion COGNITION

Both the brain metastasis and it’s treatment with radiation and chemotherapy can affect cognitive function, in

particular short-term memory.103–105 Even relatively mild chemotherapy in patients without brain metastases may cause cognitive dysfunction that cannot be explained by concomitant depression or anxiety.106 However, apparent cognitive dysfunction can be caused by concomitant depression, fatigue, pain, and delirium. These factors are considered in the following subsections. DEPRESSION

Depression is estimated to occur in 50% of patients with advanced cancer.107 Although depression and fatigue commonly occur together in patients with cancer and may at times have the same underlying cause, attempts should be made to separate them because the treatment may differ. Sometimes the treatment of depression alleviates fatigue, and conversely, the treatment of fatigue alleviates depression. Depression must also be separated from the withdrawal and apathy that accompanies frontal lobe metastases. Frontal lobe apathy (abulia) does not respond to treatment with antidepressants that can, at times, worsen the abulia. Pharmacologic therapy, including tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRI),107 or a combination of both is the mainstay treatment of depression. SSRIs have fewer side effects than tricyclics, in particular, the anticholinergic symptoms (dry mouth and somnolence), but lack the analgesic efficacy of the tricyclics. Psychostimulants such as methylphenidate108 or modafinil109 sometimes improve depression, fatigue, and cognitive dysfunction. FATIGUE

Fatigue in the setting of cancer is defined as ‘‘a distressing persistent, subjective sense of physical, emotional and/or cognitive tiredness or exhaustion related to cancer or cancer treatment and is not proportional to recent activity and interferes with usual functioning’’ (National Comprehensive Cancer Network Guidelines 2010 www.nccn.org). Fatigue is the most common symptom reported by cancer patients with estimated incidences in 40% of patients at diagnosis to as high as 90% of patients with advanced cancer.110 A substantial percentage of patients in remission from cancer also complain of fatigue. Fatigue is also a symptom in patients with brain tumors, both before and after treatment with radiation therapy.111 Although no studies compare fatigue in patients with brain metastases to those with cancer alone, the high incidence of fatigue in patients with structural disease of the brain, including brain tumors and multiple sclerosis, suggests that fatigue can be a symptom of a brain metastasis per se. The other causes of fatigue in patients with cancer with or without brain metastasis are many (Table 7).112 Fatigue may be caused by cytokine production, altered muscle metabolism, sleep deprivation, stress,


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Physiologic Underlying neoplastic disease Abnormalities of energy metabolism Decreased availability of metabolic substrates Abnormal production of substances inhibiting metabolism of normal muscle function Neurophysiologic changes of skeletal muscles Chronic stress response Hormonal changes Antineoplastic treatments Chemotherapy Radiotherapy Surgery Biologic response modifiers Concomitant systemic diseases Anemia Infections Lung diseases Liver failure Renal failure Malnutrition Neuromuscular disorders Dehydration or electrolyte imbalances Thyroid disorders Sleep disorders Immobility and lack of exercise

PAIN/HEADACHE

Headache is a common symptom in patients with brain tumors,116 but is rarely an isolated finding.117 In one series of 54 patients with cancer who complained of newonset headache or change in pattern of existing headaches, only 50% had a brain metastasis.118 For those who had brain metastases, bilateral frontotemporal headache with a pulsating quality, frequently present on arising in the morning and improving throughout the day were fairly characteristic. However, not all morning headaches are due to brain tumors.119 In a patient with known cancer, new onset headache or change in pattern demands brain imaging. In those instances where headache is a problem, the use of analgesic agents or increasing the dose of corticosteroids usually alleviates the pain. Opioid analgesics may depress respiration, and thus raise intracranial pressure, leading to an increase in headache, but opioids are not contraindicated simply because the patient has brain metastases. Pain from metastases elsewhere in the body is a common problem in patients with brain metastases. Patients with pain from cancer who have brain metastases should be treated using the same guidelines as those without brain metastases. The National Comprehensive Cancer Network has published cancer guidelines for pain control with algorithms describing the best approach (www.NCCN.org).

Chronic pain Use of centrally acting drugs (e.g., opioids) Psychosocial Anxiety disorders Depressive disorders Associated with stress Associated with different environmental factors From Stasi et al,112 with permission.

and especially depression.113 Whether or not a patient with a brain metastasis is fatigued prior to treatment, if that patient is to receive whole-brain radiation therapy, he or she should be warned that fatigue will occur during the course of radiation. Although there is usually a rebound increase in energy after radiation, the fatigue may persist even when the brain metastases are effectively treated. For fatigue that cannot be corrected with a specific intervention, several pharmacologic114 and nonpharmacologic interventions115 have been proposed. The pharmacologic agents best studied include methylphenidate and modafinil. Corticosteroids also improve the sense of wellbeing, but their side effects prohibit their long-term use. Nonpharmacologic interventions include exercise and improved nutrition.

DELIRIUM

Delirium is a mental disturbance characterized by reduced clarity of awareness of environment, inability to focus, sustain, or shift attention, with changes in cognition, including abnormalities of memory, disorientation, and perceptual disturbances such as delusions and hallucinations. The disturbance usually develops over a short period and tends to fluctuate during the course of a day. The delirious patient can be either quiet and withdrawn or agitated and hyperactive. Some patients fluctuate between being agitated and being quiet to the point where they are noncommunicative. Delirium is common in patients with cancer, affecting one-quarter to one-half of patients with advanced cancer admitted to a hospital or palliative care unit.120 At Memorial Sloan-Kettering Cancer Center (New York, NY), 18% of requests for neurologic consultation are for new-onset confusion (i.e., delirium). Patients with brain or leptomeningeal metastases may present with delirium as the predominant or only sign. This phenomenon is particularly common in patients with multiple brain metastases. In one series of 45 patients with cancer in whom a single cause of delirium could be identified, 19 had brain metastasis as the cause (Table 8).121 In 21% of 140 patients with delirium, many with multifactorial causes, brain metastases were a major contributing factor. Other contributing factors included


Table 7 Factors Implicated in the Pathogenesis of Fatigue

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Table 8 Single Causes of Delirium in 45 Patients with Cancer Central nervous system metastases

19

Decreased brain blood flow

11

Drugs

6

Sepsis Organ failure

2 3

Electrolyte abnormality

2

Focal brain lesion

2

Data from Meyers et al.

103

pain, preexisting dementia, and environmental factors.120 However, in a prospective study of cancer patients who developed delirium while in the hospital, brain metastases were not a significant risk factor.122 The major factors included advanced age (even in nononcology patients, delirium is more common in the elderly probably because cognitive reserve is poor), cognitive impairment (patients with mild cognitive impairment frequently become delirious during the hospitalization and some never return to baseline level), low albumin level, bone metastasis, and the presence of a hematologic malignancy. Using the confusion assessment method (CAM),123 delirium was identified in 28% of consecutive patients referred to a palliative care program. Brain metastases in this series were a major risk factor and the median survival was substantially less for the delirious patients than for those with similar diagnoses who were not delirious.124 The diagnosis is often missed at the bedside by both nurses and physicians unless a careful mental status examination is performed. Several bedside screening tests that take only a few minutes are available to test cognitive functions in patients.120 Both the minimental status examination and the CAM will identify cognitive abnormalities, including delirium. The problem is identifying the underlying cause. The list of potential etiologies is long, but major factors include drugs, both opioids and sedatives, organ failure, fluid and electrolyte imbalance, infection, hypoxia, CNS lesions, and an isolated environment (intensive care unit delirium). In about two-thirds of patients, more than one cause can be found, and in many patients there are multiple causes perhaps none of which alone might be sufficient. Accordingly, evaluation of delirium should include a careful laboratory evaluation with images of the brain, spinal fluid analysis, and evaluation of the blood to identify endocrine, metabolic, and electrolyte abnormalities. Nonconvulsive status epilepticus must be considered in any stuporous or comatose patient.125 One study performed in a general hospital suggested that 8% of comatose patients with no clinical signs of seizure activity suffer from nonconvulsive status epilepticus.126 Our own data indicate that the incidence in patients with

cancer is about the same. The diagnosis can be difficult. Observation of some patients indicates mild seizure activity involving the eyes, face, or hand, but these movements can often be subtle. Mild myoclonic jerks may be present. However, many patients do not demonstrate evidence of seizure activity whatsoever; they simply appear stuporous. The electroencephalogram can be confusing. The presence of diffuse or focal seizure activity does not prove that the patient is having seizures. The absence of seizure activity does not prove that the patient is not having seizures. The only way of establishing a definitive diagnosis is if the patient awakens after treatment with anticonvulsants. Chemotherapeutic agents127 and antibiotics128 can cause nonconvulsive status epilepticus. The treatment of delirium is directed both at removing the underlying cause and attempting to improve cognitive function independent of the cause of dysfunction. Often, when the etiology is multifactorial, effective treatment of one of the factors may reverse the delirium. For example, in a severely ill patient with brain metastases, multiorgan failure and anemia, blood transfusions may reverse some of the cognitive dysfunction even though other causes cannot be effectively treated. Patients should be kept in a quiet environment preferably with friends or relatives at the bedside who can reassure and help orient the patient.129 For agitated patients, haloperidol is the drug of choice.129 For hypoactive patients, one might consider methylphenidate or modafinil.129 Restraints should be avoided whenever possible as they often worsen an agitated patient. Benzodiazepines and other sedative drugs should be avoided whenever possible. INFECTIONS

Patients with brain metastases who are receiving prolonged corticosteroid therapy (more than 8 weeks), particularly when they are also receiving immunosuppressive anticancer chemotherapy, are at increased risk of opportunistic infections.130 These include craniotomy wound infections, aspiration pneumonia, and infected indwelling catheters. Among the opportunistic infections, perhaps the most feared is pneumocystis pneumonia.131 Accordingly, as indicated above, we recommend prophylaxis against pneumocystis pneumonia for those patients with brain metastases likely to be on corticosteroids for more than 2 or 3 months. Trimethoprim/sulfamethoxazole is the drug of choice. The dose is 160 mg of trimethoprim plus 800 mg of sulfamethoxazole twice a day, 3 days a week. Although this treatment represents good prophylaxis, the drugs are not without their side effects. They can cause thrombocytopenia, rash, or rarely, aseptic meningitis, seizures, headaches, cerebellar ataxia, and sensory and autonomic neuropathies. Because patients with brain metastases are often receiving other agents that can


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Table 9 Neurotoxicity of Antibiotics Commonly Used in Oncology Type of Toxic Complication

Agent(s)

Seizures

Ciprofloxacin/Imipenem/TMP-SMX/Metronidazole/

Headache

TMP-SMX/Macrolides (Erythromycin/Clarithromycin/

Encephalopathy

Clarithromycin/Ganciclovir

Acyclovir/Famciclovir/Ganciclovir/Foscarnet Azithromycin)/Itraconazole Optic neuritis

TMP-SMX/Chloramphenicol

Aseptic meningitis

TMP-SMX

Cerebellar ataxia Cochlear or vestibular damage

Metronidazole/TMP-SMX Ethambutol/INH/Aminoglycoside

Myasthenic syndrome/neuromuscular blockade

Aminoglycoside/Clindamycin/Erythromycin/

Pseudotumor cerebri

Tetracycline

Polymyxins/Tetracycline

cause the same side effects, beginning this drug at the same time may make it difficult to determine which drug is responsible when a side effect occurs. However, any patient being treated with corticosteroids, particularly as the steroid is being tapered, who develops unexplained cough or shortness of breath, should be considered to be suffering from pneumocystis pneumonia until proved otherwise. Antibiotics are necessary when a patient with a brain metastasis develops an infection, but side effects are common, and sometimes can affect the CNS132–134 (Table 9); drug interactions are common.135 Ototoxicity, vestibulotoxicity, and nephrotoxicity of the aminoglycosides are well known and usually prevented by adjusting the doses according to the measured peak and trough levels or avoiding them in the case of renal dysfunction; others, such as seizures and ataxia, are not common and often not recognized.

REFERENCES 1. Posner JB, Chernik NL. Intracranial metastases from systemic cancer. Adv Neurol 1978;19:579–592 2. Cairncross JG, Kim J-H, Posner JB. Radiation therapy for brain metastases. Ann Neurol 1980;7(6):529–541 3. Lassman AB, DeAngelis LM. Brain metastases. Neurol Clin 2003;21(1):1–23, vii vii 4. DeAngelis LM, Posner JB. Neurologic Complications of Cancer. 2nd ed. New York: Oxford University Press; 2009 5. Ranjan T, Abrey LE. Current management of metastatic brain disease. Neurotherapeutics 2009;6(3):598–603 6. Al-Shamy G, Sawaya R. Management of brain metastases: the indispensable role of surgery. J Neurooncol 2009;92(3): 275–282 7. Batchelor TT, Byrne TN. Supportive care of brain tumor patients. Hematol Oncol Clin North Am 2006;20(6):1337– 1361 8. Drappatz J, Schiff D, Kesari S, Norden AD, Wen PY. Medical management of brain tumor patients. Neurol Clin 2007;25(4):1035–1071, ix ix

9. Barnholtz-Sloan JS, Sloan AE, Davis FG, Vigneau FD, Lai P, Sawaya RE. Incidence proportions of brain metastases in patients diagnosed (1973 to 2001) in the Metropolitan Detroit Cancer Surveillance System. J Clin Oncol 2004; 22(14):2865–2872 10. Schouten LJ, Rutten J, Huveneers HAM, Twijnstra A. Incidence of brain metastases in a cohort of patients with carcinoma of the breast, colon, kidney, and lung and melanoma. Cancer 2002;94(10):2698–2705 11. Yonemori K, Tsuta K, Ono M, et al. Disruption of the blood-brain barrier by brain metastases of triple-negative and basal-type breast cancer but not HER2/neu-positive breast cancer. Cancer 2010;116(2):302–308 12. Smedby KE, Brandt L, Ba¨cklund ML, Blomqvist P. Brain metastases admissions in Sweden between 1987 and 2006. Br J Cancer 2009;101(11):1919–1924 13. Gaspar L, Scott C, Rotman M, et al. Recursive partitioning analysis (RPA) of prognostic factors in three Radiation Therapy Oncology Group (RTOG) brain metastases trials. Int J Radiat Oncol Biol Phys 1997; 37(4):745–751 14. Lutterbach J, Bartelt S, Ostertag C. Long-term survival in patients with brain metastases. J Cancer Res Clin Oncol 2002;128(8):417–425 15. Patchell RA, Tibbs PA, Walsh JW, et al. A randomized trial of surgery in the treatment of single metastases to the brain. N Engl J Med 1990;322(8):494–500 16. Drlicek M, Bodenteich A, Urbanits S, Grisold W. Immunohistochemical panel of antibodies in the diagnosis of brain metastases of the unknown primary. Pathol Res Pract 2004;200(10):727–734 17. Chang EL, Hassenbusch SJ III, Shiu AS, et al. The role of tumor size in the radiosurgical management of patients with ambiguous brain metastases. Neurosurgery 2003;53(2):272– 280, discussion 280–281 18. van der Ree TC, Dippel DWJ, Avezaat CJJ, Sillevis Smitt PA, Vecht CJ, van den Bent MJ. Leptomeningeal metastasis after surgical resection of brain metastases. J Neurol Neurosurg Psychiatry 1999;66(2):225–227 19. Narita Y, Shibui S. Strategy of surgery and radiation therapy for brain metastases. Int J Clin Oncol 2009;14(4): 275–280 20. Suh JH. Stereotactic radiosurgery for the management of brain metastases. N Engl J Med 2010;362(12):1119–1127


INH, isoniazid; TMP-SMX, trimethoprim-sulfamethoxazole.


2010

21. Shu HK, Sneed PK, Shiau CY, et al. Factors influencing survival after gamma knife radiosurgery for patients with single and multiple brain metastases. Cancer J Sci Am 1996;2:335–342 22. van de Pol M, van Aalst VC, Wilmink JT, Twijnstra A. Brain metastases from an unknown primary tumour: which diagnostic procedures are indicated? J Neurol Neurosurg Psychiatry 1996;61(3):321–323 23. Patchell RA, Tibbs PA, Regine WF, et al. Postoperative radiotherapy in the treatment of single metastases to the brain: a randomized trial. JAMA 1998;280(17):1485–1489 24. Chang EL, Wefel JS, Hess KR, et al. Neurocognition in patients with brain metastases treated with radiosurgery or radiosurgery plus whole-brain irradiation: a randomised controlled trial. Lancet Oncol 2009;10(11):1037–1044 25. Blanchard P, Le Pe´choux C. Prophylactic cranial irradiation in lung cancer. Curr Opin Oncol 2010;22(2):94–101 26. Huang F, Alrefae M, Langleben A, Roberge D. Prophylactic cranial irradiation in advanced breast cancer: a case for caution. Int J Radiat Oncol Biol Phys 2009;73(3):752–758 27. van Breemen MS, Wilms EB, Vecht CJ. Epilepsy in patients with brain tumours: epidemiology, mechanisms, and management. Lancet Neurol 2007;6(5):421–430 28. van Breemen MS, Vecht CJ. Optimal seizure management in brain tumor patients. Curr Neurol Neurosci Rep 2005; 5(3):207–213 29. Corcoran ME. Polypharmacy in the older patient with cancer. Cancer Control 1997;4(5):419–428 30. Toh CH, Wong AM, Wei KC, Ng SH, Wong HF, Wan YL. Peritumoral edema of meningiomas and metastatic brain tumors: differences in diffusion characteristics evaluated with diffusion-tensor MR imaging. Neuroradiology 2007;49(6): 489–494 31. Wick W, Ku¨ker W. Brain edema in neurooncology: radiological assessment and management. Onkologie 2004;27(3): 261–266 32. Ryken TC, McDermott M, Robinson PD, et al. The role of steroids in the management of brain metastases: a systematic review and evidence-based clinical practice guideline. J Neurooncol 2010;96(1):103–114 33. de Groot JF, Fuller G, Kumar AJ, et al. Tumor invasion after treatment of glioblastoma with bevacizumab: radiographic and pathologic correlation in humans and mice. Neuro-oncol 2010;12(3):233–242 34. Moliterno JA, Henry E, Pannullo SC. Corticorelin acetate injections for the treatment of peritumoral brain edema. Expert Opin Investig Drugs 2009;18(9):1413–1419 35. Lieberman A, LeBrun Y, Glass P, et al. Use of high dose corticosteroids in patients with inoperable brain tumours. J Neurol Neurosurg Psychiatry 1977;40(7):678–682 36. Wooldridge JE, Anderson CM, Perry MC. Corticosteroids in advanced cancer. Oncology (Williston Park) 2001;15(2): 225–234, discussion 234–236 37. Mertens WC, Higby DJ, Brown D, et al. Improving the care of patients with regard to chemotherapy-induced nausea and emesis: the effect of feedback to clinicians on adherence to antiemetic prescribing guidelines. J Clin Oncol 2003;21(7):1373–1378 38. Batchelor TT, Taylor LP, Thaler HT, Posner JB, DeAngelis LM. Steroid myopathy in cancer patients. Neurology 1997; 48(5):1234–1238 39. Sieb JP, Gillessen T. Iatrogenic and toxic myopathies. Muscle Nerve 2003;27(2):142–156

40. Schakman O, Gilson H, Thissen JP. Mechanisms of glucocorticoid-induced myopathy. J Endocrinol 2008; 197(1):1–10 41. Dirks-Naylor AJ, Griffiths CL. Glucocorticoid-induced apoptosis and cellular mechanisms of myopathy. J Steroid Biochem Mol Biol 2009;117(1-3):1–7 42. Caplan L, Saag KG. Glucocorticoids and the risk of osteoporosis. Expert Opin Drug Saf 2009;8(1):33–47 43. Weldon D. The effects of corticosteroids on bone: osteonecrosis (avascular necrosis of the bone). Ann Allergy Asthma Immunol 2009;103(2):91–97, quiz 97–100, 133 44. Nielsen GL, Sørensen HT, Mellemkjoer L, et al. Risk of hospitalization resulting from upper gastrointestinal bleeding among patients taking corticosteroids: a register-based cohort study. Am J Med 2001;111(7):541–545 45. Carson JL, Strom BL, Schinnar R, Duff A, Sim E. The low risk of upper gastrointestinal bleeding in patients dispensed corticosteroids. Am J Med 1991;91(3):223–228 46. Metz LM, Sabuda D, Hilsden RJ, Enns R, Meddings JB. Gastric tolerance of high-dose pulse oral prednisone in multiple sclerosis. Neurology 1999;53(9):2093–2096 47. Fadul CE, Lemann W, Thaler HT, Posner JB. Perforation of the gastrointestinal tract in patients receiving steroids for neurologic disease. Neurology 1988;38(3):348–352 48. Weiner HL, Rezai AR, Cooper PR. Sigmoid diverticular perforation in neurosurgical patients receiving high-dose corticosteroids. Neurosurgery 1993;33(1):40–43 49. de Quervain DJF, Henke K, Aerni A, et al. Glucocorticoidinduced impairment of declarative memory retrieval is associated with reduced blood flow in the medial temporal lobe. Eur J Neurosci 2003;17(6):1296–1302 50. Clore JN, Thurby-Hay L. Glucocorticoid-induced hyperglycemia. Endocr Pract 2009;15(5):469–474 51. Schiff D. Pneumocystis pneumonia in brain tumor patients: risk factors and clinical features. J Neurooncol 1996;27(3): 235–240 52. Sirois F. Steroid psychosis: a review. Gen Hosp Psychiatry 2003;25(1):27–33 53. Fietta P, Fietta P, Delsante G. Central nervous system effects of natural and synthetic glucocorticoids. Psychiatry Clin Neurosci 2009;63(5):613–622 54. Patten SB, Neutel CI. Corticosteroid-induced adverse psychiatric effects: incidence, diagnosis and management. Drug Saf 2000;22(2):111–122 55. Oberndorfer S, Schmal T, Lahrmann H, Urbanits S, Lindner K, Grisold W. The frequency of seizures in patients with primary brain tumors or cerebral metastases. An evaluation from the Ludwig Boltzmann Institute of Neuro-Oncology and the Department of Neurology, Kaiser Franz Josef Hospital, Vienna. Wien Klin Wochenschr 2002;114(21-22):911–916 56. Vecht CJ, Wagner GL, Wilms EB. Interactions between antiepileptic and chemotherapeutic drugs. Lancet Neurol 2003;2(7):404–409 57. Yap KY, Chui WK, Chan A. Drug interactions between chemotherapeutic regimens and antiepileptics. Clin Ther 2008;30(8):1385–1407 58. Maschio M, Dinapoli L, Gomellini S, et al. Antiepileptics in brain metastases: safety, efficacy and impact on life expectancy. J Neurooncol 2009;November 24 (Epub ahead of print) 59. Mikkelsen T, Paleologos NA, Robinson PD, et al. The role of prophylactic anticonvulsants in the management of brain


232

60.

61.

62.

63.

64.

65.

66. 67.

68.

69.

70.

71.

72. 73.

74.

metastases: a systematic review and evidence-based clinical practice guideline. J Neurooncol 2010;96(1):97–102 Glantz MJ, Cole BF, Forsyth PA, et al; Report of the Quality Standards Subcommittee of the American Academy of Neurology. Practice parameter: anticonvulsant prophylaxis in patients with newly diagnosed brain tumors. Neurology 2000;54(10):1886–1893 Mamon HJ, Wen PY, Burns AC, Loeffler JS. Allergic skin reactions to anticonvulsant medications in patients receiving cranial radiation therapy. Epilepsia 1999;40(3):341– 344 Temkin NR. Antiepileptogenesis and seizure prevention trials with antiepileptic drugs: meta-analysis of controlled trials. Epilepsia 2001;42(4):515–524 Foy PM, Chadwick DW, Rajgopalan N, Johnson AL, Shaw MD. Do prophylactic anticonvulsant drugs alter the pattern of seizures after craniotomy? J Neurol Neurosurg Psychiatry 1992;55(9):753–757 van Breemen MS, Rijsman RM, Taphoorn MJ, Walchenbach R, Zwinkels H, Vecht CJ. Efficacy of anti-epileptic drugs in patients with gliomas and seizures. J Neurol 2009;256(9): 1519–1526 Rodrigues CA, Ferrarotto R, Filho RK, Novis YA, Hoff PM. Venous thromboembolism and cancer: a systematic review. J Thromb Thrombolysis 2010; February 6 (Epub ahead of print) Lee AY, Levine MN. Venous thromboembolism and cancer: risks and outcomes. Circulation 2003;107:117–121 Chan AT, Atiemo A, Diran LK, et al. Venous thromboembolism occurs frequently in patients undergoing brain tumor surgery despite prophylaxis. J Thromb Thrombolysis 1999;8(2):139–142 Sawaya R, Zuccarello M, Elkalliny M, Nishiyama H. Postoperative venous thromboembolism and brain tumors: Part I. Clinical profile. J Neurooncol 1992;14(2):119–125 Goldhaber SZ, Dunn K, Gerhard-Herman M, Park JK, Black PM. Low rate of venous thromboembolism after craniotomy for brain tumor using multimodality prophylaxis. Chest 2002;122(6):1933–1937 ten Cate-Hoek AJ, Prins MH. Low molecular weight heparins in cancer. Management and prevention of venous thromboembolism in patients with malignancies. Thromb Res 2008;122(5):584–598 Schulman S, Kearon C, Kakkar AK, et al; RE-COVER Study Group. Dabigatran versus warfarin in the treatment of acute venous thromboembolism. N Engl J Med 2009;361(24): 2342–2352 Levine MN. New antithrombotic drugs: potential for use in oncology. J Clin Oncol 2009;27(29):4912–4918 Lassen MR, Raskob GE, Gallus A, Pineo G, Chen D, Hornick P; ADVANCE-2 investigators. Apixaban versus enoxaparin for thromboprophylaxis after knee replacement (ADVANCE-2): a randomised double-blind trial. Lancet 2010;375(9717):807–815 Lee AY, Levine MN, Baker RI, et al; Randomized Comparison of Low-Molecular-Weight Heparin versus Oral Anticoagulant Therapy for the Prevention of Recurrent Venous Thromboembolism in Patients with Cancer (CLOT) Investigators. Low-molecular-weight heparin versus a coumarin for the prevention of recurrent venous thromboembolism in patients with cancer. N Engl J Med 2003;349(2):146–153

75. Wells PS, Anderson DR, Rodger M, et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med 2003;349(13):1227–1235 76. Schiff D, DeAngelis LM. Therapy of venous thromboembolism in patients with brain metastases. Cancer 1994;73(2): 493–498 77. Young T, Tang H, Hughes R. Vena caval filters for the prevention of pulmonary embolism. Cochrane Database Syst Rev 2010;2:CD006212 78. Flaim A, Brennan M, Safranek S. Do endovascular filters prevent PE as effectively as anticoagulants in patients with DVT? J Fam Pract 2010;59(2):121–122 79. Tisdale MJ. Cancer cachexia. Curr Opin Gastroenterol 2010;26(2):146–151 80. Chipkevitch E. Brain tumors and anorexia nervosa syndrome. Brain Dev 1994;16(3):175–179; discussion 180–182; discussion 81. Takahashi T, Kazama Y, Shimizu H, Yoshimoto M, Tsujisaki M, Imai K. Brain metastases of malignant melanoma showing unbalanced whole arm chromosomal translocations der (8; 14) (q10; q10) and der (11; 15) (q10; q10) in a Japanese patient. Intern Med 2001;40(9):956– 960 82. Laviano A, Meguid MM, Rossi-Fanelli F. Cancer anorexia: clinical implications, pathogenesis, and therapeutic strategies. Lancet Oncol 2003;4(11):686–694 83. Hong JH, Omur-Ozbek P, Stanek BT, et al. Taste and odor abnormalities in cancer patients. J Support Oncol 2009;7(2): 58–65 84. Fehm-Wolfsdorf G, Scheible E, Zenz H, Born J, Fehm HL. Taste thresholds in man are differentially influenced by hydrocortisone and dexamethasone. Psychoneuroendocrinology 1989;14(6):433–440 85. Ishimaru T, Miwa T, Nomura M, Iwato M, Furukawa M. Reversible hyposmia caused by intracranial tumour. J Laryngol Otol 1999;113(8):750–753 86. Sagar SM, Thomas RJ, Loverock LT, Spittle MF. Olfactory sensations produced by high-energy photon irradiation of the olfactory receptor mucosa in humans. Int J Radiat Oncol Biol Phys 1991;20(4):771–776 87. Vissink A, Jansma J, Spijkervet FK, Burlage FR, Coppes RP. Oral sequelae of head and neck radiotherapy. Crit Rev Oral Biol Med 2003;14(3):199–212 88. Scalera G. Effects of conditioned food aversions on nutritional behavior in humans. Nutr Neurosci 2002;5(3): 159–188 89. Baracos VE. Cancer-associated cachexia and underlying biological mechanisms. Annu Rev Nutr 2006;26:435– 461 90. Cerchietti LC, Navigante AH, Peluffo GD, et al. Effects of celecoxib, medroxyprogesterone, and dietary intervention on systemic syndromes in patients with advanced lung adenocarcinoma: a pilot study. J Pain Symptom Manage 2004; 27(1):85–95 91. Sato K, Onuma E, Yocum RC, Ogata E. Treatment of malignancy-associated hypercalcemia and cachexia with humanized anti-parathyroid hormone-related protein antibody. Semin Oncol 2003;30(5, Suppl 16):167– 173 92. Del Fabbro E, Dalal S, Bruera E. Symptom control in palliative care—Part II: cachexia/anorexia and fatigue. J Palliat Med 2006;9(2):409–421

233




2010

93. Wood GJ, Shega JW, Lynch B, Von Roenn JH. Management of intractable nausea and vomiting in patients at the end of life: ‘‘I was feeling nauseous all of the time ... nothing was working’’. JAMA 2007;298(10):1196–1207 94. Minami M, Endo T, Hirafuji M, et al. Pharmacological aspects of anticancer drug-induced emesis with emphasis on serotonin release and vagal nerve activity. Pharmacol Ther 2003;99(2):149–165 95. Keeley PW. Nausea and vomiting in people with cancer and other chronic diseases. Clin Evid (Online); January 13, 2009 96. Tremblay PB, Kaiser R, Sezer O, et al. Variations in the 5-hydroxytryptamine type 3B receptor gene as predictors of the efficacy of antiemetic treatment in cancer patients. J Clin Oncol 2003;21(11):2147–2155 97. Henzi I, Walder B, Trame`r MR. Dexamethasone for the prevention of postoperative nausea and vomiting: a quantitative systematic review. Anesth Analg 2000;90(1): 186–194 98. Potter J, Hami F, Bryan T, Quigley C. Symptoms in 400 patients referred to palliative care services: prevalence and patterns. Palliat Med 2003;17(4):310–314 99. Walsh D, Rybicki L. Symptom clustering in advanced cancer. Support Care Cancer 2006;14(8):831–836 100. Reville B, Axelrod D, Maury R. Palliative care for the cancer patient. Prim Care 2009;36(4):781–810 101. Clemens KE, Klaschik E. Management of constipation in palliative care patients. Curr Opin Support Palliat Care 2008;2(1):22–27 102. Clemens KE, Klaschik E. Managing opioid-induced constipation in advanced illness: focus on methylnaltrexone bromide. Ther Clin Risk Manag 2010;6:77–82 103. Meyers CA, Smith JA, Bezjak A, et al. Neurocognitive function and progression in patients with brain metastases treated with whole-brain radiation and motexafin gadolinium: results of a randomized phase III trial. J Clin Oncol 2004;22(1):157–165 104. Soussain C, Ricard D, Fike JR, Mazeron JJ, Psimaras D, Delattre JY. CNS complications of radiotherapy and chemotherapy. Lancet 2009;374(9701):1639–1651 105. Ricard D, Taillia H, Renard JL. Brain damage from anticancer treatments in adults. Curr Opin Oncol 2009; 21(6):559–565 106. Vardy J, Wefel JS, Ahles T, Tannock IF, Schagen SB. Cancer and cancer-therapy related cognitive dysfunction: an international perspective from the Venice cognitive workshop. Ann Oncol 2008;19(4):623–629 107. Snyderman D, Wynn D. Depression in cancer patients. Prim Care 2009;36(4):703–719 108. Hardy SE. Methylphenidate for the treatment of depressive symptoms, including fatigue and apathy, in medically ill older adults and terminally ill adults. Am J Geriatr Pharmacother 2009;7(1):34–59 109. Kohli S, Fisher SG, Tra Y, et al. The effect of modafinil on cognitive function in breast cancer survivors. Cancer 2009;115(12):2605–2616 110. Hofman M, Ryan JL, Figueroa-Moseley CD, Jean-Pierre P, Morrow GR. Cancer-related fatigue: the scale of the problem. Oncologist 2007;12(Suppl 1):4–10 111. Pelletier G, Verhoef MJ, Khatri N, Hagen N. Quality of life in brain tumor patients: the relative contributions of depression, fatigue, emotional distress, and existential issues. J Neurooncol 2002;57(1):41–49

112. Stasi R, Abriani L, Beccaglia P, et al. Cancer-related fatigue: evolving concepts in evaluation and treatment. Cancer 2003; 98:1786–1801 113. Ryan JL, Carroll JK, Ryan EP, Mustian KM, Fiscella K, Morrow GR. Mechanisms of cancer-related fatigue. Oncologist 2007;12(Suppl 1):22–34 114. Carroll JK, Kohli S, Mustian KM, Roscoe JA, Morrow GR. Pharmacologic treatment of cancer-related fatigue. Oncologist 2007;12(Suppl 1):43–51 115. Mustian KM, Morrow GR, Carroll JK, Figueroa-Moseley CD, Jean-Pierre P, Williams GC. Integrative nonpharmacologic behavioral interventions for the management of cancer-related fatigue. Oncologist 2007;12(Suppl 1): 52–67 116. Forsyth PA, Posner JB. Headaches in patients with brain tumors: a study of 111 patients. Neurology 1993;43(9):1678– 1683 117. Hamilton W, Kernick D. Clinical features of primary brain tumours: a case-control study using electronic primary care records. Br J Gen Pract 2007;57(542):695– 699 118. Argyriou AA, Chroni E, Polychronopoulos P, et al. Headache characteristics and brain metastases prediction in cancer patients. Eur J Cancer Care (Engl) 2006;15(1): 90–95 119. Larner AJ. Not all morning headaches are due to brain tumours. Pract Neurol 2009;9(2):80–84 120. Bush SH, Bruera E. The assessment and management of delirium in cancer patients. Oncologist 2009;14(10): 1039–1049 121. Tuma R, DeAngelis LM. Altered mental status in patients with cancer. Arch Neurol 2000;57(12):1727–1731 122. Ljubisavljevic V, Kelly B. Risk factors for development of delirium among oncology patients. Gen Hosp Psychiatry 2003;25(5):345–352 123. Inouye SK, van Dyck CH, Alessi CA, Balkin S, Siegal AP, Horwitz RI. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Ann Intern Med 1990;113(12):941–948 124. Caraceni A, Simonetti F. Palliating delirium in patients with cancer. Lancet Oncol 2009;10(2):164–172 125. Drislane FW. Nonconvulsive status epilepticus in patients with cancer. Clin Neurol Neurosurg 1994;96(4):314– 318 126. Towne AR, Waterhouse EJ, Boggs JG, et al. Prevalence of nonconvulsive status epilepticus in comatose patients. Neurology 2000;54(2):340–345 127. Primavera A, Audenino D, Cocito L. Ifosfamide encephalopathy and nonconvulsive status epilepticus. Can J Neurol Sci 2002;29(2):180–183 128. Martı´nez-Rodrı´guez JE, Barriga FJ, Santamaria J, et al. Nonconvulsive status epilepticus associated with cephalosporins in patients with renal failure. Am J Med 2001; 111(2):115–119 129. Breitbart W, Alici Y. Agitation and delirium at the end of life: ‘‘We couldn’t manage him’’. JAMA 2008;300(24):2898– 2910, E1 130. Vento S, Cainelli F. Infections in patients with cancer undergoing chemotherapy: aetiology, prevention, and treatment. Lancet Oncol 2003;4(10):595–604 131. Mahindra AK, Grossman SA. Pneumocystis carinii pneumonia in HIV negative patients with primary brain tumors. J Neurooncol 2003;63(3):263–270


234


134. Thomas RJ. Neurotoxicity of antibacterial therapy. South Med J 1994;87(9):869–874 135. Pai MP, Momary KM, Rodvold KA. Antibiotic drug interactions. Med Clin North Am 2006;90(6):1223–1255


132. Pasquale TR, Tan JS. Nonantimicrobial effects of antibacterial agents. Clin Infect Dis 2005;40(1):127–135 133. Cunha BA. Antibiotic side effects. Med Clin North Am 2001;85(1):149–185

235