CT-guided radiofrequency ablation of a ... - BIR Publications

The British Journal of Radiology, 76 (2003), 268–270 DOI: 10.1259/bjr/92882335

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2003 The British Institute of Radiology

Case report

CT-guided radiofrequency ablation of a bronchogenic carcinoma O SCHAEFER, MD, C LOHRMANN, MD and M LANGER, MD Department of Radiology, University Hospital of Freiburg, Hugstetter Strasse 55, D-79106, Freiburg, Germany

Abstract. We report on the successful use of percutaneous CT-guided radiofrequency ablation (RFA) of a peripheral bronchogenic carcinoma in a 73-year-old patient. RFA was the favoured treatment option in this patient, who owing to comorbid factors was not a candidate for surgery. A 15 G LeVeen2 Needle Electrode (RadioTherapeutics, Sunnyvale, USA) with an array diameter of 3.0 cm was connected to a 200 Watt Generator (RF 30002, RadioTherapeutics, Sunnyvale, USA) and inserted into a 3.5 cm squamous cell carcinoma of the axillary subsegment of the right upper lobe. RFA resulted in complete tumour necrosis confirmed by histopathological examination. No complications such as a pneumothorax or bleeding occurred. Further clinical experience and prospective studies are necessary to determine the long-term efficacy of RFA in the treatment of lung tumours.

A number of patients with primary bronchogenic carcinoma and some patients with isolated lung metastases are not suitable for operation due to comorbid disease. Conventional treatment with radiation and/or systemic chemotherapy may not significantly improve survival in these patients [1, 2]. Radiofrequency ablation (RFA) is a minimally invasive, effective, and safe method for the treatment of some malignant and benign conditions [1, 3, 4]. Recent improvements in technology have made it possible to treat larger lesions by RFA and this has led to wider clinical applications [5]. The first reported results are promising, showing that substantial tumour reduction and eradication may be possible. To date this technique has mainly been used in the liver, but treatments in other organs have been described [1, 6]. To our knowledge only five cases of bronchogenic carcinoma treated by CTguided percutaneous RFA have been reported, although there are studies in animal models [7–12]. The surrounding lung parenchyma provides an ‘‘insulating effect’’, and thereby represents an optimal environment for RFA of lung tumours [1]. As a minimally invasive technique RFA may be a complement to standard treatment methods in the palliative care situation, and hence alleviate the patients’ symptoms and improve life quality.

of 38.9 mmHg. Initial CT scan revealed a 3.5 cm63.5 cm bronchogenic carcinoma in the axillary right subsegment of the upper lobe, with ipsilateral hilar lymphnode enlargement (Figure 1). No endoluminal tumour was detected at bronchoscopy. Biopsy and staging confirmed a stage IIb non-small cell lung cancer. Owing to comorbid factors the patient was not suitable for surgery. The decision was made to treat the tumour with RFA. After informed consent was obtained, CT-guided percutaneous RFA was performed under conscious sedation and analgesia, using 7 mg midazolam hydrochloride (DormicumH) and 90 mg pethidine chlorhydrate (DolantineH) injected intravenously. Vital signs and cardiac status were monitored by

Case report A 73-year-old man with a presumptive diagnosis of lung cancer on imaging was referred to our institution. The patient suffered from Parkinson’s disease, hypertension, and chronic obstructive pulmonary disease, with an forced expiratory volume in 1 s (FEV1) of 1.47 (55.7%), vital capacity (VC) of 2.81 (78.6%), pO2 of 55 mmHg and pCO2 Received 15 May 2002 and in revised form 9 September 2002, accepted 30 September 2002. Address correspondence to Oliver Schaefer, Universita¨tsklinikum Freiburg, Abteilung Ro¨ntgendiagnostik, Hugstetter Strasse 55, 79106 Freiburg i. Br., Germany.

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Figure 1. CT scan prior to radiofrequency ablation shows a cavitating peripheral squamous cell lung carcinoma of 3.5 cm63.5 cm in diameter originating from the basolateral segment of the right upper lobe.

The British Journal of Radiology, April 2003

Case report: CT-guided radiofrequency ablation of bronchogenic carcinoma

pulse oxymetry and electrocardiography throughout the procedure. Spiral CT scans (Emotion, Siemens, Erlangen, Germany) with a slice thickness of 5 mm were performed to plan the intervention. Local anaesthesia was obtained using 10 ml of 0.5% bupivacaine (CarbostesinH) solution. A 15-gauge LeVeen2 Needle Electrode (RadioTherapeutics, Sunnyvale, USA) with 10 active electrode tines forming an umbrella-shaped array diameter of 3.0 cm and a shaft working length of 12 cm was deployed under CT guidance into the centre of the bronchogenic carcinoma (Figure 2). After connecting the electrode with a Radiofrequency Generator (RF 30002, RadioTherapeutics, Sunnyvale, USA) RFA was started at an energy level of 50 watts. The deployed energy was increased by 10 watts every 3 min up to 150 watts until tissue-impedance rose and further current flow was automatically prevented (roll-off). During thermal ablation there was a constant tissue impedance of between 89 ohms and 97 ohms with no disturbance of current flow into the tumour volume. In our patient the impedance peak was 900 ohms after an interval of 31 min (Figure 3). To obtain complete necrosis, after a delay of 1 min to allow re-hydration and cooling adjacent to the array wires, a second RFA cycle was started at 90 watts and the energy was increased up to 120 watts until 9 min later when roll-off occurred. The electrode was then removed. CT scans immediately after the procedure revealed ground glass opacification representing preserved small areas of haemorrhage in to the surrounding lung parenchyma as well as pleural effusion thickening (Figure 4). No complications such as pneumothorax, bleeding or pleural effusion occurred. The procedure was covered with prophylactic oral antibiotics for 7 days after the procedure and there were no signs of infection. After experiencing mild pain overnight at the puncture site the patient was pain free. The patient developed an elevated temperature the second day following RFA possibly due to the effects of tumour lysis, he was discharged from the hospital 3 days after the procedure, pain free without analgesia. 1 month after RFA the patient

Figure 3. Course of the tissue impedance during radiofrequency ablation. The impedance of the cavitating tumour ranged between 89 ohms and 97 ohms while power was constantly increased without disturbance. After a procedure-time of 31 min a rise in impedance up to 900 ohms (roll-off) occurred.

developed a major stroke and died during a seizure. Autopsy revealed cerebral infarction. Histopathological examination of the lung revealed complete necrosis of the treated bronchogenic carcinoma.

Discussion RFA is a promising minimally invasive technique and has proved to be an effective and safe procedure for the treatment of benign and malignant tumours in several organs [1, 3, 4]. There is increasing interest in its use in the treatment of malignant lung lesions, such as bronchogenic carcinoma and occasionally lung metastases [7–12]. RFA can be performed under conscious sedation and local anaesthesia and offers the possibility of treating patients who are not suitable for surgery or other treatment

Figure 4. Control CT scan immediately after radiofrequency

Figure 2. Control CT scan during radiofrequency ablation demonstrates the central position of the unfolded electrode tines of the LeVeen Needle within the tumour.


ablation reveals the ablated tumour. Zones of haemorrhage in the surrounding lung parenchyma as well as pleural thickening are detectable indicating that coagulation necrosis has affected the whole tumour volume and thermal injury is exceeding the tumour margins into the adjacent lung. No pneumothorax occurred.

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modalities due to age, comorbidity, or extent of disease [4]. RFA of malignant lung lesions may have a lesser toxicity than radiation therapy by preserving surrounding healthy lung tissue. The risks of thoracotomy and lung resection may outweigh the potential benefits of surgery. Additionally, a number of patients with primary lung malignancy or occasionally metastases to the lung are not candidates for operation, and conventional treatment with systemic chemotherapy and radiation therapy may not influence the clinical outcome [1, 2]. The surrounding air of the adjacent lung parenchyma provides an insulating effect by concentrating the RF energy within the tumour tissue; thereby less RF energy deposition is required to produce tumour necrosis [9]. In large tumours a compound thermal lesion is advisable to increase the area of necrosis achieved as described by Curley et al [13]. Potential complications using RFA in the treatment of lung tumours are bleeding, infection, pleural effusion and pneumothorax [10, 14]. RFA was the favoured treatment option in this patient due to comorbidity. No complications such as pneumothorax, bleeding, pleural effusion or infection occurred. Interestingly the cavity of the bronchogenic carcinoma had no influence on impedence or current flow. Complete tumour necrosis was achieved and confirmed at histopathological examination. The patients temperature rise on the second day after RFA is likely to have been due to tumour lysis and this occurrence should not be misinterpreted as infection. In our experience, an important CT sign indicating the successful treatment of a lung malignancy by RFA are zones of consolidation surrounding the treated tumour in shape of ground glass opacities immediately after the procedure. These opacifications represent small areas of haemorrhage in lung parenchyma and occur if the coagulation necrosis encompasses the tumour margins as seen in this patient. The chosen 3.0 cm LeVeenNeedle electrode is able to produce a spherical thermal necrosis up to 4 cm in diameter. Dupuy and Goldberg [1] postulate that neoadjuvant cytoreduction by RFA could make radiation and systemic chemotherapy more effective. Potentially in solitary patients with lung metastases, not controlled adequately with chemotherapy, RFA may be an additional option, because it can destroy poorly oxygenated tumours that are traditionally less responsive to chemotherapy and/or radiation therapy. Guidelines for determining which patients are adequate candidates for RFA of malignant lung tumours have not been developed, and therefore a careful selection of the treatment options that best serve the individual patient is necessary. Tacke et al [15] reported that all percutaneous therapies have a siginificantly shorter hospitalization and recovery time compared with surgery. Although up to now long-term results exist only for RFA treatment of hepatic malignancies [6, 16]. In conclusion, percutaneous RFA was performed successfully in our patient. RFA of malignant lung tumours may reduce tumour burden and may be a complement to surgery,

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systemic chemotherapy or radiation therapy. The value of CT-guided percutaneous RFA in the treatment of malignant lung tumours is subject of an ongoing prospective, interdisciplinary study conducted by our institution.

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