REVIEWS J CARDIOVASC SURG 2009;50:373-9
Synchronous abdominal aortic aneurysm and colorectal cancer. The therapeutic dilemma in the era of endovascular aortic aneurysm repair
A C I D E M ® A T V H R G E I IN YR M P A O C
C. D. BALI, H. HARISSIS, M. I. MATSAGAS
The incidence of synchronous abdominal aortic aneurysm (AAA) and colorectal cancer (CRC), although quite rare, still represents an issue of controversy regarding the optimal treatment. This study attempts a historical review of the surgical practice during the past decades by reviewing the existing English literature on this topic. The dilemma between one or two stage treatment has remained as both options offer advantages but also carry some substantial risks. The current practice gives priority to the life threatening disease (AAA>5.5 cm, symptomatic or complicated CRC) (two stage treatment) or suggest simultaneous management (one stage) when both diseases require urgent surgical treatment. The evolution of vascular endografts and the reported efficacy of endovascular aortic repair (EVAR) provide an alternative method for treating these high risk patients, by surpassing some significant obstacles. If the anatomical criteria are satisfied, EVAR could become the optimal solution for the concomitant AAA and CRC patients, especially those who require one stage treatment.
Vascular Surgery Unit, Department of Surgery School of Medicine, University of Ioannina, Ioannina, Greece
in the same age group the incidence of CRC is increased from 0.039% to 0.45%.2 The incidence of CRC in patients with AAA, even though these diseases do not share common predisposing factors, are reported to be 0.5-4.7%.3-15 In the majority of patients the diagnosis of synchronous AAA and CRC is made incidentally during the imaging study of the primary disease (Figure 1). Rarely, both diseases can be symptomatic (abdominal pain, rectal bleeding, bowel
KEY WORDS: Aortic aneurysm, abdominal - Colorectal neoplasm - EVAR.
s the human population grows older, it is exposed for a longer period to noxious and degenerating factors which can lead to an increased diseases incidence, such as abdominal aortic aneurysm (AAA) and colorectal cancer (CRC). Hirsch et al., reported an increased incidence of 2.9-4.9 cm diameter AAA between the 6th and 9th decade of life from 1.3% to 12.5% in males and 0% to 5.2% in females.1 Similarly, Received on September 24, 2008. Accepted for publication on April 1, 2009. Epub ahead of print on May 19, 2009. Corresponding author: M. I. Matsagas, MD, EBSQ-Vasc, Department of Surgery, Vascular Surgery Unit, University Hospital of Ioannina, S. Niarchos Avenue 45500, Ioannina, Greece. E-mail:
[email protected]
Vol. 50 - No. 3
Figure 1.—Abdominal CT scan. Thickening of the bowel wall with narrowing of the lumen near the splenic flexure of the colon (white arrow) and the origin of the aneurysm in the infrarenal aorta (black arrow).
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MANAGEMENT OF SYNCHRONOUS AAA AND COLORECTAL CANCER
TABLE I.—Advantages and disadvantages of one and two stage open surgical treatment of synchronous AAA and CRC. Surgical treatment
One stage
Advantages
Disadvantages
— Treatment of both diseases — Avoidance of second laparotomy/anaesthesia 7
— Risk of graft infection 18-22 — Extended operative time 13
A C I D E M ® A T V H R G E I R N I Y M P O C
Two stages AAA priority CRC priority
— Avoidance of AAA rupture 3, 13, 18 — Avoidance of graft infection 18-22
— Local or distant spread of CRC ± complications 13 — Need for second and technically more difficult laparotomy 18
— Avoidance of complications or spread of CRC 13
— Risk of AAA rupture 3, 13, 18 — Need for second and technically more difficult laparotomy 18
obstruction or perforation). Yamamoto et al. conducted a screening study on the incidence of CRC in AAA or peripheral arterial disease patients. They report that 1.5% of patients had coexistent CRC and conclude that screening test for CRC should always be done in this patient group.16 In spite of its rarity, coexistence of CRC and AAA and its management have been a controversial issue for the surgical community. The main controversies are whether to proceed in one or two stage treatment and which disease will take the treatment priority. Lobbatto et al., showed very clearly this dilemma by recording the personal preference of 46 professors of general and vascular surgery, regarding the optimal treatment of synchronous AAA and CRC.17 The majority answered that they would prefer two stage management giving equal priority to either AAA or CRC and only 4% would perform one stage operation. During the last decades all these strategies have been evaluated regarding their effect on the prognosis of both diseases and also the risk of aortic graft infection (Table I). On the other hand the evolution of endovascular aortic aneurysm repair (EVAR) and its promising midterm results denote that this method might be the alternative way to surpass the current treatment obstacles.23 This review of the English literature will make an attempt to answer common questions as: how necessary is to treat both the AAA and the CRC? If yes, which disease takes the treatment priority? Is it feasible and safe to perform one stage operation? And finally, what is the role of EVAR in the treatment of synchronous AAA and CRC? To identify all relevant studies, a computerized search of the English literature (Medline, Embase and The Cochrane Library) was performed using the terms AAA repair, colorectal cancer, concomitant AAA and colorectal cancer treatment and EVAR. In addition the reference lists in selected
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articles were searched manually. The inclusion criteria were studies dealing with the concomitant management of AAA and CRC from 1960 to 2007. Data were extracted independently by two reviewers (C.B. and M.M.) and cross-checked to reach consensus. Natural history - Prognosis
Colorectal cancer
Malignant tumors, provided a delayed and inadequate treatment, are characterized by the tendency to spread either in a locoregional or a generalized manner. In CRC patients, stage comprises the most significant prognostic factor and also guides the decision making for the most appropriate and efficient treatment. The five-year survival rate of CRC patients is directly related to the stage of the disease and is estimated to be 90%, 60-80%, 20-50%, 50% for an AAA measuring 5 cm, 6 cm, and >7 cm in diameter respectively.1 In case of AAA rupture the mortality rate can reach 90%.1 Based on these data, AAA treatment guidelines have been instituted; ruptured or symptomatic AAA (abdominal or/and lumbar pain, tenderness on the palpation of the aneurysm and confirmative computed tomography scan) should be straightforwardly operated. The same practise is also applied to the patients with asymptomatic large (5-5.5 cm) AAA, which should be operated in order to avoid the risk of AAA rupture.1, 31-33 In summary, surgical treatment is substantial for either CRC or symptomatic or/and large AAA due to direct relation to the disease prognosis and patient survival. Indeed, two studies have shown that patients with CRC and AAA had better survival, when both diseases were surgically treated.5, 7 In particular, Komori et al. reported a difference in one-year survival rate of 81% vs. 17% when both lesions were treated.7 However, one should consider several factors, when dealing with patients diagnosed with synchronous AAA and CRC. Regarding the criteria for AAA repair, it would be reasonable to keep the threshold used for AAA surgery at the higher level (5.5 cm diameter), considering the possibility of patient’s shorter life expectancy, depending on the tumor’s stage. Moreover, there are CRC patients with multiple metastases, especially when the primary tumor site has low probability to cause any complication (obstruction) that should not considered candidates for any surgical intervention. In these cases, the observation of AAA might also be a sensible approach due to expectedly short survival. Eventually, the proposed treatment should be individualized depending on patient’s characteristics and the expected survival benefit.
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required. The main controversy lies with the timing of the two interventions should they be performed at the same time or in a staged manner (Table I)? Undoubtedly, two major operations are needed and this is translated into either prolongation of the operative time (one stage) or a second anaesthesia and technically more difficult relaparotomy due to postoperative adhesions and anatomy distortion (two stage). Worldwide, the dominant practice is to deal with both diseases in a two-stage approach. Szilagyi et al. was the first to suggest that the symptomatic disease should take priority.3 This includes CRC cases with bowel obstruction or perforation and AAA patients with expanding or ruptured aneurysm. If both diseases are asymptomatic, AAA patients should take treatment priority, especially when AAA diameter exceeds 6 cm. They based this suggestion to their previous study which showed that if the colectomy is performed first, the patients had worse prognosis due to AAA rupture in the postoperative period.3 The precise cause of this complication is not clearly understood but studies have shown that its incidence after any abdominal operation varies between 16-50%.7, 8, 34 Two decades later Velanovich and Andersen performed a decision making analysis to help to clarify decision options and quantify therapeutic outcomes. Their conclusions are in agreement with Szilagyi regarding the symptomatic disease. In the asymptomatic group the treatment priority is determined by the AAA size and the probability of a complicated CRC.35 This study establishes for the first time the necessity for one stage approach (open surgery) in cases of concomitant AAA and CRC, when both diseases may become life threatening and also managed with accepted mortality (
