Pelvic exenteration for recurrent rectal cancer.
Recurrent rectal carcinoma presents a formidable problem for patient and surgeon. Isolated recurrences of rectal carcinoma have been reported from 7% to 33% with a median of 14%. Increasing recurrence is associated with increasing Dukes's stage. The reason for high recurrences is probably related to the limited anatomic margins that can be obtained in the pelvis during primary resections. Patients who have recurrence after a low-anterior resection are more likely to present with nonfixed, surgically correctable lesions versus recurrences after abdominoperineal resection. The most common symptom related to pelvic recurrence is pain, which may be perineal or radiate to the lower extremities. The 5-year survival rate among unresected patients with locoregional recurrences is 4%. These patients are often in extreme pain with lower extremity swelling and perineal lesions. Although many patients will be palliated by radiation, few will experience long-term relief (6 to 8 months). A thorough physical examination should include rectal and pelvic exams to evaluate tumor extension and fixation. Computed tomographic studies are helpful when taken serially to evaluate pelvic recurrence or liver metastases. Fineneedle biopsies may also be done under CT guidance. Additional mandatory films include plain chest roentgenograph, lumbosacral spine films, and bone scan to rule out sacral involvement, which would preclude sacral resection. Magnetic resonance imaging has recently been shown to be effective in evaluating pelvic side wall involvement and metastatic lymphadenopathy. Although extensive involvement would preclude aggressive resection, in one series, 50% of patients were amenable to resection. Pelvic exenteration should include the tumor mass, along with any involved organs and their lymphatic drainage, with a 2 cm margin. Complications are increased in patients who have undergone radiation, who have undergone procedures that include urinary diversions, and who have recurrent disease. Cure rates of 30% to 50% have been reported using pelvic exenteration for rectal cancer. Recurrent disease presents a significant problem in that normal anatomic planes have been disrupted. In one series, rectal recurrences treated with pelvic exenteration had a 66% recurrence rate. In addition, there is often a posterior component to the recurrence. Although the complication rate is high, the only chance for cure in these patients would be an abdominosacral resection. There appears to be a select group of patients with recurrent locoregional disease, who benefit from sacral resection with a 20% to 30%, 5-year survival rate.