Outcomes of Surgery Alone for Lower Rectal Cancer With and Without Pelvic Sidewall Dissection

PURPOSE: The goal of this retrospective multicenter study was to investigate the efficacy of pelvic sidewall dissection for lower rectal cancer. METHODS: Data from 1,272 consecutive patients who underwent total mesorectal excision for lower rectal cancer in 12 institutions from 1991 through 1998 were reviewed. The rates of local recurrence and survival in patients with pelvic sidewall dissection were compared with those without pelvic sidewall dissection. Logistic regression analysis was used to determine independent risk factors for lymph node metastasis and local recurrence, and the Cox proportional hazards model was used to determine independent prognostic factors. RESULTS: Of the 1,272 patients, 784 underwent pelvic sidewall dissection. Among them, 117 patients (14.9 percent) had lateral pelvic lymph node metastasis. Risk factors for lateral pelvic lymph node metastasis included female gender, tumor not well-differentiated adenocarcinoma, and perirectal lymph node metastasis. Lateral pelvic and perirectal lymph node metastases were independent risk factors for local recurrence. The Cox proportional hazard model showed age, grade of histology, invasion depth of the tumor, perirectal lymph node metastasis, and lateral pelvic lymph node metastasis to be independent prognostic factors. No significant differences between patients with and those without pelvic sidewall dissection were seen regarding rates of local recurrence (10.5 percent vs. 7.4 percent) or five-year overall survival (75.8 percent vs. 79.5 percent). Although the proportion of patients with advanced stages of disease was greater in patients who had pelvic sidewall dissection, no differences between the two groups were seen in local recurrence even when tumor category was taken into account. However, lack of pelvic sidewall dissection was a predictor of poor prognosis. CONCLUSIONS: Although pelvic sidewall dissection does not appear to confer overall benefits regarding local recurrence or survival, the effectiveness of pelvic sidewall dissection in specific patient groups remains uncertain. A randomized controlled study is necessary to clarify this issue.