Factors associated with oncologic outcomes after abdominoperineal resection compared with restorative resection for low rectal cancer: Patient- and tumor-related or technical factors only?

BACKGROUND: Previous reports suggest that patients with rectal cancer undergoing abdominoperineal resection have worse oncologic outcomes in comparison with those undergoing restorative rectal resection. OBJECTIVE: This study aimed to assess factors influencing oncologic outcomes for patients undergoing surgery for rectal cancer. DESIGN: This study is a retrospective review of prospectively gathered data. SETTING: Data were gathered from a prospective cancer database. PATIENTS: Patients were included who underwent radical resection for mid and lower third rectal cancer (1991- 2006). MAIN OUTCOME MEASURES: The primary outcomes measured were the impact of various factors on perioperative outcomes, local recurrence, and diseasefree survival for patients undergoing abdominoperineal resection. RESULTS: Four hundred thirteen (29%) patients underwent abdominoperineal resection and 993 (71%) underwent restorative resection for rectal cancer. Patients with abdominoperineal resection were older (p < 0.0001), had a higher mean ASA score (p < 0.001), worse tumor differentiation (p < 0.001), and higher tumor stage (p = 0.0001). Although overall morbidity was lower in the abdominoperineal resection group (p = 0.001), the length of stay was greater (p < 0.001). After a similar period of follow-up (5.2 ± 3.9 vs 5.3 ± 3.4 y, p = 0.58), local recurrence (7% vs 3%, p < 0.02) was higher after abdominoperineal resection, but overall survival (56% vs 71%, p < 0.001) and disease-free survival (54% vs 70%, p < 0.001) were lower. On multivariate analysis, higher stage, poor tumor differentiation, involved margins, and older age were associated with worse survival, whereas higher stage, poor tumor differentiation, and abdominoperineal resection were associated with greater recurrence. These worse oncologic outcomes persisted even when the groups were stratified based on the location of the cancer in mid or distal rectum and for patients with a clear circumferential margin. LIMITATION: This study was limited by its retrospective nature. CONCLUSION: Technical factors alone are unlikely to be responsible for the worse outcomes after abdominoperineal resection in comparison with restorative resection. A combination of patient- and tumor-related factors that may have indicated the choice of the procedure also probably contribute to the worse outcomes. Because patients undergoing abdominoperineal resection represent a high risk for poor outcomes, management strategies need to consider all these factors during treatment.