Comparison of oncologic outcome of abdominoperineal resection versus sphincter saving resection for low lying rectal cancer

PURPOSE: The present study compares the peri/postoperative and oncological outcomes of abdominoperineal resections (APR) and sphincter saving resection (SSR) for low lying rectal cancer. METHODS: Between January 2001 and December 2014, 176 patients who underwent SSR (n=67) and APR (n=109) for low rectal cancer, without stage IV, were retrieved from a retrospective database. RESULTS: With a median follow-up of 66.5 months. The mean total number of harvested lymph nodes was 16.7 (SSR) versus 17.1 (APR) (P=0.801). The advanced T stage was higher in the APR group (82.6%) versus the SSR group (55.2%) (P=0.006). The positive rate of lymph nodes after surgery was significantly higher in the APR group (45.9%) versus SSR group (25.4%) (P<0.05). The 5-year overall survival rates for SSR and APR were 87.3% and 67.6%, respectively (P<0.005). The 5-year disease-free survival rate (DFS) was 83.6% (SSR) versus 65.5% (APR) (P=0.002). The recurrence rate was higher in the APR group (34.9%) versus the SSR group (14.9%) (P=0.004). Local recurrence rate was not different between the two groups. However, distant recurrence rate was significantly higher in the APR group (26.6% vs. 11.9%, P=0.023). In multivariate analysis, node positive (N0 vs. N1–2) was an independent prognostic factor for DFS (P<0.005). CONCLUSION: Based on the present data, SSR achieved better 5-year oncological outcome than APR. The positive lymph node ratio in the N stage after surgery was higher in the APR group and this seems to have an effect on the oncological outcomes of the APR group.