The Long-term Oncological Outcome of a Sphincter-saving Resection and an Abdominoperineal Resection for Lower Rectal Cancer

Abstract

Purpose: The oncological safety of a sphincter-saving resection (SSR) in lower rectal cancer is widely accepted, and both an abdominoperineal resection (APR) and a SSR are used in potentially curative surgery. This retrospective study was performed to compare the long-term oncological outcomes after an APR and a SSR in patients with lower rectal cancer (within 5 cm from the anal verge). Methods: We recruited 441 lower rectal cancer patients who underwent curative resections (APR: 305, SSR: 136) between 1995 and 2000. A total mesorectal excision and autonomic nerve preservation were routinely performed. The median follow- up period was 65 months. Results: Most demographic findings were comparable between the groups; however, the APR groups revealed more advanced pathological characteristics (tumor depth, size, cell differentiation, and metastatic LN number). The local recurrence rates after an APR and a SSR were 12.8% and 7.4%, respectively (P= 0.09). An independent risk factor of local recurrence was LN metastasis only. Distant recurrence was higher in the APR group (26.4%) than in the SSR group (13.2%), but on multivariate analysis the difference was not significant (P=0.17). The 5-year cancer-specific survival rates after an APR and a SSR were 73.2% and 87.6%, respectively (P＜0.05). Particularly, there was a significant survival difference for stage III patients (APR: 59.0% vs. SSR: 83.0%, P＜0.05). However, an APR was not an independent prognostic factor for cancer-specific survival in the multivariate analysis (P=0.07). Conclusions: An APR per se did not influence local recurrence after a curative resection for lower rectal cancer. The poor cancer-specific survival in the stage III APR group might be attributed to increased distant metastasis due to its more distal location.