Comparison of oncological outcomes between low anterior resection and abdominoperineal resection for rectal cancer: A retrospective cohort study using a multicenter database in Japan.

ABSTRACT

BACKGROUND: It remains controversial whether the abdominoperineal resection (APR) procedure itself has a negative impact on prognosis compared with sphincter-saving surgery (SSS). The purpose of this study was to investigate whether the operation type affects the prognostic outcome in rectal cancer using a multicenter database in Japan. METHODS: The study involved 2533 patients who underwent APR or SSS and were registered in the Japanese Society for Cancer of the Colon and Rectum database, which includes data from 74 centers, between 2003 and 2007. The primary endpoints were overall survival (OS) and relapse-free survival (RFS). The secondary endpoints were local recurrence rate (LRR) and pathological radial margin (pRM) status. RESULTS: Multivariate analysis identified pathological tumor depth, lymph node status, and pRM status to be associated with oncological outcomes (OS, RFS, LRR). Although the oncological outcomes were worse after APR than after SSS in univariate analysis, there was no significant difference in OS (hazard ratio 1.08; 95% confidence interval [CI] 0.85-1.37) or RFS (hazard ratio 1.06; 95% CI 0.87-1.30) between APR and SSS. There was also no significant difference in LRR (odds ratio 1.11, 95% CI 0.70-1.77). Multivariate analysis showed that operation type was associated with positive pRM (odds ratio 3.13, 95% CI 0.18-0.56). CONCLUSIONS: There was no significant difference in oncological outcomes between APR and SSS for rectal cancer. The risk of positive pRM was higher for APR and performing radial margin-negative surgery is an important factor in improving the oncological outcomes of APR.