Sphincter-saving surgery versus abdominoperineal resection in low rectal cancer following neoadjuvant treatment with propensity score analysis.

Background: Sphincter-saving operation is the treatment of choice in patients with lower rectal cancer, although abdominoperineal resection (APR) is necessary in some cases for adequate oncological outcomes. This study compared the oncologic outcomes of patients with low rectal cancer undergoing APR and intersphincteric resection (ISR) after neoadjuvant chemoradiotherapy (nCRT). Methods: We compared 104 patients who underwent ISR for lower rectal cancer between 2008 and 2014 with 79 patients who underwent APR during the same period. Cases in which tumors involved the levator ani muscle or the external anal sphincter, as well as those in which surgeons were unable to obtain a negative distal margin via sphincter-saving operation were excluded. Fifty-two patients who underwent ISR were matched via propensity scoring with 52 patients who underwent APR. The analyzed variables included patient and tumor characteristics and long-term outcomes before and after 1:1 propensity score matching (PSM). Results: After matching, there were no significant differences between the two groups in clinical stage and tumor distance from anal verge. Short- and long-term outcomes were similar between the two groups. The 5-year disease-free survival rate was 76.3% in the ISR group and 57.8% in the APR group (p = 0.080). The 5-year cancer-specific survival rate was 89.5% in the ISR group and 85.4% in the APR group (p = 0.383). Conclusions: This reveals that ISR and APR have similar oncologic outcomes following nCRT in patients with advanced low rectal cancer adjusted for background variables. [ABSTRACT FROM AUTHOR]