Prognostic factors for low rectal cancer patients undergoing intersphincteric resection after neoadjuvant chemoradiation

This study aimed to investigate prognostic factors for low rectal cancer patients undergoing intersphincteric resection (ISR) following neoadjuvant chemoradiation (CRT).We retrospectively reviewed 163 primary rectal cancer patients without distant metastasis who underwent ISR following neoadjuvant CRT between January 2006 and December 2011. Prognostic factors for disease-free survival (DFS) and local recurrence-free survival (LRFS) were evaluated.The median follow-up period was 53 months (range, 0-82 months). Kaplan-Meier survival analysis indicated different 3-year DFS (stage 0, 96.2%; I, 84.8%; II, 72.9%; III, 38.0%) and 3-year LRFS (stage 0, 100.0%; I, 92.4%; II, 91.1%; III, 70.9%) according to pathologic TNM stages, particularly stage III. Multivariable Cox regression analysis suggested that DFS was associated with ypT (3/4 vs. 0/1/2) and ypN (1/2 vs. 0) stages, whereas LRFS with ypN stage (1/2 vs. 0), tumor size (≥3.5 cm vs. <3.5 cm), and tumor height from the anal verge (≤2 cm vs. >2 cm).ISR following CRT could be feasible in stage-I and II low rectal cancer patients, but might be related to poor oncologic outcomes in those with stage-III disease. The indication for ISR or abdominoperineal resection should be carefully evaluated in cases of low rectal cancer with suspicious lymph node metastasis after CRT.