Purpose: Traditional intersphincteric resection is a technically demanding procedure that required a perineal approach dissection and a handsewn coloanal anastomosis. Our study was to investigate the feasibility and the prognostic factors of completely abdominal approach partial intersphincteric resection (APISR) after neoadjuvant chemoradiotherapy (CRT) for low rectal cancer with initial stage cT3. Methods: A total of 101 consecutive patients with initial stage cT3 juxta-anal rectal cancer who underwent APISR after neoadjuvant CRT between January 2010 and March 2015 were enrolled. Survival rates were estimated and compared using the Kaplan-Meier method and log-rank tests. Cox proportional hazard model was utilized for multivariable analysis for disease-free survival (DFS). The cutoff values of residual tumor size calculated by X-tile were used in the multivariate analysis as well. Results: The median follow-up was 39 months. The local recurrence rate within 3 years was 2.5%. The 3-year DFS rate was 80.2%, and the 3-year overall survival rate was 95.3%. The 3-year DFS in pathological stage 0-III were 96.2%, 94.4%, 85.7%, and 44.7% respectively (Log-rank = 29.791, P < .001). In multivariate analysis, stage ypN1-2 (hazard ratio (HR) = 8.256, 95% confidence interval [CI]: 2.742-24.855, P < .001) and tumor size after CRT more than 2.8 cm (HR = 3.077, 95% CI: 1.036-9.137, P = .043) were the independent factors for worse DFS. Conclusions: Laparoscopic and open APISR after CRT produces satisfactory mid-term oncological outcomes for juxta-anal rectal cancer downstaged from initial cT3 especially in stage ypN0 or with tumor size after CRT <2.8 cm. Hence, stage ypN1-2 and tumor size after CRT more than 2.8 cm are poor prognostic factors that should be estimated for APISR.
Keywords: chemoradiation therapy; intersphincteric resection; rectal cancer.