Long-term results of intersphincteric resection for low rectal cancer in Japan.

Intersphincteric resection (ISR) is the ultimate sphincter-preserving procedure for low rectal cancer. A questionnaire about the standardization of ISR was given to 2125 patients who underwent curative ISR for low rectal cancer between 2005 and 2012 at 127 affiliated institutions of the Japanese Society for Cancer of the Colon and Rectum (JSCCR), and the results were compared with the results of a systematic review. The findings revealed that although mortality and morbidity were relatively low and the survival rate after ISR was good, the rates of local recurrence and postoperative fecal incontinence were relatively high. The radicality of ISR was compared with that of abdominoperineal resection and low anterior resection using the propensity score matching prognosis analysis of patients in the JSCCR nationwide registry. The local recurrence rate was significantly higher after ISR, and especially high in patients with T3 (invasion into the external anal sphincter) and T4 disease. These results provide evidence about the factors related to fecal incontinence after ISR. As measures for the standardization of ISR, it is important to reconfirm that ISR is not indicated for patients with cT3 and cT4 disease and those with poor preoperative defecatory function, based on the ISR indication criteria.