Long-term oncologic outcomes of intersphincteric resection versus abdominoperineal resection for low rectal cancer without preoperative therapy

Abstract Purpose This study analyzed the oncologic outcomes of patients with low rectal cancer undergoing intersphincteric resection (ISR) compared with those underwent APR to evaluate the oncologic safety of ISR. Methods This study enrolled 149 patients undergoing ISR and 166 patients receiving APR for LRC from January 2010 to December 2020. The exclusion criterion included neoadjuvant therapy or other malignant tumors. Moreover, this study used propensity score matching to reduce possible confounding factors. Results After comparing 123 patients from each group, comparable long-run outcomes were observed in both groups. ISR and APR groups showed 5-year disease-free survival rates of 69.8% and 57.2% (p = 0.146), 5-year overall survival rates of 82.8% and 74.4% (p = 0.164), and 5-year local recurrence-free survival rates of 81.8% and 72.0% (p = 0.109), respectively. For paired patients receiving laparoscopic surgery, close outcomes were observed. Moreover, ISR showed comparable oncologic safety for locally advanced cancer to APR. Conclusions In this study, ISR and APR showed close oncological results regardless of the surgery approach for patients with LRC without neoadjuvant chemoradiotherapy(nCRT). In addition, this study suggested that ISR may be safe for locally advanced cancer if circumferential resection margins could be ensured negative.