Outcomes of Distal Rectal Cancer Patients Who Did Not Qualify for Watch-and-Wait: Comparison of Intersphincteric Resection Versus Abdominoperineal Resection

Introduction: Total mesorectal excision (TME) with intersphincteric resection and handsewn coloanal anastomosis (ISR-CAA) has been shown to be oncologically safe in patients with distal rectal cancer treated with preoperative chemoradiation. The introduction of the watch-and-wait (WW) strategy for rectal cancer patients with a clinical complete response to neoadjuvant therapy is changing the profile of patients undergoing TME surgery immediately following neoadjuvant treatment. The outcomes of ISR-CAA for patients with locally advanced rectal cancers not qualifying for WW have not been investigated. Methods: We conducted a retrospective analysis comparing the outcomes of ISR-CAA and abdominoperineal resection (APR) in patients with distal rectal cancer treated with neoadjuvant therapy and not qualifying for WW, at a comprehensive cancer center with an established WW program. The primary outcome was local recurrence-free survival. Results: Sixty-seven patients had ISR-CAA and 79 had APR. Median follow-up was 61.1 months. The two groups were similar in sex, tumor stage, grade, and distance from the anal verge, but patients in the APR group were older on average. An R0 resection was achieved in 94% of ISR-CAA patients and 91% of APR patients. Patients in the ISR-CAA group had a lower 5-year rate of local recurrence-free survival (79% vs. 93%; p = 0.038) compared with the APR group; however, 5-year disease-free survival did not differ significantly between groups (67% for ISR-CAA and 64% for APR; p = 0.19). Conclusions: The local recurrence rate after ISR-CAA may be higher than after APR for patients without a clinical complete response to neoadjuvant therapy requiring TME surgery.