Assessment of a Watch-and-Wait Strategy for Rectal Cancer in Patients With a Complete Response After Neoadjuvant Therapy

Abstract

What are the rates of local regrowth, pelvic control, and survival when using a watch-and-wait approach for patients with rectal cancer after a clinical complete response to neoadjuvant therapy? A watchful waiting strategy for 113 patients with rectal cancer achieving a clinical complete response after neoadjuvant therapy resulted in excellent rectal preservation (82%) and pelvic tumor control (91%) in this case series study. However, worse survival was observed compared with 136 patients undergoing total mesorectal excision who had a pathologic complete response; a higher incidence of distant progression was also noted among patients managed by the watch-and-wait strategy who developed local regrowth vs those who did not develop local regrowth. A watch-and-wait strategy may be safe for most patients, but better risk stratification is needed for more precise patient selection to identify those at high risk of local regrowth who are not optimal candidates. This case series of patients with rectal cancer compares outcomes between those who had a clinical complete response to neoadjuvant therapy and agreed to a watch-and-wait strategy and those who underwent total mesorectal excision and had a pathologic complete response at resection. The watch-and-wait (WW) strategy aims to spare patients with rectal cancer unnecessary resection. To analyze the outcomes of WW among patients with rectal cancer who had a clinical complete response to neoadjuvant therapy. This retrospective case series analysis conducted at a comprehensive cancer center in New York included patients who received a diagnosis of rectal adenocarcinoma between January 1, 2006, and January 31, 2015. The median follow-up was 43 months. Data analyses were conducted from June 1, 2016, to October 1, 2018. Patients had a clinical complete response after completing neoadjuvant therapy and agreed to a WW strategy of active surveillance and possible salvage surgery (n = 113), or patients underwent total mesorectal excision and were found to have a pathologic complete response (pCR) at resection (n = 136). Kaplan-Meier estimates were used for analyses of local regrowth and 5-year rates of overall survival, disease-free survival, and disease-specific survival. Compared with the 136 patients in the pCR group, the 113 patients in the WW group were older (median [range], 67.2 [32.1-90.9] vs 57.3 [25.0-87.9] years, P  < .001) with cancers closer to the anal verge (median [range] height from anal verge, 5.5 [0.0-15.0] vs 7.0 [0.0-13.0] cm). All 22 local regrowths in the WW group were detected on routine surveillance and treated by salvage surgery (20 total mesorectal excisions plus 2 transanal excisions). Pelvic control after salvage surgery was maintained in 20 of 22 patients (91%). No pelvic recurrences occurred in the pCR group. Rectal preservation was achieved in 93 of 113 patients (82%) in the WW group (91 patients with no local regrowths plus 2 patients with local regrowths salvaged with transanal excision). At 5 years, overall survival was 73% (95% CI, 60%-89%) in the WW group and 94% (95% CI, 90%-99%) in the pCR group; disease-free survival was 75% (95% CI, 62%-90%) in the WW group and 92% (95% CI, 87%-98%) in the pCR group; and disease-specific survival was 90% (95% CI, 81%-99%) in the WW group and 98% (95% CI, 95%-100%) in the pCR group. A higher rate of distant metastasis was observed among patients in the WW group who had local regrowth vs those who did not have local regrowth (36% vs 1%, P  < .001). A WW strategy for select rectal cancer patients who had a clinical complete response after neoadjuvant therapy resulted in excellent rectal preservation and pelvic tumor control; however, in the WW group, worse survival was noted along with a higher incidence of distant progression in patients with local regrowth vs those without local regrowth.