Organ preservation in patients with rectal cancer with clinical complete response after neoadjuvant therapy.

Abstract

509 Background: Nonoperative management (NOM) of rectal cancer following a clinical complete response (cCR) to neoadjuvant therapy is a non-standard approach. We review our experience with NOM to evaluate safety and efficacy. Methods: A retrospective review of prospectively collected data between 2006 and 2014 was conducted. We compared patients completing neoadjuvant therapy for stage I to III rectal cancers who: a) achieved cCR and were treated with NOM, or b) underwent standard total mesorectal excision (TME) and achieved a pathologic complete response (pCR). Kaplan-Meier estimates and the log-rank test were used. Results: Seventy-three patients underwent NOM after cCR. From 369 rectal resections performed, 72 (20%) achieved pCR and form the comparison group. Median follow-up across both groups was 3.3 years. Rectal preservation was achieved in 56 (77%) of the patients treated with NOM. Of the 19 NOM patients with local regrowth, 18 were salvaged successfully with standard TME (n=16) or local excision (n=2), with one patient pending a salvage operation (n=1). No significant differences were noted in the number of distant recurrences between the NOM and pCR groups. Four-year disease-specific survival and overall survival between the two groups were not significantly different. Conclusions: In this highly selected group of patients with cCR to neoadjuvant treatment, NOM with surgical salvage of local tumor regrowth achieved local control in all patients. The oncologic outcome for NOM patients at 4 years was comparable to patients with pCR after rectal resection. These data continue to suggest that NOM does not compromise oncologic outcome, and that preservation of the rectum is achieved in a majority of patients. [Table: see text]