Does External Beam Radiation Therapy to the Pelvis Portend Worse Ileal Pouch Outcomes? An International Multi-Institution Collaborative Study.

AIM: Short-term morbidity and long-term functional outcome of patients with an ileal pouch-anal anastomosis (IPAA) exposed to pelvic external beam radiation therapy (EBRT) remains unknown. We report the largest series to date regarding the effects of pelvic EBRT on 1) 30-day postoperative outcomes and 2) long term functional outcome following IPAA.

METHOD: A retrospective chart review was conducted of patients who received EBRT before or after IPAA between 1980 and 2017 across three international inflammatory bowel disease referral centers.

RESULTS: 19 patients were included. Indications for EBRT were rectal adenocarcinoma (n= 13), prostate adenocarcinoma (n=4), or anal squamous cell carcinoma (ASCC) (n=2). EBRT was given prior to IPAA in 12 (63%) and after IPAA in 7 (37%). In EBRT before IPAA, patients had a median of 5 daytime bowel movements (range 4-8), 1 nighttime bowel movements (range 0-5), no daytime incontinence, and only one patient used pads at a median follow up of 25 months (range 11-163 months); one patient underwent pouch excision 15 months after IPAA. In EBRT after IPAA, patients reported a median of 8 daytime (range 5-10) and 2 nighttime bowel movements (range 0-5), 80% had either daytime or nighttime incontinence, and 80% used pads at a median follow up of 90 months (range 25-315).

CONCLUSION: Pelvic EBRT administered prior to IPAA is associated with acceptable long-term function outcome. However, when pelvic EBRT is given to an IPAA in situ, most patients experience long-term poor pouch function without pouch failure. This article is protected by copyright. All rights reserved.