Clinical effects of preoperative radiation therapy on anorectal function after proctectomy and colonic J-pouch-anal anastomosis.

Purpose: Preoperative radiotherapy is increasingly used for certain rectal cancers, although some evidence suggests that it may adversely affect anorectal function. Reconstruction with a colonic J-pouch-anal anastomosis after complete proctectomy is thought to improve function, but few published data on pouch function after radiation exists. The aim of our study was to compare long-term bowel habits in patients receiving preoperative radiation for rectal cancer followed by colonic J-pouch-anal anastomosis with those of patients having similar rectal cancer surgery without radiation.

Methods: Patients (n = 125) having undergone colonic J-pouch-anal anastomosis for rectal cancer, of whom 28 had preoperative radiotherapy and 97 did not, responded to a detailed questionnaire about their bowel habits at least 12 months after surgery, with a mean (+/- standard deviation) interval of 64 (+/-42) months. Radiation was administered preoperatively as a short (25 Gy over 5 days, n = 22) or long (45 Gy over 4 weeks, n = 6) course. All patients had colonic J-pouch-anal anastomosis with manual anastomosis at or immediately above the dentate line.

Results: Except for tumor stage, no preoperative difference was observed between the two groups. The number of bowel movements per 24 hours in patients with and without radiation was 1.8 (+/-0.8) and 1.8 (+/-1.5), respectively (P> 0.05). In the irradiated group, diarrhea (39 vs.13 percent, P= 0.005) and nocturnal defecation (36 vs.15 percent, P= 0.03) were more frequent than in the nonirradiated group. No other significant difference existed between groups with regard to stool clustering, use of protective pads, ability to defer evacuation >15 minutes, ability to evacuate the bowel within 30 minutes, incontinence score, use of medications, or dietary restriction.

Conclusion: Preoperative radiotherapy followed by proctectomy and colonic J-pouch-anal anastomosis significantly increased nocturnal defecation frequency and diarrhea compared with similar nonirradiated patients but had no influence on the other bowel-habit parameters studied.