Preoperative radiotherapy is associated with worse functional results after coloanal anastomosis for rectal cancer.

PURPOSE: This study was designed to evaluate functional outcome in patients treated with preoperative radiotherapy after low anterior resection and a coloanal anastomosis for low rectal cancer.

METHODS: Functional outcome data from patients enrolled in a prospective randomized trial comparing 3 reconstructive procedures were evaluated with respect to administration of preoperative radiotherapy. Incontinence was assessed with a questionnaire on bowel function including the Fecal Incontinence Severity Index; sexual function was assessed with the Sexual Health Inventory for Men and a gender-specific questionnaire for women. Quality of life was assessed with SF-36 scores.

RESULTS: Of 364 patients enrolled, 153 (42%) had no radiotherapy or chemotherapy, and 211 (58%) had preoperative radiotherapy; 186 (51%) had chemotherapy in addition to radiotherapy. Comparison of irradiated vs. nonirradiated patients showed no significant differences in postoperative morbidity (29.9% vs. 35.3%; P = 0.27). Two-year follow-up of 297 patients showed greater impairment of bowel function in irradiated patients (n = 170) vs. nonirradiated patients (n = 127): e.g., mean number of daily bowel movements at 12 months, 4.2 +/- 3.5 vs. 3.5 +/- 2.6, P = 0.032; urgency, 85% vs. 67%, P = 0.002). Antidiarrheal use was significantly higher in irradiated patients vs. nonirradiated patients at 4 (P = 0.043), 12 (P = 0.002), and 24 (P = 0.001) months. Sexual Health Inventory for Men scores indicated poorer function in irradiated patients at 24 months (P = 0.039). Preoperative radiotherapy had no deleterious effects on quality of life. Multivariate analyses showed that negative effects of preoperative radiotherapy on urgency at 4 months (P = 0.002) and antidiarrheal use at 24 months were independent of reconstruction technique, but a positive effect of reconstruction with a J-pouch was still observed in patients who received radiotherapy.

CONCLUSION: Preoperative radiotherapy does not increase overall morbidity but is associated with poorer functional outcome after low anterior resection with coloanal anastomosis. Preoperative radiotherapy and the J-pouch are nonconfounding predictors of functional outcome up to 24 months after surgery.