SPHINCTER PRESERVATION WITH PREOPERATIVE RADIATION-THERAPY AND COLOANAL ANASTOMOSIS

Purpose: To determine if preoperative radiation therapy allows sphinct er preservation in the treatment of rectal cancer. Methods and Materia ls: Thirty patients with the diagnosis of invasive, resectable, primar y adenocarcinoma of the rectum limited to the pelvis were enrolled on a Phase I/II trial of preoperative radiation therapy plus low anterior resection/coloanal anastomosis. By preoperative assessment, all patie nts had invasive tumors (2: T2, 28: T3) involving the distal half of t he rectum and required an abdominoperineal resection. The median tumor size was 4 cm (range: 1.5-6 cm) and the median distance from the anal verge was 4 cm (range: 3-7 cm). The whole pelvis received 46.8 Gy fol lowed by a 3.60 Gy boost to the primary tumor bed. The median follow-u p was 43 months (range: 6-82 months). Results: Of the 29 patients who underwent resection, 3 (10%) had a complete pathologic response and 24 (83%) were able to successfully undergo a low anterior resection/colo anal anastomosis. The incidence of local failure was crude: 17% and 4- year actuarial: 23%. The 4-year actuarial survival was 75%, One patien t developed a partial disruption of the anastomosis and two developed rectal stenosis. Analysis of sphincter function using a previously pub lished scale was performed at the time of last follow-up in 22 of the 24 patients who underwent a low anterior resection/coloanal anastomosi s. Function was good or excellent in 77%, The median number of bowel m ovements/day was two (range: 1-6). Conclusions: This technique may be an alternative to an abdominoperineal resection in selected patients, Continued follow-up is needed to determine if this approach ultimately has similar local control and survival rates as an abdominoperineal r esection.