Sphincter preservation with preoperative radiation therapy and coloanal anastomosis.

Abstract

To determine if preoperative radiation therapy allows sphincter preservation in the treatment of rectal cancer. Thirty patients with the diagnosis of invasive, resectable, primary 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 patients had invasive tumors (2: T2 28:T3) involving the distal half of the 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 followed by a 3.60 Gy boost to the primary tumor bed. The median follow-up was 43 months (range: 6-82 months). 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/colonanal anastomosis. The incidence of local failure was crude: 17% and 4-year actuarial: 23%. The 4-year actuarial survival was 75%. One patient developed a partial disruption of the anastomosis and two developed rectal stenosis. Analysis of sphincter function using a previously published scale was performed at the time of last follow-up in 22 of the 24 patients who underwent a low anterior resection/coloanal anastomosis. Function was good or excellent in 77%. The median number of bowel movements/day was two (range: 1-6). 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 resection.