Abstracts
1998 Digestive Disease Week

#2336

B2 RECTAL CANCER: IS RADIATION THERAPY FOR LOCAL CONTROL NECESSARY? N.B. Merchant, J.G. Guillem, P.B. Paty, W.E. Enker, A.M. Cohen, Memorial Sloan-Kettering Cancer Center, New York, NY.

Standard of care for B2 rectal cancer includes combined chemoradiation therapy to decrease local recurrence (LR) and improve survival. However, in several reports, optimizing the operation with sharp dissection and total mesorectal excision (TME) produces a LR as low as 5% after low anterior resection (LAR) without adjuvant treatment. The purpose of this study was to determine if resection with TME combined with LAR or abdomino-perineal resection (APR) alone is adequate treatment for local control of B2 rectal cancer. Methods: Between July 1986 and December 1993, 95 T3N0M0 rectal cancer patients that were resected with TME and received no adjuvant therapy, were identified from a prospective database and reviewed retrospectively. Various prognostic factors were analyzed for determining LR. Survival was determined by the Kaplan-Meier actuarial method. Statistical analysis was performed by log-rank analysis for univariate analysis. Results: Seventy-nine patients had a LAR, 10 of whom had a coloanal anastomosis, and 16 patients had an APR. The median follow-up was 53.3 months. There were 6 patients with LR, 12 patients with DR and 3 patients with LR & DR. The overall actuarial LR rate was 9% with an overall recurrence rate of 22%. The 5-year disease-specific survival was 86.6% with an overall survival of 75%. Post-operative complications occurred in 18 (19%) patients, 5 (6%) of whom had an anastomotic leak. Peri-operative mortality was 3%. No technical factors, including type of resection (LAR vs APR), location of tumor or resection margin, were significant for determining LR. The only histopathologic marker significant for determining LR was lymphatic invasion (n=3; p<0.04). Tumor grade, vascular, peri-neural invasion or mucin production did not influence LR. Conclusion: TME with LAR or APR for T3N0M0 rectal cancer results in a LR rate of < 10% without the use of adjuvant therapy. In this select population, the standard use of adjuvant radiation therapy for local control may not be justified.

Copyright 1996 - 1998, SSAT, Inc. Revised 29 June 1998.