Postoperative Adjuvant Irradiation With or Without Chemotherapy for Rectal Carcinoma.

Abstract

p atients with rectal carcinoma who are candidates for adjuvant treatment, in spite of complete surgical resection with negative margins, are those with a moderate to high risk of local or systemic failure or decreased survival when treated with surgery alone. The high-risk factors include primary tumor extension beyond the rectal wall, involved nodes, or both (Dukes' stage B or C; Astler-Coller B2, Cl, or C2; modified Astler-Coller B2.3, C1.3; TNM T3-4 NO, Tis-4 N1-3). The ideal adjuvant treatment for resectable highrisk rectal cancer would preferably decrease both local and systemic failures, increase both disease-free and overall survival, and accomplish such with acceptable tolerance. At the 1990 National Institutes of Health (NIH) Consensus Conference on Adjuvant Therapy of Large Bowel Cancer, 1 the efficacy of adjuvant treatment for rectal cancer was evaluated by outcomes of three scientific endpoints: (1) incidence of pelvic (local) recurrence, (2) disease-free survival (time to relapse), and (3) overall survival. Inclusion of local recurrence as a separate endpoint is based on the significant morbidity of pelvic recurrence 2 and the difficulty in achieving subsequent salvage for cure. Standard treatment of pelvic recurrence results in short-term palliation (usually 6 to 12 months) and infrequent cure. 3 Although distant metastases result in less patient months of morbidity than local recurrence in high-risk patients treated with surgery alone, 2 subsequent cure can be achieved only when solitary or adjacent metastases can be resected. Reduction in the incidence of distant metastases with effective systemic adjuvants would be a justifiable separate endpoint in future trials.