Long-term survival following levamisole or placebo adjuvant treatment of colorectal cancer: a Western Cancer Study Group Trial.

In 1976, the Western Cancer Study Group initiated a prospectively randomized, double-blind trial of an 18-month adjuvant program comparing levamisole with placebo treatment following surgical resection in patients with colorectal adenocarcinoma. After stratification for site of disease (colon vs. rectum) and stage (B vs. C), 78 patients were entered. The levamisole schedule was 2.5 mg/kg/day given on days 1 and 2 of each week. The median follow-up of entered patients is now 7.5 years. Toxic effects of treatment were minimal. However, no long-term survival advantage was associated with levamisole compared to placebo administration in this population with resected large-bowel adenocarcinoma.