Adjuvant therapy of poor prognosis colon cancer with levamisole: Results of an EORTC double-blind randomized clinical trial

From 1978 to 1985, 297 patients were entered in a double-blind randomized trial comparing levamisole to placebo as adjuvant therapy of Dukes' C carcinoma of the colon. Therapy consisted of from two to five tablets of 50 mg levamisole (or placebo) twice a week, depending on bodyweight for 1 year. Levamisole was generally well tolerated, with only four reversible cases of agranulocytosis reported among 129 patients. The trial failed to show a benefit of levamisole on disease-free survival (P = 0.53) or on survival (P = 0.35). There was no difference between the two treatment groups in terms of number of disease relapses, sites of relapse, or time to relapse. The proportion of patients still alive at 5 years was 51 per cent (standard error, 5.5 per cent) in the levamisole group versus 39 per cent (standard error, 5.4 per cent) in the placebo group.