Adjuvant treatment of node-positive colon carcinoma with levamisole and 5-fluorouracil.

Levamisole, an anthelminthic drug, has been studied clinically as a nonspecific immunomodulator in the adjuvant treatment of a variety of malignancies. Over a decade ago, a small, non-randomized trial of levamisole versus no further therapy after primary surgical resection of colorectal carcinoma showed a survival benefit for the cohort receiving levamisole, particularly among patients with transmural penetration or positive regional nodes. Since this seminal trial, numerous adjuvant trials of levamisole alone or in combination with 5-fluorouracil have been conducted. Two randomized, placebo-controlled trials failed to show a benefit of levamisole in patients with node-positive colon carcinoma. Three adjuvant trials have shown a therapeutic benefit of levamisole plus 5-fluorouracil compared to observation. Adjuvant therapy with levamisole and 5-fluorouracil reduced the risk of cancer recurrence by 41% and the death rate by 33% in patients with node-positive disease. The results of this trial have defined a new standard of care in the treatment of patients with Stage C colon carcinoma.