The role of levamisole in the adjuvant treatment of stage III colon cancer patients: a randomized trial of 5-fluorouracil and levamisole versus 5-fluorouracil alone.

Adjuvant 5-fluorouracil (5FU) and levamisole (Lev) have been considered standard treatment for stage III colon cancer patients. However, the uncertain contribution of Lev to the efficacy of treatment has led many oncologists to prefer the 5FU/leucovorin combination. To establish the role of Lev, we conducted a randomized trial comparing the 5FU/Lev combination with 5FU alone in patients with Dukes' C colon cancer. Patients with stage III colon cancer were randomized to receive 5FU alone (450 mg/m2 i.v. bolus daily for 5 days and then, beginning at day 28, weekly for 48 weeks) or the same plus Lev (50 mg orally three times/day for 3 days, repeated every 2 weeks for 1 year). From December 1994 to March 1998, 92 patients were assigned to receive 5FU/Lev, and 93 were assigned to receive 5FU alone. Leukopenia and hepatic toxicity were more frequent in patients receiving 5FU/Lev as compared with those receiving 5FU (respectively, p = 0.003 and p = 0.039), whereas other toxicities were equivalent and mild in both arms. After a median follow-up time of 48 months, 80 patients have had recurrences (40 in each arm) and no advantages in terms of disease-free survival and overall survival could be demonstrated for the combination arm. The addition of Lev to 5FU does not seem to be relevant for the clinical activity of this adjuvant regimen, whereas toxicity related to Lev should be considered when an adjuvant treatment for stage III colon cancer patients is proposed.