Levamisole and 5-fluorouracil therapy for resected colon cancer: a new indication.
 OBJECTIVE: To evaluate the benefits and risks of postoperative treatment with levamisole plus 5-fluorouracil (5-FU) in patients with colon cancer.
 DESIGN: Computerized searches of MEDLINE and CANCERLIT were performed, and the reference list of each retrieved article was checked.
 Only randomized trials of therapy with levamisole alone or combined with 5-FU for colon cancer without distant metastases were included.
 The studies were then evaluated with the use of four criteria.
 RESULTS: We reviewed six randomized trials, of which three satisfied our criteria.
 Two studies demonstrated a significant improvement in the survival rate with levamisole plus 5-FU among patients with colon cancer and pathologically confirmed metastases to adjacent lymph nodes (Dukes' stage C).
 A subgroup analysis in another study demonstrated a similar benefit.
 The toxic effects of the drugs were generally mild.
 The three other studies showed no difference in survival rates between the treatment groups; however, the samples were too small to detect a clinically or statistically important difference.
 CONCLUSIONS: Because many patients with colon cancer will suffer a relapse we recommend that they be offered the opportunity to participate in clinical trials of adjuvant therapy.
 For those with stage C disease not entering a clinical trial levamisole plus 5-FU is appropriate adjuvant therapy.
