Purpose: Adjuvant postoperative treatment with fluorouracil (5-FU) and levamisole in curatively resected stage III colon cancer significantly reduces the risk of cancer recurrence and improves survival. Biochemical modulation of 5-FU with leucovorin has resulted in increased remission rates in metastatic colorectal cancer, thus reflecting an increased tumor-cell kill. The impact of 5-FU plus leucovorin on survival and tumor recurrence was analyzed in comparison with the effects of 5-FU plus levamisole in the prospective multicentric trial adjCCA-01.
Patients and methods: Patients with a curatively resected International Union Against Cancer stage III colon cancer were stratified according to T, N, and G category and randomly assigned to receive one of the two adjuvant treatment schemes: 5-FU 400 mg/m(2) body-surface area intravenously in the first chemotherapy course, then 450 mg/m(2) x 5 days; 12 cycles, plus leucovorin 100 mg/m(2) (arm A), or 5-FU plus levamisole (Moertel scheme; arm B).
Results: Six hundred eighty (96.9%) of 702 patients enrolled onto this study were eligible. After a median follow-up time of 46.5 months, the 5-FU plus leucovorin combination significantly improved disease-free survival (P =.037) and significantly decreased overall mortality (P =.0089) in comparison with 5-FU plus levamisole. In a multivariate proportional hazards model, adjuvant chemotherapy emerged as a significant prognostic factor for survival (P =.0059) and disease-free survival (P =.03). Adjuvant treatment with 5-FU plus levamisole as well as with 5-FU plus leucovorin was generally well tolerated; only a minority of patients experienced grade 3 and 4 toxicities.
Conclusion: After a curative resection of a stage III colon cancer, adjuvant treatment with 5-FU plus leucovorin is generally well tolerated and significantly more effective than 5-FU plus levamisole in reducing tumor relapse and improving survival.