Objective: In the latter 1990s, adjuvant chemotherapy for completely resected Stage III colorectal cancer remained controversial in Japan. We conducted two independent randomized controlled trials in patients with Stage III colon and rectal cancer.
Methods: Patients were randomly assigned to receive surgery alone or surgery followed by treatment with UFT (400 mg/m²/day), given for five consecutive days per week for 1 year. The primary endpoint was relapse-free survival (RFS), and the secondary endpoint was overall survival (OS).
Results: A total of 334 patients with colon cancer and 276 with rectal cancer were enrolled. The patients' characteristics were similar between the UFT group and the Surgery-alone group. There was no significant difference in RFS or OS in colon cancer. In rectal cancer, however, RFS and OS were significantly better in the UFT group than in the Surgery-alone group. The only grade 4 toxicity in the UFT group was diarrhea, occurring in one patient with colon cancer and one patient with rectal cancer.
Conclusions: Postoperative adjuvant chemotherapy with UFT is successfully tolerated and improves RFS and OS in patients with Stage III rectal cancer. In colon cancer, the expected benefits were not obtained (hazard ratio = 0.89).