Review of comparative studies of postoperative adjuvant chemotherapy after curatively resected colorectal cancer in Japan

Six randomized control studies (RCT) in Japan conducted after 1984 were reviewed. These studies basically investigated postoperative oral administration of 5-FU followed by venous injection of MMC. The efficacy of this treatment compared with a surgery alone group was demonstrated with statistical significance in some papers only in patients with Dukes' B and C cancer. However, there were many mistakes in these studies, including incorrect stratification, incorrect administration of the drugs, and follow-up mistakes. Furthermore, two new types of RCT were introduced. One was studies with prospective stratification of the patients according to predicting factors for recurrence, and the other was those examining continuous arterial infusion of 5-FU for the purpose of suppressing recurrence in the residual liver after curative resections of hepatic metastases.