Using a cohort of macroscopic curative resections of gastric cancer at stages 11, Ill, and IV, a randomized controlled trial was performed to clucidate the dose efficacy of intensive adjuvant cancer chemotherapy with mitomycin C. Between June 1983 and December 1986, 336 patients with gastric cancer from 3 1 institutes were enrolled in the study. The cohort was stratified randomly by the telephone method into two arms. Group A received 20 mg and 10 mg of mitomycin C per body intravenously (IV) on postoperative days 0 and I , respectively, and then tegafur at 600 mg/body daily perorally (PO) from postoperative week 2 for 1 year. Group B also received 0.2 mg of mitomycin C per kg IV at 3 , 6,9, and 12 months after surgery. The background factors in groups A and B were essentially identical, and the adverse effects were tolerable in both groups. Thc total administered doses of mitomycin C were significantly higher in groulp B than in group A, according to the protocol. Although no significant differences were observed in the actuarial overall survival rates between groups A and B at stages 11, 111, and lV, favorable survival was observed in group B, which received histologically absolute curative resection. This doseintensive adjuvant cancer chemotherapy would be useful for gastric cancer patients treated by histologically curative surgery. o 1994 Wiiey-Liss, lnc.