5-YEAR RESULTS OF A RANDOMIZED CONTROLLED TRIAL OF ADJUVANT CHEMOTHERAPY FOR CURATIVELY RESECTED COLORECTAL-CARCINOMA

In order to evaluate the significance of postoperative adjuvant chemot herapy for colorectal carcinoma, the Colorectal Cancer Chemotherapy St udy Group, from 140 leading hospitals in Japan, conducted a prospectiv e, randomized, controlled trial on patients who had undergone curative resections for colorectal carcinomas during the period from February 1984, to December 1985. The regimens for colon cancer were, Arm I: mit omycin C [intraoperative portal vein bolus (12 mg/m(2))+postoperative, twice weekly and then three times bimonthly for six months intermitte nt i.v. bolus (6 mg/m(2))]+5-fluorouracil (5-FU) 200 mg/body/day p.o. for six months; Arm II: postoperative twice weekly and then three time s bimonthly intermittent i.v. bolus mitomycin C (6 mg/m(2)) for six mo nths+5-FU 200 mg/body/day.p.o. for six months; Arm III: surgery alone. The regimens for rectal cancer were, Arm IV: same as Arm I, with supe rior rectal artery infusion of the same mitomycin C dose instead of po rtal vein infusion; Arm V: same as Arm II; Arm VI: same as Arm III. Of 2001 collected cases, 1805 eligible cases (899 colon cancers and 906 rectal cancers) were analyzed. Significant differences in five-year su rvival rates were found between Arms IV and V and Arm VI [Arm IV: 70.7 % (95% confidence interval (C.I.): 65.6-75.8%), P=0.004 vs Arm V: 73.6 % (68.5-78.7%), P=0.000 vs Arm VI (control): 60.2% (54.5-65.9%)]. No s ignificant difference in overall survival rate was found in the colon cancer patients [Arm I: 80.4% (75.7-85.1%), not significant (N.S.) vs Arm II: 82.1% (77.8-86.4%), N.S. vs Arm III (control): 79.5% (74.6-84. 4%)]. When stratified into Dukes classes, however, Dukes C patients in Arm II showed a significantly improved survival rate compared with th at of those in Arm III [Arm I: 72.6% (64.8-80.4%), N.S. vs Arm II: 75. 0% (67.9-82.1%), P=0.012 vs Arm III (control): 61.0% (51.4-70.6%)]. We conclude the adjuvant use of long term oral 5-FU and intermittent mit omycin C (i.v.) to improve the survival rate of patients with curative ly resected rectal cancer. Further comparative study is, however, reco mmended to confirm the effectiveness of 5-FU alone and the combination of 5-FU and mitomycin C. Regional chemotherapy made no contribution t o reducing an hepatic recurrence of colon cancer or a local recurrence of rectal cancer.