Optimal duration of oral adjuvant chemotherapy with Carmofur in the colorectal cancer patients: the Kansai Carmofur Study Group trial III

A multi-institutional study was performed to evaluate the appropriate duration of oral administration of Carmofur (1-hexylcarbamoyl-5-fluorouracil, HCFU), a 5-fluorouracil (5-FU) derivative, for postoperative adjuvant chemotherapy in patients with colorectal cancer undergoing curative operation. Patients were divided into two: i) short duration group receiving 6 months of HCFU administration and ii) long duration group receiving 1 year of the administration, using a centralized registration system. Among 364 patients entered in this study, 293 evaluable cases were analyzed to investigate the appropriate duration of adjuvant oral chemotherapy. No statistical differences were found in the cumulative 5-year disease-free or survival rates between the groups. However, the actual duration of oral HCFU administration differed in the patients of short and long duration groups from the protocol. Namely, more than 70% of the patients received a different duration of oral adjuvant chemotherapy in each of the groups. Therefore, apart from this division of two groups, correlation between the actual duration of oral HCFU administration and the prognosis was examined in these patients. As a result, it was suggested that oral adjuvant chemotherapy with HCFU would be effective in colon cancer patients when the duration of administration exceeded 330 days. In rectal cancer patients, however, adjuvant chemotherapy with HCFU alone was considered to be not sufficient to affect the prognosis.