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.