[Concentration of 5-fluorouracil in the blood and tissues of gastric and colo-rectal cancer patients after oral administration of UFT].

UFT is given to the patients with digestive cancer from the time before operation to prevent intra- and post-operative cancer dissemination and metastases. UFT (400 mg/day in terms of tegafur) was given preoperatively for 1-6 days in 6 patients with gastric cancer and 13 with colorectal cancer. The interval between the last administration and the beginning of the operation was 3.9 +/- 1.5 hours (mean +/- SD). The concentrations of tegafur, 5-FU, and uracil in the blood collected at the time of tumor resection were 9.68, 0.017, and 0.08 microgram/ml, respectively. In the patients with gastric cancer 5-FU concentration was 5.5 times higher in the normal mucosa, 3.3 times in lymph nodes, and 10.7 times in the tumor tissues than in the blood. In colorectal cancer patients, also, the 5-FU concentration was 5.6, 8.3 and 20.8 times higher in the normal mucosa, lymph nodes, and the tumor tissue, respectively, than in the blood. The 5-FU concentration in gastric cancer and colorectal cancer tissues decreased with time after administration of UFT but remained above the effective concentration 1.5-7 hours after administration of 200 mg. The tissue concentrations of FT-207, uracil, and 5-FU were correlated with each other.