[5-FU concentration in brain tumors after co-administration of FT and uracil]

Nineteen patients with brain tumors were orally administered 300 mg of UFT (a combination of FT and uracil with a molar ratio being 1:4) before operation and the concentrations of FT, 5-FU and Uracil in tumors and serum were measured by chemical assay. Time course of FT in serum rapidly attenuated, but 5-FU was kept almost constant below 0.014 micrograms/ml. T/B ratio (5-FU in tumor/5-FU in blood) in 11 samples of meningioma was 6.86 +/- 3.67, while in 8 samples obtained from glioblastoma was significantly higher (23.79 +/- 11.43, p less than 0.001). In malignant brain tumors there was a correlation between the concentration of 5-FU and Uracil in tumor (gamma = 0.67). This correlation was more enhanced when the value of Uracil in tumor was over 15 micrograms/g (gamma = 0.81). The concentration of 5-FU in cyst was low, but tended to accumulated later. This result may be based on the diffusion of 5-FU from the surrounding solid part of tumor into the cyst. Our present study demonstrated that enhancing effect of 5-FU in brain tumors, particularly solid malignant glioma, was yielded after oral administration of UFT.