[Pharmacokinetic study in biochemical modulation therapy of UFT with leucovorin tablet]

Preoperative oral treatment with UFT and leucovorin tablet was performed. Pharmacokinetics, degree of degeneration in the tumor tissue and side effects were studied in 34 patients with colorectal cancer preoperatively given 400 mg/day of UFT with 20 mg/day of leucovorin tablet or 400 mg/day of UFT alone. Results were as follows; 1) there was no significant difference between UFTL group and UFT group regarding concentration of FdUMP in the tumor tissue. In UFTL group, concentration of FdUMP was higher in the tumor tissue of moderately differentiated adenocarcinoma than that of well differentiated adenocarcinoma. No significant differences regarding concentration of FdUMP were obtained between diploid and aneuploid groups. 2) TS inhibition rate in the tumor tissue was 66.8% in UFTL group and 53.2% in UFT group, and there was a significant difference between these two groups. TS inhibition rate in the tumor tissue was higher than that in the normal tissue either in UFTL group or UFT group. However, there were no significant differences of TS inhibition rates regarding differentiation of tumor tissue or DNA ploidy pattern. 3) Degree of degeneration of more than Grade 2 was not obtained in any patients of either UFTL or UFT group. 4) There was no change in blood laboratory data between before and after medication. Only one patient complained Grade 1 pruritus in UFTL group. These results suggest that oral biochemical modulation therapy of UFT with leucovorin tablet is effective because of pharmacokinetically high anti-tumor effect and minimal side effects.