[A study of preoperative administration of 5'-DFUR in patients with colo-rectal cancer].

: For the purpose to assess tumor-selectivity of doxifluridine (5'-DFUR), an anticancer drug of fluorinated pyrimidine class, the authors conducted a clinical-pharmacological study with the drug. The subjects in the present study, 26 patients with colorectal cancer received surgeries, were preoperatively administered 5'-DFUR orally at either doses of 800 or 1,200 mg/day for 3 days followed by oral administration of the drug at a dose of 400 mg 4-6 hrs before operation. The tissues were collected from specimens removed at operations and we measured both the activities of pyrimidine nucleoside phosphorylase (PyNPase), an activating enzyme for 5'-DFUR, and 5-FU concentrations in the tissue samples. The PyNPase activities showed higher levels in tumor tissues and regional lymph nodes than in normal tissues adjacent to the tumors. The 5-FU concentrations were: 102.7 ng/g in tumor tissues, 12.5 ng/g in normal tissues adjacent to the tumors, 97.6 ng/g in metastatic lymph nodes, and 7.3 ng/g in normal lymph nodes. In other words, the 5-FU concentrations were significantly (p < 0.01) higher in either of tumor tissues and metastatic lymph nodes than in the rests. The 5-FU concentrations in the sera were also extremely low. The results above clearly indicate that 5'-DFUR has a high selectivity for tumors.