[Determination of 5-FU tissue concentrations after oral UFT administration in tumors of the head and neck].

We determined the 5-FU concentrations in the tumor tissue, normal tissue surrounding the tumor, metastatic lymph nodes, normal lymph nodes, and serum after oral UFT administration to 26 patients with primary squamous cell carcinoma in the head and neck. The 5-FU concentration was mean 0.20 +/- 0.13 micrograms/g in the tumor tissue and mean 0.14 +/- 0.08 micrograms/g in the metastatic lymph nodes. The 5-FU concentrations in the tumor tissue and metastatic lymph nodes were significantly higher than in the corresponding normal tissue surrounding the tumor and normal lymph nodes. In addition, the 5-FU concentration was significantly higher in the tumor tissue than in the metastatic lymph nodes. No significant differences were observed in the 5-FU concentration according to the sites of the primary tumor. However, the difference in the 5-FU concentration between the tumor and normal tissues was smaller in tongue cancer than in pharyngeal cancer.