[5-FU concentration in the tissues (tumor and lymph node) of breast cancer patients given preoperative administration of UFT and FT].

In 16 patients with breast cancer who were administered UFT or FT-207 (UFT: 9 cases, FT-207: 7 cases) for a were prior to surgery, we studied the concentrations of 5-FU in the blood and tumor tissues, and in normal and metastatic lymph nodes sampled during surgery. As a result, a high level of 5-FU was found in tumors, especially in metastatic lymph nodes, in the patients who were administered UFT. On the other hand, no significant difference was found between the 5-FU levels of blood in UFT- and FT-treated patients. These facts suggest that UFT can be expected to increase antitumor activity without side effects, especially in cases of metastatic lymph nodes.