Preoperative UFT administration for patients with advanced colorectal cancer--increased uptake of 5-fluorouracil by tumor tissue is a prognostic factor

Tegafur and 5-fluorouracil pelvic tissue concentrations in rectal cancer patients receiving preoperative chemoradiation

BACKGROUND AND PURPOSE

To investigate the presence of 5-Fluorouracil (5-FU) in pelvic tissue after oral administration of tegafur. To measure tegafur and 5-FU concentrations in normal rectal mucosa, perirectal fat and residual tumor in rectal cancer patients receiving preoperative chemoradiation. To correlate drug concentrations with cancer downstaging effects.

PATIENTS AND METHODS

Three tissue samples taken from 16 surgical specimens after recto-sigmoid resection were analyzed. Tegafur and 5-FU concentrations were measured using high-performance liquid chromatography. 16 patients with locally advanced rectal cancer were treated with preoperative pelvic irradiation (45-50 Gy) sensitized with oral tegafur (400 mg for every 8 hours daily). Seven patients received a precharge dose of tegafur (400 mg oral every 8 hours) 24 hours before surgery.

RESULTS

In 8 of the 9 patients who did not receive a precharge dose, detectable levels of tegafur were observed in fat tissue, normal mucosa and tumor, but detectable 5-FU levels were only observed in one patient. Mean concentrations (ranges) for tegafur in fat, normal mucosa and tumor in patients without the precharge dose were 72.19 (12.1-205.6), 179.53 (11.30-727.7) and 252.35 (27.9-874.6) ng/g, respectively; mean concentrations for 5-FU in the same samples were 0.95, 1.92 and 2.68 ng/g (1 patient), respectively. In patients receiving a tegafur precharge, both tegafur and 5-FU were present in all tissue samples with the exception of 2 fat samples, in which drug concentrations were undetectable. 5-FU levels were higher in tumor than other sites, with a median value of 68.24 ng/g (range 3.8-283.05 ng/g). Tegafur levels were also higher in tumor samples than other sites (mean 3446.53 ng/g, range 1044.5-7847.0 ng/g), except in 2 patients who had higher levels of tegafur in normal mucosa.

CONCLUSIONS

Tegafur and 5-FU are not always present in pelvic tissues 5 to 6 weeks after oral administration of tegafur. Both drugs were present in the tissues analyzed, in relevant concentrations, 24 hours after oral administration of tegafur. The data obtained suggest a tendency (not significant) toward a correlation between levels of 5-FU present in the residual tumor and cancer downstaging.

Animal model of para-aortic lymph node metastasis

The purpose of this study was to establish a model of experimental lymph node metastasis by intra-rectal implantation of human cancer cells in nude mice. Four types of human cancer cell lines (TE-1, MKN-45, HT-29, and MIAPaca-2) were investigated. Tumor cells suspended in Matrigel were injected into the submucosal layer of the rectum. All cancer cell lines produced locally aggressive rectal tumors and, subsequently, para-aortic lymph node metastasis. We were unable to produce other distant metastases in the dying state in such locations as the liver, spleen, lung, and peritoneum. However, using this method, we were able to evaluate the effect of the anti-cancer agent uracil/tegafur (UFT) on primary tumor growth and lymph node metastasis. Oral intake of UFT significantly suppressed implanted tumor volume and inhibited lymph node metastasis. We expect that the process of lymph node metastasis shown in this model will be studied as an experimental model of lymph node metastasis simulating human cancers.