UFT and oral leucovorin as radiation sensitizers in rectal and other gastrointestinal malignancies.

UFT is the combination of the fluorouracil (5-FU) prodrug tegafur, and the dihydrophyrimidine dehydrogenase inhibitor uracil. UFT and leucovorin have been used in the oral treatment of a variety of malignancies. Given the radiosensitizing properties of UFT, its combination with radiation therapy is a logical step in the development of novel strategies for the treatment of gastrointestinal malignancies. Several phase I and phase II studies, described in this review, have attempted to substitute UFT for 5-FU in chemoradiation strategies for the treatment of patients with esophageal, pancreatic and rectal cancer. The results thus far suggest that this approach has acceptable toxicity and promising efficacy. Given the availability of the novel oral fluorinated pyrimidines and their efficacy in metastatic diseases, it remains to be determined whether 5-FU will eventually be substituted by oral fluorinated pyrimidines in the adjuvant and chemoradiation settings.