Background and purposeChemoradiotherapy is increasingly used in the primary management of patients with loco-regionally advanced gastrointestinal (GI) cancer. Oral chemotherapy with uracil and tegafur (UFT) plus leucovorin (LV) may represent a convenient way of delivering protracted infusion of fluorouracil. Our goal was to evaluate the safety of UFT plus LV combined with radiation and determine the maximum-tolerated dose (MTD) and a recommended dose for further testing. Patients and methodsPatients with inextirpable GI cancer received escalating doses of UFT (starting at 300 mg/m2/d with 50 mg/m2/d increments between consecutive cohorts) and fixed doses of LV (90 mg/d). UFT and LV were given 5 days per week concurrently with radiation to 50Gy (2Gy/fraction). ResultsTwenty-five patients were treated, and 22 received the planned treatment. Three patients were withdrawn from treatment, two due to disease-progression and one due to toxicity. The MTD of UFT with radiation was 400 mg/m2/d with 90 mg/d of LV. Diarrhoea was the main dose limiting toxicity (DLT). Since some toxicity (3/12 DLTs) was seen in the expanded cohort at the level below, but none (0/9 DLT) at the starting level, the recommended dose chosen for further testing is 300–350 mg/m2/d depending upon the size of the target volume. ConclusionConcomitant chemoradiation with oral UFT plus LV is feasible and well tolerated and should be further investigated since tumour responses were frequently seen.