Phase II study of radiochemotherapy with UFT and low-dose oral leucovorin in patients with unresectable rectal cancer.

Purpose: To determine the activity and evaluate the toxicity of uracil and tegafur in a 4:1 molar concentration (UFT) plus low-dose leucovorin administered concomitantly with pelvic irradiation in patients with unresectable or recurrent rectal cancer.
Methods and Materials: Thirty-five patients (22 with primary unresectable tumors and 13 with locally recurrent tumors) were enrolled in the trial. Thirty-five patients were evaluable for toxicity and 32 of these were evaluable for clinical response. Patients received 300 mg/m2/day UFT and 30 mg/day leucovorin on days 8-35 concomitantly with pelvic radiotherapy, to a total dose of 45 Gy.
Results: Eight of the 35 (23%) patients developed Grade 3 diarrhea and were treated with radiotherapy alone after this event. Of the 22 patients with unresectable primary tumors, 17 underwent surgery, and resection was feasible in 15 cases (88%). Of the 32 patients evaluable for clinical response, 4 (13%) had a complete clinical response (CR) and 22 (69%) a partial response (PR). A complete pathologic response was observed in 3 cases (18%) and, a PR in 11 cases (65%).
Conclusion: The response rates achieved with this schedule seem comparable to those obtained with 5-FU and radiotherapy. These results warrant further evaluation of this combination in patients with unresectable or locally advanced tumors.