552P - Phase III Trial of Treatment Duration for Oral Uracil and Tegaful/Leukovorin Adjuvant Chemotherapy for Patients (PTS) with Stage IIB/III Colon Cancer: Result of JFMC33-0502

Abstract

ABSTRACT Background Treatment duration of adjuvant chemotherapy for colon cancer has been controversial while adjuvant chemotherapy is preferable for high risk colon cancer. Oral uracil and tegafur (UFT)/ leucovorin (LV) is widely used as a standard adjuvant chemotherapy regimen for colorectal cancer (CRC) in Japan. We conducted a phase III trial to investigate the optimal duration of adjuvant chemotherapy with UFT/LV for stage IIB/III colon cancer. Here, we report our preliminary results. Material and methods Pts with curatively resected stage IIB/III colon cancer (PS, 0 to 1; age, 20 to 75 years; no other therapy) were eligible for enrollment in this trial. Pts were registered within 6 weeks after surgery and were randomly assigned to receive UFT (300 mg/m2/day)/LV (75 mg/day) for 28 out of 35 days for 6 months (C arm) or for 5 consecutive days per week for 18 months (S arm). The sample size of pts was 840 (hazard ratio = 0.667, two-sided α = 0.05, β = 0.2). The primary endpoint was the disease-free survival (DFS) period, and the secondary endpoints were overall survival (OS) and safety. Results A total of 1071 pts were registered from 233 centers. No differences in the patient demographics were observed between the arms. Overall, 135, 114, 559, and 217 pts had stage IIB, IIIA, IIIB, and IIIC disease, respectively. A statistically significant difference in the DFS for the primary endpoint was not observed between the S arm and the C arm. The 3-year DFS was 74% in the S arm and 73% in the C arm. The 3-year OS was 95% in the S arm and 95% in the C arm. The 3-year DFS periods for the patients with stage IIB, IIIA, IIIB, and IIIC disease were 84%, 86%, 71%, and 66% in the S arm and 84%, 86%, 73%, and 59% in the C arm, respectively. The treatment regimens used in both arms were feasible. Conclusion The prolonged duration of adjuvant chemotherapy with UFT/LV for 18 months seemed to offer no significant superiority, compared with the standard 6-month treatment, and prolonging the duration of adjuvant chemotherapy was not useful. In terms of efficacy and feasibility, UFT/LV therapy for 6 months may be the best regimen for Japanese patients with stage IIB/III colon cancer. Disclosure: All the authors have declared no conflicts of interest. Disclosure All authors have declared no conflicts of interest.