Randomized phase III trial comparing surgery alone to UFT + PSK for stage II rectal cancer (JFMC38 trial)

BACKGROUND: We conducted a randomized phase III trial comparing tegafur/uracil (UFT) and Polysaccharide-K (PSK) to surgery alone in curatively resected stage II rectal cancer patients. METHODS: Patients were randomly assigned to receive either UFT and PSK or surgery alone in a 1:1 ratio with a minimization method to balance the treatment allocation. The primary end point of this study was the disease-free survival (DFS). The secondary end point was the overall survival (OS). RESULTS: From October 2011 to February 2013, 111 patients were registered from 62 institutions. The study was prematurely closed due to poor accrual after reaching 20% of its goal. The patients’ characteristics were similar between the UFT and PSK group and the surgery-alone group. The DFS rate was 76.0% at 3 years and 65.1% at 5 years in the UFT and PSK arm and 84.0% at 3 years and 77.2% at 5 years in the surgery-alone arm. The DFS was slightly worse in the UFT + PSK arm than in the surgery-alone arm, but the difference did not reach statistical significance (log rank p = 0.102). The OS rate was 100% at 3 years and 97.9% at 5 years in the UFT + PSK arm, while that was 100% at 3 years and 93.4% at 5 years in the surgery-alone arm. The OS was similar in the UFT + PSK arm and surgery-alone arm (p = 0.533). CONCLUSION: The present study suggests that UFT and PSK are not attractive candidates to advance to the next phase III study because the DFS was slightly worse in the UFT and PSK arm than in the surgery-alone arm.