Purpose: Oral adjuvant uracil and tegafur plus leucovorin (UFT/LV) is not inferior to standard weekly fluorouracil and folinate for stage II/III colon cancer. However, protein-bound polysaccharide K (PSK) has been evaluated as postoperative adjuvant therapy for colorectal cancer. This report is the first of MCSGO-CCTG, which compared UFT/LV to UFT/PSK as adjuvant chemotherapy for stage IIB or III colorectal cancer in patients who had undergone Japanese D2/D3 lymph node dissection. Methods: The primary endpoint was the 3-year disease-free survival (DFS). A randomized non-inferiority study compared UFT/LV to UFT/PSK. The overall survival, adverse events, compliance, and quality of life were also investigated as the secondary endpoints. Results: Between March 2006 and December 2010, 357 patients were randomized to UFT/PSK (n = 178) or UFT/LV (n = 179) (median age 65 years, colon/rectum 67.4/32.6%, stage IIB/IIIA/IIIB/IIIC 11.1/15.7/55.0/18.2%). The 3-year DFS rate was 82.3% in those receiving UFT/LV and 72.1% in those receiving UFT/PSK. The non-inferiority of UFT/PSK adjuvant therapy to UFT/LV therapy was not verified (−9.06%, 90% confidence interval −17.06 to −1.06%). The 3-year overall survival rate was 95.4% in those receiving UFT/LV and 90.7% in those receiving UFT/PSK. Conclusions: As adjuvant chemotherapy for stage IIB and III colorectal cancer patients, UFT/PSK adjuvant therapy was not non-inferior to UFT/LV therapy with respect to the DFS.
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