Improved Overall Survival With Oxaliplatin, Fluorouracil, and Leucovorin As Adjuvant Treatment in Stage II or III Colon Cancer in the MOSAIC Trial

Purpose Three-year disease-free survival (DFS) was significantly improved in patients who had undergone resection with curative intent for stage II or III colon cancer who received bolus plus continuousinfusion fluorouracil plus leucovorin (LV5FU2) with the addition of oxaliplatin (FOLFOX4). Final results of the study, including 6-year overall survival (OS) and 5-year updated DFS, are reported. Patients and Methods A total of 2,246 patients were randomly assigned to receive LV5FU2 or FOLFOX4 for 6 months. The primary end point was DFS. Secondary end points were OS and safety. Results Five-year DFS rates were 73.3% and 67.4% in the FOLFOX4 and LV5FU2 groups, respectively (hazard ratio [HR] 0.80; 95% CI, 0.68 to 0.93; P .003). Six-year OS rates were 78.5% and 76.0% in the FOLFOX4 and LV5FU2 groups, respectively (HR 0.84; 95% CI, 0.71 to 1.00; P .046); corresponding 6-year OS rates for patients with stage III disease were 72.9% and 68.7%, respectively (HR 0.80; 95% CI, 0.65 to 0.97; P .023). No difference in OS was seen in the stage II population. The incidence of second noncolorectal cancers was 5.5% and 6.1% in the FOLFOX4 and LV5FU2 groups, respectively. Among patients receiving oxaliplatin, the frequency of grade 3 peripheral sensory neuropathy was 1.3% 12 months after treatment and 0.7% at 48 months. Conclusion Adding oxaliplatin to LV5FU2 significantly improved 5-year DFS and 6-year OS in the adjuvant treatment of stage II or III colon cancer and should be considered after surgery for patients with stage III disease. J Clin Oncol 27:3109-3116. © 2009 by American Society of Clinical Oncology