Adjuvant therapy with fluorouracil and oxaliplatin in stage II and elderly patients (between ages 70 and 75 years) with colon cancer: subgroup analyses of the Multicenter International Study of Oxaliplatin, Fluorouracil, and Leucovorin in the Adjuvant Treatment of Colon Cancer trial.

Abstract

Oxaliplatin combined with fluoropyrimidine improves survival in patients with stage III colon cancer. However, adjuvant chemotherapy with oxaliplatin is controversial in stage II and elderly patients. We performed subgroup analyses of stage II and elderly patients randomly assigned fluorouracil with leucovorin (FL) ± oxaliplatin (FOLFOX4) in the Multicenter International Study of Oxaliplatin/Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer study. Comorbidities, severe adverse events, second cancers, management of relapse and death as a result of causes than other colon cancer were studied. Two thousand two hundred forty-six patients were enrolled. Overall, 899 patients had stage II disease, including 330 low-risk and 569 high-risk patients. A total of 315 patients were ages 70 to 75 years. For stage II patients, the hazard ratio (HR) for comparing FOLFOX4 with FL was 0.84 (95% CI, 0.62 to 01.14) for disease-free survival (DFS), 0.70 (95% CI, 0.49 to 0.99) for time to recurrence (TTR), and 1.00 (95% CI, 0.70 to 1.41) for overall survival (OS). There was no interaction between treatment and stage or age. Low-risk stage II patients did not benefit from oxaliplatin. In high-risk stage II patients, the HR comparing FOLFOX4 with FL was 0.72 (95% CI, 0.51 to 1.01) for DFS, 0.62 (95% CI, 0.41 to 0.92) for TTR, and 0.91 (95% CI, 0.61 to 1.36) for OS. In elderly patients, the HR comparing FOLFOX4 with FL was 0.93 (95% CI, 0.64 to 1.35) for DFS, 0.72 (95% CI, 0.47 to 1.11) for TTR, and 1.10 (95% CI, 0.73 to 1.65) for OS. The results of these subset analyses show no statistically significant benefit (OS and DFS) for the addition of oxaliplatin to FL as adjuvant treatment for either stage II and elderly patients.