This phase III clinical trial evaluated the impact on disease-free survival (DFS) of adding oxaliplatin to bolus weekly fluorouracil (FU) combined with leucovorin as surgical adjuvant therapy for stage II and III colon cancer.

Patients who had undergone a potentially curative resection were randomly assigned to either FU 500 mg/m2 intravenous (IV) bolus weekly for 6 weeks plus leucovorin 500 mg/m2 IV weekly for 6 weeks during each 8-week cycle for three cycles (FULV), or the same FULV regimen with oxaliplatin 85 mg/m2 IV administered on weeks 1, 3, and 5 of each 8-week cycle for three cycles (FLOX).

A total of 2,407 patients (96.6%) of the 2,492 patients randomly assigned were eligible. Median follow-up for patients still alive is 42.5 months. The hazard ratio (FLOX v FULV) is 0.80 (95% CI, 0.69 to 0.93), a 20% risk reduction in favor of FLOX (P < .004). The 3- and 4-year disease-free survival (DFS) rates were 71.8% and 67.0% for FULV and 76.1% and 73.2% for FLOX, respectively. Grade 3 neurosensory toxicity was noted in 8.2% of patients receiving FLOX and in 0.7% of those receiving FULV (P < .001). Hospitalization for diarrhea associated with bowel wall thickening occurred in 5.5% of the patients receiving FLOX and in 3.0% of the patients receiving FULV (P < .01). A total of 1.2% of patients died as a result of any cause within 60 days of receiving chemotherapy, with no significant difference between regimens.

The addition of oxaliplatin to weekly FULV significantly improved DFS in patients with stage II and III colon cancer. FLOX can be recommended as an effective option in clinical practice.