The Role of Oxaliplatin for Localized Disease
Based on the results of several studies, oxaliplatin does not appear to add any benefit in terms of primary tumor response, but it has been associated with increased acute treatment-related toxicity.
Oxaliplatin has significant activity when combined with 5-FU-LV in patients with metastatic colorectal cancer. In the randomized Multicenter International Study of Oxaliplatin/5-Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer (MOSAIC) study, the toxic effects and efficacy of FOLFOX4 (a 2-hour infusion of 200 mg/m2 LV, followed by a bolus of 400 mg/m2 5-FU, and then a 22-hour infusion of 600 mg/m2 5-FU on 2 consecutive days every 14 days for 12 cycles, plus a 2-hour infusion of 85 mg/m2 oxaliplatin on day 1, given simultaneously with the LV) were compared with the same 5-FU-leucovorin regimen without oxaliplatin when administered for 6 months. Each arm of the trial included 1,123 patients.
Preliminary results of the study, with 37 months of follow-up, demonstrated a significant improvement in DFS at 3 years (77.8% vs. 72.9%; P = .01) in favor of FOLFOX4. When initially reported, there was no difference in OS.[Level of evidence: 1iiDii] Further follow-up at 6 years demonstrated that the OS for all patients (both stage II and stage III) entered into the study was not significantly different (OS = 78.5% vs. 76.0%; HR, 0.84; 95% CI, 0.71–1.00). On subset analysis, the 6-year OS in patients with stage III colon cancer was 72.9% in the patients receiving FOLFOX and 68.9% in the patients receiving 5-FU/LV (HR, 0.80; 95% CI, 0.65–0.97, P = .023).[Level of evidence: 1iiA] Patients treated with FOLFOX4 experienced more frequent toxic effects, consisting mainly of neutropenia (41% >grade 3) and reversible peripheral sensory neuropathy (12.4% >grade 3). These results are still preliminary, and additional information with regard to OS is anticipated. Nevertheless, these data suggest that FOLFOX4 may be a therapeutic option for patients with resected stage III colon cancer.
The results of the now completed NSABP C-07 study confirmed and extended the results of the MOSAIC trial. In NSABP C-07, 2,492 patients with stage II or III colon cancer were randomly assigned to receive either FLOX (2-hour intravenous infusion of 85 mg/m2 oxaliplatin on days 1, 15, and 29 of each 8-week treatment cycle, followed by a 2-hour intravenous infusion of 500 mg/m2 LV plus bolus 500 mg/m2 5-FU 1 hour after the start of the LV infusion on days 1, 8, 15, 22, 29, and 36, followed by a 2-week rest period, for a total of three cycles [24 weeks]) or the same chemotherapy without oxaliplatin (Roswell Park regimen). The 3- and 4-year DFS rates were 71.8% and 67% for the Roswell Park regimen and 76.1% and 73.2% for FLOX, respectively. The hazard ratio was 0.80 (95% confidence interval [CI], 0.69–0.93), a 20% risk reduction in favor of FLOX (P <.004).