Purpose: To evaluate the efficacy and tolerability of the metastatic irinotecan plus oxaliplatin (MIROX) strategy (adjuvant FOLFOX-7 followed by FOLFIRI), in patients with resectable metastatic colorectal cancer.
Patients and methods: Forty-seven patients with resectable metastases of colorectal cancer were prospectively enrolled onto this study. Treatment consisted of six cycles of leucovorin 400 mg/m(2), oxaliplatin 130 mg/m(2) in a 120-minute infusion, and fluorouracil (FU) 2,400 mg/m(2) in a 46-hour infusion, every 2 weeks (FOLFOX-7), followed by six cycles of leucovorin 400 mg/m(2), irinotecan 180 mg/m(2) in a 90-minute infusion, bolus FU 400 mg/m(2), and FU 2,400 mg/m(2) as a 46-hour infusion, every 2 weeks (FOLFIRI). Surgery was performed before chemotherapy in 25 patients and after six cycles of FOLFOX-7 in 22 patients (six cycles of FOLFIRI were administered after surgery).
Results: All but one of the patients underwent curative surgery. Two patients refused postoperative chemotherapy. Tolerability was generally good. The main toxicities were grade 3 to 4 neutropenia (13%) and thrombocytopenia (11%); no febrile neutropenia or bleeding occurred, and there were no deaths caused by toxicity. Two pathologically confirmed complete responses and 15 partial responses were obtained with FOLFOX-7 in the 22 patients who received this regimen before surgery (overall response rate, 77%; 95% CI, 68 to 86). The median disease-free survival time was 21 months; the median overall survival has not yet been reached. The 2-year overall and disease-free survival rates were 89% and 47%, respectively.
Conclusion: The MIROX strategy is feasible and well tolerated by patients with resectable metastatic colorectal cancer. Progression-free and overall survival rates are promising, with a median of 38 months of follow-up. This strategy currently is being compared with the leucovorin and FU regimen in a phase III trial.