The MIROX Regimen: Intensive systemic chemotherapy combined with surgical treatment of colorectal cancer metastases. Results of a phase II study

Abstract

3592 Background: This work was designed to evaluate the efficacy and tolerance of adjuvant FOLFOX-7 followed by FOLFIRI (the MIROX strategy) in patients with resectable metastatic colorectal cancer. Methods: Forty seven patients with resectable colorectal cancer metastases were prospectively enrolled in this study between September 1999 and October 2001. The treatment consisted in six cycles of FOLFOX-7 (leucovorin 400 mg/m2, Oxaliplatin 130 mg/m2 and 5-FU 2400 mg/m2 as a 46-hour infusion, every two weeks), followed by six cycles of FOLFIRI (leucovorin 400 mg/m2, CPT11 180 mg/m2 in 90 min infusion, 5-FU 400 mg/m2 and 5-FU 2400 mg/m2 as a 46-hour infusion, every two weeks). Surgery was performed before chemotherapy (26 patients) or after the 6 cycles of FOLFOX7 (21 patients), 6 cycles of FOLFIRI being administered thereafter. Results: All but one patient underwent curative surgery and two pts refused post-operative chemotherapy. Tolerance was generally good. The most relevant toxicities were grade 3–4 neutropenia and thrombocytopenia, observed in 12 patients (25%), without any febrile neutropenia or bleeding event. No toxic death occurred. Two pathologically confirmed complete responses and 15 partial responses (overall response rate of 80%, CI: 69–88) occurred with FOLFOX-7 for the 21 patients receiving this regimen before surgery. The 2-year overall survival rate was 88%. The two year recurrence free survival was 51%. Conclusion: The MIROX strategy is feasible and well tolerated in patients with resectable metastatic colorectal cancer. Progression free and overall survivals, with a 25 months median follow up, are similar to those observed with the best therapeutic strategies currently available, though a longer follow-up is needed to confirm these results. This regimen is currently compared to a LV5-FU2 regimen in a randomized phase III study. No significant financial relationships to disclose.