Intensive Systemic Chemotherapy Combined With Surgery for Metastatic Colorectal Cancer: Results of a Phase II Study

Abstract

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. Forty-seven patients with resectable metastases of colorectal cancer were prospectively enrolled onto this study. Treatment consisted of six cycles of leucovorin 400 mg/m², oxaliplatin 130 mg/m² in a 120-minute infusion, and fluorouracil (FU) 2,400 mg/m² in a 46-hour infusion, every 2 weeks (FOLFOX-7), followed by six cycles of leucovorin 400 mg/m², irinotecan 180 mg/m² in a 90-minute infusion, bolus FU 400 mg/m², and FU 2,400 mg/m² 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). 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. 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.