Benefit of Bevacizumab-Based Frontline Therapy in Patients with Metastatic Colorectal Cancer (mCRC): a Turkish Oncology Group Study.

BACKGROUND: Several chemotherapy regimens using bevacizumab have been developed. Our goal was to investigate regimens that have demonstrated significant clinical activity in patients with metastatic colorectal cancer (mCRC).

MATERIALS AND METHODS: Six hundred and sixty six patients with mCRC who received first-line chemotherapy combination with bevacizumab were studied. Fluoropyrimidine (F) plus irinotecan (I)-based (FI-bev), F plus oxaliplatin (O)-based (FO-bev), and F-based (F-bev) treatment regimens were compared with respect to progression-free survival (PFS) and overall survival (OS).

RESULTS: The median PFS of FI-bev (n = 414) was 10.9 months (95 % CI 10-11.8), of FO-bev (n = 211) was 9.4 months (95 % CI 8.3-10.4), and of F-bev (n = 41) was 9.5 months (95 % CI 5.9-13.1) (p = 0.089). The median OS of FI-bev was 26.3 months (95 % CI 21.7-30.9), of FO-bev was 27 months (95 % CI 24.3-29.7), and of F-bev was 23.3 months (95 % CI 12.7-33.9) (p = 0.102). In KRAS wild-type patients, the median PFS of FI-bev group was significantly longer than FO-bev group (10.5 vs. 9.1 months, p = 0.006). The FI-bev group had better OS than FO-bev group with borderline significance (p = 0.058). The FI-bev group had significantly longer OS than F-bev group. Patients who underwent metastasectomy or those with Eastern Cooperative Oncology Group performance status (ECOG-PS) ≤1 had longer PFS and OS independent of the type of chemotherapy regimen.

CONCLUSION: FI-bev may be the preferred frontline regimen for patients with KRAS wild-type mCRC. Metastasectomy and performance score were the strongest positive predictors of OS and PFS regardless of backbone chemotherapy regimen.