The 'real-life' impact of adding bevacizumab to first-line therapy in metastatic colorectal cancer patients: A large Israeli retrospective cohort study

Background. After a decade of extensive use, the actual contribution of bevacizumab in first-line treatment of metastatic colorectal cancer (mCRC) is still unclear. Objective. To evaluate 'real-life' outcomes of patients with mCRC before and after the introduction of bevacizumab to standard mCRC first-line practice. Methods. Using the computerized administrative database of Clalit Health Services' (CHS), Israel's largest health care provider, we retrospectively compared two cohorts (n = 1739): (A) all CHS' patients diagnosed with mCRC between January 2000 and December 2004 that received first-line irinotecan or oxaliplatin-based combination chemotherapy (before bevacizumab was introduced) (n = 1052), and (B) all patients that started first-line irinotecan or oxaliplatin combination chemotherapy together with bevacizumab between September 2006 and December 2009 (after bevacizumab was fully reimbursed in Israel for mCRC first-line therapy) (n = 687). The primary endpoint was overall survival (OS) and secondary endpoints were first-line progression-free survival (PFS) and metastatectomy rates. Results. Median OS was longer in Cohort B than in Cohort A [23.0 months vs.15.0, adjusted hazard ratio (HR), 0.75]. Secondary outcomes were also better; PFS of 14.0 months vs. 9.8 in the earlier period (HR, 0.75) and metastatectomy rate of 8.1% versus 3.9%. The longer OS in Cohort B was preserved even after controlling for latter-line epidermal growth factor receptor (EGFR) inhibitor use (HR = 0.77). Conclusion. In this analysis, OS, PFS and metastatectomy rates of first-line treatment of mCRC were significantly higher in the later period of the study. These results, derived from 'real-life' practice, suggest that the use of bevacizumab, among other alterations in the clinical management of mCRC between the two periods, might have had a significant contribution to these outcomes, and may therefore support the current practice of adding bevacizumab to first-line treatment of mCRC.