Bevacizumab efficacy in metastatic colorectal cancer is dependent on primary tumor resection.

Purpose Bevacizumab plus fluoropyrimidine-based chemotherapy is standard treatment for first-line and second-line metastatic colorectal cancer (mCRC). However, to date, there is no current biomarker predictive for the benefit of bevacizumab use for these patients. Preclinical data suggest that the presence of the primary tumor could be involved in less efficient antitumor activity of antiangiogenic agents, but no clinical data currently support this hypothesis. Methods We performed a retrospective analysis of factors associated with overall survival (OS) in a study cohort of 409 mCRC patients. Univariate and multivariate Cox proportional hazard regression models were used to assess the infl…