Dose KRAS mutation status affect on the effect of VEGF therapy in metastatic colon cancer patients?

Abstract

Purpose: Mutations affecting the KRAS gene are an established negative predictor for antiepidermal growth factor receptor (anti-EGFR) therapies in metastatic colorectal cancer (CRC). However, the role of KRAS mutation as a biomarker for anti-vascular endothelial growth factor (VEGF) remains controversial. Materials and Methods: We analyzed retrospective data from 32 CRC patients who were available for KRAS mutation status and received cytotoxic chemotherapy plus bevacizumab as a first-line therapy. Six of 32 patients received anti-EGFR therapies. We used KRAS mutation status as a predictive or prognostic factor in CRC patients receiving bevacizumab. Results: We observed mutations in KRAS in 59.4% of patients. Bevacizumab was used in combination with oxaliplatin based regimens. There was no significant difference for progression free survival (PFS) and overall survival (OS) in patients with oxaliplatin based cytotoxic chemotherapy plus bevacizumab according to the status of KRAS mutation. After first-line therapy, 28 patients (87.5%) received second-line therapy. In univariate analysis, KRAS mutations did not have a major prognostic value for PFS (hazard ratio, 1.007; 95% confidence interval [CI], 0.469 to 2.162; p > 0.05) or OS (hazard ratio, 0.548; 95% CI, 0.226 to 1.328; p > 0.05). In addition, anti-EGFR therapies did not affect the impact on OS. Conclusion: KRAS mutation is neither a predictive for bevacizumab nor a prognostic for OS in CRC patients receiving anti-VEGF therapy. © 2014 by the Korean Cancer Association.