BACKGROUND AND OBJECTIVES

In metastatic colorectal cancer, v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) is a predictive biomarker for anti-epidermal growth factor receptor (EGFR) treatment and V-raf murine sarcoma viral oncogene homolog B1 (BRAF) is a prognostic biomarker. We aimed to determine the impact of KRAS and BRAF mutation as determined from liver metastases specimens on overall survival (OS) in patients following colorectal liver metastasectomy.

METHODS

Liver metastases specimens (n = 292) obtained from patients after liver metastasectomy were used to determine the KRAS/BRAF genotype. Associations between clinicopathological parameters and KRAS/BRAF genotype were identified by univariate and multivariate analyses using the Cox proportional hazards model. The impact of KRAS/BRAF genotype on survival was analyzed using the Kaplan-Meier method.

RESULTS

The 5-year survival rate of the cohort was 55.8%. The KRAS and BRAF mutation rates were 38.0 and 2.1%, respectively. BRAF genotype, but not KRAS, was found to be an independent prognostic biomarker (HR = 5.181, P = 0.002) after adjustment for other significant confounding clinicopathological variates: Number of liver metastases (HR = 1.983, P = 0.009), concomitant extrahepatic disease (HR = 1.858, P = 0.014), and surgical margin (HR = 3.241, P < 0.001). BRAF genotype was an independent prognostic biomarker in patients with liver metastases only after metastasectomy (HR = 6.245, P < 0.003).

CONCLUSIONS

BRAF mutation is an independent prognostic biomarker for colorectal liver metastasectomy.