BRAF mutations predict poorer outcomes for colorectal cancer patients

This study examined the implications of having a BRAF mutation for patients with colorectal cancer that has spread (metastasized). 

Genetic analysis has been a useful development in cancer research. Analyzing patients’ genes can provide information on their risk for developing cancer, response to medication and predicted outcome if cancer has developed. For colorectal cancer the most common mutation is the KRAS gene, but mutations of the BRAF gene can also occur.

BRAF-mutated metastatic colorectal cancer is a cancer that has a mutated BRAF gene and that has spread beyond the colon or rectum. BRAF mutations occur in 5% to 11% of patients with metastatic colorectal cancer and have been linked to poorer patient outcomes. 

In this study 1,941 patients with metastatic colorectal cancer were genetically tested for BRAF mutations. Overall 92 patients (4.7%) had a BRAF mutations. These patients were compared with 423 patients with metastatic colorectal cancer but normal (non-mutated or wild-type) BRAF. Patients with a BRAF mutation were more likely to be older, female, have cancer on the right side of the colon or rectum, and have more aggressive tumors.

BRAF mutation was linked to altered spread of the cancer: less liver involvement and higher abdominal cavity involvement. The cancer spread to the peritoneum (the lining of the abdominal cavity) in 26% of patients with BRAF mutations compared to 14% of patients with normal BRAF. However, the cancer was less likely to spread to the liver in patients with BRAF mutations (60%) compared to patients with normal BRAF (80%).

Having a BRAF mutation increased the risk of death by 2 times compared to patients with normal BRAF. The average survival time after diagnosis of metastasis was 20 months for patients with the BRAF mutation compared to 47 months for patients with normal BRAF.  

The authors concluded that BRAF-mutations are associated with worse clinical outcome. They suggest that BRAF mutation testing could be used to predict patient outcome.

Consider talking to your doctor about genetic testing to help choose the best course of treatment for your cancer type.