Real-World Outcomes of Patients With BRAF-Mutated Metastatic Colorectal Cancer Treated in the United States

Abstract

BRAF mutations portend a poor prognosis in metastatic colorectal cancer (mCRC). Whether these patients may benefit from more aggressive frontline chemotherapy with a triplet regimen such as FOLFOXIRI remains unclear. We used real-world data from a cohort of patients in the United States to assess the BRAF testing rate, determine the prevalence of FOLFOXIRI use, and compare survival outcomes in mCRC, stratified by BRAF mutation status and first-line therapy. A nationwide electronic health record-derived deidentified database was reviewed for patients diagnosed with mCRC between 2013 and 2018. Those with documented BRAF mutation testing who received standard first-line therapy were included. Kaplan-Meier estimates with corresponding log-rank tests and Cox proportional hazards modeling compared survival outcomes stratified by BRAF status and first-line therapy. Of 4,457 included patients, 3,991 (89.5%) had BRAF wild-type (BRAFwt) and 466 (10.5%) had BRAF-mutated (BRAFmt) mCRC. Median overall survival (OS) was 15.4 months in the BRAFmt group versus 28.1 months in the BRAFwt group (hazard ratio [HR], 0.48; 95% CI, 0.41-0.56; P<.001). Only 3% of patients with BRAF mutations received first-line FOLFOXIRI ± bevacizumab, with a median OS of 13.8 months compared with 15.5 months in those treated with doublet chemotherapy ± bevacizumab (P=.38). In patients with BRAF mutations, propensity-weighted analysis did not detect a significant improvement in OS with FOLFIRI + bevacizumab (HR, 0.90; 95% CI, 0.58-1.39; P=.63) or FOLFOX/CAPEOX + bevacizumab (HR, 0.81; 95% CI, 0.52-1.26; P=.35) versus doublet chemotherapy alone. In 2018, only 56% of patients diagnosed with mCRC had documented BRAF testing at any time. This real-world data analysis confirms the negative prognostic impact of BRAF mutations in mCRC and suggests that FOLFOXIRI has not been widely adopted in the United States. The proportion of patients with documented BRAF testing in this real-world population was low at 56%. We were unable to show any significant difference in OS of patients with BRAFmt mCRC based on the first-line therapy received.