Clinical characteristics and course of 63 patients with BRAF mutant lung cancers

Introduction: Mutant BRAF is a driver oncogene found in 2% of lung adenocarcinomas and represents a target for therapy. We examined the clinical characteristics and course of patients with lung adenocarcinomas harboring BRAF mutations. Methods: We identified patients with lung adenocarcinomas harboring BRAF mutations between 2009 and 2013 detected using a mass spectrometry-based polymerase chain reaction genotyping assay of hot-spot mutations involving codons corresponding to amino acids V600, D594, and G469 of BRAF. Patient characteristics and treatment outcomes were analyzed. Overall survival (OS) was compared with stage-matched patients with KRAS and EGFR mutant lung adenocarcinomas. Results: Sixty-three patients were diagnosed with BRAF mutant lung adenocarcinomas between 2009 and 2013 (V600, 36; non-V600, 27). The majority of patients with BRAF mutations were smokers (92%), although patients with V600 mutations were more likely to be light/never-smokers compared with patients with non-V600 mutations (42% versus 11%; p = 0.007). Of the 32 patients with early-stage disease, six (19%; 95% confidence interval 7%-36%) developed second primary lung cancers harboring KRAS mutations. Patients with advanced V600 mutant lung adenocarcinomas had a better survival from diagnosis compared with those with non-V600 mutant lung adenocarcinomas (3-year OS: 24% versus 0%; p <0.001). Conclusions: This is the largest series of patients with BRAF mutant lung cancers described. Most patients were heavy smokers. Nineteen percent of patients with early-stage BRAF mutant lung cancers developed second primary lung cancers harboring KRAS mutations. Patients with advanced lung adenocarcinomas harboring V600 mutations have an improved OS compared with those with non-V600 mutations.