Cumulative Incidence of Thromboembolism and Prognostic Impact of Stroke in BRAF V600E-mutant Non-small-cell Lung Cancer

Background/Aim: Cancer and ischemic stroke are closely associated. Thromboembolism susceptibility in lung cancer may differ depending on oncogenic alterations. However, the clinical characteristics of thromboembolism in patients with BRAF-mutant non-small-cell lung cancer remain unknown. Thus, this study aimed to evaluate the cumulative incidence of thromboembolism in this population and describe such cases in detail. Patients and Methods: We retrospectively investigated consecutive patients with BRAF V600E-mutant non-small-cell lung cancer. Cumulative incidence was calculated using a competing risk analysis. Results: Of 10 patients with BRAF-V600E mutant lung cancer, five developed a total of seven thromboembolic events, showing a 1-year cumulative incidence of 43% (95% confidence interval=11-72%). These events consisted of four cancer-related stroke (CRS) events and three venous events including deep vein thrombosis or pulmonary embolism. Of note, most of the early thrombotic events were CRS. Two patients with CRS had multiple brain infarctions during anticancer drug therapy, characterized by high D-dimer levels, resulting in short-term mortality (13 and 22 days after stroke onset). Conclusion: A substantial proportion of patients with BRAF V600E-mutant lung cancer experienced thromboembolism during their disease course. CRS of undetermined source may predict a worse prognosis in this population.