Case Report: Vemurafenib Treatment in Brain Metastases of BRAF(S365L)-Mutant Lung Papillary Cancer by Genetic Sequencing of Cerebrospinal Fluid Circulating Tumor DNA Detection

BRAF mutations, primarily sensitizing mutations, such as BRAF(V600E), have been proven to response to the BRAF inhibitor, Dabrafenib combined with trametinib therapy, but there have been no data demonstrating that it has activity against NSCLC-related brain metastases (BM). How patients harboring BRAF(S365L) mutation (a rare mutation following BRAF(V600E)-inhibitor treatment) in NSCLC is unknown. Vemurafenib, another BRAF inhibitor, can reverse the resistance that develops with the BRAF(S365L) mutation following dabrafenib combined with trametentinib treatment in melanoma, but none has been reported in NSCLC. Lung papillary cancer, as a rare typing, occupies about 4% of NSCLC. Hence, we reported the first case of a patient with BM of lung papillary carcinoma harboring a BRAF(V600E) mutation who benefited from dabrafenib combined with trametinib, and following the development of the BRAF(S365L) mutation, vemurafenib remained an effective therapeutic option. Moreover, we found that the next-generation sequencing (NGS) of cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) may potentially provide more accurate information about intracranial lesions than ctDNA in the blood serum, which will be a better detection method.