Preface on “Emerging treatment options for brain metastases from non-small cell lung cancer”

Significant progress in the treatment of advanced non-small cell lung cancer (NSCLC) became first evident with the recognition that certain molecular subtypes (e.g., EGFR-mutant or ALK-rearranged tumors) could tremendously benefit from sequential treatment with small molecules tyrosine-kinase inhibitors (TKIs). In fact, an unprecedented median survival of more than 24 months has been reported in patients with oncogene-addicted disease when appropriate targeted therapies are used (1,2). More recently, the introduction of immunotherapy for use after failure of platinum-based chemotherapy has significantly improved the survival of some patients with no identifiable driver mutations (3), and future treatment landscape is rapidly evolving in order to incorporate immunotherapy in the front-line setting (4,5). Having made this preliminary remark, the downside of the improved survival experienced by patients has led to a significant increase in the spread of the disease to the brain, a phenomenon which already affects nearly one third of advanced NSCLCs at diagnosis. On the other hand, frequent use of serial CT scan or MRI of the brain for tumor (re-) staging has significantly contributed to the increased detection of brain metastases (BMs), especially when asymptomatic. Once developed, BMs predictably represent an important cause of morbidity and mortality in NSCLC patients, and counteracting strategies against BMs are crucial in this context.