Leptomeningeal metastases: the future is now.

Leptomeningeal metastases (LM) constitute an involvement of cancer which is associated with marked morbidity and mortality. The contemporary diagnostic and therapeutic management of LM from solid tumors is reviewed. Therapeutic modalities including systemic therapies, cerebrospinal fluid (CSF)-directed therapies, and radiation therapy are discussed. This is to provide context for how the field of LM management may evolve in the near term. The future directions currently undergoing investigation for diagnostic, response assessment, and therapeutic purposes are highlighted. This is done within the context of the pathophysiology of the disease. Specifically the role of CSF circulating tumor cells and cell free circulating tumor DNA in diagnosis and response assement are reviewed. Novel therapeutic approaches across a range of modalities are discussed. Numerous ongoing studies which have the potential to alter the management of LM are referenced.