With the advent of effective therapies for systemic disease control, the prevalence of brain metastases (BMs) has been increasing.

Relapses in the brain are a major barrier to cure in many patients with lung cancer and other malignancies. Effective agents are needed to prophylactically treat micrometastatic disease in patients at high risk for BMs, thereby reducing the incidence.

In this report, we review the pathogenesis of and clinical risk factors for BMs, obstacles to BM treatment, and BM chemoprevention in lung cancer, breast cancer, melanoma, and renal cell carcinoma.