Historically, the prognosis for patients with brain metastases was thought to be uniformly poor, which led to a purely palliative approach to treating the many patients diagnosed with this very common neurologic complication of cancer. In addition, brain metastases were previously considered a homogeneous disease, despite the myriad of tumors that could potentially spread to the brain and the observed variability in response to local and systemic therapies. Because physicians believed that the vast majority of patients with brain metastases would have uniformly poor outcomes, they adopted whole-brain radiation therapy (WBRT) as the standard of care: it is easy to administer, widely available, and effective at providing palliation.
Suh JH. Association of Molecular Marker Status With Graded Prognostic Assessment of Lung Cancer With Brain Metastases. JAMA Oncol. Published online November 17, 2016. doi:10.1001/jamaoncol.2016.3818