"A recent trial presented in the ASCO 2015 meeting has shown that whole brain radiation therapy did not improve the overall survival for those patients with a limited number of brain metastases, besides the fact it is related to a neurocognitive impairment."
"Although we tend to think of cerebral metastases as being multiple, approximately 50% are seemingly solitary at diagnosis and in a minority of cases no known or identifiable malignancy is present.4 They often occur at the grey-white matter junction or in the arterial watershed areas."
"Typically metastases are relatively well demarcated from the surrounding parenchyma and usually there is a zone of peritumoural oedema out of proportion with the tumour size."
"Parenchymal blood flow is an important determinant of the distribution of metastases: 80% of metastases localize to the cerebral hemispheres, 15% localize to the cerebellum and 3% localize to the basal ganglia.8 Often these tumours can be found at the gray/white matter junction."
Cerebral metastases [Radiopaedia]
http://radiopaedia.org/articles/cerebral-metastases