Background and methods: Brain metastases are far more common than primary central nervous system tumours. Based on our own clinical experiences and relevant literature published over the last decade (Medline), we present an overview of diagnosis and treatment.
Results: Brain metastases are caused by haematogenous spread from extracranial tumours, most frequently from cancers in the lung, breast, melanoma, renal carcinomas and colorectal carcinomas. Three out of four patients present with multiple brain metastases. Cerebral MR is the most sensitive investigation. The most important prognostic factors for survival are Karnofsky score, age < 65, well controlled primary cancer and absence of systemic cancer disease.
Interpretation: Some patients are offered neurosurgical treatment (surgery or gamma knife), depending on their clinical status, the number and location of brain metastases, and the histology and degree of systemic involvement of the primary tumour. The gamma knife is the treatment of choice with multiple and solitary tumours smaller than 3 cm that lie deep within the brain or within eloquent areas, whereas surgery is the treatment of choice with solitary metastases larger than 3-3.5 cm that are surgically accessible and cause significant mass effects. Solitary lesions without significant mass effect can be treated with either technique, as their documented efficacies are similar. However, the gamma knife is often preferred since this method is rapid, less invasive, has low morbidity and shortens the hospital stay.