What are metastatic brain tumours?
Brain metastases are the most common forms of brain cancer at a rate that is ten times higher than the intrinsic primitive brain tumours. About 10% of patients diagnosed with systemic cancer develop brain metastases at the central nervous system. The metastases from lung cancer are the most frequent, even though the frequency of breast cancer is growing, and melanoma presents the greater propensity than all systemic cancers that give rise to brain metastases. 80% of metastasis is localized to the hemispheres, 15% is localized at the level of the cerebellar, and 5% at the level of the bone.
What are the causes of brain metastases?
Brain metastases originate from the tumour cells born in other parts of the body that have spread to the brain where they can be localized in one or more locations.
What are the symptoms of brain metastases?
The symptoms of brain metastases are similar to that of any cancer of the nervous system and include epileptic seizures, headaches, and neurological deficit.
The diagnosis is initially made by a CT scan of the head, followed by a scan with contrast and more accurately with brain MRI, including basic MRI and MRI with contrast (gadolinium). Often patients with suspected diagnosis of metastasis undergo a total body CT scan with contrast medium or body PET scan with FDG purposes of systemic tumour staging.
The treatment of metastases depends on the number of metastases in the brain and the control of the primary tumour at the systemic level.
In patients with no evidence of a primary systemic tumour, surgery has the role to obtain a histological diagnosis of the disease and to remove metastases accessible with limited morbidity. In other cases a needle biopsy is performed (stereotactic) to obtain a histological diagnosis of the disease.
In patients with a managed systemic tumour, in the case of metastases of small size (up to 3 cm) there are no effective differences between radiosurgery and direct surgery on the metastases. Moreover, there are no differences in effect when radiosurgery is performed with an accelerator such as a Ciberknife or a Gamma knife.
Surgery has a specific role in the case of large, symptomatic metastases that are surrounded by significant oedema, and are accessible. After surgery the patient may be subjected to whole brain radiation, although recent studies (EORTC) have shown that the postponement of the WBRT does not change the overall survival of patients, it is associated with a faster rate of local or distant recurrence, but it improves the cognitive performance of the patient. The performance of focal radiotherapy post surgery, improves the local control of the disease and does not affect the cognitive performance of the patient.
In patients with a managed systemic tumour and various brain metastases (up to 3), surgery is performed in the case of large and accessible metastasis and it has a major effect in patients in good general condition. In all other cases, radiation therapy (radiosurgery) is recommended.
In patients with more than three metastases and in those with uncontrolled, systemic tumours, radiation treatment (whole brain) is the standard treatment.