Metastatic Brain Tumours
A ‘Secondary’ or Metastatic tumour is defined as a tumour which has spread distantly from the original or ‘Primary’ cancer site, through the blood circulation, lymphatic system or spinal fluid. This can involve either a single lesion (Metastasis) or multiple tumours (Metastases). Metastases can in theory spread to any point in the body, but for the purposes of Gamma Knife, only brain metastases are suitable for treatment.
As they are defined by the spread of tumours from one organ to another, metastases are different from ‘Primary’ brain tumours, which are tumours that start within the tissues of the brain. This is an important factor, as treatment options for Primary and Metastatic Brain tumours are often different.
These secondary tumours arise most commonly from primary carcinomas of the lung, breast, kidney, colon and melanomas of the skin, although it is possible for a number of other primary tumours to occasionally spread to the brain. Sex differences play a role with lung, colon and renal cancers accounting for 80% of metastatic brain tumours in men, and breast, lung, colon and melanoma cancers accounting for 80% of metastatic brain tumours in women. Independent of the Primary disease, successful results can be elicited from Gamma Knife Radiosurgery for metastases from a number of primary tumour sites.
Not all patients are suitable for Radiosurgery, as often it requires that there are only a low number of lesions within the head, all of which ideally are below a threshold volume, (as the larger the volume, the more healthy brain tissue will be treated). The location of the lesions within the brain may also play a deciding role in the most suitable treatment method for the patient. An important factor is also that any disease present in the rest of the body should be controlled, i.e. non-active.
Further information on brain metastases is available from:-