Brain tumours – Brain metastases
The standard treatment for patients with one or two brain metastases is removal by microsurgery. Yet microsurgery is not usually an option for patients with multiple metastases in delicate parts of the brain and those with an increased risk of problems associated with operations or anaesthetics. In these patients, radiosurgery is often the only effective alternative treatment. Numerous scientific studies confirm that the efficacy of radiosurgery is comparable with that of open microsurgery to remove tumours. Radiosurgical treatment causes either tumour shrinkage or stops tumour growth in the short term in 90 % of cases and in the long term in 80% of cases. As a rule, the onset of this effect comes 4 to 8 weeks after treatment.
Approximately 10% of patients may experience side-effects 4–12 months after treatment. This is generally local swelling in combination with enhanced contrast medium uptake in check-ups using magnetic resonance imaging (MRI). If the swelling causes other symptoms (in 5% of cases), this can usually be effectively treated with cortisone. If the patient does not have any symptoms or if the cortisone is successful, the doctor can generally wait but regular MRI check-ups at later dates are essential. Symptom-free reactions to the radiation do not require any specific treatment. In approximately 1-3% of cases, uncontrollable swelling occurs. This can lead to lasting neurological deficits. It may then be necessary for the patient to undergo an operation to remove the destroyed cancer tissue.
Restrictions on the method
Tumours larger than 3 cm represent a problem because they compress the adjacent tissue. An operation is the only option for short-term relief and creating the conditions necessary for symptoms to regress. Radiosurgical treatment is not indicated in such cases. Since the onset of side-effects depends on the total dose of radiation, there is also a limit on the number of tumours to be treated depending on their size. In principle, fewer large tumours or several small tumours can be treated in a single session.