A secondary brain tumour develops when cancer cells spread to the brain from another part of the body. Another term for this is a brain metastasis. The cells can spread from any type of primary cancerous tumour, but the most common types include lung, breast, bowel, skin, and kidney cancer.
What are the symptoms of a secondary brain tumour?
The symptoms of brain metastases are similar to those of any brain tumour. The most common symptoms include headaches, unexplained changes in behaviour and mood swings, nausea, memory loss and confusion, tiredness, muscle weakness or numbness, particularly on one side of the body, and seizures.
The symptoms are caused by the brain tumour (there may be one, or multiple tumours) placing pressure on the brain tissue, which causes malfunctions. Anyone experiencing these symptoms persistently should consult a doctor, especially if they have already had a diagnosis of primary cancer at another site in the body.
What are the causes of a secondary brain tumour?
Brain metastases develop when the cancer cells at the primary site break away from the tumour, and travel through the lymphatic system or bloodstream to the brain. Any type of primary cancer may be the original cause, but some types, such as breast, bowel, and kidney cancer, are more frequent causes of brain metastases.
How are they diagnosed?
If your doctor suspects brain metastases, you may be referred for a neurological exam. This will involve checking your vision, balance, hearing, coordination, and reflexes.
You may them be referred for a magnetic resonance imaging (MRI) scan, or a computerised tomography (CT) scan. Both these scans involve taking multiple images of the inside of your brain, which are then pieced together to form a 3D image. This allows doctors to have a precise knowledge of the size, shape, and location of the tumours.
A sample of the tumour may be taken for a biopsy, which will be used to confirm if the cells are cancerous or not.
What types of brain metastases treatment are there?
The treatment may depend on what type of primary cancer you have, and how this has been treated. It will also depend on the size and location of the brain tumours, and your overall state of health.
You may be offered stereotactic radiotherapy (SRT), which involves applying a strong dose of radiation from an external machine. The radiation beam is precisely targeted, to destroy the abnormal tissues and cause as little damage as possible to the surrounding tissue. One type of SRT is known as Gamma Knife surgery.
This does not involve a traditional surgical procedure with a knife. Rather, it is a method of applying a strong and highly focused dose of radiation from multiple angles at once. This maximises the deliberate damage done to the cancerous tissue, and minimises the risk of side effects and complications.
SCT is regarded as a safe and effective alternative treatment to open brain surgery. The patients may also be offered treatment with steroids or chemotherapy as a part of their treatment.