The fight against cancer has seen many technological and medical advances in recent years.
When it comes to brain cancers, precise and efficient tools like the Gamma Knife have changed the way treatment is conducted on patients. Gamma Knife radiosurgery – a common procedure carried out on brain cancers – is a painless computer-guided treatment that delivers highly focused radiation at small to medium sized tumours, lesions and growths in the brain, and/or above the neck.
Also known as stereotactic radiotherapy, the Gamma Knife machine can be used to treat malignant (cancerous) or benign (non-cancerous growths that are slow-replicating) tumours.
While many tend to become anxious when they hear the word “radiation”, Dr Malwinder Singh, a clinical oncologist at Pantai Hospital Kuala Lumpur, says that the Gamma Knife procedure is actually much safer. Any radiation to the brain will cause some nausea, vomiting, lethargy and headache. But when we talk about side effects of Gamma Knife, it is actually much less.
The toxicities that are experienced during conventional radiotherapy are mainly because of the radiation received by the surrounding normal tissue. But with the Gamma Knife, we radiate the tumour alone during the procedure. So, the normal brain tissue only gets a very minimal dose of radiation.
“In normal radiotherapy, a big portion of the brain gets radiated, probably a few centimetres of brain tissue. But with Gamma Knife, you are talking about mere millimetres of normal tissue exposed to radiation,” he says.
He shares that the Gamma Knife can also treat multiple tumours and lesions at once. It also comes with the added ability to differ and specify radiation doses, based on the size of the growths and lesions. The beauty of Gamma Knife is that you can have different doses compared to conventional radiation that sends one dose – big or small – to a larger region of the brain. Every time the tumour shrinks, we give a smaller area of radiation dose. We call it staged radiotherapy.
“Not all tumours are the same. The average sized ones, you can treat it all at once. Whereas big tumours might be fractionated due to the size. You can treat everything in one round, and the big tumour might need a second round of treatment.”
Dr Malwinder says that radiation is always precisely targeted at a tumour, and any minor side effects can be alleviated with prescribed medications from a physician.
He adds that there is little to no pain during procedures, and that hair fall is rare while undergoing treatment, although it can occur if the growth or tumour is peripherally located in the brain.
“Recuperation is also much shorter for Gamma Knife procedures,” he says.
“For Gamma Knife procedures, sometimes we will discharge patients with medication for a few days to alleviate any symptoms. The toxicity will only last about two to three days in the body, a week at most. The procedure can also be completed in 15 to 20 minutes for anything simple, depending on the size and number of lesions. Anything that is more complex can go up to four hours, but can still be completed in a single session.”
Gamma Knife procedures also do not require any incisions to be made, nor do patients have to be admitted after treatment. For larger tumours, Dr Malwinder says that conventional radiotherapy is still preferred, as it has shown better results in treating larger lesions and growths.
However, the Gamma Knife can still be used during the re-treatment phase if the tumour regrows.