Radiotherapy uses high-energy X-rays to kill cancer cells. It works by damaging the DNA of quickly dividing cells. Normal brain cells may also be affected by the treatment; however, they are much better equipped at repairing the damage.
Radiotherapy is often used to attack inoperable tumours, to shrink a tumour before surgery, to relieve symptoms, and to try and kill cancer cells left behind after surgery. It is generally available as a treatment for both adults and children.
Radiotherapy is personalised by the treating doctors and team of experts. It varies depending on the type of tumour and its location in the brain. In some cases, the patient might receive radiotherapy at the same time as chemotherapy. You can read more about chemotherapy here.
Radiotherapy is delivered by radiation oncologists and radiation therapists. They leave the treatment room while the radiation is being administered, but you can talk to them via an intercom throughout. To ensure the radiotherapy is directed to the tumour, a tailor-made treatment mask holds the patient’s head in position. Radiation is delivered by a machine called a Linear Accelerator that does not make contact with your body. It does not hurt or produce any heat, although a buzzing sound will be heard as the machine moves around the patient.
There are several types of radiotherapy. These include:
In external beam radiation therapy radiation doses are delivered to the tumour from outside the body via a machine which directs radiation to the brain tumour.
Stereotactic radiosurgery delivers a high dose of radiation to smaller tumours. This reduces the amount of radiation delivered to healthy brain tissue. Stereotactic radiosurgery may be considered in certain cases when surgery to remove the tumour is not possible.
Whole-brain radiation therapy delivers radiation to the entire brain, not just the tumour. This type of radiotherapy is used when a tumour has spread throughout the brain, or when there are multiple tumours.
CyberKnife is a machine that uses real-time imaging data to deliver radiation via a robotic arm. The only CyberKnife currently available in Australia is located at the Sir Charles Gairdner Hospital in Perth, Western Australia.
Gamma Knife is a machine that delivers precision gamma rays to a brain tumour. The treatment is overseen by neurosurgeons and radiation oncologists to deliver an accurate, high dose of radiation to the tumour, while reducing exposure to healthy brain tissue. A lightweight frame is used to hold the patient’s head in place. Currently, in Australia, this is performed at Macquarie University Hospital in New South Wales and Princess Alexandra Hospital in Queensland.
Proton beam therapy uses protons instead of X-rays to treat brain cancers. Proton beams may cause less damage to healthy tissue. This is because protons deliver very specific doses of radiation and release most of their energy within the tumour region. A proton beam facility is under construction at the South Australian Health and Medical Research Institute and is expected to start treating patients in 2022.
People respond differently to radiotherapy and side effects vary depending on the duration of treatment, age, and area of the brain treated. Possible side effects include: