• Example of a treatment plan using SRS to treat a brain lesion.
IT’S a persistent belief that the only treatment for brain cancer is to go under the knife, but Dr Chris Harper and his team have been effectively treating hard-to-reach metastatic brain tumours and other lesions with “stereotactic radiosurgery”.
There are no incisions, and no heavy doses of radiation in stereotactic radiosurgery (SRS), which sends several low-intensity beams of radiation directly to the site needing treatment.
These beams add up to deliver a therapeutic dose to the problem area, while leaving surrounding tissues relatively unaffected.
SRS is an alternative for patients unable to undergo surgery, or when the tumour or abnormality is in an area that is difficult to operate on for fear of damaging surrounding parts of the brain. It’s also very low impact: “The benefit is your hair doesn’t fall out, it’s a one-day procedure done as an outpatient, and the side effects are minimal,” Dr Harper says.
The technique was originally designed to treat small, well-defined intracranial targets and is most suited when the cancer is under control elsewhere in the body but is stubbornly difficult to budge in the brain.
“There’s a significant number of cases where chemotherapy or other treatments have controlled the cancer inside the body, but these treatments are not getting into the brain,” Dr Harper says.
SRS is also very successful at treating other conditions like benign lesions on the acoustic nerve that can cause deafness. Traditional treatment involved surgery, with the associated anaesthetic and recovery time, but SRS has shown great effectiveness in treating these tumours with minimal impact.
Strokes
Arteriovenous malformations — abnormal connections between the arteries and veins that can lead to strokes — can also be treated by SRS.
Dr Harper says there’s a lot of marketing hype around name-brand machines, but it’s much like the difference between a Mercedes and a Porsche; they do the same thing as long as the driver knows what they’re doing.
“People shouldn’t get hung up on the salesmanship,” he says. Patients sometimes ask if they should travel to Sydney for the branded Gamma Knife® but the equipment available in Perth has identical functions.
“Effectively it doesn’t matter which device you use, so you don’t need to go overseas or to Sydney to use a particular device … you can achieve the exact same thing using a machine known as a linear accelerator.”
Dr Harper says patients are relieved when they find out how simple the SRS is. After an initial meeting with the doctor and about a week of careful planning and computer modelling to target the right area, the procedure itself takes about an hour.