Glioblastoma is described as the most common and aggressive tumour that starts in the brain, Sunnybrook Health Sciences Centre in Toronto says.
At a news conference on Tuesday, the hospital announced it is treating Tragically Hip singer Gord Downie for the terminal brain cancer.
Downie's tumour was located in a sufficiently accessible part of the brain that Dr. Douglas Cook, of Kingston General Hospital, was able to largely remove it, said Sunnybrook neuro-oncologist Dr. James Perry.
Biomarkers on the tumour showed it was amenable to treatment, he said, and Downie has since responded favourably. Cook called the biomarker the 1p/19q deletion.
"Gord does have one positive factor, which is the 1p/19q deletion, which will improve his response to chemotherapy," Dr. Cook said in an interview with CBC News Network.
It's hoped Downie's case will create an opportunity for awareness and fundraising for all glioblastoma patients, Perry said.
In general, the most common form of glioblastoma arises from star-shaped cells called astrocytes in the nervous system, according to the American Brain Tumor Association.
The association says glioblastomas are generally found in the brain's cerebral hemispheres, but they can occur anywhere in the brain or spinal cord.
How many people get it?
The rate of glioblastoma is about two to three per 100,000 people in Canada, the U.S. and Europe, Sunnybrook says.
It is one of the most common causes of cancer death in Canadians between the ages of 40 and 60, Perry told a news conference.
It is also more common in men than women and less common in children, according to the Brain Tumour Foundation of Canada.
Downie first went to the emergency room in Kingston because of a seizure, Perry said.
"We performed an MRI and found a lesion," Cook said.
"I was able to take him to the operating room and map out his language area while he was awake," Cook said.
Cook's surgical team then did a more extensive resection to give Downie the best chance heading into radiation and chemotherapy.
The pathology diagnosis revealed glioblastoma, Cook said.
In general, glioblastoma usually comes to attention because of a seizure, deficits such as paralysis and sometimes a stroke, Perry said.
The symptoms depend on where the tumour is in the brain. (Downie's was in the left temporal lobe.) Other common symptoms can include:
- Weakness on the left or right side of the body.
- Memory difficulties.
- Personality changes.
Sometimes symptoms occur quickly. On occasion, symptoms don't arise until the tumour reaches a larger size, Sunnybrook says.
Downie has a primary glioblastoma, the most common form, which tends to make its presence known quickly, according to the Toronto hospital.
Glioblastoma often recurs. "Unfortunately, one day it will come back," Perry said.
Surgery is the first step to remove as much of the tumour as possible. Since glioblastoma infiltrates the brain, it makes it difficult to remove the whole tumour during surgery. The surgery is almost always followed by secondary treatment with radiation and chemotherapy.
There's a clear standard of care treatment across North America, which Downie received and responded to, Perry said. No experimental treatment was involved.
Researchers have learned of biomarkers or proteins on the surface of the tumour that are associated with more favourable response to treatment and a significantly higher chance of longer-term survival.
Perry said in 99 per cent of cases, the cause is unknown. Occupations of those such as firefighters who work with hazardous materials may face an increased risk by a small fraction, but nothing compared with how smoking increases the risk for cancer, Perry said.
Musicians like Downie are not overrepresented among people with glioblastoma.