News

A drug that disrupts DNA to stop cancer cells from multiplying can prolong the lives of some people with the most common and deadliest type of brain tumour, a study by Canadian and European researchers has found.

While not a cure, the drug temozolomide marks the first advance in treating glioblastoma in three “frustrating” decades of trying to control the disease, the researchers say.

“We have a new standard of care, a new standard treatment,” said Dr. Greg Cairncross, a brain tumour specialist at the University of Calgary, who led the Canadian arm of the study. “I think it's quite clear that this will be the way in which patients with glioblastoma are treated from” now on.

The study, appearing Thursday in the New England Journal of Medicine, involved 573 adults with glioblastoma in Canada and 12 European countries. Researchers compared patients treated with radiation and temozolomide to those who received radiation alone. Most had already had surgery to remove as much tumour as possible.

After two years, 26 per cent of patients on the drug-radiation combination were still alive, compared to 10 per cent who did not get the drug. Overall, the average survival rate was almost 15 months for those taking temozolomide versus 12 months for those given just radiation.

“It doesn't sound like much ... but if you can demonstrate that you can extend life for two to three months for the average patient, that's a significant advance,” said study co-author Dr. Warren Mason, a neuro-oncologist at Toronto's Princess Margaret Hospital.

“For the first time, we've shown that a chemotherapy, when used at diagnosis, can improve survival,” Mason said. “This is the first advance in 30 years in the management of this disease, and we've not been able to make a dent until now.”

When Bob Tucker of Orillia, Ont., was diagnosed with glioblastoma in late 2000, his post-operative prognosis was “very dire. I was given three to nine months to live.”

Four years later, after a second surgery and more than one course of temozolomide pills and radiation, the 56-year-old accountant said his tumour appears to have shrunk to almost nothing. “I believe it is an amazing drug, that it is a big breakthrough. I think without the drug, my prognosis might have come to fruition.”

Still, he knows his cancer is incurable. “It's going to be there and whether it will stay there in a state of remission, hopefully that's what's going to happen.”

More than 1,100 Canadians are diagnosed with glioblastoma multiforme each year. Most die within nine to 12 months of diagnosis. The octopus-like tumour can arise anywhere in the brain, insidiously sending its tentacles to infiltrate brain tissue. That means surgery can never fully eradicate the tumour, as is the case in some other types of cancer.

While a small percentage of patients are genetically predisposed to develop glioblastomas, most occur “sporadically,” with no known underlying cause, say doctors, speculating that the culprit may be some environmental agent.

Among others helped — and given hope — by temozolomide is Calgary architect Don McHenry, who was diagnosed with brain cancer after suffering a seizure while asleep one night last September. The 59-year-old had surgery in November, followed by radiation and the chemotherapy.

“The side-effects were relatively minimal, and we were able to control them very well with some anti-nausea medication,” the father of two young girls said Wednesday from Calgary. “I'm feeling very well. I'm actually back running and bike riding and I've also been downhill skiing.

“Given the fact that I've gotten this condition, I feel very fortunate that I'm able to receive this treatment. And the quality of life that I've been able to live, even though I'm having to deal with this, has been very good.”

Dr. Michael Wosnick of the Canadian Cancer Society praised the study findings. “To be able to treat at least 30 per cent of glioblastoma patients with a straightforward, well-tolerated treatment that significantly improves their life-expectancy is a huge advance that should change clinical practice overnight.”

The study showed that temozolomide, made by Britain's Shearing-Plough, prolonged the lives of about 40 per cent of patients. A second paper appearing in Thursday's journal suggests one possible reason why: some glioblastoma cells have a genetic alteration that silences the DNA-repair mechanism, making the cancer cells more sensitive to the medication.

About 45 per cent of patients alive at two years in the study have this genetic change, said Dr. Cairncross, suggesting that doctors may be able to target those who would benefit most from the drug and research ways to make it work better in those without the genetic sensitivity.

For physicians who have long dealt with this bad-news disease, the study's results come with a huge sense of relief.

“It's so difficult to treat and it's such a tragic illness,” said Dr. Cairncross. “I'm very pleased after many years of slugging away at the problem to see a genuine improvement.... And we're hopeful that this is the first of many advances that we'll see in the coming years.”