Voices from the community:
Making a difference
Dr. Dennis Slamon's breast-cancer research has improved the lives of hundreds of thousands of women.
It's not very often that we get the opportunity to meet a recognized world leader in medical research-someone whose life's work could directly impact our own lives or the lives of people we love.
Each October, however, a Canadian institution called the Gairdner Foundation presents awards to researchers from around the globe for their "major contributions through research to the conquest of disease and the relief of human suffering." The winners participate in a national speaking tour, connecting with the public to talk about their medical breakthroughs. Of the 290 award winners since 1959, the inaugural year, 70 have gone on to receive Nobel Prizes. A prestigious group indeed.
This past fall, Albertans were introduced to Dr. Dennis Slamon of the University of California, Los Angeles, one of the 2007 winners of the Gairdner International Award. Dr. Slamon is a pioneer in the field of targeted therapy for cancer treatment.
In 1986, his group discovered that the tumours of women who suffer from a particularly aggressive form of breast cancer contained too many copies of a gene called HER2 , and therefore too many copies of the HER2 protein. Women who have breast cancer and who are also HER2-positive have a median life expectancy less than half that of patients who are HER2-negative. The team still had to show that a causal link existed between the high number of gene copies and the incidence of the cancer. Years of basic-science research made that link clear.
Dr. Slamon's research led to the development of the breast-cancer drug Herceptin. The drug binds to the HER2 protein specifically, thus suppressing the growth of cancerous cells. In each phase of drug testing, the cancer was kept at bay. In a very understated fashion, Dr. Slamon explains the impact of this drug: "[Worldwide] there are a million new breast cancers each year. The HER2 alteration is associated with about 200,000 to 250,000. Herceptin will increase the survival of about 30% of those patients." This is a dramatic increase over the 2% to 6% improvement in survival observed using traditional treatments. The bottom line: Dr. Slamon's work has improved the lives of hundreds of thousands of women.
Herceptin represents a new class of cancer therapy. For almost 40 years, oncologists have relied on chemotherapy to treat cancer-either on its own or in combination with surgery or radiation therapy to remove tumours. Dr. Slamon points out that chemotherapies are essentially poisons. Physicians have the delicate task of trying to find the right mix of these poisons in order to kill more bad cells than good cells and minimize serious side effects. "But we're using a non-specific bomb," he says. "It's a pretty primitive therapy when you think about it."
To break out of the one-size-fits-all therapeutic approach, Dr. Slamon asserts that a shift in thinking was necessary. "Cancer isn't a single disease. Cancer, even within a given organ, is not a single disease. It's diverse. If you accept these principles, then you need therapies that are tailored to the subtype of cancer you're treating.
"Targeted therapy is what the future holds for all medicine," says Dr. Slamon, summarizing the significance of the discovery. Breast cancer has led the field. And we think that with further refinement we can do better than the current survival rates. But that's in progress right now. That's where the excitement is."