U of A scientist works on better cancer test
A medical team, including a researcher at the University of Alberta, has identified a biomarker able to predict which prostate cancer patients are more likely to have serious, quicker recurrences of the disease.
The discovery, if confirmed in larger clinical studies, could one day help doctors give chemotherapy, surgery and more aggressive treatment to the men most likely to benefit.
John Lewis, a cancer researcher in the faculty of medicine at the U of A, said he and a team from Vanderbilt University in Nashville, Tenn., have discovered an antibody that, when added to a biopsy sample taken from a man with prostate cancer, sticks only to certain proteins that metastasize or spread the cancer through the body.
The men who carry the mutating CD151 protein — the biomarker of more aggressive prostate cancer — are likely to have a recurrence of the cancer in four years, rather than the usual 15 to 20 years, since most prostate cancer grows slowly, Lewis said.
Such information could help doctors identify and more aggressively treat the men whose cancer is more serious, potentially saving other men whose prostate cancer isn’t as serious from unnecessary treatment.
“We found the difference was remarkable,” said Lewis, whose research was published in a recent issue of the peer-reviewed Cancer Research journal.
While the study looked at samples from 138 prostate cancer patients treated in Ontario, Lewis’ expanded study will search for 1,400 prostate cancer patients in Alberta who will be tested for the mutating proteins. They won’t be told if they test positive for the bio-marker because more research needs to be done to ensure more aggressive treatment is the best option for them. That is the same with those who test negative, since it has yet to be proven keeping these patients under active surveillance doesn’t put them at risk. But Lewis estimated the test could be available in three or four years.
“Tests like these will arm patients and clinicians with more accurate and better information that will allow them to make treatment decisions that will improve their outcomes and quality of life,” Lewis said.
Each year, approximately 2,100 Alberta men are diagnosed with prostate cancer, with a survival rate above 90 per cent, Alberta Health Services reports.
“The great thing about PSA (prostate-specific antigen) screening and all of the public awareness about prostate cancer is that we’re diagnosing a lot more prostate cancers,” Lewis said.
Men who have a high PSA count are more likely to have prostate cancer.
“But the flip side of that is our diagnostic tools aren’t good enough to really say, you have very bad prostate cancer and you need surgery, and your cancer, you’re not likely to die from it,” Lewis explained. “So as a result, it’s likely that many people are getting surgery that didn’t need it.”
Lewis said autopsies show 70 per cent of men who die in their 70s have prostate cancer, but don’t even know it.
“It may allow us to put more people on this active surveillance,” Lewis said. “We’re excited about the test. We’re optimistic.”