Simple urine test might spot early colorectal cancer
CTV.ca News Staff
Published Sunday, May 8, 2011 6:21PM EDT
A made-in-Canada urine test appears to be able to spot the signs of early colorectal cancer, and might eventually do away with less appealing screening methods.
The urine test is based on "metabolomics," which is the analysis of the chemical fingerprints left by cellular processes in the body, including the changes of normal cells into cancer cells.
It works by identifying cancer cell waste products that are then excreted into the urine by small polyps and tumours.
If the test proves accurate, researchers hope it could one day change the way patients are screened for colorectal cancer and maybe other cancers as well.
Paul Sharp has survived colon cancer, but only because his father died of it. After his father passed away, he had a colonoscopy eight months later.
"They found I had cancer. I went for surgery four days later," he remembers.
Sharp is now one of over 1,200 patients who donated a urine sample to help University of Alberta doctors develop what could be the simplest screening screening method for this deadly cancer.
"Our test is like a fingerprint. It can tell you what those waste products are and then allows us to predict whether you have a polyp or not or whether you have colon cancer," says one of the test's developers, Dr. Richard Fedorak of the University of Alberta's Faculty of Medicine.
Fedorak and his colleagues have released a study which looked at 354 healthy people with normal colonoscopies provide urine samples, as well as 110 people with benign, "hyperplastic" colon polyps, which usually don't develop into cancer and 243 with ‘adenomatous" polyps, which are considered pre-cancerous growths that could become cancerous.
The urine lab test was over 80 per cent effective at spotting the existing cancer as well as pre-cancerous growths, a success rate that pleased the scientists.
"So if we can find the growth or the cancer at these early stages we can prevent or cure the cancer before it's too late," says Fedorak's fellow researcher, Dr. Haili Wang.
Many provinces already offer patients over the age of 50 a fecal occult blood test, a test that looks for blood in stool and that requires patients to test their own stool at home with a test kit. Fewer than 20 per cent of people offered the test use it. And it only finds cancer about 30 per cent of the time.
A simpler and possibly more accurate urine test might encourage more patients to get checked out.
"This way, we are thinking of the patients first. What's easiest for the patients," says Dr. Clarence Wong, an oncologist with the Alberta Colon Cancer Screening Program.
"When they come in, if they are more compliant and are more willing to do the test, we will save more lives because we are making it easier for them."
The screening test likely wouldn't replace colonoscopies, which are still considered the definitive test for colon cancer, but it would help doctors decide who should get the more invasive test to find patients before their cancer grows and spreads.
With a report from CTV medical specialist Avis Favaro