Blood test shows promise in detecting colorectal cancer
Sorry, men and women over 50. This isn't a replacement for the colonoscopy.
But a blood test developed by researchers at Epigenomics in Seattle has the potential to help doctors spot colorectal cancer sooner — before symptoms appear — and when relatively tolerable treatments offer an excellent chance for survival.
The molecular diagnostics company said Monday that studies on more than 2,000 blood samples showed its test can detect an altered gene associated with colorectal cancer between 50 and 65 percent of the time, in both early and advanced cancer.
It's the first blood test for colorectal cancer to deliver such promising results, said Dr. William Grady of the Fred Hutchinson Cancer Research Center, whose laboratory is working on similar early-detection methods.
"They really have improved things significantly for colorectal-cancer screening," said Grady, who is not affiliated with the company, but knew it was working on the test.
The test was developed by the Seattle unit of Epigenomics, formed when the German company acquired Orca Biosciences in 2000. The company has 34 employees here and 111 at its Berlin headquarters.
It will be up to Roche Diagnostics, which inked a $100 million development agreement with Epigenomics almost three years ago, to commercialize the test.
The test could sell for $100 or less and there are more than 70 million Americans in the target population of men and women over 50, said Gary Schweikhardt, president of Epigenomics' Seattle unit.
"Development of a blood-based test to find cancer has been the goal of a lot of companies and a lot of scientists for decades," he said.
The Epigenomics test could replace the fecal occult blood test (FOBT), which doctors use as an annual or biannual surveillance tool in concert with a colonoscopy. A colonoscopy is an invasive, though highly accurate, method for finding the disease. Doctors recommend men and women get one at age 50 and periodically thereafter depending on individual risk and results of FOBTs.
"Most people don't find the (FOBT) acceptable," Grady said, because it involves collecting one's own stool sample. Only around 30 percent of people at risk for colorectal cancer undergo any kind of screening, he said.
"The sad part is we know that screening for colorectal cancer is effective and can prevent the vast majority" of deaths, he said. More than 56,000 Americans will die from colon cancer this year.
A simple blood test for colorectal cancer could improve participation in screening.
Also, the FOBT misses many cancers. Its sensitivity is about 20 or 30 percent — about half the sensitivity Epigenomics reported — when used as part of an annual program, Grady said.
Dr. Anthony Bach, a gastrointestinal-cancer specialist with the Seattle Cancer Care Alliance, added that the test can't reliably identify the disease in its early stages.
He called Epigenomics' test a "good step" toward early detection of the disease, but "the big test will be, does it really decrease the mortality from cancer?"
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