Colon Cancer Screening Tests Work, Studies Report
Colonoscopy, sigmoidoscopy and even fecal blood testing all lower risk of cancer death
The second study focused on the fecal occult blood test, which uses chemical agents to detect trace amounts of blood in a person's stool.
Researchers led by Dr. Aasma Shaukat of the VA Medical Center and University of Minnesota, Minneapolis, followed up on more than 46,500 Minnesotans who had been randomly assigned either to undergo fecal testing every year or every other year, or receive no testing. The research ran from 1976 through 1982 and from 1986 through 1992.
The study team used death records to see which of the original study participants had died of colon cancer by 2008.
Those who underwent annual testing had a 32 percent reduced risk of colon cancer death, while biennial testing reduced colon cancer death rates by 22 percent, researchers reported.
Brooks said the fecal blood test findings were "of particular importance, because there is the perception among many primary-care clinicians that by offering patients the stool test they are somehow offering them an inferior test."
Patients who now undergo a fecal blood test should expect to see even better protection from cancer, said Dr. Theodore Levin, who wrote an editorial accompanying the two studies in the journal. Levin is an assistant clinical professor of medicine at the University of California, San Francisco.
"The old fecal blood test that was done in the Minnesota trial has been improved and enhanced through modern biochemical methods," said Levin, who also is a research scientist at the Kaiser Permanente Northern California Division of Research. "It's much more accurate and much more sensitive, so we would expect the benefit to be even greater today with that test."
The blood test may have some potential advantages over colonoscopy, Levin added.
Patients have to undergo an uncomfortable cleansing process prior to a colonoscopy using powerful laxatives, and if they fail to properly cleanse their colon, it could hamper doctors' ability to detect pre-cancerous polyps. Colonoscopy also can miss smaller lesions.
"It may be that a moderately sensitive test that is done more often will have a better chance of detecting colon cancer or preventing death from colon cancer," Levin said.