People with a family history of colon cancer express strong interest in having genetic testing, but many do not take advantage of already available screening tests for the disease, researchers from the University of Utah report.
Among 95 people whose parent or sibling had colon cancer, 84 percent said they would take a genetic test to determine their susceptibility to the disease if one were available. However, substantial numbers may fail to follow screening recommendations by the American Cancer Society. Among those 40 and older, for example, 31 percent had completed a screening test for blood in their stool in the previous year and 59 percent had their colons examined (via sigmoidoscope or colonoscope) in the previous five years.
"Our data underscore the need for educational efforts regarding colorectal cancer genetics, and testing and interventions targeted at family members of colorectal cancer patients, to increase compliance with colorectal cancer screening guidelines," said lead author Anita Yeomans Kinney, PhD, of the University of Utah College of Nursing. The researchers reported their findings in the April issue of the American Journal of Preventive Medicine.
The researchers surveyed 95 people with a parent or sibling who had been diagnosed with colorectal cancer. Two thirds (68 percent) said they believed that they were at higher than normal risk for colon cancer, and a similar proportion (64 percent) thought their likelihood of being a genetic carrier was greater than 50 percent. A majority (56 percent) thought they had a 50 percent or greater chance of developing colon cancer at some point during their lives.
About 5 percent of cases of colon cancer can be attributed to an inherited alteration in one of several genes, the researchers say. An additional 10 to 15 percent of cases may be due to an increased susceptibility from as yet unidentified genetic aberrations. Genetic tests for two rare inherited forms of colon cancerÐfamilial adenomatous polyposis and hereditary nonpolyposis colorectal cancerÐare available, but tests for more common forms are not.
"Identifying high-risk individuals for whom advanced surveillance would be recommended is a potential benefit of genetic testing," said Kinney. "Knowledge of whether or not they carry the gene may motivate individuals at risk to adhere to preventive measures such as colorectal screening."
The American Journal of Preventive Medicine, sponsored by the Association of Teachers of Preventive Medicine and the American College of Preventive Medicine, is published eight times a year by Elsevier Science. The Journal is a forum for the communication of information, knowledge, and wisdom in prevention science, education, practice, and policy. For more information about the journal, contact the editorial office at (619) 594-7344.
This study was funded by the University of North Carolina at Chapel Hill Lineberger Comprehensive Cancer Center
Posted by the Center for the Advancement of Health http://www.cfah.org. For information about the Center, call Petrina Chong, pchong@cfah.org (202) 387-2829.
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American Journal of Preventive Medicine