“A problem with current colorectal cancer screening is that it is not as risk based as it should be. We do not have accurate and reliable methods of estimating an individual person’s risk. Our findings support the observation that age is a good predictor of risk,” said Thomas F. Imperiale, MD, associate professor of medicine at the Indiana University School of Medicine, research scientist at the Regenstrief Institute for Healthcare and staff physician at the Richard Roudebush VA Medical Center. Established risk factors for colorectal cancer include a family history of the disease, previous ovarian, uterine, breast or colorectal cancers, and ulcerative colitis.
The study reviewed the procedures and pathology reports of colonoscopies of 906 individuals between the ages of 40 and 49 who did not have symptoms of colorectal cancer and who have no established genetic risk for the disease. No cancer was found in any of these individuals.
“People, of any age, who think they may be at high risk or have symptoms such as rectal bleeding should speak with their physician about the need for screening or for a diagnostic evaluation,” said Dr.Imperiale, who is a gastroenterologist.
In spite of the low prevalence of cancer detected by screening in persons under age 50 in this study, about 7 percent of colorectal cancers are known to occur in individuals under age 50. It is not clear to what extent whether these cases occur in individuals with a predisposition to the disease according to Dr. Imperiale. He and colleagues are currently undertaking a pilot study to look for risk factors for precancerous and cancerous colon polyps in individuals under age 50 who have no known genetic risk for colorectal cancer.
Collaborators on the study were Gregory Larkin, MD, Director of Health Services at Eli Lilly; James Rogge, MD and David Wagner, MS of the Indianapolis Gastroenterology Research Foundation; Ching Lin, BS of the IU School of Medicine and David Ransohoff, MD of the University of North Carolina.
The study was funded, in part, by the National Institute of Diabetes & Digestive & Kidney Diseases.
Journal
New England Journal of Medicine