INDIANAPOLIS — Although the incidence of colon cancer is decreasing in adults over 50, the numbers are increasing among younger adults. A new study by a team from the Regenstrief Institute has now identified seven risk factors that may explain this increased risk, especially among young men.
“This study is important because it puts on the table whether and possibly how to screen people who are younger than 45 — below the recommended screening age for colorectal cancer and have some of the risk factors we identify — in order to consideration for screening,” says researcher-clinician Thomas Imperiale, MD, of the US Department of Veterans Affairs, in a media release.
“We know that colon cancer at younger ages is increasing, although the absolute risk is still much lower than even in the 45 to 54 age group. Nevertheless, this does not mean that we should not try to identify younger people at higher risk of screen them with some modality.”
“Clinicians may have a discussion with a patient and say that even though screening guidelines don’t come into effect until age 45 and you don’t have a family history, you have some risk factors. Could you consider a non-invasive screening test? It could be fecal occult blood test or multi-target stool DNA test. It doesn’t have to be a colonoscopy. For men younger than 45 who are at higher than average risk, it would make sense to do some sort of screening,” continues Dr. Imperiale .
The study included 600 people with non-hereditary colon or rectal cancer plus 2,400 control patients from VA medical centers across the United States. Electronic health records and national VA data sets were used to determine sociodemographic and lifestyle factors, family and personal medical history, anthropometry, vital signs, medication use, and laboratory results for six to 18 months. All participants were male veterans between the ages of 35 and 49, with 65 percent white and 30 percent black.
Initially, the team identified 15 variables associated with early-onset colorectal cancer in men. They then condensed their risk prediction model into seven factors to simplify its use in clinical settings while remaining accurate in estimation. The seven factors are:
- older age (within the age group 35 to 49 years)
- no regular use of non-steroidal anti-inflammatory drugs (such as aspirin or ibuprofen)
- no regular use of statins
- current alcohol consumption
- first- or second-degree relative with colon cancer
- a higher burden of disease
- service-connection/copay variable – a marker of socioeconomic status
“We do not believe that any of these risk factors, with the exception of the service-connection/copay variable, which we believe may be a proxy for income and/or socioeconomic status (and only an approximate one), are unique or specific to the veteran population,” explains Dr. Imperiale.
Dr. Imperiale is now analyzing data on risk factors in female veterans. Still, the risk of colon cancer is so far twice as high for men as for women regardless of age.
That find is published in the journal Cancer prevention research.
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