New risk score for colorectal cancer could guide selection of screening tests
A new risk assessment scoring system could help physicians determine which patients can forgo invasive colonoscopy for cancer screening and which patients should undergo the procedure. The research findings were published in the Annals of Internal Medicine (2015; doi:10.7326/M14-1720).
According to published literature and guideline organizations, 85% of the population is classified as average risk for colorectal cancer, which accounts for 55,000 deaths per year. Although colorectal cancer screening tests are cost-effective, they are underused and can be used inefficiently because of the current inability to tailor screening methods more precisely to risk.
"The main question was, 'can the risk factors most frequently associated with the risks for colorectal cancer and advanced, precancerous polyps be used in combination to stratify risk for advanced neoplasia in average-risk persons?'" said study lead author Thomas F. Imperiale, MD, Regenstrief Institute investigator and professor of medicine at the Indiana University School of Medicine in Indianapolis.
The study was conducted with average-risk patients (ie, no high-risk familial cancer syndromes) ages 50 to 80 years who were undergoing initial screening colonoscopy in several Midwestern endoscopy units and practices. Points for the risk assessment score were assigned based on risk factors for both colorectal cancer and advanced precancerous polyps: age, gender, family history of colorectal cancer, smoking history, and waist circumference.
Participants were then separated by score into very low-, low-, intermediate-, and high-risk categories. The researchers found that there indeed were fewer advanced neoplasms in the low- and very low-risk groups, suggesting that a less invasive test such as sigmoidoscopy or occult blood test might be appropriate for those patients. However, those in the higher-risk groups may still need to undergo colonoscopy.
"Our hope is that knowing the risk of advanced neoplasia may make colorectal screening more patient-centered with respect to choosing a screening test," Imperiale said.
The biggest challenge, he said, "Is getting to the point where providers are comfortable using the scoring system, reassuring patients at very low- and low-risk that non-colonoscopy based strategies may be as effective, and convincing high-risk patients who do not want colonoscopy, to have one."