New scoring system aids in colorectal cancer screening decisions

Last Updated: 2015-08-11

By Will Boggs MD

NEW YORK (Reuters Health) - A new scoring system allows stratification of colorectal cancer screening by identifying individuals at risk for advanced colorectal neoplasia.

"While the USPSTF (US Preventive Services Task Force) states that any of several tests / strategies for colorectal cancer screening is acceptable for average-risk persons -- and this new scoring system does not challenge this -- use of this risk stratification tool may help clinicians and their patients decide, and be very comfortable with, a choice that is tailored to their risk subgroup among average-risk persons," Dr. Thomas F. Imperiale, from Indiana University Medical Center, Indianapolis, told Reuters Health by email.

Dr. Imperiale's team used a derivation group of 2993 individuals to develop a five-variable risk index that included age, sex, first-degree relative with colorectal cancer, waist circumference, and cigarette smoking. Total scores could range from 0 to 13.

They then established four risk groups based on total scores: very low (0), low (1-3), intermediate (4-6), and high (>6).

When applied to a validation group of 1467 individuals, they found the risk for advanced neoplasia ranged from 1.65% in the very-low-risk group to 3.31% in the low-risk group, 10.9% in the intermediate-risk group, and 22.3% in the high-risk group, according to the August 11 Annals of Internal Medicine online report.

There were no cancer cases detected in the very-low-risk and low-risk groups, and most advanced neoplasms (87.5%) in these groups would have been detected if sigmoidoscopy had been performed with subsequent colonoscopy for finding of a distal polyp.

Dr. Imperiale recommends informing patients that "this scoring system was designed to try to separate patients who are average risk into low, intermediate, and high risk." There are a few reasons for doing so, he said:

1. To allow (low-risk) patients to choose (and clinicians to recommend) in a more informed way, less invasive screening than colonoscopy.

2. To show high-risk patients who are undecided about whether and how to be screened to get screened and preferentially with colonoscopy because of their high risk.

3. To show intermediate-risk patients that they really are 'average-risk' and may choose from one of several screening test option.

"Our scoring system does not say, 'You don't require any screening if you're low risk,'" Dr. Imperiale cautioned. "Our hope for the scoring system is that it will engage and empower clinicians and patients to make and to feel comfortable with decisions that consider risk of advanced colorectal neoplasia."

Dr. Chyke A. Doubeni, from the University of Pennsylvania Perelman School of Medicine, Philadelphia, wrote an editorial related to this report. He told Reuters Health by email, "There is a large amount of variation in the risk of colon cancer among people who are currently considered average risk. The tool may be useful in encouraging patients, who have the risk factors but are reluctant, to get screened."

"Clinicians should routinely collect detailed risk factor data, particularly accurate family history, to allow patients to be counseled appropriately on the right type of screening test," Dr. Doubeni said. "While there is a need for better tools to group people into finer risk categories, there are currently no tools that can used clinically to achieve that ideal."

In his editorial, Dr. Doubeni noted that the model described in this report only modestly discriminated between patients with advanced adenomas and those without. Therefore, he concluded, "Until high-performing tools are available, the best approach to optimize screening is to provide patients the best test they are willing and able to complete with high fidelity."

Dr. Paul C. Schroy III, from Boston University School of Medicine, told Reuters Health by email, " I think that prediction models, such as ours and the one proposed by Imperiale et al., have utility in facilitating shared decision making when selecting a preferred screening option (particularly in situations when provider and patient preferences differ) and in tailoring the use of screening colonoscopy in healthcare settings where financial or capacity constraints to population-based colonoscopy screening exist."

"Average-risk individuals can be stratified into different risk categories, which in turn can facilitate shared decision making when selecting a preferred screening option, provide a rationale for tailoring the use of screening colonoscopy in resource-deprived healthcare settings, and for counseling patients on possible lifestyle modifications that might reduce risk (e.g., cessation of smoking and weight loss if obese)," Dr. Schroy concluded.

The National Cancer Institute, the Walther Cancer Institute, the Indiana University Melvin and Bren Simon Cancer Center; and the Indiana Clinical and Translational Sciences Institute supported this research. The authors reported no other disclosures.

SOURCE: http://bit.ly/1L2QYcm and http://bit.ly/1DGfWyC

Ann Intern Med 2015.