NEW YORK — Regular colorectal cancer screening is recommended for asymptomatic adults aged 50 to 75 who are at average risk for the disease, according to newly released guidelines from the American College of Physicians (ACP).
Recommended screening approaches include fecal-based tests, colonoscopy, and sigmoidoscopy, and should be selected by physicians based on discussions with patients, the physician group said Monday in a report appearing in the Annals of Internal Medicine. Frequency of screening, meanwhile, depends on which method is selected, and screening should be discontinued for average-risk individuals over 75 years old or with a limited life expectancy.
The ACP defined average-risk individuals as those without a personal or family history of colorectal cancer, a long-standing history of inflammatory bowel disease, or genetic syndromes such as familial adenomatous polyposis.
The new recommendations are based on a review of screening guidelines from other organizations, which are commonly used in clinical practice but can vary on recommended age to start and stop screening, screening intervals, and preferred screening method, the ACP said.
In order to reconcile the different guidelines, the ACP's clinical guidelines committee (CGC) reviewed the latest guidance statements and supporting evidence from national-level organizations including the American College of Radiology, Canadian Task Force on Preventive Health Care, and the US Preventive Services Task Force (USPSTF). It also weighed guidelines commonly used in clinical practice such as ones from the American Cancer Society, Scottish Intercollegiate Guidelines Network, and US Multi-Society Task Force on Colorectal Cancer.
Prioritizing direct evidence from research studies over modeling data, the CGC found that no one screening approach could be recommended over the others since none of the reviewed guidelines directly compared screening interventions. "All screening tests are associated with potential benefits as well as harms," the panel wrote in its report. As such, "clinical decisions need to be individualized using patient clinical characteristics, patient preferences, and screening test frequency and availability."
The CGC did, however, recommend specific screening intervals depending on method. Fecal immunochemical testing (FIT) or high sensitivity guaiac-based fecal occult blood testing should be performed every two years, colonoscopy every 10 years, and flexible sigmoidoscopy every 10 years in combination with FIT every two years, it said.
The CGC determined that all average-risk individuals aged 50 to 75 should receive colorectal cancer screening even in the absence of symptoms, but found a little direct evidence to inform screening recommendations in older populations.
Modeling studies for the USPSTF, however, indicate there are limited mortality benefits but increased harms to screening in adults aged 75 years and older, especially for those who have had prior screening. This, combined with the estimated 10 years it takes for colorectal cancer to develop from an adenomatous polyp and predicted life expectancy, suggests that persons 75 years and older are "unlikely to benefit from screening but would undergo unnecessary, burdensome, potentially harmful, and costly screening tests," the panel stated.
In a related editorial, University of Texas at Austin's Michael Pignone notes that there are some questions about colorectal cancer screening that are difficult to answer based on existing data, and that "guidance requires judgment about what constitutes sufficient magnitude and certainty of effect to justify a recommendation." Cost-effectiveness analyses, meanwhile, can provide additional insights.
Overall, "any recommended form of screening in the 50- to 75-year age range is likely to be very cost-effective (if not cost-saving) compared with no screening and should be strongly encouraged," Pignone wrote. "As we consider how best to proceed at the margins, it is important not to lose sight of the strong consensus supporting screening for this age group."
Last month, the The BMJ issued guidelines recommending against colorectal cancer screening in healthy people aged 50 to 79 years who are at low risk for the disease, citing a lack of evidence that the practice benefits this population. The journal did recommend screening for men and women in this age group who have a 3 percent or greater colorectal cancer risk.