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New Guidelines Recommend Colorectal Cancer Screening Based on Risk, Not Age

NEW YORK — Routine colorectal cancer screening is not recommended for healthy people 50 to 79 years of age who are at very low risk for the disease as the practice offers little benefit in this population, according to new guidelines from a panel of international researchers and other experts.

Regular screening is still recommended for men and women in this age group who have a 3 percent or greater risk for colorectal cancer, the group states. The guidelines appear in The BMJ as part of the journal's Rapid Recommendations program, which aims to provide doctors with updated treatment guidance based on the latest evidence. 

While existing guidelines on colorectal cancer screening vary by country, most recommend screening for all individuals starting at age 50 years, when the risk of cancer in the next 15 years is typically between 1 percent and 2 percent, the panel wrote in The BMJ. The most common screening methods include fecal immunochemical testing (FIT) every year or every two years, a single sigmoidoscopy, and a single colonoscopy.

Prompted by the availability of new colorectal cancer screening data, the team aimed to examine whether the practice makes an important difference to health outcomes in individuals who initiate screening at age 50 to 79, as well as which screening option is best. 

To that end, the panel conducted a linked systematic review of colorectal cancer screening trials and microsimulation modeling to weigh the benefits and harms of screening over a 15-year period, taking into consideration an individual's cumulative risk of the disease, as well as the practical issues and burdens of different screening methods.

Overall, the panel wrote, there was "substantial uncertainty" regarding the 15-year benefits, burdens, and harms of screening, with the four most common screening methods resulting in similar colorectal cancer mortality reductions. "FIT every two years may have little or no effect on cancer incidence over 15 years, while FIT every year, sigmoidoscopy, and colonoscopy may reduce cancer incidence, although for FIT the incidence reduction is small compared with sigmoidoscopy and colonoscopy," the panel noted. Serious gastrointestinal and cardiovascular adverse events related to screening, meanwhile, were found to be rare. 

Based on its review, the panel determined screening is not needed for healthy adults between 50 and 79 years of age with an estimated 15-year colorectal cancer risk below 3 percent. Screening with either FIT, sigmoidoscopy, or colonoscopy is recommended for those with a higher estimated risk. 

In a related editorial in The BMJ, the International Prevention Research Institute's Philippe Autier noted that the "evidence backing colorectal cancer screening is still fragile and strong recommendations cannot be issued at the moment." 

Personalized screening decisions based on individual disease risk offers advantages over simply screening everyone in a specific age group include the optimization of screening effectiveness while reducing overdiagnosis for those at low risk, he wrote. 

Additional research is still needed to refine risk-based recommendations, Autier added. "The goal of screening is to reduce cancer mortality by preventing late-stage cancer. Hence, better knowledge of risk factors associated with late stage at diagnosis and colorectal cancer death is likely to improve risk-based approaches."