Colorectal Cancer Screening Should Begin at Age 45: Coalition

Earlier this year, the American Cancer Society (ACS) updated its guidelines for colorectal cancer (CRC) screening, and recommended that screening begin at age 45 for those at average risk for the disease. The update of the ACS guidelines was prompted by recent data showing increased rates of CRC in young and middle-aged populations.

Now a coalition of 22 public health and patient advocacy groups has joined the ACS and submitted a letter to the US Preventive Services Task Force (USPSTF) asking that the task force reconsider its 2016 guidance, in which it recommends that CRC screening begin at age 50 years and continue until age 75 years. This recommendation is scheduled for review in 2021, but the coalition is asking for earlier action.

In addition to the ACS and the USPSTF, guidelines on CRC screening have been issued by several other organizations: the US Multi-Society Task Force on Colorectal Cancer and the American College of Radiology, which issued a joint guideline; the American College of Physicians; the American College of Gastroenterology; and the National Comprehensive Cancer Network.

All these guidelines (with the exception of the ACS's) currently recommend routine screening for CRC and adenomatous polyps in asymptomatic adults beginning at age 50, although they differ with respect to frequency of screening, age at which to discontinue screening, and preferred screening method. Recommendations also differ for persons at high risk with respect to the age at which to begin screening, as well as the frequency and method of screening.

Increasing Rates in Younger Adults

The updated ACS guideline is the first and so far only one to recommend that screening begin at age 45 years. It reflects more recent data that show an increase in the incidence of CRC in younger populations. "This new recommendation is based on new evidence of rising incidence and modeling studies that showed an improvement in life-years gained and a favorable balance of benefits and harms after incorporating the new incidence data into models," explained Robert Smith, PhD, vice president of cancer screening at the ACS. He spoke to Medscape Medical News in May 2018, when the new recommendation was announced.

"Will it be problematic? No question that there are initial challenges, including raising awareness in the public and healthcare professionals and advocating that health plans make screening available beginning at age 45," Smith said.

The screening initiation age is a qualified recommendation. It was the only change made to the current ACS guideline. It maintains the status quo in that it does not prioritize among the various screening test options that are available but recommends regular screening with either a high-sensitivity stool-based test or a structural (visual) examination, depending on patient preference and test availability.

Now, the ACS is liaising with other groups to urge the USPSTF to review its CRC screening guidelines and to lower the age at which screening should begin, from the current age of 50 years to 45 years.

In a press release about the coalition's move, Chris Hansen, president of the American Cancer Society Cancer Action Network, explained that the "USPSTF has a process that allows for important new data and studies that were not available at the time of USPSTF's 2016 screening update to be taken into consideration immediately rather than waiting for its scheduled review cycle of a guideline.

"The new studies show an increasing prevalence of colorectal cancer in younger age cohorts; therefore, we hope the task force will take this new information into account as we work to give Americans evidence-based, age-appropriate access to preventive care services," he added.

Hansen also pointed out the importance of USPSTF recommendations, as national healthcare law references its screening guidelines for insurance coverage requirements. Therefore, "it is important that the task force seriously consider the new body of evidence that exists in support of beginning preventive screening at a younger age," he said. "We further urge the task force to consider the concept of the screening continuum, and as such, if a patient has a positive finding on a noncolonoscopy test, the screening process should not be considered complete until the patient has had a colonoscopy."

Possible Caveats?

Is there any downside to lowering by 5 years the age at which CRC screening should begin?

In a recent Medscape Perspective, Kenny Lin, MD, a family physician at Georgetown University Medical Center in Washington, DC, pointed out that a microsimulation modeling study commissioned by the USPSTF for its 2016 updated CRC screening recommendations suggested that a strategy of starting screening earlier than age 50 might be more effective.

"The ACS asked the authors to update their study using newer incidence data, and their new analysis concluded that starting screening at age 45 rather than age 50 could prevent two deaths from colorectal cancer for every 800 additional colonoscopies performed," said Lin.

An important caveat, however, is that few clinical trials of CRC screening methods have included adults younger than age 50, so real-life data to back up the beneficial projections shown in models are lacking, Lin pointed out. As for harms associated with earlier screening, he noted that any screening method will lead to more colonoscopies, either as a primary screening test or as a follow-up test for an abnormal result.

In addition, a systematic review and meta-analysis of postcolonoscopy complications found that 1 in 1000 colonoscopies cause bleeding, 1 in 2000 result in perforation, and 1 in 33,000 lead to death. "Although complications are rare, they add up quickly when screening millions of eligible adults," he said.

"In my mind, more studies are needed to establish the benefits of the ACS's recommendation for earlier screening to be sure than they outweigh these harms," Lin concluded.

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