Key takeaways:
- A new American Cancer Society guideline has added recommendations for blood-based screening tests for CRC.
- The updated guidance may lead some patients to first choose lower-performing tests, ACG warned.
ACG has issued a statement urging clinicians to interpret American Cancer Society’s revised colorectal cancer screening guidance with caution.
In the statement, ACG expressed concern that the recommendation of blood-based tests for some patients risks undermining adherence to higher-sensitivity screening options.
The new American Cancer Society (ACS) guidance reaffirms that adults at average risk for CRC should be screened between ages 45 and 75 years, but recommends blood-based tests as a “not preferred” option for patients who decline or do not complete stool-based screening or colonoscopy.
“We want to ensure that the ACS guideline is implemented the way it was written,” ACG president William D. Chey, MD, MACG, AGAF, FACP, RFF, told Healio. “Gastroenterologists, as experts in CRC screening, will need to educate [patients] in ways that minimize substitution of colonoscopy or high-quality stool tests for the less accurate blood test.”
There is a misconception among some patients that blood-based screening outperforms stool-based tests, as noted in an editorial accompanying the ACS guideline.
“The diagnostic accuracy of Shield (Guardant Health) is lower than that of stool tests for early stage CRC and advanced polyps,” ACG Trustee Aasma Shaukat, MD, MPH, told Healio.
Colonoscopy is estimated to detect more than 95% of colorectal cancers, according to ACG, as well as provide an opportunity to remove precancerous polyps. In contrast, ACG highlighted that a Shield test — which detects tumor DNA in the blood — misses 1 in 3 early-stage cases of CRC and 1 in 6 total cases. A study in The New England Journal of Medicine found the blood-based test had a sensitivity of 83.1% for CRC across all stages and a sensitivity of 55% for stage I CRC.
Highlighting these statistics may help convey the efficacy of different screening options to patients, Chey said.
When CRC is detected early, outcomes are dramatically improved — with 5-year survival rates exceeding 90%, according to an ACS press release issued with the guideline. However, around 1 in 3 eligible U.S. adults have not had recommended CRC screening.
“ACG supports improving adherence to CRC screening among unscreened individuals,” the organization said in the statement. “However, we want to be certain that the unscreened individuals are given genuine opportunity to complete a ‘preferred’ test first, before being offered a blood test.”
CMS this month announced it would cover noninvasive biomarker tests, with specific parameters, every 3 years for patients at average risk for CRC. Additionally, patients must be “provided with information about the test performance and the importance of a follow-on colonoscopy if the test returns a positive result.”
In its statement, ACG also expressed concern that limited time during patient visits may lead to patients receiving incomplete information about CRC screening options.
Specifically, ACG noted that clinicians may not have time to ensure patients are aware of the limitations of each, and that if they have a positive result from a blood or stool test, they still require a follow-up colonoscopy.
“Gastroenterologists already understand the advantages and benefits of colonoscopy compared with blood-based tests,” Chey said. “As a broader pool of health care professionals begins to advise patients on CRC screening, it’s unlikely that every patient interaction will practically be able to cover the nuances of this guideline.”
According to Shaukat, direct-to-consumer marketing may also contribute to misconceptions among patients, because “the main message that the blood test should be offered second line is lost.”
Chey agreed but emphasized a big-picture concern.
“Even if every headline and every clinician communicated all of the appropriate caution, this recommendation requires too much of patients,” Chey said. “Patients shouldn’t have to parse and process what it means to be ‘recommended’ but ‘not preferred.’”
ACG encourages clinicians to “work with primary care colleagues and health systems to develop systems unique to each practice enabling colonoscopy and stool tests to be offered first line,” Shaukat told Healio.
Shaukat recommends clinicians use a checklist when counseling patients to ensure they cover the benefits and limitations of each CRC screening test. She also suggests sharing educational materials with patients ahead of or during office visits.
“Many Americans are learning about these tests for the first time,” Chey said. “We hope to assist patients that already have misconceptions and to appropriately inform patients before misconceptions can develop.”
For more information:
William D. Chey, MD, MACG, AGAF, FACP, RFF, is H. Marvin Pollard Professor of Gastroenterology, professor of nutrition sciences, and chief of the division of gastroenterology and hepatology at Michigan Medicine. He also is a Healio Gastroenterology Peer Perspective Board Member. He can be reached on X at @umfoodoc.
Aasma Shaukat, MD, MPH, is Robert M. and Mary H. Glickman Professor of Medicine and director of outcomes research in the division of gastroenterology and hepatology at NYU Grossman School of Medicine. She can be reached at gastroenterology@healio.com.
Sources/Disclosures
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Disclosures:
Chey reports consulting roles with Ardelyx, Atmo, Bausch Health, Biomerica, Blueprint Medicines, Gemelli Biotech, Phathom Pharmaceuticals, Takeda Pharmaceuticals, Vibrant and Viscera Labs; grant/research funding from Bausch Health, Commonwealth Diagnostics International, FDA and NIH; stock options in Coprata, Evinature, FoodMarble, Kiwi Biosciences and ModifyHealth; serving as a board member/on the advisory panel at ACG, GI Health Foundation, International Foundation for Gastrointestinal Disorders and Rome Foundation; and holding patents for Digital Manometry, My Nutrition Health and Rectal Expulsion Device. Shaukat reports consulting roles with Freenome, Geneoscopy and Universal Diagnostics.
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