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- New ACS guidelines add blood-based and updated at-home tests to expand colorectal cancer screening participation.
- Colonoscopy remains the most comprehensive screening option and the only test that can remove precancerous polyps.
- Blood-based screening tests are intended for patients who decline or do not complete preferred screening methods.
New colorectal cancer screening recommendations, released today by the American Cancer Society, may help millions more Americans test for the disease.
The updated guidelines will now allow for a blood-based screening test, taken in a doctor's office, if a patient declines or does not complete one of the other preferred screening options, like a colonoscopy or a home-based stool test. In addition to the new blood-based test, the guidelines now include one updated and one new home-based test.
Experts say expanding the number of screening options could help improve participation, especially as colorectal cancer rates continue to rise in younger adults.
“We need to increase our emphasis on colorectal cancer as a highly preventable disease as much as a treatable one,” Robert Smith, PhD, senior vice president of early cancer detection science at the American Cancer Society, said in a news release. “By offering more screening tools in our guideline update, more eligible adults will be able to participate in lifesaving colorectal cancer testing, helping to close the screening gap and catch more cancers at an earlier, treatable stage.”
What's New in the Updated Guidelines
Experts say the most effective screening test for colorectal cancer is one that a patient will actually complete. While a colonoscopy is still the most accurate tool for colorectal cancer screening, the updated guidelines include additional new and updated tests to expand participation. Colonoscopy also remains the only screening test that can both detect and remove precancerous polyps during the same procedure.
Home-based stool tests:
- Cologuard: An updated version of a current at-home mt-sDNA (multi-target stool DNA) test that analyzes stool samples for specific DNA mutations and biomarkers associated with cancer or precancerous polyps.
- ColoSense: A new at-home mt-sRNA (multi-target stool RNA) test that analyzes stool samples for specific RNA biomarkers and hemoglobin.
Blood-based tests:
- Shield: A new blood-based screening test used to detect tumor DNA in the blood. Compared with established stool-based tests, these blood-based tests have a lower sensitivity for both advanced precancerous lesions and early-stage cancers.
The updated guidelines stress that the blood-based test is, essentially, a last resort for people who decline or do not complete other preferred screening tests. That's because of their lower sensitivity for detecting both advanced precancerous lesions and early-stage cancers. Studies also predict they are less effective in reducing colorectal cancer incidence and mortality. Additionally, any abnormal result from a stool- or blood-based screening test should be followed up with a colonoscopy.
“No matter which test you choose, what’s most important is to get screened, and that includes underserved, rural, and minority populations,” William Dahut, MD, chief scientific officer at the American Cancer Society, said in a news release. “These changes were developed to add to the colorectal cancer screening arsenal and help ensure preventive cancer care is available to all.”
What's Staying the Same
The ACS still recommends that everyone at average risk of colorectal cancer begin regular screenings at age 45, and continue through age 75 if they are in good health and expected to live more than 10 years. Screening is no longer recommended after age 85. People at a higher risk of colorectal cancer may need to begin screenings before age 45, have screenings more often, or only do specific tests.
Colonoscopy remains the most comprehensive screening option, but average-risk individuals who choose an approved stool test or a visual exam instead of the blood test have several options.
Home-based stool tests:
- High-sensitivity guaiac-based tests (gFOBT), every year
- High-sensitivity fecal immunochemical tests (FIT), every year
- Multi-target, stool DNA (mt-sDNA) tests, every three years
- Multi-target, stool RNA (mt-sRNA) tests, every three years
Visual exams:
- Colonoscopy, every 10 years
- Flexible sigmoidoscopy (similar to a colonoscopy, but only examines the lower third of the colon), every five years
- Computed tomography (CT) colonography (a test that creates 3D images of the colon and rectum to detect polyps or cancer), every five years
The guidelines also acknowledge the role affordability and accessibility play in colorectal cancer screening and prevention.
“Expanding screening options only matters if people can actually access them,” Lisa A. Lacasse, president of ACS CAN, a nonprofit, nonpartisan advocacy affiliate of the American Cancer Society, said in a news release. “Coverage and affordability remain among the biggest factors in whether eligible individuals get screened for colorectal cancer."
She added that ACS CAN "will continue pressing for policies that eliminate out-of-pocket costs and other barriers, so everyone has a fair opportunity to get the evidence-based screening they need.”
