The new recommendations add blood-based testing and multi-target stool testing as options for average-risk adults starting at age 45.
The American Cancer Society (ACS) released updated guidelines for colorectal cancer screening, adding a blood-based screening test and new at-home stool-based options to the list of recommended tools.
The update, published in CA: A Cancer Journal for Clinicians, reaffirms that average-risk adults should begin screening at age 45 and continue through age 75. The move reflects advances in disease detection and a public health strategy intended to lower barriers to access. According to the ACS, colorectal cancer is now the top cancer killer of adults under the age of 50 in the US.
“We need to increase our emphasis on colorectal cancer as a highly preventable disease as much as a treatable one,” says Robert Smith, PhD, senior vice president of early cancer detection science at the American Cancer Society, in a 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.”
New Stool-Based and Blood-Based Options
The updated guidelines include two specific multi-target stool tests: next-generation multi-target stool DNA (mt-sDNA) testing (brand name Cologuard) and multi-target stool RNA (mt-sRNA) testing (brand name ColoSense). Both mt-sDNA and mt-sRNA tests analyze samples for specific molecular markers and hemoglobin. These at-home tests are recommended for screening every three years.
The ACS also added blood-based tests that detect tumor DNA. These tests are only recommended for individuals who decline or do not complete preferred screening tests, such as a colonoscopy or stool-based options. Compared to established stool tests, blood-based tests demonstrated lower sensitivity for both stage I cancers and advanced precancerous lesions.
For any stool or blood-based screening test to be effective, the ACS notes that a positive result requires a follow-up colonoscopy, preferably within six months, to complete the screening process.
Addressing the Screening Gap
While early-stage detection yields five-year survival rates of more than 90%, approximately one in three eligible adults have not been tested as recommended.
“No matter which test you choose, what’s most important is to get screened, and that includes underserved, rural, and minority populations,” says William Dahut, MD, chief scientific officer at the American Cancer Society, in a release. “These changes were developed to add to the colorectal cancer screening arsenal and help ensure preventive cancer care is available to all.”
While new options have been added, the ACS continues to recommend several existing methods, including high-sensitivity fecal immunochemical tests and guaiac-based tests every year, and visual exams such as a colonoscopy every 10 years or a flexible sigmoidoscopy every five years.
The ACS Guideline Development Group indicates it will continue to monitor clinical outcomes and real-world implementation to inform future updates for these targeted-based screening tests.
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