American Cancer Society updates colorectal cancer screening guidelines with new blood test option
The American Cancer Society released updated colorectal cancer screening guidelines on May 27, 2026, adding guidelines for a blood-based screening test and new at-home stool testing options.
Objective Facts
The American Cancer Society released updated colorectal cancer screening guidelines on May 27, 2026, reaffirming that average-risk adults should begin screening at age 45 and continue through age 75, while adding guidelines for a blood-based screening test taken in a doctor's office and new at-home stool testing options. Colonoscopy remains the gold standard for colorectal cancer screening, while new blood-based tests are now among the recommended tests but are not a preferred option because research shows they are less likely to find precancerous growths and early-stage cancer. Blood-based tests (brand name Shield) are only recommended for individuals who decline or do not complete preferred screening tests, with studies predicting less effectiveness in reducing colorectal cancer incidence and mortality compared to stool-based tests. The guidelines also recommend an updated next-generation stool DNA test (Cologuard) and a new stool RNA test (ColoSense), both of which demonstrate high sensitivity for colorectal cancer and are recommended for screening every 3 years. The ACS states that by offering more screening tools, more eligible adults will be able to participate in lifesaving colorectal cancer testing, though more than 20 million Americans eligible for screening remain unscreened.
Left-Leaning Perspective
The American Cancer Society Cancer Action Network, led by President Lisa A. Lacasse, emphasized in the guideline announcement that 'coverage and affordability remain among the biggest factors in whether eligible individuals get screened for colorectal cancer,' with the organization pledging to 'continue pressing for policies that eliminate out-of-pocket costs and other barriers'. Medical experts supporting expanded options, such as Dr. Babak Firoozi, a gastroenterologist at MemorialCare Orange Coast Medical Center, argued that 'presenting more options is better' and stressed that 'it's important to increase the number of people who are being screened anyway we can'. Progressive health equity advocates flagged that lack of insurance and lower socioeconomic status are associated with lower screening prevalence, and that the anticipated high cost of newer tests—including blood-based tests and updated stool tests—will represent a significant barrier for uninsured and underinsured populations, emphasizing that this contradicts the stated goal of expanding access.
Right-Leaning Perspective
Dr. Scott Kopetz, a gastrointestinal medical oncologist at the University of Texas MD Anderson Cancer Center, raised concerns that while doctors are 'generally enthusiastic' about widening colorectal cancer testing options, 'we're going to lose ground in our battle for colorectal cancer prevention and early detection, that this is going to reduce the quality of screening that some of these patients may otherwise have received, because there is such a demand for what's easy and fast'. Dr. Robin Mendelsohn, Co-Director of Memorial Sloan Kettering Cancer Center's Center for Young Onset Colorectal and Gastrointestinal Cancers, emphasized that Shield was much less effective at detecting stage 1 colorectal cancers—missing 35%—and that Memorial Sloan Kettering experts do not recommend the Shield test as a screening tool because the goal of screening is to catch cancers early when they are more treatable. Dr. Kopetz concluded that 'blood-based screening does not perform as well for detection of pre-cancer as the other screening options and therefore should be reserved for individuals who will not complete other recommended screening,' adding that 'patients who otherwise would be willing to be screened by colonoscopy, stool-based tests, or other recommended methods should not swap to the blood-based assays'.
Deep Dive
The American Cancer Society's May 27 guideline update reflects a fundamental tension in cancer screening policy: the desire to increase participation among the one-third of eligible Americans who remain unscreened versus maintaining detection quality. The guideline carefully positions the blood-based Shield test as a backup option only for those declining other tests, not as a preferred alternative. However, this distinction may blur in clinical practice. Research shows Shield detects 83% of colorectal cancers but misses 35% of stage 1 cancers—the most treatable form—and only 13% of precancerous polyps. Cost-effectiveness analyses consistently show blood-based screening, even with higher participation rates, would prevent fewer cancers and deaths than established stool tests or colonoscopy due to its poor adenoma detection. The real policy challenge is that the guideline solves a participation problem (by offering options) while potentially creating a quality problem: whether patients receiving information about Shield will choose it over more effective alternatives, or whether insurance and healthcare systems will prefer to offer cheaper blood tests to reduce costs. Health equity advocates note that newer tests are expensive, potentially creating a two-tier system where insured patients get effective screening while cost barriers prevent uninsured and underinsured populations from accessing any screening at all.