Patients who have been avoiding colorectal cancer screening due to concerns about colonoscopy or stool testing procedures now have a new alternative, according to updated recommendations released Wednesday by the American Cancer Society.
The medical organization has included Guardant Health’s Shield blood test among its approved screening methods for detecting colorectal cancer. The U.S. Food and Drug Administration gave its approval to Guardant’s Shield test in 2024, which works by identifying genetic material from tumors that circulates in the bloodstream.
According to the ACS, incorporating Guardant’s Shield blood test as a colorectal cancer detection method “reflects advances in disease detection and a critical shift in public health strategy to expand screening options and lower barriers to access,” as stated in their revised guidelines published in CA: A Cancer Journal for Clinicians.
“We need to increase our emphasis on colorectal cancer as a highly preventable disease as much as a treatable one,” Dr. Robert Smith, ACS vice president and senior author of the updated guideline, said in a statement.
The ACS emphasized that colonoscopy continues to be the preferred method for colorectal cancer screening, as it enables physicians to directly view the colon and rectum.
The revised guidelines also include home-based stool testing options, featuring an improved version of Exact Sciences’ Cologuard and Geneoscopy’s newly developed Colosense test. Both tests search for concealed blood and molecular indicators of cancer.
According to the ACS, stool-based tests show strong accuracy in identifying colorectal cancer and reasonable effectiveness in finding advanced precancerous growths.
While the blood test demonstrates excellent precision in identifying advanced cancers, it shows lower effectiveness than stool tests in finding precancerous growths and early-stage cancers. The ACS therefore suggests it only for people who refuse or fail to complete the recommended screening methods.
The organization has consistently emphasized that the best screening test is whichever one patients actually undergo.
Both stool and blood testing require more regular scheduling than colonoscopy, and any positive findings necessitate immediate colonoscopy follow-up to finalize the screening process, according to the ACS.
The guidelines maintain the existing recommendation that adults with average risk should begin colorectal screening at age 45 and continue until age 75 for individuals with more than 10 years of life expectancy.
Guardant reported that one-third of eligible Americans have not undergone colorectal cancer screening, and most fatalities from the disease occur among unscreened individuals.
By incorporating a blood testing option, “the new guidelines create another opportunity to reach patients who might otherwise go unscreened,” Guardant said.
The organization noted that neither stool nor blood tests are appropriate for individuals considered high-risk for the disease.
