People who do not follow cancer screening recommendations can take a blood test, according to the American Cancer Society.
Blood testing can be used to detect colorectal cancers, the American Cancer Society said on May 27.
The society recommends regular screening for colorectal cancer for most people starting at age 45.
In an update to screening recommendations, the group kept in place its preference for colonoscopies, procedures in which doctors examine a patient’s bowels while the person is under anesthesia. Under the guidance, colonoscopies should be performed every 10 years.
People who opt against a colonoscopy should either choose a different visual exam, such as one using X-ray technology, or stool-based tests, according to the society.
People who do not undergo visual exams or stool-based tests can have a blood test instead.
“Blood-based screening tests are not preferred screening options at this time; they should be recommended only to individuals who decline or have not completed one of the preferred colorectal cancer screening tests,” authors of the updated guidelines said in a paper published by the society’s journal.
The blood tests are not preferred in part because data suggest they have lower sensitivity for precancerous lesions and stage 1 cancers.
“Ongoing evaluation of adherence, real-world implementation, and clinical outcomes will inform future updates for these new tests,” the authors wrote.
A positive blood test should be followed by a colonoscopy, ideally within 6 months, according to the society.
The recommended blood-based test, known as the Shield test, analyzes changes to DNA floating in the blood that may indicate a tumor or precancerous growth in the colon. Federal regulators approved it in 2024.
The updated guidelines also added an upgraded stool-based test, Cologuard Plus, and ColoSense, a newly approved test. Both can be done at home.
“We need to increase our emphasis on colorectal cancer as a highly preventable disease as much as a treatable one,” Dr. Robert Smith, senior vice president for early cancer detection science at the American Cancer Society and senior author of the report, said in a statement. “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.”
