ACS Now Backs Blood Tests for Colon Cancer Screening in Those Who Skip Other Options
Updated American Cancer Society guidelines endorse blood-based colorectal cancer tests as an alternative for adults who decline colonoscopy or stool tests.
Summary
The American Cancer Society has updated its colorectal cancer screening guidelines to include blood-based tests like the FDA-approved Shield cell-free DNA test. While colonoscopy remains the gold standard, blood tests are now an accepted fallback for the roughly 1 in 3 Americans who skip screening entirely. New stool-based options, Cologuard Plus and ColoSense, were also added. Screening is recommended starting at age 45 for average-risk adults. The key message: the best test is the one you actually complete. Blood tests are less sensitive than stool or colonoscopy options but far better than no screening at all.
Detailed Summary
Colorectal cancer is the second leading cause of cancer death in the US, yet screening rates remain stubbornly low. The American Cancer Society's updated guidelines aim to close that gap by expanding the menu of accepted screening tools, including blood-based tests now cleared by the FDA.
The core recommendation is unchanged: average-risk adults should begin colorectal cancer screening at age 45 and continue through age 75 if life expectancy exceeds 10 years. Colonoscopy remains the preferred method. However, the updated guidelines formally recognize blood-based screening as an acceptable alternative for individuals who decline or cannot complete colonoscopy or stool-based testing.
The FDA-approved Shield test, a circulating cell-free DNA blood test, showed 83% sensitivity for colorectal cancer and 90% specificity for advanced neoplasia in the ECLIPSE clinical trial. Another blood test from Freenome is currently under FDA review. Importantly, the ACS cautions that blood tests show lower sensitivity for early-stage cancers and precancerous lesions compared to stool-based tests, and modeling predicts they will be less effective at reducing cancer incidence and mortality over time.
Two new stool-based tests were also added to the guidelines: Cologuard Plus, a next-generation multi-target stool DNA and hemoglobin test, and ColoSense, which analyzes stool RNA plus hemoglobin. Both are recommended every three years and demonstrate high sensitivity for colorectal cancer. A critical caveat applies to all non-colonoscopy tests: a positive result must be followed up with a diagnostic colonoscopy to be clinically meaningful.
For health-conscious individuals, the practical takeaway is straightforward. Barriers to colonoscopy, whether logistical, financial, or personal, no longer need to mean zero screening. A blood draw every few years is now a guideline-backed option, though it should be viewed as a minimum rather than an equivalent substitute for more sensitive methods.
Key Findings
- Blood-based colorectal cancer tests are now ACS-guideline-backed for adults who decline colonoscopy or stool tests.
- Shield blood test showed 83% sensitivity for CRC and 90% specificity for advanced neoplasia in clinical trials.
- Cologuard Plus and ColoSense stool RNA/DNA tests added to guidelines; both recommended every 3 years.
- Screening starts at age 45 for average-risk adults; colonoscopy remains the gold standard option.
- Any positive non-colonoscopy test result must be followed by a diagnostic colonoscopy to be valid.
Methodology
This is a news report summarizing updated clinical practice guidelines published in CA: A Cancer Journal for Clinicians by the American Cancer Society. The evidence basis includes FDA approval data, the ECLIPSE clinical trial, and cancer modeling studies. The source, MedPage Today, is a credible peer-reviewed medical news outlet targeting clinicians.
Study Limitations
The article is truncated and the full guideline document was not reviewed directly. Blood test sensitivity data comes from a single pivotal trial (ECLIPSE) and real-world performance may differ. Long-term outcome data for newer stool RNA tests and blood tests are not yet available.
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