The American Cancer Society (ACS) has updated its colorectal cancer (CRC) screening guidelines, giving patients more screening options than ever before. While colonoscopy remains the gold standard for detecting colorectal cancer, the updated recommendations now include new FDA-approved blood tests and at-home stool tests that may help more people get screened.
The message from experts is clear: the best screening test is the one you actually complete.
Why colorectal cancer screening matters
Screening can detect cancer before symptoms appear and may even find precancerous growths, called polyps, that can be removed before they turn into cancer. The ACS continues to recommend that adults at average risk begin screening at age 45 and continue through age 75, provided they have a life expectancy of more than 10 years.
What’s new in the guidelines?
Since the last ACS screening recommendations were published in 2018, several new screening tests have received FDA approval. The updated guidelines now include:
- New blood-based screening tests
- An updated stool DNA test
- A new stool RNA test
These additions give patients more flexibility in how they choose to screen.
Blood tests: A new option, but not the preferred one
One of the most talked-about updates is the inclusion of blood-based CRC screening.
In 2024, the FDA approved Shield, a blood test that looks for fragments of tumor DNA circulating in the bloodstream. In a large clinical trial, the test detected 83% of CRCs and correctly identified individuals without cancer about 90% of the time.
While this is an important advancement, experts caution that blood tests are not as effective as some established screening methods at detecting early-stage cancers and advanced precancerous lesions.
For that reason, the ACS doesn’t consider blood testing a preferred screening option. Instead, it may be appropriate for people who decline or don’t complete recommended screening methods, such as colonoscopy or stool-based tests.
Importantly, a positive blood test result must be followed by a colonoscopy to determine whether cancer or precancerous polyps are present.
New at-home stool tests join the list
The updated guidelines also include two FDA-approved stool-based screening tests:
Cologuard Plus
An updated version of the original Cologuard test, Cologuard Plus analyzes stool samples for specific DNA changes and traces of blood that may signal colorectal cancer.
ColoSense
A newer option, ColoSense looks for specific RNA markers and traces of blood in stool samples that may indicate cancer or precancerous changes.
Both tests can be completed at home and are recommended every three years for eligible individuals.
Experts note that these tests show high sensitivity for detecting colorectal cancer and moderate sensitivity for detecting advanced precancerous lesions.
Colonoscopy remains the gold standard
Despite the addition of new screening options, colonoscopy continues to be considered the most comprehensive screening test.
Unlike blood and stool tests, a colonoscopy can both detect and remove precancerous polyps during the same procedure. This ability to prevent cancer—not just find it—is one reason colonoscopy remains the preferred screening method for many patients.
The most important step: Follow-up after a positive result
One key concern raised by experts is what happens after a positive screening test.
Any abnormal result from a blood-based or stool-based screening test should be followed by a colonoscopy, ideally within six months.
Research suggests that some patients who receive abnormal blood test results may be less likely to complete the recommended follow-up colonoscopy compared with those who receive abnormal stool test results. Without this follow-up procedure, the screening process is incomplete, and potential cancers or precancerous growths could be missed.
What this means for patients
The updated guidelines reflect a growing effort to make CRC screening more accessible and convenient.
For some people, the idea of preparing for a colonoscopy may be enough to delay screening altogether. Having additional options may encourage more people to take that first step.
It’s important to understand the strengths and limitations of each screening method. While blood tests offer convenience, they may miss some early cancers or precancerous lesions that other screening tests are more likely to detect.
If you’re approaching age 45 or are overdue for screening, talk with your healthcare team about which option is right for you.
No matter which screening method you choose, staying up to date with screening and following through with recommended colonoscopy after a positive result remains one of the most powerful ways to reduce your risk of CRC
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