A Gastroenterologist’s Perspective on Colon Cancer Screening
Cologuard advertisements paint a picture of convenient, at-home colon cancer screening that seems almost too good to be true. As a board-certified gastroenterologist with over 25 years of experience, I feel compelled to share a more balanced picture. While any colon cancer screening is better than no screening at all, patients deserve to understand the significant differences between their options.
Detection Rates:
- Colonoscopy: Detects 95% of large polyps
- Cologuard: Detects only 42% of large polyps; this includes a considerable number of polyps with potentially serious “dysplasia”
- FIT Test: Detects only 24% of large polyps
This means that 58% of dangerous precancerous polyps go completely undetected with Cologuard testing.
Cologuard is designed to detect cancer, not prevent it. When we find polyps during a colonoscopy, we remove them immediately during the same procedure. This isn’t just detection—it’s actual cancer prevention.
Cologuard is much poorer at detecting small and medium sized precancerous polyps, when it is easier and safer to remove them. It is of little value in someone who has had a prior colonoscopy, and is due for routine follow-up.
Cologuard has a significant false-positive rate. This rate increases with age, precisely when colon cancer risk is highest. It is especially high in someone who’s last colonoscopy is up to date. False positive tests often lead to unnecessary anxiety, and unnecessary colonoscopies.
If you fall into a high-risk categories including a family history of colon cancer, personal history of colon polyps, current GI symptoms, or previous positive stool based tests, you should skip Cologuard entirely and proceed directly to colonoscopy. Using Cologuard first wastes time and money. You’ll end up needing a colonoscopy anyway, but you may have given precancerous polyps additional time to grow or potentially become malignant.
Cologuard costs around $500-600, often subject to deductibles and co-insurance. Screening colonoscopy is usually covered 100% by insurance with no out of pocket costs. Cologuard is both less effective and more expensive than other screening options when you factor in the need for follow-up colonoscopies.
Marketing vs. Medical Reality
Advertisements may suggest that Cologuard can replace colonoscopy, but this simply isn’t accurate. Even Cologuard’s own medical literature doesn’t position it as a replacement for colonoscopy—it’s marketed as an alternative for those who would otherwise avoid all screening.
When Might Cologuard Be Appropriate?
Cologuard does have a place in colon cancer screening, but it’s limited. It may be appropriate for patients who absolutely refuses colonoscopy despite counseling about the benefits, have medical conditions that make colonoscopy too risky, or live in areas where access to colonoscopy is severely limited.
Even in these cases, patients must understand that they’re accepting significantly reduced detection rates and may still need colonoscopy if the test is positive.
My Professional Recommendation
Colonoscopy remains the gold standard because it:
- Detects 95% of large polyps (vs. 42% for Cologuard)
- Removes polyps immediately, actually preventing cancer
- Is far more accurate in detecting smaller precancerous polyps
- Typically costs patients nothing out-of-pocket
- Provides peace of mind with the most accurate screening available
Dr. Michael Braunstein is a board-certified gastroenterologist with over 25 years of experience in private practice. He personally performs every procedure and sees every patient, ensuring continuity of care and personalized attention
Sources: 1- NEJM 2014;370:1287-1297
2- US Preventative Services Task Force; JAMA: Published Online May 18, 2021
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