March is Colon Cancer Awareness Month, a crucial time to highlight the importance of regular screenings in preventing and detecting colorectal cancer early. Colon cancer is the second leading cause of cancer-related deaths in the United States, but with timely screenings, it is also one of the most preventable and treatable cancers.

Why Screenings Matter

Colon cancer often develops from precancerous polyps in the colon or rectum. These polyps can be detected and removed before they turn into cancer. Beginning at age 45 (or earlier for those with a family history), regular screenings are essential for early detection.

The Gold Standard: Colonoscopy

Among the various screening options available, a colonoscopy remains the most effective and comprehensive test. Gastroenterologists consider it the gold standard for several reasons:

• Direct Visualization & Biopsy: Colonoscopy allows doctors to examine the entire colon, identify abnormalities, and remove precancerous polyps in real time.
• High Detection Rates: Colonoscopy detects over 95% of advanced adenomas and polyps, significantly reducing the risk of developing colorectal cancer.
• Longer Screening Interval: If no abnormalities are found, most patients only need a repeat colonoscopy every 10 years, unlike other tests that require more frequent screening.
• Therapeutic Benefits: Unlike other screening methods, colonoscopy can both detect and treat issues in one procedure.

Learn about what to expect from your procedure at the link below.

Procedures: Start to Finish (for download)

Other Screening Options: How Do They Compare?

For those unable or unwilling to undergo a colonoscopy, alternative, non-invasive screening methods are available. While useful, they have limitations in detection rates and effectiveness.

Cologuard (Stool DNA Test)
Cologuard is an at-home stool test that detects abnormal DNA and blood associated with colorectal cancer.

• Detection Rate: It identifies 92% of colorectal cancers but only about 42% of precancerous polyps.
• Frequency: It needs to be repeated every 3 years.
• Limitations: High false-positive rates can lead to unnecessary follow-up colonoscopies. Additionally, it cannot detect or remove polyps.

Learn more about colonoscopies versus Cologuard in the printable infographic linked below:

Picking the Right Test (for download)

FIT (Fecal Immunochemical Test)
FIT is another stool-based test that detects hidden blood in the stool, which may be an indicator of cancer.

• Detection Rate: It finds 74% of colorectal cancers but only about 24% of advanced adenomas.
• Frequency: Requires annual testing.
• Limitations: Like Cologuard, it does not detect or remove polyps, and positive results require follow-up with a colonoscopy.

Guardant Health Shield (Blood-Based Test)
A newer option in colorectal cancer screening, Guardant Health’s Shield test is a blood-based test that detects tumor-derived DNA.

• Detection Rate: Studies show it detects 83% of colorectal cancers but has lower sensitivity for precancerous polyps.
• Frequency: Annual testing is recommended.
• Limitations: While promising, it is not yet a replacement for a colonoscopy, especially in individuals at higher risk.

Dr. David Ramsay explains more about this blood test and it is effectiveness in the video.

Why Colonoscopies Remain the Best Choice

While stool-based and blood-based tests are convenient and may be useful for those unwilling to undergo a colonoscopy, they have lower detection rates for precancerous polyps. Only a colonoscopy allows direct visualization, removal of polyps, and immediate biopsy, making it the most effective tool for preventing colorectal cancer.
For those who opt for an alternative screening test and receive a positive result, a follow-up colonoscopy is required. This underscores the importance of colonoscopy as the definitive diagnostic and preventive procedure.

Take Action: Schedule Your Screening

If you’re 45 or older, or have a family history of colorectal cancer, talk to your doctor about scheduling a colonoscopy or the best screening test for you. Early detection saves lives.

Learn More
For more information on colorectal cancer screenings, visit:
• American Cancer Society: https://www.cancer.org
• Colorectal Cancer Alliance: https://www.ccalliance.org
• Guardant Health: https://www.guardanthealth.com

This Colon Cancer Awareness Month make your health a priority, schedule your screening, and encourage loved ones to do the same!

– Published March 4, 2025