How often should Cologuard (multitarget stool DNA test) be used for colorectal cancer screening?

Cologuard (Multitarget Stool DNA Test) Screening Frequency for Colorectal Cancer

Cologuard should be performed every 3 years for colorectal cancer screening in average-risk adults. 1, 2

Evidence-Based Recommendation

The American Cancer Society (ACS) and the U.S. Preventive Services Task Force (USPSTF) both recommend that multitarget stool DNA testing (Cologuard) should be performed every 3 years for colorectal cancer screening in average-risk adults 1. This recommendation is based on the test's performance characteristics and ability to detect both colorectal cancer and precancerous lesions.

Test Performance Characteristics

Cologuard offers several advantages compared to traditional stool-based tests:

• Higher sensitivity for detecting colorectal cancer (92.3% vs. 73.8% for FIT) 1
• Better detection of advanced precancerous lesions (42.4% vs. 23.8% for FIT) 1
• Superior detection of polyps with high-grade dysplasia (69.2% vs. 46.2%) 1
• Improved detection of serrated sessile polyps >1 cm (42.4% vs. 5.1%) 1

However, Cologuard has lower specificity (86.6%) compared to FIT (94.9%), resulting in more false positives 1.

Screening Algorithm for Average-Risk Adults

1. Begin screening at age 45-50:

   • ACS recommends starting at age 45 1
   • USPSTF and NCCN recommend starting at age 50 1

2. Choose screening method based on patient preference:

   • Cologuard every 3 years 1
   • Annual FIT or high-sensitivity gFOBT 1
   • Colonoscopy every 10 years 1
   • CT colonography every 5 years 1
   • Flexible sigmoidoscopy every 5 years 1

3. Follow-up after positive Cologuard:

   • Diagnostic colonoscopy should be performed within 3-6 months 2
   • Delaying colonoscopy beyond 6 months increases risk of colorectal cancer and advanced-stage disease 2

Important Considerations

• Cologuard is designed to detect both cancer and advanced adenomas, making it more comprehensive than traditional stool-based tests that primarily detect cancer 1
• The 3-year interval balances sensitivity with practicality and cost-effectiveness 1
• Monthly variations in screening test usage have been observed, with FIT-DNA (Cologuard) usage peaking in March (11.3%) and being lowest in January and June (7.2-7.3%) 3

Common Pitfalls to Avoid

1. Using inappropriate screening intervals: Some providers mistakenly recommend annual Cologuard testing, which is unnecessary given its high sensitivity and designed 3-year interval.

2. Failing to follow up positive results: Only 32.8-62.1% of patients with positive stool tests complete follow-up colonoscopy 2. Ensure proper follow-up protocols are in place.

3. Inappropriate use in high-risk individuals: Cologuard is intended for average-risk screening. Individuals with personal or family history of colorectal cancer, advanced adenomas, inflammatory bowel disease, or genetic syndromes require different screening approaches, typically with colonoscopy 4.

4. Overscreening elderly patients: Consider discontinuing screening after age 75 in those with prior negative screening results, or age 85 for all patients 1.

By adhering to the recommended 3-year interval for Cologuard testing, healthcare providers can optimize colorectal cancer screening while minimizing unnecessary testing and follow-up procedures.