What are the screening guidelines for Cologuard (multitarget stool DNA test)?

From the Guidelines

Cologuard is recommended as a colorectal cancer screening option for average-risk adults aged 45 to 75 years at 3-year intervals. Average risk means individuals without a personal history of colorectal cancer, advanced adenomas, inflammatory bowel disease, or a family history of colorectal cancer syndromes. The test should not be used in high-risk individuals who require more frequent screening with colonoscopy. Before using Cologuard, patients should not take anti-diarrheal medications or laxatives, and should inform their provider about any rectal bleeding as this may affect results. The test works by detecting altered DNA and blood in stool that might indicate the presence of colorectal cancer or precancerous lesions. If the Cologuard test returns positive results, a follow-up diagnostic colonoscopy is required. While Cologuard is less invasive than colonoscopy, it has a higher false positive rate and may miss some precancerous lesions. The 3-year interval balances detection capability with practical considerations, as the test is less sensitive than colonoscopy but more convenient for many patients.

Key Considerations

• The American Cancer Society recommends that adults aged 45 years and older with an average risk of CRC undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) exam, depending on patient preference and test availability 1.
• The options for CRC screening are: fecal immunochemical test (FIT) annually, high sensitivity guaiac-based fecal occult blood test (HSgFOBT) annually, multi-target stool DNA test (mt-sDNA) every 3 years, colonoscopy every 10 years, CT colonography (CTC) every 5 years, flexible sigmoidoscopy (FS) every 5 years 1.
• The American College of Physicians also recommends screening for colorectal cancer in asymptomatic average-risk adults, with options including FIT, HSgFOBT, mt-sDNA, colonoscopy, CT colonography, and flexible sigmoidoscopy 1.

Patient Selection

• Average-risk adults aged 45 to 75 years are eligible for Cologuard screening.
• High-risk individuals, such as those with a personal history of colorectal cancer, advanced adenomas, inflammatory bowel disease, or a family history of colorectal cancer syndromes, require more frequent screening with colonoscopy and are not suitable for Cologuard screening.

Test Characteristics

• Cologuard detects altered DNA and blood in stool that might indicate the presence of colorectal cancer or precancerous lesions.
• The test has a higher false positive rate and may miss some precancerous lesions compared to colonoscopy.
• A follow-up diagnostic colonoscopy is required if the Cologuard test returns positive results.

From the Research

Cologuard Screening Guidelines

• The Cologuard test is a multitarget stool DNA test that has been approved by the FDA for average-risk colorectal cancer (CRC) screening 2.
• The test includes quantitative molecular assays for KRAS mutations, aberrant NDRG4 and BMP3 methylation, and β-actin, plus a hemoglobin immunoassay 3.
• The sensitivity for detecting colorectal cancer was 92.3% with DNA testing, and the sensitivity for detecting advanced precancerous lesions was 42.4% with DNA testing 3.

Comparison with Other Screening Tests

• Cologuard has been compared to fecal immunochemical testing (FIT) and colonoscopy in terms of effectiveness and cost-effectiveness 4.
• The results showed that FIT and colonoscopy were more effective and less costly than Cologuard when participation rates were equal for all strategies 4.
• However, Cologuard was preferred by some patients due to its non-invasive nature and ease of use 5.

Patient Preferences and Adherence

• A study found that 31.1% of black and Latino patients preferred Cologuard, while 64.4% preferred colonoscopy 5.
• The preference for Cologuard was influenced by distinct test attributes, such as ease of use and non-invasive nature 5.
• Adherence to Cologuard was found to be higher than FIT, with equivalent specificity over a 3-year period 6.

Performance Benchmarks and Expected Efficacy

• Stool-based CRC screening tests, including Cologuard, are expected to reduce the incidence and mortality of CRC through detection of early-stage cancers and high-risk polyps 6.
• The performance benchmarks for Cologuard include high sensitivity for screen-relevant lesions and equivalent specificity to FIT over a 3-year period 6.