Guidelines for Cologuard Use in Colorectal Cancer Screening
Cologuard (multitarget stool DNA test) should be offered every 3 years as an acceptable screening option for average-risk adults aged 45-75 years, but colonoscopy every 10 years or annual FIT remain the preferred first-tier screening strategies. 1, 2
Age to Begin and Stop Screening
Start screening at age 45 years for all average-risk adults, though this is a qualified recommendation with the strongest evidence supporting screening from age 50 onward (strong recommendation). 1
Stop screening at age 75 years in patients who are up-to-date with prior screening and have negative results, particularly if they have had high-quality colonoscopy or life expectancy is less than 10 years. 1
For ages 76-85 years, offer screening only to those who have never been screened previously, considering their overall health status, comorbidities, and whether they are healthy enough to undergo treatment if cancer is detected. 1
Discontinue screening after age 85 years regardless of prior screening history, as harms outweigh benefits in this population. 1, 3
Cologuard-Specific Guidelines
Cologuard is classified as a second-tier screening test behind colonoscopy every 10 years and annual FIT, which are the cornerstones of screening and recommended as first-tier options. 1, 2
The screening interval for Cologuard is every 3 years when used as the primary screening modality. 1
All positive Cologuard results mandate timely diagnostic colonoscopy as part of the screening process—this is non-negotiable and patients must understand this commitment before initiating stool-based screening. 1, 3, 4
Critical Implementation Requirements
Cologuard is appropriate only for average-risk individuals, defined as those without: family history of colorectal cancer, long-standing inflammatory bowel disease, genetic syndromes (such as familial adenomatous polyposis), or personal history of colorectal cancer or adenomatous polyps. 1
Never use Cologuard in symptomatic patients with alarm symptoms including rectal bleeding, narrowed stools, or unexplained weight loss—these patients require immediate diagnostic colonoscopy regardless of any stool test results. 4
Assess life expectancy before initiating screening: avoid screening if life expectancy is less than 10 years due to comorbidities, as the average time to prevent one colorectal cancer death is 10.3 years from screening initiation. 1, 3
Positioning Relative to Other Screening Options
When offering multiple screening options, present colonoscopy every 10 years and annual FIT as the preferred choices, with Cologuard every 3 years as an acceptable alternative for patients who decline the first-tier tests. 1, 2
In a sequential approach, offer colonoscopy first; if declined, offer annual FIT; if FIT is also declined, then Cologuard every 3 years becomes an appropriate option. 2
Cologuard has disadvantages relative to colonoscopy and FIT, including higher cost per test, lower sensitivity for advanced adenomas compared to colonoscopy, and less robust evidence for mortality reduction compared to FIT. 2
Common Pitfalls to Avoid
Do not continue screening past age 75 years in patients with adequate prior negative screening history, as harms increasingly outweigh benefits with advancing age. 1, 3, 4
Do not use Cologuard as a diagnostic test in patients with symptoms or known colorectal pathology—it is a screening tool only for asymptomatic average-risk individuals. 4
Ensure colonoscopy capacity exists before ordering Cologuard, as positive results require diagnostic colonoscopy follow-up and failure to complete this workup renders the screening program ineffective. 4
False-positive rates for Cologuard range from 13-40%, meaning a substantial proportion of positive tests will not reveal significant pathology on colonoscopy, but follow-up colonoscopy remains mandatory. 5