Colorectal Cancer Screening: Practical Tips for Clinicians
Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the U.S. While most cases are diagnosed in individuals over 65, rates are rising in adults under 50, making early screening more critical than ever. Screening reduces CRC mortality by catching cancer in its early, treatable stages, yet many patients remain hesitant or unsure of their options.
As clinicians, our role is to identify eligible patients, educate them on screening benefits and help them select the best test based on their preferences and risk factors.
Updated Screening Guidelines
Due to the rise in early-onset CRC, the U.S. Preventive Services Task Force (USPSTF) updated their guidelines in 2023:
- Ages 50-75 → Screening recommended (Grade A)
- Ages 45-49 → Screening recommended (Grade B)
- Ages 76-85 → Screening on a case-by-case basis (Grade C)
Some patients need screening earlier than 45, per the U.S. Multi-Society Task Force on Colorectal Cancer:
- Family or personal history of CRC or adenomatous polyps
- Inflammatory bowel disease (IBD) (Crohn’s or ulcerative colitis)
- Hereditary CRC syndromes, such as Lynch syndrome or familial adenomatous polyposis (FAP)
- History of abdominal or pelvic radiation
Colorectal Cancer Screening Options
Patients have several screening options, including stool-based tests, direct visualization tests, and emerging blood-based screening tests. The best test is the one the patient will actually complete.
|
Type of Test |
Sensitivity and Specificity |
Recommendations & Considerations |
|
Blood-Based Tests (ex: Shield™) -Tests for cell-free DNA in the blood. |
- 83% sensitivity for CRC and 13% for identifying advanced precancerous polyps -90% specificity |
-Not currently recommended by the USPFTF -Not able to detect precancerous polyps -May not be covered by patient insurance. -Patients with a positive result should be referred for a colonoscopy |
|
Stool-Based Tests: -High sensitivity guaiac-based fecal occult blood test (gFBOT) -Fecal immunochemical test (FIT) -Multitarget stool DNA test (sDNA-FIT) |
-High sensitivity gFBOT has a sensitivity of 5-7.4% (95% confidence interval, 0.9-10%) and a specificity of 96-98% (95% confidence interval, 95-99%) -FIT has a sensitivity of 74% (95% CI, 64-83%), and a specificity of 94% (95% CI, 93-96%) -sDNA-FIT has a sensitivity of 93% (95% CI, 87-100%) and a specificity of 84% (95% CI, 86-92%) |
-Stool-based tests do not require bowel prep -High sensitivity gFBOT requires 3 stool samples, the FIT and sDNA-FIT require only one sample -High sensitivity gFBOT and FIT are recommended annually, sDNA-FIT is recommended every 1-3 years. -Positive results required a colonoscopy. |
|
Direct Visualization Tests: -Colonoscopy -Flexible sigmoidoscopy (FS) -CT colonography |
-Colonoscopy has a sensitivity to detect adenomas >6mm of 75% (95% CI, 63%-84%) to 93% (95% CI, 88%-96% and specificity of 89% (95% CI, 86-91%) -The sensitivity and specificity of FS alone is 67% (95% CI, 58-75%) and 67% (95% CI, 59-75%). Studies have shown the combination of FS and FIT has a sensitivity and specificity of 89% (95% CI, 83-92%) and 75% (95% CI, 68-80%). -CT colonography has a 86-100% (95% CI range, 21-100%) to detect adenomas >6mm. The specificity was reported at 75.4 % (95 % CI 58.6 to 86.8 %). |
-Colonoscopy is recommended every 10 years -FS and CT colonography are recommended every 5 years -Patients can do FS every 10 years and FIT annually -All require bowel prep -Colonoscopy and FS require anesthesia and sedation |
How to Help Patients Choose the Right Test
With multiple screening options available, guiding patients toward the right colorectal cancer (CRC) test can feel overwhelming. A clear, practical discussion of the pros and cons of each method helps patients feel more confident in their choice.
But above all? The best screening test is the one they’ll actually complete.
Here’s how to navigate the conversation and address common barriers:
Start with Preferences
Does the patient prefer a non-invasive option? FIT or stool DNA testing may be a better fit. Are they willing to undergo a colonoscopy if a stool test is positive? If not, direct colonoscopy might be preferable.
Consider Compliance and Convenience
Annual FIT is effective, but only if done consistently. Some patients may struggle with bowel prep, making stool-based tests a good starting point.
Discuss Cost and Insurance Coverage
Insurance typically covers CRC screening, but some tests (like stool DNA and blood tests) may require out-of-pocket costs. Patients should understand what’s covered and what’s not before making a decision.
Address Barriers to Screening
Fear, embarrassment and discomfort are common reasons patients avoid CRC screening. Normalize the conversation, emphasizing that screening prevents cancer. For patients concerned about discomfort, highlight non-invasive options.
CRC screening saves lives and the best screening test is the one the patient will actually complete. By framing the conversation around choice, convenience, and accessibility, we can help patients overcome hesitation and follow through.
Want more practical tips on CRC screening? Check out the January episode of Primary Care RAP, "FIT vs. Stool DNA Sensitivity Testing" for a deep dive into stool-based tests!
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