Colorectal Cancer Screening in Primary Care: Who, When, and How

Colorectal cancer (CRC) screening saves lives. For most adults, screening begins at age 45 and continues through 75. After that, decisions are individualized.

Who Should Be Screened?

• Age 45–75: Screen everyone.

• Age 76–85: Individualize based on health, prior screening, and preferences.

• >85: Screening generally not recommended.

Average vs. Increased Risk

Average risk

• No personal history of adenomas/polyps or CRC

• No first-degree relative with CRC/advanced adenoma

• No hereditary syndrome (e.g., Lynch, FAP)

• No IBD with colitis (ulcerative colitis, Crohn’s colitis)

Increased risk (must use colonoscopy)

• Personal history of CRC or adenomas

• First-degree relative with CRC/advanced adenoma (especially <60, or ≥2 relatives at any age)

• Hereditary syndromes (Lynch, FAP, etc.)

• IBD with extensive colitis
  (Timing often: start at 40 or 10 years earlier than the youngest affected relative; repeat about every 5 years—GI will guide.)

Test Options & Intervals (Average Risk)

FOBT: Traditional guaiac FOBT is less specific; if used, it should be high-sensitivity gFOBT annually. Most clinics prefer FIT over FOBT.

Quick Picks (Average Risk)

• Wants at-home, lowest cost → FIT yearly

• At-home but more sensitive → FIT-DNA (Cologuard) q1–3 yrs

• One-and-done for a decade + polyp removal → Colonoscopy q10 yrs

Important: A positive stool test = diagnostic colonoscopy (don’t repeat the stool test).

After Colonoscopy

• Normal: typically q10 yrs

• Polyps found: surveillance usually 3–5 yrs (depends on number/size/histology; GI will set the interval)

Who Should Not Get CAC… wait, wrong test 😅

Who should not get stool-only screening:

• High-risk patients (see above) → colonoscopy only

• Symptoms (bleeding, iron-deficiency anemia, weight loss, change in bowel habits) → this is diagnostic, not screening—refer for colonoscopy

Prep & Practical Tips

• Colonoscopy prep: clear-liquid diet day before + bowel prep; arrange a driver.

• Insurance: screening colonoscopy is usually covered; a colonoscopy after a positive stool test may be billed as diagnostic—prepare patients for potential cost differences.

• Medication review: anticoagulants/antiplatelets—coordinate with GI if polypectomy likely.

Pearls (that save time)

• The best test is the one your patient will complete—offer a choice.

• Positive stool test ≠ repeat stool test → go straight to colonoscopy.

• High-risk or symptomatic → skip stool tests and refer for colonoscopy.

• Document family history details (which relative, age at diagnosis) to set the right pathway.

Education only; follow your local guidelines and payer policies. Use clinical judgment for special populations.

Questions or tricky scenarios? [email protected]  or DM me on social.
Want plug-and-play prevention templates for your clinic? My 1:1 mentorship can help—email me to book a free 15-minute call.