When Should Colorectal Cancer Screening Begin and End?

Answer in brief: For average-risk U.S. adults, colorectal cancer screening should begin at age 45. Screening is routinely recommended through age 75; after 75, continuation should be individualized according to health, prior screening and life expectancy. High-risk family history, hereditary syndromes, prior advanced polyps, IBD colitis and other conditions require earlier or different surveillance pathways.

Age 45 is the current average-risk starting point

The ACG 2021 guideline and USPSTF recommendations lowered average-risk screening from age 50 to 45 because colorectal cancer incidence has risen in younger adults. This applies to people without symptoms and without a separate high-risk indication.

Colonoscopy and FIT are primary options

Colonoscopy every 10 years and annual fecal immunochemical testing are major first-line strategies when prior testing is normal and the patient remains average risk. Other options include stool DNA testing, CT colonography, flexible sigmoidoscopy and colon capsule in selected settings. Any positive non-colonoscopic test requires diagnostic colonoscopy.

After 75, benefit becomes individualized

Chronologic age alone is not enough. Consider prior screening history, comorbidity, functional status, life expectancy and willingness to undergo follow-up colonoscopy if a noninvasive test is positive. A healthy 77-year-old never screened is different from an 80-year-old with major competing illness and repeated normal colonoscopies.

Family history changes timing

A first-degree relative with colorectal cancer or an advanced polyp—especially when diagnosed before age 60 or when multiple first-degree relatives are affected—can justify colonoscopy beginning earlier, commonly around age 40 or 10 years before the youngest diagnosis, depending on the family-history pattern.

Symptoms are not screening

Rectal bleeding, iron-deficiency anemia, unexplained weight loss or a concerning change in bowel habit require diagnostic evaluation regardless of whether the patient is “due” for routine screening.

What trainees should remember

Average-risk CRC screening starts at 45, not 50. Continue routinely through 75, individualize thereafter, and move into a high-risk pathway when family history, prior neoplasia or colitis changes baseline risk.

Frequently asked questions

Can a positive stool test simply be repeated?

No. A positive screening stool test should be followed by colonoscopy rather than repeated to see if it becomes negative.

Should screening stop automatically at 75?

No. After 75 the decision is individualized; it is not an automatic stop date.

References and further reading

1. Thomson ABR. Best Practice Guidelines in Gastroenterology Disorders. CAPstone Academic Publishers; 2024.

2. Thomson ABR. Guideline-Based Management in Gastroenterology. CAPstone Academic Publishers; 2015.

3. Shaukat A, et al. ACG Clinical Guidelines: Colorectal Cancer Screening 2021. Am J Gastroenterol. 2021;116:458-479.