Colonoscopy.us
Risk conversation

Family history can change when screening starts

A parent, sibling, or child with colorectal cancer or an advanced colorectal polyp can change your screening plan. The exact recommendation depends on who was affected, what they had, and the age at diagnosis.

Do not use this tool to self-prescribe a colonoscopy schedule. It organizes the information a clinician needs. Hereditary syndromes, multiple affected relatives, and young diagnoses can require genetics evaluation and substantially different surveillance.
1. Which relative is affected?
2. What did they have?
3. How old were they when diagnosed?
4. Any known hereditary syndrome?
General professional guidance

Why first-degree relatives matter

Earlier screening may be recommended

ACG guidance uses age 40 or 10 years before the youngest affected first-degree relative’s diagnosis as an important starting point in certain family-history situations.

The details change the plan

If the affected first-degree relative was younger than 60, or if two or more first-degree relatives are affected, ACG guidance may favor colonoscopy and shorter intervals. Other family-history patterns may use average-risk options.

This page intentionally does not turn that rule into an automatic schedule. A clinician needs the exact pathology, ages, number of relatives, and sometimes genetic-counseling information.

Bring this to the appointment

Family-history checklist

Bring better information to the visit

Family-history worksheet

Enter only what you know. Approximate ages are still useful. The worksheet stays in your browser and can be printed.

RelativeCondition/findingAge at diagnosis
Evidence

Primary sources for this page

American College of GastroenterologyFamily-history screening recommendationsAmerican Cancer SocietyAverage-risk vs increased/high-risk categoriesNCIGenetics of colorectal cancer

Medical content reviewed against these sources on September 5, 2026. This does not replace clinician review before public launch.