People with family histories of colorectal cancer (CRC) are at increased risk for CRC; the magnitude of the risk depends on the age of the person, age of the affected relative(s), number of affected relatives, and degree of relation. Several professional organisations have published screening guidelines, but these are inconsistent and based on relatively sparse literature. This new guideline provides recommendations on CRC screening in this population, using systematic reviews and the Grading of Recommendation Assessment Development and Evaluation approach to assess the quality of evidence.
- For people who have at least one first-degree relative (FDR) with CRC or advanced adenoma, screening is strongly recommended over no screening.
- For people who have one FDR with CRC, colonoscopy is the preferred screening modality, and fecal immunochemical testing (FIT) is second-line.
- For people who have one FDR with CRC or documented advanced adenoma, screening is suggested starting at age 40–50 or 10 years younger than the FDR's age at diagnosis, whichever is earlier, with screening intervals of 5–10 years for colonoscopy and 1–2 years for FIT.
- For people who have two or more FDRs with CRC, colonoscopy is the preferred test, starting at age 40 or 10 years younger than the earliest affected FDR and repeated at 5-year intervals.
- People who have one or more FDR with non-advanced adenoma, or second-degree relative with CRC, can be screened according to average-risk guidelines.