Screenings for people with familial adenomatous polyposis

The main guidance

In the UK, the British Society of Gastroenterology, the Association of Coloproctology of Great Britain and Ireland and the UK Cancer Genetics Group published joint guidelines for hereditary colorectal cancer in 2020. (BSG/ACPGBI/UKCGG, 2020) In Europe, updated FAP guidelines from the European Hereditary Tumour Group and the European Society of Coloproctology were published in 2024. (European FAP guidelines, 2024) In the US, the American College of Gastroenterology (ACG) guideline dates from 2015, and the National Cancer Institute summarises the newer National Comprehensive Cancer Network (NCCN) recommendations. (ACG guideline, 2015)(NCI PDQ, 2025)

Checks the guidelines list

Colon. The British guideline recommends colonoscopy from 12 to 14 for people confirmed to have FAP on genetic testing, with intervals of 1 to 3 years based on the colon findings. (BSG/ACPGBI/UKCGG, 2020) The European guidelines say surveillance should begin at 12 in people without symptoms, and at any age and as soon as possible in people with symptoms. They suggest a repeat within a year or less when there are 100 or more adenomas, polyps of 10 mm or more, symptoms or fast growth, and at 2 years when there are 0 to 20 small adenomas and no symptoms. Flexible sigmoidoscopy can be a first option in classic FAP, by preference, with colonoscopy once adenomas are found. (European FAP guidelines, 2024) Decisions about colon surgery are made by the surgeon with the patient; this page does not cover them. See screening colonoscopy: what to expect.

Attenuated FAP. The NCI says colonoscopy is preferred over flexible sigmoidoscopy in attenuated FAP because the adenomas can be mostly in the right side of the colon, and that adenomas are believed to form in the mid to late twenties. Its summary of NCCN guidance lists high-quality colonoscopy every 1 to 2 years for people with attenuated FAP and a small adenoma burden. (NCI PDQ, 2025)

Stomach and duodenum. The NCI says upper endoscopy usually begins between 20 and 25, and earlier if the family has a history of large duodenal adenomas or duodenal cancer; later intervals vary with the previous findings, often based on the Spigelman stage. (NCI PDQ, 2025) The ACG lists intervals from every 4 years for stage 0 to every 6 to 12 months for stage III. (ACG guideline, 2015)

Thyroid. The European guidelines put the lifetime risk of thyroid cancer in FAP at 1.5 to 12 percent, and say thyroid surveillance, when done, should include a physical exam and thyroid ultrasound. (European FAP guidelines, 2024) The NCI notes that shorter intervals can be used when there is a family history of thyroid cancer. (NCI PDQ, 2025) See thyroid cancer screening.

After colectomy. Checks continue after the colon is removed. The European guidelines say surveillance after an ileorectal anastomosis should be by endoscopy at intervals of no more than 2 years, and that an ileo-anal pouch should be checked yearly, starting 12 months after colectomy. (European FAP guidelines, 2024) The ACG also lists an examination of an ileostomy every 2 years. (ACG guideline, 2015)

Young children. The NCI says NCCN suggests liver palpation, abdominal ultrasound and an alpha-fetoprotein blood test every 3 to 6 months for the first 5 years of life be considered for children with a predisposition to FAP. (NCI PDQ, 2025) The ACG lists these checks every 6 months until 7, while the European guidelines say there are not enough data to prove this screening improves survival and, if done, suggest every 6 to 12 months from birth to 5. (ACG guideline, 2015)(European FAP guidelines, 2024)

Checks for relatives

FAP is inherited in an autosomal dominant pattern: an affected person has a 50 percent chance of passing the APC change to each child, and in 75 to 80 percent of cases one parent has FAP. (MedlinePlus Genetics) The European guidelines say testing should be offered to all first-degree relatives, followed by cascade testing. (European FAP guidelines, 2024) The NCI says FAP justifies genetic testing of children in families with a known gene change, because about half will not carry it and can be spared surveillance; if at-risk children are not tested, colonoscopy starts between 10 and 15. NCCN recommends that relatives who test negative for the family's APC change follow average-risk screening. (NCI PDQ, 2025) When no gene change has been found in a relative with FAP, the British guideline suggests colonoscopy every 5 years from 12 to 14 until national screening age, unless polyps appear. (BSG/ACPGBI/UKCGG, 2020) See family history and screening and how to collect your family health history. For the other main inherited bowel cancer condition, see Lynch syndrome screening.

When to contact a provider

Routine age-based screening

FAP checks are added to, not instead of, the routine screenings for your age and sex; see screenings by age and gender.

Where they differ:

• Start of bowel checks. The British guideline starts colonoscopy at 12 to 14, the European guidelines at 12, the ACG at puberty, and the NCI summary at 10 to 15 for untested at-risk children. (BSG/ACPGBI/UKCGG, 2020)(European FAP guidelines, 2024)(ACG guideline, 2015)(NCI PDQ, 2025)
• Which bowel test. The ACG allows yearly colonoscopy or flexible sigmoidoscopy in classic FAP; the European guidelines prefer colonoscopy, with sigmoidoscopy as a first option by preference. (ACG guideline, 2015)(European FAP guidelines, 2024)
• Start of upper endoscopy. 25 in the British guideline, 25 to 30 in the ACG, 20 to 25 in the NCI summary and 18 to 30 in the European guidelines. (BSG/ACPGBI/UKCGG, 2020)(ACG guideline, 2015)(NCI PDQ, 2025)(European FAP guidelines, 2024)
• Thyroid ultrasound. Yearly in the ACG, every 2 to 5 years in the NCI summary of NCCN, and optional every 2 to 3 years in the European guidelines. (ACG guideline, 2015)(NCI PDQ, 2025)(European FAP guidelines, 2024)
• Liver checks in young children. Suggested until 5 (NCCN, in the NCI summary) or 7 (ACG); the European guidelines say the benefit is not proven. (NCI PDQ, 2025)(ACG guideline, 2015)(European FAP guidelines, 2024)

Your doctor decides what your result means for you.

Questions people ask

When do bowel checks start in FAP?

The 2020 British guideline says colonoscopy should normally start at 12 to 14 for people with a confirmed APC gene change, then every 1 to 3 years depending on what is found. The 2024 European guidelines say surveillance should begin at 12, and the 2015 ACG guideline says yearly colonoscopy or flexible sigmoidoscopy beginning at puberty. (BSG/ACPGBI/UKCGG, 2020) (European FAP guidelines, 2024) (ACG guideline, 2015)

Is attenuated FAP checked differently?

Yes. The European guidelines say surveillance can start later, but no later than 18 to 20, for people with an APC change linked to attenuated FAP and an attenuated family pattern, and that colonoscopy is the preferred test. The NCI summary of NCCN guidance lists colonoscopy every 1 to 2 years from the late teens for at-risk relatives who carry the family APC change. (European FAP guidelines, 2024) (NCI PDQ, 2025)

Why is the upper gut checked?

People with FAP have a higher risk of cancer of the duodenum, the first part of the small intestine. Upper endoscopy, including the duodenum, is advised from 25 in the British guideline, 25 to 30 in the ACG guideline and between 18 and 30 in the European guidelines, with later intervals set by the Spigelman stage of the polyps found. (MedlinePlus Genetics) (BSG/ACPGBI/UKCGG, 2020) (ACG guideline, 2015) (European FAP guidelines, 2024)

Is the thyroid checked?

Guidance varies. The ACG recommends a yearly thyroid ultrasound; the NCI summary says NCCN recommends a baseline ultrasound in the late teens repeated every 2 to 5 years if normal; the European guidelines say thyroid screening, if performed, can start at 16 in females and in adulthood in males, every 2 to 3 years after a normal first scan. (ACG guideline, 2015) (NCI PDQ, 2025) (European FAP guidelines, 2024)

Should relatives be tested?

Yes. FAP is autosomal dominant, so each child of an affected person has a 50 percent chance of inheriting the APC change. The European guidelines say testing should be offered to all first-degree relatives, followed by cascade testing, and the NCI notes FAP is one case where testing children in families with a known gene change is justified. (MedlinePlus Genetics) (European FAP guidelines, 2024) (NCI PDQ, 2025)

Related

• Screenings for people with Peutz-Jeghers syndrome
• Lynch syndrome screening and colonoscopy ages
• Family history: when screening starts earlier
• Colonoscopy after polyps
• Screenings for people with Cowden syndrome
• Screenings for people with Li-Fraumeni syndrome
• Thyroid cancer screening
• Screenings by age and gender
• Questions to ask your doctor