What to do now

1. Refer the parent and family to a genetic counselor / hereditary colorectal cancer clinic.
   • Confirm the exact genetic result in the parent, usually a disease-causing variant in the APC gene.
   • If the parent has FAP, each child has a 50% chance of inheriting the APC variant because FAP is autosomal dominant.
2. Test the children for the specific APC variant found in the parent.
   • Predictive testing is usually offered in childhood because the result changes medical screening during childhood.
   • Testing should be done with genetic counseling, including discussion with parents and, when age-appropriate, the child.
3. If a child tests positive for the familial APC variant:
   • Begin colon surveillance with a pediatric gastroenterologist, typically colonoscopy starting at age 10-15 years, then repeated about every 1-2 years. The exact interval is adjusted for polyp number and findings.
   • If many adenomas develop or they cannot be safely controlled endoscopically, the specialist will discuss preventive colorectal surgery at the appropriate time.
   • Later, they also need surveillance for upper gastrointestinal polyps, commonly with upper endoscopy beginning in early adulthood, as directed by the FAP team.
4. If a child tests negative for the known familial APC variant:
   • They generally do not need FAP-specific colonoscopic surveillance and can follow routine population colorectal screening advice when they become adults.
5. If genetic testing is unavailable, declined, or no familial APC variant is identified despite clinical FAP:
   • Treat each child as at risk and start high-quality colonoscopy between ages 10 and 15 rather than waiting for symptoms.

Hepatoblastoma screening in young APC-positive children

What to do now

1. Refer the parent and family to a genetic counselor / hereditary colorectal cancer clinic.
   • Confirm the exact genetic result in the parent, usually a disease-causing variant in the APC gene.
   • If the parent has FAP, each child has a 50% chance of inheriting the APC variant because FAP is autosomal dominant.
2. Test the children for the specific APC variant found in the parent.
   • Predictive testing is usually offered in childhood because the result changes medical screening during childhood.
   • Testing should be done with genetic counseling, including discussion with parents and, when age-appropriate, the child.
3. If a child tests positive for the familial APC variant:
   • Begin colon surveillance with a pediatric gastroenterologist, typically colonoscopy starting at age 10-15 years, then repeated about every 1-2 years. The exact interval is adjusted for polyp number and findings.
   • If many adenomas develop or they cannot be safely controlled endoscopically, the specialist will discuss preventive colorectal surgery at the appropriate time.
   • Later, they also need surveillance for upper gastrointestinal polyps, commonly with upper endoscopy beginning in early adulthood, as directed by the FAP team.
4. If a child tests negative for the known familial APC variant:
   • They generally do not need FAP-specific colonoscopic surveillance and can follow routine population colorectal screening advice when they become adults.
5. If genetic testing is unavailable, declined, or no familial APC variant is identified despite clinical FAP:
   • Treat each child as at risk and start high-quality colonoscopy between ages 10 and 15 rather than waiting for symptoms.

Hepatoblastoma screening in young APC-positive children

1. ACG Clinical Guideline: Diagnosis and Management of Adenomatous Colorectal Polyposis Syndromes, 2026
   Mankaney et al., American Journal of Gastroenterology. This is the newest North American society guideline found and covers genetic testing, colon and upper-GI surveillance, surgery, extracolonic manifestations, and chemoprevention. PMID 42683623

1. EHTG-ESCP Updated European Guidelines, 2024
   Broad multidisciplinary FAP, attenuated FAP, MAP, and GAPPS management guideline. Note that an erratum was published, so use the corrected version. PMID 38722804
2. ASCRS Clinical Practice Guideline, 2024
   Particularly useful for indications and choice of colorectal surgery, plus post-surgical surveillance. PMID 37682806
3. NCCN Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric, version 1.2025
   Current NCCN framework for FAP/APC testing and clinical management. Registration may be required. NCCN guideline page
4. GeneReviews: APC-Associated Polyposis Conditions
   A practical, frequently updated surveillance summary, though it is a reference resource rather than a society guideline. APC surveillance table

Practical surveillance schedule for classic APC-positive FAP

• Colonoscopy: begin age 10-15 years, repeat every 1-2 years. Shorten interval if adenomas are numerous, rapidly increasing, large, advanced histology is found, or colon clearance becomes difficult.
• Colectomy discussion: if cancer is suspected or present, there are symptoms, high-grade dysplasia, increasing or unmanageable adenoma burden, large unresectable adenomas, or surveillance is not feasible.
• Upper GI surveillance: EGD with careful ampullary visualization by age 20-25 years, or before colectomy. Follow-up is based on duodenal/ampullary burden and Spigelman stage, ranging approximately from 6 months to 5 years.
• Thyroid: current European guidance suggests that if thyroid surveillance is used, include physical examination and ultrasound. It may start around age 16 in females and adulthood in males; if baseline ultrasound is normal, repeat approximately every 2-3 years.
• Hepatoblastoma: some programs consider liver examination, abdominal ultrasound, and serum AFP every 3-6 months from birth through age 5 years. This is less uniformly recommended because evidence of benefit is limited.
• Desmoids/CNS: clinical neurologic and abdominal assessment, with imaging driven by symptoms, examination, family history, surgery planning, or concern for desmoid disease.

Latest pediatric FAP surveillance recommendations

For a child with a confirmed pathogenic APC variant causing classic FAP

Surgery

Important differences between current sources

• The pediatric AACR update supports annual colonoscopy after surveillance begins.
• GeneReviews and some other guideline summaries state every 1-2 years for classic FAP, beginning at age 10-15.
• For hepatoblastoma, older sources often suggested ultrasound/AFP every 3-6 months until age 5. The newer AACR pediatric update recommends the more intensive every-3-month schedule through age 7.