Familial Adenomatous Polyposis

Establish an APC-associated polyposis condition by identifying a heterozygous germline pathogenic APC variant. Classic and attenuated FAP are APC-associated phenotypes; gastric adenocarcinoma and proximal polyposis of the stomach is also included in the APC-associated spectrum. PubMedPubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI Bookshelf

A clinical phenotype of more than 100 colorectal adenomatous polyps supports classic FAP; fewer than 100 adenomas with a family history of FAP also supports the diagnosis. Attenuated FAP generally has fewer than 100 adenomas, later polyp development, and a more proximal colonic distribution. ScienceDirect+1ScienceDirectFamilial Adenomatous Polyposis - an overview | ScienceDirect TopicsccjmDetecting and managing hereditary colorectal cancer syndromes in ...

For a known familial APC pathogenic variant, offer predictive molecular testing to at-risk relatives early enough to determine whether childhood surveillance is necessary. In confirmed FAP after predictive testing, colonic surveillance should normally begin at age 12-14 years; GeneReviews recommends colonoscopy every 1-2 years beginning at age 10-15 years for classic FAP. BMJ+1BMJGuidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG) | GutPubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI Bookshelf

When a patient has multiple colorectal adenomas but no germline APC or MUTYH variant, retain concern for APC mosaicism rather than labeling the condition sporadic without further assessment. Low-level APC mosaicism accounts for a substantial fraction of otherwise unexplained adenomatous polyposis, and first-degree relatives may warrant colonoscopic risk assessment at referral or again at age 50 years, although this latter recommendation lacked guideline consensus. BMJ+1BMJGuidelines for the management of hereditary colorectal cancer ... - GutBMJGuidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG) | Gut

Continue colonoscopic surveillance while adenomas remain endoscopically manageable, but refer for colectomy planning when multiple adenomas larger than 10 mm cannot reasonably be removed, adenoma number increases substantially between examinations, high-grade dysplasia is identified, or innumerable diminutive adenomas prevent adequate colonic surveillance. Limited endoscopic access or inability to adhere to surveillance is also a relative indication for colectomy. PubMedPubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI Bookshelf

Colectomy is the preventive standard for classic FAP because it reduces colorectal cancer risk. The operation should be selected and timed through a colorectal surgery team able to integrate rectal polyp burden, endoscopic feasibility, patient reliability for lifelong surveillance, and competing extracolonic disease. PubMedPubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI Bookshelf

Surveillance materially changes outcomes. In a systematic review, symptomatic FAP presentation was associated with colorectal cancer in 33.6%-66.2% of patients versus 3.8%-9.4% among those under surveillance; surveillance delayed colorectal cancer development by up to 16 years and improved mean survival by up to 12 years. BMJBMJRole of endoscopy in patients with familial adenomatous polyposis

Do not defer indicated surgery because pharmacologic polyp regression occurs. NSAIDs and erlotinib have reduced adenoma burden in studies, but no agent is FDA-approved for FAP chemoprevention because reduction in later cancer risk remains unclear. Colectomy or proctocolectomy remains initial standard care. PubMed+1PubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI BookshelfWolters KluwerCombination of Sulindac and Eflornithine Delays... - Lippincott

Perform esophagogastroduodenoscopy with visualization of the ampulla of Vater by age 20-25 years or before colon surgery. Upper GI surveillance should not omit ampullary inspection, because duodenal and ampullary adenomas can progress independently of the colorectal phenotype. PubMed+1PubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI BookshelfWolters KluwerEndoscopic Surveillance of Duodenal Polyposis... : ACG Case Reports Journal

Stage duodenal adenomatosis using the Spigelman classification, which is recommended for risk stratification and has demonstrated excellent interobserver reliability among experienced endoscopists (intraclass correlation coefficient 0.95, 95% CI 0.91-0.98). In advanced Spigelman stage, consider complete small-bowel visualization. Wolters Kluwer+1Wolters KluwerValidation of the Endoscopic Part of the Spigelman... : Official journal of the American College of Gastroenterology | ACGPubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI Bookshelf

The clinical stakes are substantial: duodenal adenomas develop in an estimated 88%-98% of patients with FAP, and estimated duodenal cancer risk reaches 18% by age 75 years. High-risk duodenal adenoma features are reported in 50% of patients by age 70 years. BMJBMJRole of endoscopy in patients with familial adenomatous polyposis

Endoscopically remove duodenal polyps larger than 10 mm when feasible. Repeated endoscopic resection and ampullectomy can downstage severe disease, but high-grade dysplasia or unresectable lesions should trigger evaluation for radical surgery, including duodenectomy or pancreaticoduodenectomy when malignancy is threatening. Wolters Kluwer+1Wolters KluwerEndoscopic Surveillance of Duodenal Polyposis... : ACG Case Reports JournalWolters KluwerSurveillance of Duodenal Polyposis in Familial... : Diseases of the Colon & Rectum

Maintain a low threshold to evaluate new abdominal mass symptoms in FAP for intra-abdominal desmoid tumor, particularly after abdominal surgery. Desmoid tumors are locally aggressive and infiltrative but rarely metastasize; reported FAP incidence is 10%-20%, and family history, surgery, and APC mutation are recognized risk factors. facs+1facsJejunal Desmoid Tumor After Roux-en-Y Gastric Bypass Mimicking GIST | ACSfacs[PDF] Jejunal Desmoid Tumor after Roux-en-Y Gastric Bypass Mimicking ...

For children known to carry an APC pathogenic variant or at 50% familial risk, annual hepatoblastoma screening from birth through age 5 years has been recommended. ScienceDirectScienceDirectFamilial Adenomatous Polyposis - an overview | ScienceDirect Topics

Do not automatically infer FAP from an isolated desmoid tumor. Although 5%-15% of desmoids are associated with FAP, reported yield of identifying FAP among patients with intra-abdominal or truncal desmoids without prior history was 4%-5%; a selective colonoscopy or genetic-testing strategy is therefore more appropriate than universal screening. facsfacsJejunal Desmoid Tumor After Roux-en-Y Gastric Bypass Mimicking GIST | ACS

At each surveillance encounter, document three variables that change management: colorectal adenoma size and removability, interval change in adenoma number, and dysplasia grade. These determine whether continued endoscopic control remains reasonable or colectomy should be advanced. PubMedPubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI Bookshelf

Coordinate colorectal and upper GI planning rather than treating them as sequential problems. EGD should occur by age 20-25 years or before colon surgery, and advanced duodenal disease may require complete small-bowel visualization or referral for therapeutic endoscopy and surgery. PubMed+1PubMedAPC-Associated Polyposis Conditions - GeneReviews® - NCBI BookshelfWolters KluwerSurveillance of Duodenal Polyposis in Familial... : Diseases of the Colon & Rectum

After colorectal surgery, continue surveillance of remaining at-risk gastrointestinal mucosa and maintain upper GI monitoring. Post-prophylactic adenocarcinomas and neoplastic change in ileal pouches have been reported, while duodenal cancer becomes a major malignancy after colectomy. BMJ+1BMJGuidelines for the management of hereditary colorectal cancer ... - GutWolters KluwerEndoscopic Surveillance of Duodenal Polyposis... : ACG Case Reports Journal