Familial Adenomatous Polyposis
DefinitionFamilial adenomatous polyposis (FAP) is a rare, inherited condition that causes colorectal cancer. FAP results in the development of hundreds of polyps inside the large intestine.
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CausesFAP is caused by a genetic defect. Polyps usually begin developing during during the teenage years, and 95% of people with FAP will have polyps by age 35. The average person with FAP will have colorectal cancer found by the age of 39 years.
Risk FactorsThe primary risk factor for FAP is having family members with this condition. However, this condition can occur in people without a family history of the condition. This is because the genetic defect can caused by a new mutation in the affected person.
SymptomsIn the early stages, there may be no symptoms. When symptoms do occur, they may include:
- Rectal bleeding or blood in the stool
- Cramping pain in the stomach
- Weight loss
DiagnosisYour doctor will ask about your symptoms and medical history. A physical exam will be done. To confirm a diagnosis, your doctor will do some tests. These may include:
- DNA analysis to determine if you have the defective gene
- Biopsy to see if polyps are cancerous
- Eye exam to look for lesions in the retina
- An exam of the stomach and the upper part of the small intestine
- An exam of the rectum and colon
TreatmentFAP is treated with surgery. Since FAP causes so many polyps, they cannot be removed individually. Therefore, the goal of surgery is to remove the portion of the intestine that contains the cancerous or precancerous polyps. The surgical procedure used depends on the length of intestine involved.
SurgeryThe three main surgical treatments are:
- Colectomy with ileorectal anastomosis (IRA) —Removal of the colon except for a small section above the rectum. The last part of the small intestine is connected to the remaining part of the colon, preserving bowel function.
- Restorative proctocolectomy (pouch) —Removal of the colon and rectum, leaving the anal canal. A pouch is created with the lower end of the small intestine. The pouch mimics the function of the rectum. The pouch is connected to the anal canal, preserving bowel function.
- Total proctocolectomy with permanent ileostomy —Removal of the colon, rectum, and anal canal. A permanent ileostomy is created. An ileostomy is a surgical opening through the wall of the abdomen. It is used as a path for waste material to leave the body. After an ileostomy, you will wear a special bag to collect body waste.
MedicationsMedications are used shrink polyps and to prevent new ones from forming. Medications include:
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- COX-2 inhibitors
Follow-UpThe remaining intestine will need to be inspected by endoscopy as often as every 6 months for the rest of your life. Because the risk of developing other polyps that could grow to become cancer is so high, it is crucial for your doctor to keep a very close watch. If more polyps arise, further surgery may be required.
PreventionThere are no current guidelines to prevent FAP.
American Cancer Society
Canadian Cancer Society
Colorectal Cancer Association of Canada
FAP. Cleveland Clinic website. Available at: http://my.clevelandclinic.org/disorders/inherited%5Fcolon%5Fcancer/dd%5Ffap.aspx. Accessed May 24 ,2013.
Familial adenomatous polyposis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated June 25, 2012. Accessed May 24, 2013.
Familial adenomatous polyposis. Genetics Home Reference website. Available at: http://ghr.nlm.nih.gov/condition/familial-adenomatous-polyposis. Updated April 2008. Accessed May 24, 2013.
Jasperson KW, Burt RW. APC -associated polyposis conditions. GeneReviews. Available at: http://www.ncbi.nlm.nih.gov/books/NBK1345. Updated October 27, 2011. Accessed May 24 ,2013.
- Reviewer: Mohei Abouzied, MD
- Review Date: 05/2014
- Update Date: 05/28/2014
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