How does FAP cause cancer?

FAP causes extra tissue (polyps) to form in your large intestine (colon) and rectum. Polyps can also occur in the upper gastrointestinal tract, especially the upper part of your small intestine (duodenum). If untreated, the polyps in the colon and rectum are likely to become cancerous when you are in your 40s.

What are cancers that are associated with FAP?

FAP is also associated with an increased risk for cancer of the small intestine including the duodenum, and cancer of the thyroid, pancreas, liver (hepatoblatoma), central nervous system (CNS), and bile ducts, although these typically occur in less than 10% of affected individuals.

Is FAP precancerous?

Familial adenomatous polyposis (FAP) is a rare disease where a number of precancerous polyps develop in the large intestine, increasing chances for cancer. Preventive surgery is the standard treatment.

Is familial adenomatous polyposis curable?

Follow-up treatment Surgery doesn’t cure FAP. Polyps can continue to form in the remaining or reconstructed parts of your colon, stomach and small intestine. Depending on the number and size of the polyps, having them removed endoscopically may not be enough to reduce your risk of cancer.

What percent of adenomatous polyps become cancerous?

Adenomas: Many colon polyps are the precancerous type, called adenomas. It can take seven to 10 or more years for an adenoma to evolve into cancer—if it ever does. Overall, only 5% of adenomas progress to cancer, but your individual risk is hard to predict. Doctors remove all the adenomas they find.

Is FAP serious?

If FAP is not recognized and treated, there is a very high likelihood that a person will develop colorectal cancer. Individuals with FAP also have an increased chance of developing cancer in other organs, including the stomach, small intestine, and the pancreas and biliary tree.

How long does it take for an adenoma polyp to become cancerous?

At what age is FAP diagnosed?

Generally, a clinical diagnosis is suspected when an individual has between 10 and 99 adenomatous colon polyps, or more than 100 polyps diagnosed at an older age than that expected for FAP (age 35–40 or older).

What are the risk factors for cancer in children with FAP?

Risk for hepatoblastoma, a rare type of liver cancer, is increased in children with FAP. A locally aggressive, non-cancerous tumor type called desmoid tumors/desmoid fibromatosis and a rare type of brain tumor called medulloblastoma can also occur in some individuals. Risk for papillary thyroid cancer is also increased.

What are the risks of FAP/AFAP?

Individuals with FAP/AFAP also have an increased risk for other cancers, including upper gastrointestinal tract tumors, pancreatic, thyroid, central nervous system, and liver (hepatoblastoma in children under age 5) cancer.

What is the prevalence of FAP in colorectal cancer?

FAP accounts for less than 1% of colorectal cancer cases. An individual should meet clinical criteria or have a mutation that is identified by molecular genetic testing of the APC gene. A diagnosis of FAP is now established by molecular genetic testing.

What happens if FAP is not recognized and treated?