FAP
Risk of having FAP
If you have FAP and you have not had a colectomy, the average age colon cancer develops is 39. If you have had a colectomy, the risk for colon cancer is significantly reduced. But, your risk will depend on the type of colectomy and if the rectum is left in place.
For 25% to 30% of people with FAP, the condition is not inherited from a parent, and there is no family history of it.
As with other genetic conditions, you can have a hereditary syndrome without a clear explanation to how or why you have it. Regardless of whether or not FAP has been passed down in the family, a person with FAP has a 50% chance to pass on the condition to their children.
Did I have FAP from birth?
You are born with FAP, it’s not a condition that develops over time. But, the increased risk for cancer and symptoms develops over time.
As more polyps form, they may cause the same symptoms as colorectal cancer, such as:
- Abdominal pain
- Blood in the stool
- Changes in bowel habits
- Unexplained weight loss
- Anemia
Other symptoms of FAP can include:
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Dental issues
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Connective tissue tumors
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Tumors of the duodenum (small intestine), liver, bones, skin, and other tissues, which may be cancerous or noncancerous.
If you have FAP, it’s extremely important to proactively develop a screening schedule with your doctor and notify them of any symptoms. FAP patients have an extremely high risk of developing colorectal cancer at a younger age. They are also at increased risk of developing several other cancers (stomach, small intestine, pancreas, bile duct, liver, adrenal gland, thyroid, and brain).
Colorectal cancer screening if you have FAP
Here is what’s recommended for screening if you have FAP. As FAP also increases the risk for other cancers, additional screenings to look at the stomach and small bowel are also recommended.
- A high-quality colonoscopy every 12 months beginning at age 10–15.
- Once polyps are found in the colon, an annual colonoscopy is recommended until/unless surgery to remove the colon takes place.
- An annual colonoscopy is recommended if a colectomy is delayed.
Surgery
Not everyone with FAP will undergo surgery; however, it’s a recommended step for most patients. Some people with FAP have undergone a prophylactic subtotal colectomy and others have had a total colectomy to prevent colorectal cancer from developing.
Your age, family history, polyp number, and precancerous changes in the polyps can all determine when and if surgery will take place. While some individuals with FAP may be in their 20s or 30s when their doctor recommends colectomy, others may be in their teens.
While colectomy may feel extreme, here are some reasons doctors recommend it:
Prevention
A colectomy removes the entire colon before cancer has a chance to develop, significantly reducing risk of colorectal cancer.
Without removal of the colon through a colectomy, there’s almost a 100% chance of the polyps turning into colorectal cancer.
Polyps Regrowing
New polyps may grow in the same site after initial polyps have been removed. This means people with FAP need frequent invasive procedures.
Inability to find all the polyps or risk of missing them
Polyps aren’t always visible or easily accessible during endoscopy or colonoscopy. Some may be hard to find, making it difficult to ensure they’re all removed.
Too many polyps
People with FAP may have hundreds to thousands of polyps throughout their colon. It may not be possible to remove every polyp. Surgery significantly reduces colorectal cancer risk.
Do I need genetic counseling or genetic testing for FAP?
Since FAP is a hereditary syndrome, you should strongly consider genetic counseling. A genetic counselor can explain and educate about FAP and what it means for you and your family.
Importantly, your counselor will review cancer risks and screening recommendations for FAP and the benefits of doing increased screening starting at a younger age. Genetic testing, which can be done through a saliva or blood test, may be offered.
While genetic counselors help individuals consider all of their options and choices, the patient always has the final decision.
A genetic counselor can also explain how your personal health history may impact your other blood relatives and help you identify family members who are at risk. A genetic counselor can also coordinate tests for you and/or your family members and notify you if anything changes regarding your test results.
Explore these resources to locate a genetic counselor or a GI Cancer Genetics Clinic.
Are there varying degrees of FAP or are other genes involved?
Attenuated familial adenomatous polyposis (AFAP) is a less severe version of FAP. People with AFAP may experience it later than someone with FAP and may have 100 or fewer polyps. About 70% of people with AFAP will develop colorectal cancer if colon polyps are left untreated.
MUTYH-associated polyposis (MAP) is caused by mutations in the mutY homolog (MUTYH) gene. MAP, like AFAP and FAP, is a rare hereditary syndrome where people may develop 100 or fewer polyps, which likely may develop into colorectal cancer if left untreated. People with MAP may have an increased risk of developing other cancers as well.
While some of the features and cancer risks may be similar between AFAP and MAP, there are differences in screening recommendations and how the conditions are inherited. Because of this, genetic testing is extremely important to clarify the exact hereditary syndrome and what the risks are to other family members.
What should I do if I know or think I have FAP?
If someone has a family history of FAP, AFAP, or MAP remain proactive. Be sure to seek medical advice for a screening schedule based on family history or signs and symptoms. Also be sure to consider genetic testing.
Living with FAP Podcast
Jon, a colorectal cancer survivor living with Familial Adenomatous Polyposis (FAP). Listen in as Jon shares his story about his FAP diagnosis, his thoughts on FAP and his family, and the importance of finding community and support.