What is Familial Adenomatous Polyposis? Symptoms, Causes, & Treatment

Familial adenomatous polyposis (FAP) is a rare genetic condition that causes hundreds to thousands of small growths called polyps to develop in your colon and rectum. These polyps are benign at first, but they will almost certainly become cancerous if left untreated.

This inherited condition affects about 1 in 10,000 people worldwide. While FAP can feel overwhelming when you first learn about it, understanding your condition and working with your healthcare team can help you manage it effectively and maintain a good quality of life.

What are the symptoms of Familial Adenomatous Polyposis?

FAP symptoms usually don't appear until your teenage years or early twenties, when polyps have had time to grow and multiply. Many people with FAP don't notice any symptoms in the early stages, which is why regular screening is so important for families with this condition.

When symptoms do develop, you might experience several warning signs that suggest something needs medical attention:

• Blood in your stool or rectal bleeding
• Changes in your bowel habits, like diarrhea or constipation
• Abdominal pain or cramping that doesn't go away
• Unexplained weight loss
• Fatigue that seems to worsen over time
• Anemia due to chronic blood loss

Some people with FAP also develop non-cancerous growths in other parts of their body. These might include small bumps under your skin, extra teeth, or growths in your stomach.

Remember, having these symptoms doesn't automatically mean you have FAP. Many common digestive issues can cause similar problems, so it's important to talk with your doctor about what you're experiencing.

What are the types of Familial Adenomatous Polyposis?

FAP comes in two main forms, and understanding which type you might have helps your doctor create the best treatment plan for your situation.

Classic FAP is the more common form, where you develop hundreds to thousands of polyps throughout your colon and rectum. Most people with classic FAP will develop colorectal cancer by age 40 if their colon isn't removed.

Attenuated FAP (AFAP) is a milder version where you develop fewer polyps, usually between 10 and 100. The polyps in AFAP tend to appear later in life, often in your 40s or 50s, and cancer risk develops more slowly.

There's also a very rare severe form called Gardner syndrome, which combines the colon polyps of FAP with growths in other parts of your body. People with Gardner syndrome might develop bone growths, skin cysts, and extra teeth along with their colon polyps.

What causes Familial Adenomatous Polyposis?

FAP happens because of changes in a specific gene called APC, which normally helps control how cells grow and divide in your colon. When this gene doesn't work properly, cells grow out of control and form polyps.

Most people with FAP inherit the faulty gene from one of their parents. If one of your parents has FAP, you have a 50% chance of inheriting the condition. This is called autosomal dominant inheritance, which means you only need one copy of the changed gene to develop FAP.

However, about 25% of people with FAP don't have any family history of the condition. In these cases, the gene change happened spontaneously, creating what doctors call a "de novo" mutation.

The APC gene acts like a brake pedal for cell growth in your colon. When it's working normally, it tells cells when to stop growing and dividing. When the gene is faulty, cells lose this important stop signal and keep multiplying, eventually forming polyps.

When to see a doctor for Familial Adenomatous Polyposis?

You should see a doctor right away if you notice blood in your stool, especially if it happens repeatedly or comes with other symptoms like abdominal pain or changes in your bowel habits. While these symptoms can have many causes, they always deserve medical attention.

If you have a family history of FAP or colorectal cancer, it's important to talk with your doctor about genetic testing and screening, even if you don't have any symptoms. Starting screening early can catch polyps before they become cancerous.

Schedule an appointment if you experience persistent digestive symptoms that last more than a few weeks. This includes ongoing diarrhea, constipation, abdominal pain, or unexplained weight loss.

Don't wait to seek help if you're feeling overwhelmed by a family history of FAP. Genetic counselors can help you understand your risks and make informed decisions about testing and screening.

What are the risk factors for Familial Adenomatous Polyposis?

Your biggest risk factor for FAP is having a parent with the condition, since FAP is primarily an inherited disease. If one of your parents has FAP, you have a 50% chance of inheriting the faulty gene.

Having a family history of colorectal cancer, especially if it occurred at a young age or if multiple family members were affected, might suggest FAP in your family line. Sometimes FAP goes undiagnosed for generations if family members died young or didn't have access to proper medical care.

Age plays a role in when FAP symptoms appear, but not in whether you'll develop the condition. If you carry the FAP gene, polyps typically start forming during your teenage years, though you might not notice symptoms until your twenties or thirties.

Unlike many other health conditions, lifestyle factors like diet, exercise, or smoking don't cause FAP. This genetic condition develops regardless of how healthy your lifestyle is, though maintaining good overall health can help you manage the condition better.

What are the possible complications of Familial Adenomatous Polyposis?

The most serious complication of FAP is colorectal cancer, which develops in nearly 100% of people with untreated classic FAP, usually by age 40. This is why preventive surgery is often recommended before cancer has a chance to develop.

People with FAP face several other health challenges that can affect different parts of their body:

• Small bowel cancer, particularly in the duodenum (the first part of your small intestine)
• Stomach polyps and potential stomach cancer
• Thyroid cancer, especially in women with FAP
• Liver tumors called hepatoblastomas, which are rare but more common in children with FAP
• Brain tumors, though these are quite uncommon

Some people with FAP develop desmoid tumors, which are non-cancerous growths that can form in your abdomen, chest, or arms. While not cancerous, these tumors can grow large and press on nearby organs, sometimes requiring treatment.

The good news is that with proper monitoring and treatment, many of these complications can be prevented or caught early when they're most treatable. Regular check-ups with your healthcare team are key to staying ahead of potential problems.

How is Familial Adenomatous Polyposis diagnosed?

Diagnosing FAP usually involves a combination of genetic testing, colonoscopy, and family history review. Your doctor will start by asking detailed questions about your symptoms and whether anyone in your family has had colorectal cancer or FAP.

A colonoscopy is the main test used to look for polyps in your colon and rectum. During this procedure, your doctor uses a flexible tube with a camera to examine the inside of your colon. If they find hundreds of polyps, especially in someone under 50, FAP becomes a strong possibility.

Genetic testing can confirm an FAP diagnosis by looking for changes in the APC gene. This test uses a simple blood sample and can usually tell you definitively whether you have the FAP gene. However, the test doesn't find the gene change in about 10-15% of people who clearly have FAP based on their symptoms.

Your doctor might also recommend additional tests to check for polyps or tumors in other parts of your body. This could include an upper endoscopy to examine your stomach and small intestine, or imaging tests to look at your thyroid and other organs.

What is the treatment for Familial Adenomatous Polyposis?

The main treatment for FAP is preventive surgery to remove your colon and rectum before cancer develops. This might sound frightening, but these surgeries can be life-saving and allow you to live a normal, healthy life afterward.

Your surgeon will typically recommend one of two main procedures. A total proctocolectomy with ileostomy removes your entire colon and rectum, and creates an opening in your abdomen where waste can exit into a collection bag. Alternatively, a total proctocolectomy with ileal pouch-anal anastomosis removes your colon and rectum but creates an internal pouch from your small intestine, allowing you to have bowel movements normally.

The timing of surgery depends on several factors, including how many polyps you have, whether any show signs of becoming cancerous, and your age and overall health. Most people with classic FAP have surgery in their late teens or twenties.

If you're not ready for surgery or have attenuated FAP with fewer polyps, your doctor might recommend medications like sulindac or celecoxib. These drugs can help slow polyp growth, though they can't prevent cancer completely and aren't a substitute for surgery in high-risk cases.

Regular monitoring is crucial even after treatment. You'll need ongoing colonoscopies of any remaining intestinal tissue, plus screening for cancers in other parts of your body like your thyroid, stomach, and small intestine.

How to manage Familial Adenomatous Polyposis at home?

While you can't prevent or cure FAP through lifestyle changes, taking good care of your overall health can help you feel better and potentially reduce some complications. Eating a balanced diet rich in fruits, vegetables, and whole grains supports your digestive health and overall well-being.

Stay connected with your healthcare team and keep all your scheduled appointments, even when you're feeling well. FAP requires lifelong monitoring, and regular check-ups are your best defense against complications.

Consider joining a support group for people with FAP or hereditary cancer syndromes. Connecting with others who understand your experience can provide valuable emotional support and practical advice.

Keep detailed records of your medical history, test results, and family health information. This information becomes especially important if you move or change doctors, and it can be valuable for your children and other family members.

Don't hesitate to ask questions or seek a second opinion about your treatment plan. FAP is a complex condition, and you deserve to feel confident and informed about your care decisions.

How should you prepare for your doctor appointment?

Before your appointment, gather as much information as possible about your family's health history, especially any cases of colorectal cancer, polyps, or other cancers. Even details about relatives who died young or from unknown causes can be helpful.

Write down all your symptoms, including when they started, how often they occur, and what makes them better or worse. Don't forget to mention symptoms that might seem unrelated, like skin bumps or dental problems.

Prepare a list of all medications, vitamins, and supplements you're taking. Also, write down any questions you want to ask your doctor, starting with the most important ones in case you run out of time.

Consider bringing a family member or friend to your appointment, especially if you're discussing genetic testing or treatment options. Having another person there can help you remember important information and provide emotional support.

If you're seeing a specialist for the first time, ask your primary care doctor to send your medical records ahead of time. This helps ensure your new doctor has all the information they need to provide the best care.

What's the key takeaway about Familial Adenomatous Polyposis?

FAP is a serious genetic condition, but with proper medical care and monitoring, people with FAP can live full, healthy lives. The key is early detection and proactive treatment, usually including preventive surgery before cancer develops.

If you have a family history of FAP or unexplained colorectal cancer, genetic counseling and testing can help you understand your risks and make informed decisions about your health. Early intervention truly makes a difference with this condition.

Remember that having FAP doesn't define you, and advances in treatment continue to improve outcomes for people with this condition. Work closely with your healthcare team, stay informed about your condition, and don't hesitate to seek support when you need it.