Has anyone in your family, perhaps at a young age, developed colon cancer? Or has a doctor told you that you have small growths (polyps) in your colon along with stomach problems? Whether you have heard of such a thing or not, it can be very important to be aware of this condition called `FAP` that we are going to talk about today. Because although it is a bit rare, if recognized early, it can save you a lot of big problems.
What is FAP in simple terms?
Simply put, Familial Adenomatous Polyposis, or FAP for short, is a genetic condition that causes large numbers of small growths (polyps) called adenomas, which can become cancerous, to form in your colon and sometimes inside your rectum.
Think about it, some people develop one or two of these tumors in their colon as they get older. That's normal. But for someone with `FAP`, they usually have more than a hundred, sometimes thousands of these tumors, but they start developing at a very young age, maybe as young as ten years old. Therefore, the chance that one of these tumors will turn into cancer (`colorectal cancer`), that is, the risk over a lifetime, is very high .
To control this risk, doctors usually recommend a surgery to remove the entire colon (total colectomy) . Sometimes, the rectum is also removed (proctocolectomy). This is because in FAP, these tumors grow too quickly to be controlled by removing them one by one. In fact, if this surgery is not done, many people with FAP will develop cancer by middle age .
People with FAP can develop other types of tumors, not just in the colon, but also in other places, such as the skin, soft tissue, teeth, and bones. Even after the colon is removed, you may need to continue to have screenings to check for these other tumors, and you may need to have surgery for them as well.
What is the risk of developing cancer for people with FAP?
If left untreated, a person with FAP has a nearly 100% chance of developing colon cancer. They can also develop the cancer at a younger age than others. If a family member has the condition, their children should have a colonoscopy every year starting at age 10 .
In addition to colon cancer, people with FAP are at risk for developing other types of cancer:
- Cancer of the upper part of the small intestine (`Duodenal cancer`) - about 8%
- Papillary thyroid cancer - about 2%
- Pancreatic cancer - about 2%
- Liver cancer called ``Hepatoblastoma`` (especially in children) - about 1.5%
- Stomach cancer - about 1%
- Brain and spinal cord tumors - less than 1%
Are there different types of FAPs?
Yes, there is a main type of `FAP` and several other subtypes in addition to that.
- "Classic" FAP: This is characterized by the presence of more than 100 adenomas in the colon.
- "Attenuated" FAP (AFAP): This is a slightly less severe subtype. There are between 20 and 100 cysts in the colon.
- Gardner syndrome: Like classic `FAP`, there are more than 100 tumors in the colon. In addition, other types of tumors develop elsewhere in the body.
- Turcot syndrome: A cancerous tumor develops in the brain along with multiple tumors in the intestine.
How common is this condition called FAP?
FAP is a very rare condition . It affects about one in 8,000 people. FAP accounts for about 0.5% of all colon cancers. Subtypes such as AFAP, Gardner syndrome, and Turcotte syndrome are even rarer.
What is the difference between FAP and Lynch syndrome?
Lynch syndrome is another hereditary condition that increases the risk of developing colon cancer and other cancers. Lynch syndrome is also called HNPCC (hereditary nonpolyposis colorectal cancer syndrome). As the name suggests, this does not necessarily mean that a large number of colon tumors develop .
People with Lynch syndrome can develop cancer even with one or more tumors in the colon. Also, tumors and cancer develop a little later than in FAP, and the risk is slightly lower. These two conditions are caused by different gene mutations .
What are the symptoms of FAP? How do we recognize it?
In FAP, colon polyps start to form much earlier than in the general population, often in the teenage years . These polyps may not cause any symptoms until they are dangerously large. But if you have a colonoscopy, your doctor can find them.
People with `FAP` may have hundreds or thousands of polyps in their colon . People with `AFAP` have at least 20. Because the polyps are more numerous and grow faster in `FAP`, they are more likely to cause symptoms than polyps. Symptoms include:
- Rectal bleeding
- Diarrhea
- Chronic abdominal pain
People with FAP may sometimes have symptoms that doctors can recognize on the outside:
- Dermatofibromas: Fibrous, scar-like lumps under the skin.
- Epidermal cysts: Keratin-filled, spherical lumps located under the skin.
- Osteomas: Noncancerous tumors that form in the bones. They are most commonly found in the jawbone or skull.
- Extra teeth or impacted teeth: These can be seen on an X-ray of the teeth.
- Congenital hypertrophy of the retinal pigment epithelium (CHRPE): These can be seen during an eye exam. However, they usually do not cause vision problems.
At what age do FAP symptoms usually begin?
In FAP, the growth of the colon usually begins around the age of 16. In AFAP, it can start a little later. If your parents and doctors know that you are at risk for the condition, they may start testing you after the age of 10. If you don't, you may be diagnosed with the condition because of your symptoms.
What is the main cause of FAP?
The main cause of FAP is a gene mutation . This gene is called the adenomatous polyposis coli (APC) gene . It is also called a tumor suppressor gene. This means that this gene prevents cells from growing out of control and forming tumors. When a gene mutation occurs, the function of this gene is disrupted.
The gene mutation that causes FAP is a germline mutation. This means that it is not something that occurs during life, but something that occurs at conception . This is something that is passed down from generation to generation. If one of your parents has this mutation, you have a 50% chance of inheriting it. However, about 30% of these mutations are new (original mutations), that is, they are not inherited . Therefore, about 30% of patients diagnosed with FAP may have no family history of the disease.
What are the possible complications of FAP?
The most important complication to manage in FAP is colon cancer . Surgery to remove your colon (colectomy) can greatly reduce this risk. However, living without a colon can have some effects on your life because the way you pass stool changes. You may need to use an ileostomy pouch or ileal pouch instead of a colon.
Because the gene mutation that causes FAP is present in every cell in your body, tumors can develop anywhere in your body . Other tumors can also develop outside the colon, and they can sometimes become cancerous. Your doctor may recommend a screening schedule to look for these types of tumors:
- Duodenal/periampullary polyps: These develop in the upper part of your small intestine (duodenum), or where the bile duct or pancreatic duct joins the small intestine. Almost everyone with FAP develops them. A small number of people can develop duodenal cancer, ampullary cancer, pancreatic cancer in the duct, or bile duct cancer.
- Stomach polyps: About 90% of people with FAP develop stomach polyps, but only 1% of these develop into cancer.
- Desmoid tumors: These are noncancerous tumors that form in connective tissue. They occur in about 15% of people with FAP. Although they are not cancerous, they can sometimes (about 5%) cause serious health problems and even death. They can be very aggressive, spread to nearby structures, and press on or block blood vessels, organs, and nerves. They are difficult to remove and can recur.
- Papillary thyroid cancer: This type of thyroid cancer occurs in about 2% of people with FAP. It is relatively less dangerous and is often curable.
- Liver cancer: Children with FAP, in particular, have a small risk of developing a rare liver cancer called hepatoblastoma.
- Medulloblastoma: This is a brain cancer. It can occur with Turcot syndrome, which is associated with FAP. Even with FAP, it is very rare.
- Rectal polyps: If you don't have your rectum removed along with your colon, you're at risk for developing rectal polyps, so you'll need to have proctoscopy exams throughout your life.
How do you know for sure if you have FAP?
If you want to know if you have inherited the APC gene mutation, you can find out by doing genetic testing . A genetic test takes a sample of your DNA (such as blood or saliva) and looks for specific gene mutations. If you have the mutation, the next step is to have a colonoscopy to check for adenomas.
FAP is diagnosed when there are at least 100 polyps (20 if AFAP) and the presence of the APC gene mutation . FAP is not the only hereditary condition that causes adenomatous polyps. MUTYH-associated polyposis is a similar condition, but it is caused by a mutation in a different gene called MUTYH.
What is the treatment plan for someone with FAP?
The treatment plan for FAP includes lifelong surveillance and, if necessary, surgery . In the early stages, if you have a small number of polyps (or AFAP), your doctor may remove them individually during a colonoscopy (polypectomy). Surgery may be necessary if the polyps become too large or if they become cancerous.
Surgery
Most people with classic FAP will need to have a total colectomy in their late twenties or early thirties . Your doctor will decide when to have your surgery based on your specific risk factors. He or she will also talk to you about the different types of colectomy you can have.
When your colon is removed, a gap is created between your small intestine and rectum (or anus). Sometimes, a surgeon can reconnect these two ends. Then you can have a bowel movement through your rectum as usual. If that's not possible, they will create an 'ostomy', which is a new opening in your abdomen for your stool to come out.
Screening
Your medical team will advise you on how often you should have screening tests for different types of tumors, based on your personal risk factors. For classic FAP, annual colonoscopies are recommended from age 10 until colectomy . For AFAP, screening should begin every year, starting at age 20.
After your colectomy, you should continue to have sigmoidoscopy exams, which examine the lower part of your GI tract. If you have a part of your rectum left, you should have it checked every 6 to 12 months. If your rectum was removed and replaced with an ileal pouch, you should have it checked every 1 to 4 years.
Other scheduled tests may include:
- Upper endoscopy: This is similar to a colonoscopy, but it's done on the upper part of your digestive system. An endoscope is passed down your throat and into your stomach and the upper part of your small intestine (duodenum) to check for polyps. If there are any, your doctor can remove them at the same time as the procedure.
- Ultrasound tests for thyroid or liver cancer.
- CT scan (computed tomography scan) or MRI (magnetic resonance imaging) tests for desmoid tumors.
Can FAP be prevented?
Genetic counseling can help you understand the risk of passing on FAP to your children. Talking about these risks can help you plan your family. Usually, it is not possible to prevent a genetic mutation from occurring at conception, but there are various family planning options you can consider.
What is the life expectancy of someone with FAP?
If left untreated, the average life expectancy is about 42 years . However, with proper medical care and treatment, you can live a normal life . After your colon is removed, your biggest risk comes from other digestive system cancers and the more problematic 'desmoid' tumors. These are much less common than colon cancer.
If I have this condition, what should I expect?
If you are diagnosed with FAP, you can expect to have a lifetime of medical tests and possibly several surgeries to remove the tumors . Tumors that develop outside your colon are less likely to become cancerous than polyps in your colon. Although desmoid tumors are not cancerous, they can sometimes be a minor nuisance or a major nuisance.
You can expect to have a total colectomy early in life . After that, your intestines may be reconnected, or you may have an ileal pouch or an ostomy. Each of these options carries a risk of specific complications. However, you can still live a long, healthy life after a colectomy.
It's normal to feel sad and anxious when you learn that you have a genetic condition that will require lifelong medical care. However, once you know, you can take steps to manage your cancer risk . While surgery is definitely in your future, doctors will try to make it as seamless as possible.
Many people can have a laparoscopic procedure to remove the colon, which is done through small incisions and heals quickly . People who have an ileal pouch may have to undergo several surgeries, but they will eventually be able to use the toilet as before.
The most important things to remember from what we have discussed (Take-Home Message)
Okay, so, from what we've talked about `FAP`, here are the most important things you need to remember:
- FAP is a genetic condition that can be passed down through generations.
- This causes hundreds or thousands of polyps to form in the colon, which can become cancerous.
- If left untreated, the risk of developing colon cancer is very high .
- It is very important to start having colonoscopy tests from a young age (10-12 years old) .
- The main treatment is surgery to remove the colon (colectomy) .
- Even after the colon is removed, lifelong screenings are needed to check for tumors developing elsewhere in the body.
- Although this is a lifelong condition that must be managed, with proper medical treatment and testing, it is possible to live a normal, healthy life .
If you or someone in your family has any of these symptoms, or if you want to know more about this, definitely seek medical advice . Early awareness and early action are the most important things.
` FAP, Familial Adenomatous Polyposis, Genetic Diseases, Colon Polyps, Colon Cancer, APC Gene, Colonoscopy, Colectomy, Surgery
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