Description

Familial adenomatous polyposis (FAP) is a rare inherited disease caused by a defect in the adenomatous polyposis coli (APC) gene. Most people inherit the genes of the parents. But for 25 percent to 30 percent of people, the genetic mutation occurs spontaneously.

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

Most people with familial adenomatous polyposis eventually need surgery to remove the large intestine to prevent cancer. Polyps in the duodenum can also develop cancer, but they can be managed by careful monitoring and the removal of polyps on a regular basis.

Some people have a milder form of the disease called familial adenomatous polyposis, attenuated (AFAP). People with the AFAP usually have fewer polyps in the colon (average of 30) and of developing cancer later in life.

Symptoms

The main sign of the FAP is in the hundreds, or even thousands, of polyps growth in the colon and the rectum, usually from the mid-teens. Polyps are almost 100 percent certain to develop cancer of the colon or rectal cancer by the time you're in your 40s.

Causes

Familial adenomatous polyposis is caused by a defect in a gene that would normally be inherited from a parent. But some people develop the abnormal gene that causes the condition.

Risk factors

The risk of familial adenomatous polyposis is higher if you have a father, a son, a brother, or sister with the condition.

Complications

In addition to colon cancer, familial adenomatous polyposis can cause other complications:

  • The polyps, duodenal. These polyps grow in the upper part of the small intestine and can become cancerous. But with careful monitoring, polyps, duodenal often can be detected and removed before cancer develops.
  • Periampullary polyps. These polyps occur when the bile and pancreatic ducts enter the duodenum (the blister). Periampullary polyps may become cancerous, but can often be detected and removed before cancer develops.
  • Gastric fundic polyps. These polyps grow in the lining of your stomach.
  • Desmoids. These masses are not cancer may arise in any part of the body, but often develop in the stomach area (abdomen). Desmoids can cause serious problems if they grow on the nerves or the blood vessels or pressure on other organs in your body.
  • Other types of cancer. Rarely, the FAP can cause the development of cancer in the thyroid gland, central nervous system, the adrenal glands, the liver, or other organs.
  • Non-cancerous (benign) tumors of the skin.
  • Benign bone tumors (osteomas).
  • Congenital hypertrophy of the retinal pigment epithelium (CHRPE). These are benign pigmentary changes in the retina of your eye.
  • The dental abnormalities. These include the teeth, or teeth that don't come in.
  • A low number of red blood cells (anemia).

Prevention

The prevention of FAP is not possible, since it is an inherited genetic condition. However, if you or your child is at risk of PAF because of a family member with the condition, you will need genetic testing and counseling.

If you have FAP, you will need regular exams, followed by surgery if necessary. The surgery can help to prevent the development of colorectal cancer or other complications.

Diagnosis

You are at risk of familial adenomatous polyposis if you have a father, a son, a brother, or sister with the condition. If you are at risk, it is important to be examined frequently, starting in childhood. Annual exams can detect the growth of the polyps before they become cancerous.

Detection

  • The sigmoidoscopy. A flexible tube that is inserted into the rectum to inspect the rectum and the sigmoid colon — the last two feet of the colon. For people with a genetic diagnosis of FAP or family members at risk who have not had genetic testing, the American College of Gastroenterology recommends annual sigmoidoscopy beginning at the age of 10 to 12 years.
  • Colonoscopy. A flexible tube that is inserted into the rectum to inspect the entire colon. Once polyps are found in the colon, you need to have a colonoscopy until a surgery to remove the colon.
  • Esophagogastroduodenoscopy (EGD) and the side-viewing duodenoscopy. Two types of spheres were used to examine the esophagus, stomach and the upper small intestine (duodenum and the ampulla). The doctor may remove a small tissue sample (biopsy) for further study.
  • Computed tomography or magnetic resonance imaging. Images of the abdomen and pelvis can be used, especially for evaluating desmoid tumors.

Genetic testing

A simple blood test can determine if you carry the abnormal gene that causes FAP. Genetic testing can also detect if you are at risk of complications from the FAP. Your doctor may suggest genetic testing if:

  • You have members of the family with FAP
  • You have some, but not all, of the signs of the FAP

Discard FAP spares at-risk children years of the detection, and emotional distress. For the children who carry the gene, the early detection and treatment greatly reduce the risk of cancer.

Additional tests

Your doctor may recommend tests of the thyroid and other tests to detect other health problems that can occur if you have FAP.

Treatment

In the first place, your doctor will remove small polyps found during colonoscopy examination. Eventually, though, the polyps become too many to delete individually, usually in your late teens or early 20's. Then you are going to need surgery to prevent colon cancer. You will also need surgery if a polyp is cancerous. You may not need surgery for the AFAP.

Minimally invasive colorectal surgery

Your surgeon may decide to perform your surgery laparoscopically, through several small incisions that require only a point or two to close. This minimally invasive surgery usually shortens the hospital stay and allows you to recover more quickly.

Depending on your situation, you may have one of the following types of surgery to remove part or all of the colon:

  • Subtotal colectomy with ileorectal anastomosis, in which the rectum is left in place
  • Total proctocolectomy with continent ileostomy, in which the colon and rectum are removed, and an opening (ileostomy) is created, usually on the right side of your abdomen
  • Total proctocolectomy with ileoanal anastomosis (also called J-pouch surgery), in which the colon and rectum are removed, and a part of the small intestine connects to the rectum

Follow-up treatment

The surgery does not cure FAP. Polyps can continue to the way in which it is or rebuilt parts of your colon, the stomach and the small intestine. Depending on the number and size of polyps, having removed via endoscopic may not be enough to reduce your risk of cancer. You may need an additional surgery.

You will need regular exams and treatment if necessary — for the complications of familial adenomatous polyposis that can develop after colorectal surgery. Depending on your history and the type of surgery you had, the analysis may include:

  • A sigmoidoscopy or colonoscopy
  • Upper endoscopy
  • Ultrasound of the thyroid
  • Computed tomography or magnetic resonance imaging to detect desmoid tumors

Depending on the results of the initial test, your doctor may perform additional treatments for the following problems:

  • Polyps and duodenal periampullary polyps . Your doctor may recommend surgery to remove the upper part of the small intestine (duodenum and ampulla) because these types of polyps can progress to cancer.
  • Desmoid tumors. You can receive a combination of drugs, including nonsteroidal anti-inflammatory, anti-estrogen and chemotherapy. In some cases, surgery may be needed.
  • Osteomas. Doctors can remove these benign bone tumors for the relief of pain or cosmetic reasons.

Potential future treatments

Researchers continue to evaluate additional treatments to FAP. In particular, the use of pain relievers such as aspirin and nonsteroidal anti-inflammatory drugs (Nsaids), as well as a chemotherapy drug, are being investigated.

Coping and support

Some people find it helpful to talk with other people who share similar experiences. Consider joining a support group online, or ask your doctor about support groups in your area.

Preparing for your appointment

What you can do

Your time with your doctor is limited, so try to prepare a list of questions. Of the FAP, some basic questions to ask your doctor may include:

  • What are the chances that I will pass the disease on to my children?
  • How often should I have?
  • What type of testing my detection means?
  • I'm going to need surgery?
  • If I need surgery, when I need you?
  • What type of surgery you need?
  • Does surgery cure my FAP?
  • If not, what follow-up and treatment will I need?
  • How accurate is the test?
Symptoms and treatment of Familial adenomatous polyposis