This condition is inherited as an autosomal dominant manner. That is, each child born to an affected parent has a 1 in 2 (50%:50%) chance of inheriting this condition. Similarly, there is 50% chance of not inheriting this condition. Males and females are equally affected.

When there is a new defect, there is a 50% chance that the children of the affected individual will get FAP.

This makes it essential that individuals at risk are screened

In the early stages there may be no symptoms. This is why you need to present yourself or your child to a doctor for early identification of this condition. As the polyps grow and become large you may get

• Alternating diarrhea and/or constipation
• Blood mixed with stools
• Thin stools
• Abdominal pain / distention associated with defaecation
• Continued weight loss
• Lack of energy/ lethargy
• Anaemia

As these changes indicate late disease, FAP patients should not wait for symptoms to occur.

Picture of polyps in the colon		Picture of cancer of the colon

This may be done by

• Genetic testing
• Examination of eyes
• Bowel screening

Genetic testing

A blood sample is taken for DNA analysis. In this way a defect can be identified in the APC gene in about 80% of affected individuals. This will not only establish the diagnosis but will also help identify family members with FAP as they will also have the same defect. Family members who do not have this defect do not need to undergo other screening tests as they are negative for FAP, but will require colonoscopy screening as recommended for all adults at around 45 years of age.

However, as the defect differs from family to family, in about 20% of families it may be difficult to identify this defect.

Genetic testing should start at 10 – 20 years of age in FAP and at 18 years in AFAP families.

Examination of eyes

Eyes are checked by the ophthalmologist, who can identify birthmark like spots inside the eyes called congenital hypertrophic retinal pigment epithelium (CHRPE). CHRPE almost always predicts the presence of colonic polyps in a person.

Bowel screening

After examination of the abdomen, the large bowel is examined by an endoscope. The left side of the large bowel is examined with the flexible sigmoidoscope and whole of the colon with the colonoscope.

The bowel has to be cleaned prior to the examination. Flexible sigmoidoscopy may be undertaken without sedation with a simple enema before the examination. Colonoscopy is performed under sedation using complete bowel cleansing employing up to 3 liters of a laxative. If polyps are found they will be removed for examination. The examination is not usually painful. It will confirm if a polyp is likely to result in cancer in the future years. Once detected, not all polyps will require to be removed.

Polyps in the colon

If you are diagnosed with FAP, depending on the age and the severity of disease, you may be advised to undergo regular screening of the colon and rectum.In the early stages, medication with regular screening is all that may be required. Surgical removal of the colon may also be advised.

Surveillance of the large intestine

Starting at 10-12 years, a surveillance sigmoidoscopy is recommended annually. Once polyps are found or by 20 years of age, colonoscopy should be done every year. Patients with Attenuated FAP should undergo colonoscopy yearly starting at 18 years.

If polyps are found these are removed unless they are too large or too numerous to be removed.

Surveillance of the upper gastro intestinal tract

FAP polyps in the colon may be associated with equally risky polyps in the duodenum, which may give rise to cancer. Surveillance of the upper gastro intestinal tract is recommended at 20-25 years of age or just before your colonic operation..

Other recommended tests are

• Annual physical examination and thyroid examination.
• Before surgery desmoid tumors may need to be excluded by CT Scan or an ultrasound scan.

In some families it may be necessary to screen young children from birth to five years for tumors of the liver (also known as hepatoblastoma).

Surveillance of the upper intestine is mandatory in a person with FAP and polyps in the colon.

Arrow pointing towards a desmoids tumour

Surgical options are

• Colectomy( removal of the colon) with ileo rectal anastomosis.(IRA)
• Total proctocolectomy(removal of colon and rectum) with permanent ileostomy.
• Restorative proctocolectomy (Ileal Pouch Anal Anastomosis)

Colectomy with ileo rectal anastomosis (IRA)

Here, the colon is removed leaving most of the rectum. The end of the small bowel (ileum) is joined to the rectum. (ileo rectal anastomiosis)

This is usually done in young patients with small numbers of polyps. However they are required to return at six monthly intervals for regular rectal screening. Later, the doctor may recommend further surgery to remove the rectum; if polyps in the rectum enlarge, become cancerous or cause troublesome symptoms.

Total proctocolectomy with permanent ileostomy

Here the colon,rectum and anus are removed. The ileum is brought out through the right lower abdomen (Ileostomy is formed). You will need to wear a bag over the ileostomy as liquid stools will exit from the ileostomy. Nowadays, this type of operation is rarely undertaken.

Restorative proctocolectomy (Ileal Pouch Anal Anastomosis)

Here the colon and the rectum are removed. A new reservoir which takes over the function of rectum (pouch) is created with the lower end of the ileum and anastomosed to the anus. A temporary ileostomy may also be created to protect the anastomosis, which is removed 8 to 10 weeks after the initial operation.

This is usually recommended for those over thirty five years of age and when there are many rectal polyps.

Annual flexible sigmoidoscopy (pouchoscopy) is required in all.

The Professorial Surgical Unit of North Colombo Teaching Hospital has created a registry for patients with FAP and their families.

When enlisted in this register you will be required to fill a questionnaire providing personal details, medical details and family history and a consent form. All information provided will be ensured confidentiality.

This will help identify FAP patients and screen at risk family members. Registry staff will provide all necessary information about Familial Adenomatous Polyposis, refer you for necessary examinations and investigations and also provide educational material. They will also undertake the necessary referrals for the management of diagnosed FAP patients.

Joining the FAP registry is strictly on a voluntary basis and is intended to serve the patient, the individual's family and the patient's future generations.

You may get more information about Familial Adenomatous Polyposis and the FAP Registry from the Professorial Surgical Unit of the North Colombo Teaching Hospital.