How is familial adenomatous polyposis (FAP) treated?
Because FAP cannot be cured, the aim of treatment is to prevent cancer and preserve a healthy, unaffected lifestyle for the patient.
People who have FAP will need examinations of the gastrointestinal tract and other at-risk organs for the rest of their lives. They will receive medical care by a healthcare team that may include:
- Gastroenterologists (specialists in diseases of the digestive system).
- Colorectal and general surgeons.
- Endocrinologists (specialists in metabolism and diseases of the endocrine system).
- Primary care physicians.
- Genetic counselors.
- Oncologists (cancer specialists).
Patients with FAP are diagnosed either by symptoms if they have no family history to warn them of their risk, or on screening if they are in a family affected by FAP, or have been identified by a positive genetic test. Symptomatic patients are at high risk for cancer and usually need surgery relatively quickly. Screened patients have no symptoms and treatment timing depends on how severe the FAP is.
Children who have inherited the APC mutation normally start yearly colonoscopy when they are 10 or 11. Children who have FAP and develop colon symptoms such as, blood in bowel movements, abdominal pain and/or diarrhea are checked immediately. Examination of the stomach and duodenum usually starts between ages 20 and 25.
Surgery is the standard treatment to prevent colorectal cancer in FAP. The timing and type of colon surgery depend on the number and size of the polyps in the large bowel. If the patient does not have a large number of colon polyps, surgery may not be recommended until later in his or her life.
If there are too many polyps or if they are growing too quickly to be controlled by colonoscopy, it might be necessary to remove the colon and/or rectum with surgery. The bowel is reconstructed by joining the small intestine to the rectum (an ileorectal anastomosis) or making a J pouch out of the small intestine to replace the rectum, so that the patient can avoid having a permanent stoma (bag). While the prospect of surgery may be upsetting, it is important to realize that without it, the risk of colorectal cancer is very high.
The timing and choice of colon surgery depend on several factors, but in particular the number and size of the polyps. Laparoscopic surgery has made removal of the colon less painful and less disabling.
Laparoscopic surgery is performed through very small "keyhole" incisions in the abdomen. A laparoscope -- a small, telescope-like instrument containing a camera -- is placed through an incision near the bellybutton in order to see the inside of the abdomen. The surgery is done using instruments placed via these small incisions. Even after surgery, the remaining bowel is checked every year.
Medications can also reduce the burden of polyps in the colon and rectum. This is known as chemoprevention, and it is prescribed for selected patients by an expert in chemoprevention.
Two medications — sulindac (Clinoril®) and celecoxib (Celebrex®) — have been shown to reduce the number of colorectal polyps and delay the timing of the first surgery. These medications can also control polyps in the pouch or rectum after surgery, or the need for additional surgeries. These medications do not prevent the need for colonoscopy, however, and have not been proven to prevent colon cancer.
Upper gastrointestinal endoscopy
Since adenomatous polyps can develop in the duodenum, an upper endoscopy along with a biopsy (removal of cells or tissue for examination) of the polyps should be done beginning around the age of 20, and then every 1-3 years. In an upper endoscopy, a physician uses an endoscope (a long, thin, flexible instrument about 1/2 inch in diameter) to examine the inside of the upper digestive system.
If the patient has a large number of polyps in the duodenum, surgery to prevent duodenal cancer may be recommended. The duodenum is removed and the intestinal tract is reconnected internally. Patients with advanced stage duodenal polyposis may be treated with celecoxib.
The upper part of the stomach may become carpeted with thick mounds of polyps of various types. In this case, an upper endoscopy and removal of the stomach polyps may need to be done every 3-6 months to make sure that cancer is not developing. If cancer or high-grade dysplasia (abnormal growth) is found in stomach polyposis, removal of the stomach and reconnection of the intestinal tract is recommended.
The thyroid is checked every year with an ultrasound scan at the time of diagnosis or in the mid-teen years, whichever is earlier. Abnormalities in the thyroid, such as cysts or calcifications (hardenings), are usually biopsied at the time of ultrasound. If cancer is detected, the thyroid gland is removed, and the function of the thyroid gland is replaced with medications.