What is Familial Adenomatous Polyposis?
Familial Adenomatous Polyposis is an extremely rare inherited pathological condition in which there is development of excessive polyps in the colon and rectum. Polyps can also be found in the GI tract, especially in the upper part of the duodenum. The signs and symptoms of Familial Adenomatous Polyposis can be seen in an individual as young as in his or her teens with the detection of polyps on imaging done for some other reasons or if the individual has a family history of this condition. The polyps caused by Familial Adenomatous Polyposis in majority of the cases become cancerous by the time the affected individual reaches the fourth decade of his or her life.
In majority of the cases of Familial Adenomatous Polyposis, surgery is preferred to deal with the condition with removal of the entire colon to prevent cancer from developing. The polyps in the duodenum can also get cancerous but the chances are much lesser when compared to polyps in the colon and even if the polyps in the duodenum become cancerous they can be managed by close observation and removal of polyps whenever they occur which means on a regular basis.
What Causes Familial Adenomatous Polyposis?
The main cause for development of Familial Adenomatous Polyposis is a defect in the APC or the Adenomatous Polyposis Coli gene. This defective gene is inherited by the patient from his or her parents but in some cases mutation in the APC gene occurs on its own without any inheritance pattern. This abnormal mutation in APC gene causes innumerable polyps to grow in the colon and the rectum by the time the individual is in his or her teens. These polyps especially those in the colon in almost all the cases become cancerous by the time the individual is in his or her 40s. There may also be certain other complications caused due to Familial Adenomatous Polyposis. These complications are:
Duodenal Polyps: The development of polyps in the duodenum is also seen with Familial Adenomatous Polyposis but the chances of them becoming cancerous are much less then of the polyps in the colon and can be managed with observation and removal of polyps whenever they occur.
Periampullary Polyps: These polyps are present where the bile and pancreatic ducts enter the duodenum. These polyps might also become cancerous at a later stage but can be managed with close observation and removal of polyps at regular intervals.
Desmoids: These are benign masses that may develop in any part of the body but are mostly found in the abdominal area. This is also one of the complications of Familial Adenomatous Polyposis. These masses may become a serious concern if they start putting pressure on other vital organs of the body or if they start growing into the nerves or vessels
What are the Symptoms of Familial Adenomatous Polyposis?
If an individual has a family history of Familial Adenomatous Polyposis, then it is recommended that the individual be screened at regular intervals since the age of 16 years. The starting symptom of Familial Adenomatous Polyposis is bowel problems. The patient may have innumerable polyps in the bowel and remain asymptomatic but if they are not screened they slowly start to show some symptoms. In some cases, Familial Adenomatous Polyposis may remain asymptomatic until the polyps become malignant. Some of the symptoms that an individual with Familial Adenomatous Polyposis may experience are:
- Blood or mucus in the stools
- Rectal bleeding
- Alternating diarrhea and constipation
- Abdominal pain
- Unintentional weight loss.
How is Familial Adenomatous Polyposis Diagnosed?
If during a screening an individual is noticed to have greater than 100 polyps in the colon or the rectum area then Familial Adenomatous Polyposis is suspected. In such cases a family history of the patient is taken and of it is found that there is a family history of this disease then the individual is recommended for a genetic testing took for mutation in gene APC. Once the mutation is confirmed then a confirmatory diagnosis of Familial Adenomatous Polyposis is made.
How is Familial Adenomatous Polyposis Treated?
The best possible treatment for Familial Adenomatous Polyposis is partial or complete removal of the colon, as the polyps in the colon are the most likely ones to become cancerous. This procedure is done usually when the patient is between 15 and 40 years of age as that is the age when these polyps mostly likely start becoming malignant. Post a colectomy, the patient will be prescribed an NSAIDs called Sulindac for treatment of polyps in the rectum. Post removal of the colon, the risk of cancer certainly becomes less but it is recommended that the patient be screened at regular intervals for any type of recurrence of malignancy.
For polyps in the duodenum, observation and routine screening is recommended and once the polyps become large in number then polypectomy is performed to remove the polyps in the duodenum.
For desmoid masses, they are benign but may cause a problem if they exert pressure on any organ or enter the nerve or vessel. These can be treated by a variety of approaches including surgery to remove the mass, NSAIDs, anti-estrogen medications, chemotherapy and/or radiation. If there is no growth seen in the mass then only observation is recommended.
What is the Prognosis of Familial Adenomatous Polyposis?
Even though Familial Adenomatous Polyposis is quite a serious condition if it remains untreated but with careful monitoring and screenings at regular intervals and with surgery and other recommended treatments an individual can lead a normal life even with Familial Adenomatous Polyposis.
- National Organization for Rare Disorders. (2019). Familial Adenomatous Polyposis. https://rarediseases.org/rare-diseases/familial-adenomatous-polyposis/
- U.S. National Library of Medicine. (2020). Familial Adenomatous Polyposis. https://medlineplus.gov/genetics/condition/familial-adenomatous-polyposis/
- Cancer.Net. (2021). Familial Adenomatous Polyposis. https://www.cancer.net/cancer-types/familial-adenomatous-polyposis