- Hereditary Breast and Ovarian Cancer syndrome (HBOC)
- Lynch syndrome/Hereditary Non-Polyposis Colorectal Cancer (HNPCC)
- Familial Adenomatous Polyposis (FAP)/Attenuated Familial Adenomatous Polyposis (AFAP)
- MUTYH-associated Polyposis syndrome (MAP)
- MUTYH-associated Colon Cancer Risk
- Melanoma Cancer Syndrome (MCS)
- Li-Fraumeni Syndrome (LFS)
- PTEN Hamartoma Tumor syndrome (PHTS)
- Peutz-Jeghers Syndrome
- Hereditary Diffuse Gastric Cancer (HDGC) Syndrome
- Juvenile Polyposis Syndrome (JPS)
- Juvenile Polyposis Syndrome (JPS) and Hereditary Hemorrhagic Telangiectasia (HHT)
- PALB2-associated Cancer Risk
- CHEK2-associated Cancer Risk
- ATM-associated Cancer Risk
- NBN-associated Cancer Risk
- BARD1-associated Cancer Risk
- BRIP1-associated Cancer Risk
- RAD51C-associated Cancer Risk
- RAD51D-associated Cancer Risk
- Polymerase Proofreading-associated Syndrome (PPAS)
- Hereditary Mixed Polyposis Syndrome (HMPS)
Familial Adenomatous Polyposis syndrome (FAP) or Attenuated Familial Adenomatous Polyposis syndrome (AFAP) APC ASSOCIATED CANCER RISKS
Familial Adenomatous Polyposis syndrome (FAP) or Attenuated Familial Adenomatous Polyposis syndrome (AFAP)
APC ASSOCIATED CANCER RISKS
What does it mean to have an APC gene mutation and a diagnosis of Familial Adenomatous Polyposis (FAP) or Attenuated FAP (AFAP) syndrome?
People with mutations in the APC gene have a high risk for developing large numbers of pre-cancerous polyps in their colon and rectum. Each of these polyps can develop into a cancer, and since there are so many of them, the risk for colorectal cancer is very high. Individuals with APC mutations who develop more than 100 polyps are said to have Familial Adenomatous Polyposis syndrome (FAP). People who have fewer than 100 polyps due to their APC gene mutation are said to have a milder form of the condition, which is called Attenuated FAP syndrome (AFAP). People with AFAP have a lower risk for colorectal cancer than people with FAP, but the risk is still very high.
Other symptoms of FAP and AFAP include a higher than average risk for gastric (stomach), small bowel, thyroid, brain and possibly pancreatic cancer. During childhood, there is an increased risk for hepatoblastoma, a kind of liver cancer. Some people have non-cancerous symptoms, such as desmoid tumors (a non-cancerous growth of connective tissue), dental abnormalities, growths on bones, skin cysts and an eye abnormality called congenital hypertrophy of the retinal pigment epithelium (CHRPE). All of these things are more likely to occur in people with FAP compared to people who have AFAP.
What can be done to protect individuals with an APC mutation?
The National Comprehensive Cancer Network (NCCN) provides detailed recommendations for lowering the risk of cancer in people with mutations in the APC gene. Because of the high risk for colorectal cancer, people with APC mutations should begin screening with colonoscopies at young ages (10-15 years) and have them done every year. As people get older, complete removal of the colon may be recommended. This may be the best choice if there are too many polyps to remove with regular colonoscopies or if it is believed that this is the most reliable way to prevent colorectal cancer.
There are also recommendations for screening to reduce the risk of the other cancers that can occur in people with FAP or AFAP. These recommendations are complicated, so it is recommended that people with FAP or AFAP be cared for by healthcare professionals with experience treating this condition.
Additional details about FAP/AFAP, including information about the risks for different kinds of cancer, specific recommendations for medical care, and useful information for relatives of people who have a diagnosis of FAP/AFAP, are available within our Support Organizations pages.
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