There are several known genetic mutations that significantly increase a person’s risk of developing colorectal cancer. Approximately 5 to 10 percent of colorectal cancers are believed to result from the inheritance of a genetic mutation (or mutations) from a parent. Some families appear to have hereditary colorectal cancer but are not found to have any of the known mutations.
If you and others in your family are at higher risk of developing colorectal cancer because of a genetic condition or family history, Memorial Sloan-Kettering is ready to help. Our geneticists, surgeons, gastroenterologists, and medical oncologists have special expertise diagnosing and managing this set of syndromes.
Two diseases that account for most hereditary colorectal cancers are familial adenomatous polyposis (FAP) and Lynch syndrome (also called hereditary nonpolyposis colorectal cancer, or HNPCC). Other hereditary colorectal cancer diseases, including MYH-associated polyposis (MAP) and hyperplastic polyposis syndrome (HPS) have also been identified in recent years, but less is known about the risks they confer for cancer. Researchers continue to search for other mutations that can raise a person’s risk of getting colorectal cancer. Learn more about these different types of hereditary colorectal cancer.
Risk Factors and Symptoms
The most important risk factor for hereditary colon cancer is a family history of one of these diseases. Your risk of having hereditary colorectal cancer is also increased if there is a family pattern of certain other cancers, including endometrial, ovarian, gastric, urinary tract, brain, and pancreatic cancers.
Some patients with hereditary colorectal cancer develop multiple colon polyps (abnormal growths projecting from the colon surface) at a young age. The polyps are benign at first, but some become cancerous over time. Other patients with hereditary colorectal cancer do not have any polyps before their cancer diagnosis.
Many people with multiple colon polyps or colorectal cancer may have no symptoms at all. Some experience symptoms such as abdominal pain, rectal bleeding, anemia, mucus discharge, or a change in bowel habits.
Screening and Diagnosis
If others in your family have developed polyps or colorectal cancer at age 50 or earlier, it is recommended that you have a colonoscopy earlier than you might otherwise. This test can determine whether multiple polyps are present even if you are not experiencing any symptoms.
The detection of multiple polyps during a colonoscopy may indicate the presence of a hereditary colon cancer, but it is not conclusive. Our Clinical Genetics Service offers counseling and education about the risks associated with hereditary colorectal cancer syndromes, as well as genetic testing for individuals and their families who might be affected. Other members of our team such as gastroenterologists and surgeons may also be able to advise you about management of your polyps.
During genetic testing, your doctor will take a blood sample to look for genetic mutations that are associated with hereditary colorectal cancers. Knowing which mutation is present helps doctors to determine which condition you have, and to plan treatment. Even if no mutation is found, our counselors may recommend that you have increased screening and surveillance for cancer, or that you consult with another specialist for further management.
Management of Hereditary Colorectal Cancer Syndromes
Medical experts from Memorial Sloan-Kettering discuss Lynch syndrome, a genetic disorder that can cause colon and other cancers.
Each hereditary colorectal cancer syndrome calls for a particular management strategy, but in general they can include frequent surveillance, and in some cases, surgical removal of the colon to prevent the development of colon cancer.
In patients with multiple polyps, it is critical to have frequent colonoscopies beginning at an early age. This allows your doctors to monitor the number and growth of polyps, and to remove polyps that develop. Having frequent colonoscopies can also help you and your doctor to determine if surgery is appropriate.
When you should begin screening and how frequently it should take place depend on which syndrome you have and the number (and makeup) of polyps that are detected. Your physician can explain the benefits and risks of managing the disease through this kind of surveillance.
In some cases, patients receive medications during this surveillance period to shrink existing polyps or to prevent new polyps from emerging.
In some patients with hereditary colorectal cancer, surgical removal of the colon is recommended either when the patient reaches a certain age is reached and the risk of developing colorectal cancer becomes significant, or when polyps cannot be removed using colonoscopy.
Memorial Sloan-Kettering doctors have a great deal of expertise in prophylactic surgery for inherited colorectal cancers. Which type of operation is performed depends on your exact condition. Our surgeons perform a significant number of these procedures using minimally invasive techniques. Following surgery, patients usually adjust well and regain normal bowel function after a recovery period, maintaining a good quality of life while knowing that a major cancer risk has been greatly reduced.