Have You or a Family Member Had Colorectal (Colon) Cancer?
Having a family health history of colorectal (colon) cancer can make you more likely to get colorectal cancer yourself. If you have close family members with colorectal cancer, collect your family health history of colorectal and other cancers, and share this information with your doctor. If you have had colorectal cancer, make sure that your family members know about your diagnosis, especially if you have Lynch syndrome.
Why is it Important to Know Your Family Health History?
If you have a family health history of colorectal cancer, your doctor may consider your family health history when deciding which colorectal cancer screening might be right for you. For example, if you have a close family member who had colorectal cancer at a young age or have multiple close family members with colorectal cancer, your doctor may recommend screening starting at a younger age, being done more frequently, and using colonoscopy only instead of other tests. In some cases, your doctor may recommend that you have genetic counseling, and a genetic counselor may recommend genetic testing based on your family health history.
When collecting your family health history, be sure to include your close relatives: parents, brothers, sisters, children, grandparents, aunts, uncles, nieces, and nephews. List any cancers that each relative had and at what age he or she was diagnosed. For relatives who have died, list age and cause of death.
What is Lynch Syndrome and Why is it Important to Know if You Have it?
In some cases, colorectal cancer is caused by an inherited genetic condition called Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer or HNPCC. About 3% (1 in 30) of colorectal cancer cases are due to Lynch syndrome. People with Lynch syndrome are much more likely to develop colorectal cancer, especially at a younger age (before 50), and women with Lynch syndrome are much more likely to get endometrial (uterine) cancer. People with Lynch syndrome also have an increased chance of getting other cancers, including ovarian, stomach, liver, kidney, brain, and skin cancer. If you or your family members are found to have Lynch syndrome, your doctor can help you take steps to reduce your risk of getting cancer in the future or to find it early if you get it.
Lynch syndrome is hereditary, meaning that it is caused by an inherited genetic changes, or mutations, that can be passed from parents to children. If you are diagnosed with Lynch syndrome, your parents, children, sisters, and brothers have a 50% (1 in 2) chance of having this condition. Your other close relatives are also at increased risk of having Lynch syndrome.
After surgery to remove colorectal cancer, tumor tissue samples are often screened to see if the tumor could have been caused by Lynch syndrome. In some cases, additional testing is needed to know for sure if the tumor was caused by Lynch syndrome. If you have had colorectal cancer in the last few years, your tumor may have been checked for Lynch syndrome. Genetic counseling and testing for Lynch syndrome also might be recommended for you if:
- You were diagnosed with colorectal cancer in the past
- You have been diagnosed with endometrial cancer (especially before age 50)
- You have several family members with colorectal or other cancers associated with Lynch syndrome
- You have a family member with Lynch syndrome
If you have been diagnosed with Lynch syndrome, talk to your doctor about your increased chances of getting the other cancers caused by Lynch syndrome. Be sure to let your family members know if you have Lynch syndrome. Once a mutation that causes Lynch syndrome is found in one person in a family, other family members can then be tested for that mutation to find out if they have Lynch syndrome.
If you are concerned about your personal or family health history of colorectal cancer, talk to your health care provider. In addition, you can visit the web sites below to find information on colorectal cancer, Lynch syndrome, cancer genetic testing, and genetic counseling services.
- Page last reviewed: March 23, 2016
- Page last updated: March 23, 2016
- Content source:
- Office of Public Health Genomics
- Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs