Genetic Testing for Hereditary Colorectal Cancer

The EGAPP Working Group recommends that everyone with a new diagnosis of colorectal cancer (regardless of age or family health history) be offered genetic testing for Lynch syndrome. If you have colorectal cancer, getting tested for Lynch syndrome can help your family members find out if they are at risk and, if so, take steps to lower their risk.

Lynch Syndrome

About 3% (1 in 30) of colorectal cancer cases are due to an inherited condition known as Lynch syndrome (sometimes referred to as hereditary nonpolyposis colorectal cancer or HNPCC). People with Lynch syndrome are much more likely to develop colorectal cancer, especially at a younger age (before age 50 years), and other cancers, such as endometrial cancer in women. 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 blood relatives such as grandparents, aunts, uncles, nieces, and nephews are also at increased risk of having Lynch syndrome.

Genetic Testing for Lynch Syndrome

If you have colorectal cancer, genetic testing for Lynch syndrome can help you find out if your colorectal cancer is hereditary (caused by an inherited gene change). Your family members can learn if they are also at increased risk and can take steps to help protect them from getting colorectal cancer.

The Evaluation of Genomic Applications in Practice and Prevention (EGAPP™) Working Group is an independent, multidisciplinary panel of scientists and health care experts who review available research and evidence to make recommendations about the use of genetic tests. The EGAPP Working Group concluded that all people with a new diagnosis of colorectal cancer should be offered counseling and educational materials about genetic testing for Lynch syndrome. Learn more.

The EGAPP™ Working Group found good scientific evidence to show that if individuals with colorectal cancer are found through genetic testing to have Lynch syndrome, their family members can benefit by:

undergoing genetic testing to learn if they are also at increased genetic risk, and
having earlier and more frequent screening, which can prevent colorectal cancer, if the person is at increased genetic risk.

Several different genetic testing strategies are available for Lynch syndrome. These can involve screening of tumor tissue samples and DNA testing to find the inherited genetic change. The EGAPP™ Working Group found that there was not enough evidence to specify which genetic testing strategy works best.

Listen to a podcast about genetic testing for Lynch syndrome.

Although the EGAPP recommendation did not address use of testing in other situations, people with colorectal cancer diagnosed in the past (especially before age 50), and/or people with several family members with colorectal and/or endometrial cancer may also benefit from genetic evaluation for Lynch syndrome.

While Lynch syndrome is the most common form of hereditary colorectal cancer, it is not the only one. If you are concerned about colorectal cancer in your family, talk to your doctor.

In addition to talking with your health care provider, the Web sites below provide more information on colorectal cancer, Lynch syndrome, cancer genetic testing, and access to genetic counseling services.