Testing for Hereditary Colon Cancer

More families are finding out about their genetic risk for colon cancer due to new testing norms in Ontario.
If you're under the age of 60 and have been diagnosed with colon cancer, special testing is now automatically done at Lakeridge Health, which can reveal if your tumour has characteristics specific to Lynch syndrome.

A number of inherited syndromes can increase your risk of colon cancer, but Lynch syndrome is the most common. Doctors estimate that about 3 out of every 100 colon cancers are caused by Lynch syndrome.

Up until recently, the testing criteria were much more restrictive. In order to qualify for testing, individuals needed
to have at least three family members diagnosed with colon cancer over two successive generations. At least one of them had to be diagnosed under the age of 50. These newer guidelines are helping direct more families to genetic testing sooner.

Families that have Lynch syndrome usually have more cases of colon cancer than would typically be expected. These families may also have cases of other cancers, especially uterine cancer. Lynch syndrome also causes these cancers to occur at an earlier age than it might in the general population.

Tumours are first tested for Lynch syndrome using special dyes that stain tissue samples. This helps doctors look for certain proteins that if missing may indicate that a mutated gene caused the cancer. If the tumor test shows a concern, then genetic test is offered.

Keep in Touch With Us

The world of Hereditary Cancer Genetics is always changing and evolving. Advances in technology and testing means our Genetics teams are able to give families even more information about their risk for developing certain types of cancer. Have a question? Call Lakeridge Health Genetics at 905-433-2733.

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