Knowing Your Family Cancer History Could Save Your Life

Genetic testing looks for specific inherited changes in a person’s genes that may increase the risk of diseases such as cancer. It is generally recommended that people with certain personal or family medical histories that suggest the possibility of a hereditary cancer syndrome consult with their doctor or a genetic counselor to see if genetic testing might be appropriate for them. Features that suggest the possibility of a hereditary genetic syndrome can be found in the link below.

Genetic testing looks for specific inherited changes (sometimes called mutations or pathogenic variants) in a person’s genes that may increase the risk of diseases such as cancer. About 5%–10% of all cancers are thought to be caused by harmful genetic changes that are inherited from a parent.

Genetic tests are usually requested by a genetic counselor, doctor, or other health care provider who has reviewed an individual’s personal and family medical history and identified a potential inherited cancer pattern. Testing is done on a small sample of bodily fluid or tissue—usually blood but sometimes saliva, cells from inside the cheek, or skin cells. The sample is then sent to a genetic testing laboratory. Test results are usually returned in about 2 to 3 weeks.

Clinical practice guidelines recommend genetic testing for anyone diagnosed with triple-negative breast cancer, ovarian cancer, pancreatic cancer, colorectal cancer before age 50, metastatic prostate cancer, or male breast cancer. For people with these cancers, knowing whether their cancer is related to an inherited harmful genetic change may help to select the optimal treatment for them. This information may also be relevant to their blood relatives.

The standard approach uses tests that look for harmful variants in multiple genes at the same time. These tests, called multigene (or panel) tests, are often used when there is not a known gene mutation in a family. Depending on the patient’s personal and family history as well as their preference for the amount of information they want, the health care provider may order a panel test that focuses on genes for a particular type of cancer, or they may order a broad panel test that looks at genes.

Genetic counseling is generally recommended before any genetic testing for inherited cancer risk. It may also be performed after the test, especially if a positive result is found and a person needs to learn more about what this result means for them. This counseling should be performed by a trained genetic counselor or other health care professional who is experienced in cancer genetics.

Genetic testing can give several possible results: positive, negative, true negative, uninformative negative, or variant of uncertain significance (VUS). You can find more information in the link below.