Cascade Testing for Hereditary Breast and Ovarian Cancer
Cascade testing for BRCA1, BRCA2, and other genetic changes that cause hereditary breast and ovarian cancer can find family members who are more likely to get breast, ovarian, and other cancers. They can take steps to prevent these cancers or find them early, when treatments are more likely to be successful.
If you have been diagnosed with a BRCA1, BRCA2, or another genetic change that makes you more likely to get breast, ovarian, and other cancers, your family members could have the same genetic change. Family members who decide to get tested should be checked for the same genetic change that you have. Getting screened using a cancer test available for a variety of cancers might not include the genetic change that you have, so family members should talk to their doctors about making sure that their test includes your genetic change.
Ask your genetic counselor or other health care provider if the company that did your genetic testing offers free or discounted genetic testing to your at-risk family members. In some cases, free or discounted testing is only available for a limited amount of time after your initial test.
Genetic testing for BRCA1, BRCA2, and other genetic changes is currently recommended for some women with breast cancer, men with breast cancer, and women with ovarian, peritoneal, or fallopian tube cancer. However, most people who get breast cancer do not have a BRCA1, BRCA2, or other genetic change that causes hereditary cancer, so having a family member with cancer does not always mean that cascade testing is needed. A genetic counselor can help you decide if genetic testing is recommended.
What Are My Family Members’ Chances of Having the Same Genetic Change?
- If you have a BRCA1 or BRCA2 genetic change, your mother, father, children, and siblings have a 1 in 2 (50%) chance of having the same genetic change.
- Your half-siblings, aunts, uncles, grandmothers, and grandfathers have a 1 in 4 (25%) chance of having the same genetic change.
- Your cousins and other more distantly related family members can have as much as a 1 in 8 (12.5%) chance of having the same genetic change.
A health care provider, such as a genetic counselor, can help with personalized risk estimates for each person in your family.
Who Should Get Tested?
When possible, genetic testing should start with family members who are most closely related to the person who has the BRCA1, BRCA2, or other genetic change. However, if a family member is not available for testing (for example, if the family member does not want to be tested or has died), then testing can start with more distant family members.
Because interventions for BRCA1, BRCA2, and most other genetic changes that cause hereditary breast and ovarian cancer start in adulthood, most current guidelines recommend that testing for these genetic changes should only be done on adults (18 years of age and older). This allows children, rather than their parents, to make their own decision about genetic testing once they become adults. However, if the genetic change increases the chances of getting cancer in childhood, then genetic testing of children in the family would be appropriate. Talk to your genetic counselor or other health care provider about how to provide information to your children so they are empowered to make their own decisions about genetic testing when the time is right.
How do family members get tested?
The genetic counselor or health care provider who diagnosed you might be able to help schedule genetic counseling and testing for your family members. Provide your genetic test report to any genetic counselor or health care provider who orders testing for your family. If free or discounted cascade testing for family members is limited to a certain amount of time from the first genetic test report, they might need a copy of your report to show the date of your test. Some insurance companies will cover genetic testing for families if a known genetic change is found. A genetic counselor or health care provider can give more information on your specific insurance coverage.