Genetic Testing

Genetic testing for BRCA1 and BRCA2 alterations is available. It is done from a blood sample. Ideally, genetic testing is first performed on someone in the family who has had cancer. If a BRCA1 or BRCA2 alteration is identified, other family members can have targeted and informative testing for the same DNA change. Those relatives who share the genetic alteration have an increased risk of cancer and will need more intensive monitoring and/or risk-reducing interventions. Those who do not have the familial gene alteration do not have elevated cancer risks (based on family history from that side). Those who choose not to have testing should be followed as though they carry the altered gene.

If a BRCA1 or BRCA2 alteration is not found in a family, there are several possible explanations. The family history of cancer may not be related to an inherited risk factor. Or the family history could be due to a gene that has not yet been discovered. Also, current technologies do not detect all BRCA1 or BRCA2 alterations. If no alteration can be found, cancer screening and prevention recommendations are made on the basis of the family history.

Genetic testing for cancer predisposition should be a deliberate decision. As for any medical test or procedure, there are risks and benefits. These may be different for each family and even for each member of the same family. For example, the experience of genetic testing may be very different for a family member who has already had cancer than for one who has not. Also, both men and women in a family may choose to have BRCA1 and BRCA2 testing, but often for different reasons and with different issues. In making decisions about genetic testing, we encourage careful consideration of the personal, family, and medical issues that may arise.