Genetic Testing for Breast Cancer

Your genes have a lot to say about who you are and how healthy you are. But for certain diseases, including cancer, so many genes are likely involved that it’s hard for doctors to come up with a useful, reliable way to turn your DNA information into a precise risk score.

Three of the most well-known abnormal genes are BRCA1, BRCA2, and PALB2. There are also genetic variants of these genes that are linked to an increased risk of breast cancer. Women who inherit a mutation in any of these genes have up to 80% higher risk of developing breast cancer and ovarian cancer. Men with these mutations have an increased risk of breast cancer, especially if the BRCA2 gene is affected and are considered to be at higher-than-average risk for prostate cancer. Many inherited cases of breast cancer have been associated with these two genes.

 

Genetic screening is a young science, and while we may have detected genes linked to a host of ills — Alzheimer’s disease, prostate cancer, rheumatoid arthritis, diabetes, heart disease — we often do a terrible job of calculating our resulting risks. Just over 0.01% of all women carry the same BRCA mutation Jolie has. In the U.S., 36% of women who test positive opt for preventive mastectomy.

 

Before you run to the clinic, The best way to get started is to learn more about your family history on both your mother’s and your father’s side. If breast cancer is common on either side (or both) then it may be in your interest to have genetic testing. A genetic counselor is specially trained to give information about genetics and disease, can explain family-related cancer risks, and whether or not genetic testing makes sense for you based on your family history.

 

Some doctors argue that regular MRIs and other screening tests may be sufficient to detect the disease. If you are worried that you may have increased risk of breast cancer, there are steps you can take to lower your risk of cancer. You might take advantage of more frequent clinical exams and breast screenings — every 6 months instead of once per year — and ask for digital mammography (versus film-screen mammography), 3D mammography and/or MRI (magnetic resonance imaging) in addition to mammography. You also may wish to have regular pelvic exams and ultrasounds, and possibly a blood test called CA-125, in an attempt to detect any early signs of ovarian cancer.

 

In 2013, actress Angelina Jolie announced that she had undergone a preventive double mastectomy because she was a BRCA1 gene mutation carrier, which puts her at very high risk for breast and ovarian cancer. Jolie also had a family history of these cancers. In the six months following Jolie’s highly-publicized surgeries, testing and counseling around genetic testing nearly doubled.

 

Human beings are very good at worrying — it’s what keeps us alive and healthy. But we’re also good at overworrying, making irreversible decisions to reduce or avoid risks that don’t really exist at all. Genetic testing may not answer all your questions. Jolie’s brave example can make us all smarter and help keep us all healthier — but only if we take the right lessons from it.

 

To find a genetic counselor who specializes in family-related cancer risk, talk to your doctor or check with the hospitals and cancer centers in your area. You also can contact the National Cancer Institute Cancer Genetics Services Directory (1-800-4-CANCER) or the National Society of Genetic Counselors (312-321-6834).