Genetic Predisposition to Breast Cancer

By: Dr. Lisa Chapa
DHR Health Breast Center of Excellence

When I sit down with patients who have just been diagnosed with breast cancer, one of the most common questions they ask is “What caused my cancer”? For 85-90% of women diagnosed with breast cancer, the answer to that question is likely due to a combination of environmental risk factors, personal risk factors, and age. However, for the other 10-15% of women, the answer to that question lies in their DNA.

Our DNA is often described as the blueprint for our body – all of the instructions for how to build us are encoded in the genes that make up our DNA. Most of the time, the instructions are clear without any mistakes and our bodies work the way they are supposed to. Unfortunately, sometimes the instructions for how to build a part of our body gets changed and it has harmful effects. We call these changes genetic mutations.

Twenty-five years ago, the BRCA genes were discovered. These are genes that, if mutated, significantly increase someone’s lifetime risk of having breast cancer, ovarian cancer, pancreatic cancer, and prostate cancer in men.

The average lifetime risk of developing breast cancer is 12% for women. Women who have the BRCA mutation have a 60-70% lifetime risk of developing breast cancer, and because these women are at such a high risk, it is important for us to identify them early so that we can intervene before they are diagnosed.

Some of the warning signs that prompt us to offer genetic testing are having multiple family members on one side of the family with breast, ovarian, pancreatic, and/or prostate cancers. Also, having breast cancer in your 40’s or younger is considered a warning sign because most breast cancers develop in women 50 years of age or older.

For these women, it is important to sit down with someone who is comfortable discussing the potential results of genetic testing as well as offering genetic testing. DHR Health Breast Center of Excellence, offers genetic testing to our breast cancer patients and also to the patients who are at high risk of having a genetic mutation based on their family history.

As a surgeon, it’s important for me to know whether or not my patient’s breast cancer was caused by a genetic mutation, because if it was, they have a very high risk of developing breast cancer in their other breast and we should talk about the risks and benefits of a bilateral mastectomy to reduce the risk of breast cancer returning in the future.

For women with breast cancer, it is important to know if their cancer was caused by a genetic mutation – not just for them, but also for their family because these mutations are passed down from parent to child. If you have a genetic mutation, there is a 50% chance that each of your children and each of your siblings will also have this mutation and this is information that could save their lives.

If you think you are someone who has a high likelihood of having a genetic mutation that increases your risk of breast cancer, speak with your physician, make arrangements to have genetic testing. At the DHR Health High Risk Breast Clinic, we’ll sit down with you, determine your lifetime risk of developing breast cancer, and create a plan for how to monitor you and help decrease your risk of developing breast cancer in the future.