Deborah Howell (Host): If someone in your family has had breast cancer, what's the likelihood you also will get it? Is it hereditary and should you get genetic testing? We'll find out more about breast cancer genes and your family and if testing is right for you with nurse practitioner Mya Robertson. Welcome to St. Joseph's Health MedCast. I'm Maggie McKay.

Each year in the US, about 240,000 cases of breast cancer are diagnosed in women and about 2,100 in men. About 42,000 women and 500 men in the U. S. die each year from breast cancer. Approximately five to 10% of cases are thought to be hereditary and genetic testing is available. How does it work and is it a good idea?

We'll find out with Mya Robertson. She joins us today. She is a nurse practitioner at St. Joseph's Health specializing in cancer risk genetics. Thank you so much for being here, Mya.

Mya Robertson: Thank you, Maggie. Thanks for having me on today.

Host: Absolutely. So, what makes a person high risk for breast cancer?

Mya Robertson: So, some of the factors that increase your risk for breast cancer include hereditary changes, also known as mutations to certain genes such as BRCA1 or BRCA2; reproductive history, women who have never given birth are considered higher risk; starting your menstrual periods before age 12 or after age 55 exposes women to hormones longer, raising their risk for breast cancer; and family history, just to name a few.

Host: And what is considered a strong family history of breast cancer?

Mya Robertson: That's a good question. What one person considers a strong family history may not be interpreted that way for another. Any family history of cancer is worth a discussion with your provider to determine your risk. Of course, we look at first-degree relatives, but if you have multiple two or more second-degree relatives from the same side of the family, that is significant. Age of diagnosis is also important. Anyone who is diagnosed prior to the age of 50 is also significant.

Host: And Mya, what's the most common genetic mutation in breast cancer?

Mya Robertson: In breast cancer, BRCA1 and BRCA2 are the most common causes of hereditary breast cancer. It is an inherited change or mutation on the DNA. In normal cells, these genes help make proteins that repair damaged DNA. However, in mutated versions of these genes, they can lead to an abnormal cell growth, which can lead to cancer.

Host: And how accurate is genetic testing for breast cancer?

Mya Robertson: If genetic testing is negative, it does not mean you will never develop a cancer. If testing is negative, a person still has the general population risk or higher based on risk factors for developing breast cancer. Only about 10% of all breast cancer cases are linked to genetic mutation. So on the flip side, if testing shows a person has a positive genetic mutation, it does not mean they will develop cancer. Their risks are higher than the average general population. And that risk varies based on the specific genetic mutation that they have.

Host: And how is the testing done?

Mya Robertson: Testing is pretty simple because we are collecting DNA. It does require informed consent and I strongly recommend pre and post-test counseling. Then, it's a blood draw, usually one or two small vials or a saliva sample, which is sent out to the lab for analysis. It could take anywhere between two to four weeks to get the results back.

Host: That does seem pretty straightforward. How common is it for breast cancer to be passed down? Because we were talking about if someone in your family had it, will you get it? And so how common?

Mya Robertson: That's a great question. Absolutely. So, both women and men with an abnormal breast cancer gene have a 50% risk of passing that abnormal gene onto their children. So, there's a misconception that the father's side doesn't matter and that's not the case. Men can carry the abnormal gene, even for breast cancer. Their risk for developing breast cancer with a BRCA gene is only about 7%, but there's an increased risk for prostate and pancreatic cancer, and men can pass that gene down to their children. So everyone, men and women, should tell their doctors about the health histories of both their mothers' and fathers' families. Like I mentioned before, about 10% of all breast cancers are hereditary, caused by an abnormal breast cancer gene. So, majority of breast cancers are sporadic. It happens by chance, or causes we're unaware of. But those people who have a hereditary predisposition have a 50% chance of passing that specific gene onto their children.

Host: Wow. That's kind of sobering. I've never heard that. That's a big chance. So now, what happens if you test positive for the BRCA gene?

Mya Robertson: Yep. So, people who test positive for BRCA1 or BRCA2 mutations have a higher than average risk of developing breast or ovarian cancer than someone who doesn't have either mutation. So, women who have a BRCA mutation roughly have about an 80% chance of developing breast cancer and roughly about a 60% chance of developing ovarian cancer by the time they're 70 years of age.

Other genes do not carry such a high risk for breast cancer. So, options are available, which could include, preventative surgery, increased surveillance, or even preventative medication. So, it's really important for those that have testing, especially those that test positive, to have post-test counseling to explain the specific risks and recommendations based on that specific gene.

Host: What about the people who say, "I don't want to know"?

Mya Robertson: Yeah. So, I do have some people who say they don't want to know. That's actually a great question. And I always feel that knowledge is power. And if you have a genetic predisposition, you can do something with that information, whether again, it's just being monitored more closely with increased surveillance or even preventative surgeries where it could save your life. And it's very important information for your family members.

Host: What should someone do, Mya, if their mammogram comes back showing something?

Mya Robertson: So if your breast imaging shows something, it's important to discuss your results with your provider. However, some results are almost clearly benign and they just recommend a six-month followup.

So, I always tell people, you know, if the radiologist feels that there is something there, he would recommend a biopsy. I think the cutoff from the radiologist is if there is a 2% chance or greater of it being a cancer, they recommend a biopsy. So if the radiologists are just recommending a followup, then there's a less than 2% chance of this being benign, and that's usually a safe option.

Host: Thank you so much, Mya, for this invaluable information. This has been really informative and helpful.

Mya Robertson: My pleasure. I'm happy that I had this opportunity to come in and inform everybody.

Host: Again, that's nurse practitioner, Mya Robertson. And if you'd like to find out more, you can visit sjhsyr.org. Remember to get regular mammograms and talk with your doctor if you have any concerns. If you found this podcast helpful, please share it on your social channels and check out our entire podcast library for topics of interest to you.

Thanks for listening. I'm Maggie McKay. This is St. Joseph's Health Medcast, presented by St. Joseph's Health.