The truth behind genetic testing and breast cancer diagnoses

It’s been over five years since Angelina Jolie dropped her bombshell editorial in the New York Times—openly discussing her double mastectomy. And while people may not be talking about that anymore, the conversation about BRCA is still alive and well.

Which makes sense. Because the mere mention of these breast cancer genes sends most women into a panic. And for good reason.

Mutations in the BRCA1 gene combined with a family history may put a woman’s risk for breast cancer at 85 percent and her risk for ovarian cancer around 50 percent. (In the case of the BRCA2 mutation, this risk drops to 15 percent and 25 percent, respectively.)

But it’s important to realize that these statistics are only part of the story. Which is why I want to share some facts—and some recent research—with you today.

The stakes are high—but the odds are low

The most important thing to keep in mind is this: The vast majority of breast cancer cases are not associated with BRCA.

In fact, more than 99 percent of women don’t have a BRCA gene mutation (which, for the record, is only one single genetic cause of breast cancer, among many others that we don’t even know about yet). And current figures attribute a mere five percent of breast cancers (and 10 to 15 percent of ovarian cancers) to inherited BRCA gene mutations.

Now, don’t get me wrong. It’s true that these mutations raise the risk of breast cancer dramatically. But genetic testing isn’t completely accurate. Even with a negative result, you can still develop breast cancer. And on the flip side, with a positive result, there’s still a 15 percent chance that you won’t ever get that dreaded diagnosis.

So, who should consider genetic testing? Well, up until recently, the U.S. Preventive Services Task Force (USPSTF) only recommended women with family histories of breast, ovarian, fallopian tube, or peritoneal cancer. But they recently issued new guidelines, expanding this recommendation to two more groups:

1) Women with a personal history of the above cancers
2) Women with genetic ancestry associated with a higher risk of BRCA mutations (like Ashkenazi Jews, for example)2

The decision to test should be part of a multi-step process, beginning with risk assessment by your primary care doctor, then genetic counseling, if indicated. Only then should actual testing be considered.

And this word of caution is warranted, especially considering the widening availability of in-home, direct-to-consumer genetic tests. Not to mention the introduction of multi-gene panels, which deliver more information, but less clarity, than basic BRCA testing ever did.

Surgery isn’t the only option

To the USPSTF’s credit, the updated recommendations advise strongly against routine genetic testing in women with normal risk profiles. So at least they understand the gravity of the situation.

Still, these updates mean that more women may potentially receive testing that they otherwise wouldn’t have… and be faced with some very difficult decisions as a consequence.

Because unfortunately, these results are often taken as a preemptive “diagnosis.” And the door to unnecessary intervention swings wide open. That’s why I urge all women to think long and hard before submitting to genetic testing in the first place.

Ask yourself a few questions first… What will you do with the results, whether positive or negative? Will they change your situation for the better? Will they improve your life, your relationships, or your prevention strategy in any way?

If the answer to any of these questions isn’t a resounding yes, you may want to reconsider your decision to test.

On the contrary, if you do move forward with testing and the result comes back positive for mutations… what then?

The decision is yours to make. But I’ll tell you now that I don’t generally recommend preventive surgery to my patients. So I feel obligated to offer you logical alternatives—ones that, I hope, will make your choice easier and more informed.

Vigilance is key, no matter what

First things first—I have to give credit where it’s due. Preventive mastectomies do reduce your risk of breast cancer by 90 percent. Similarly, removal of fallopian tubes and ovaries cuts breast cancer risk in half among pre-menopausal women. And it lowers ovarian cancer risk by 90 percent in all women.

This is an undeniable benefit. But it’s not an ironclad guarantee. And I’m assuming I don’t need to explain the other drawbacks here. Regardless of your genetic status, you’re still removing healthy tissue from your body. And the consequences of these types of surgery are obvious.

So, I can’t stress this enough: Testing positive for a BRCA mutation doesn’t mean you will ultimately develop breast cancer. Instead, if you have a BRCA gene mutation, I’d recommend more serious breast self-exams, breast ultrasounds, and/or MRIs twice per year.

Mammograms aren’t ideal, due to the excessive radiation exposure. But semi-annual pelvic exams, transvaginal ultrasounds, and a blood test called “CA-125” are important, due to the heightened risk of ovarian cancer that accompanies this marker.

And of course, like most things, these screenings are only as valuable as the steps you’re taking to personally minimize your own risk.

In fact, some recent research shows the choices you make play an enormous role in whether or not you develop breast cancer—regardless of genetic mutations.

Fat is fuel on the fire 

Researchers looked at breast tissue samples from 82 different BRCA carriers, to assess for negative changes. They found a significant connection between body mass index (BMI) and levels of DNA damage in breast tissue.

Specifically, obesity was linked to increased DNA damage in both BRCA and non-BRCA samples. But the effect was much more pronounced in breast tissue from the BRCA positive women.1

These findings are crucial for a couple of reasons. First, they’re proof positive that obesity directly impacts breast cells. But more importantly, it shows that BRCA mutation carriers may be able to ward off what’s largely considered to be an inevitable breast cancer diagnosis, simply by keeping their weight in check.

I’ve devoted almost the entirety of this month’s issue to cancer prevention, so be sure to read it cover to cover. Because following these different lifestyle recommendations is even more critical for women with BRCA mutations.

But the message remains the same, across the board: Your choices make a difference… so be sure they’re choices you can live with.

References:

  1. The Endocrine Society. “In BRCA mutation carriers, obesity is linked with increased DNA damage.” Science Daily, 03/18/2018. (sciencedaily.com/releases/2018/03/180318144821.htm)
  2. “USPSTF Recommendations on BRCA Mutation Testing.” Medscape Medical News, 08/20/2019. (medscape.com/viewarticle/917032)

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