National Geographic Daily News
Angelina Jolie.

Angelina Jolie announced Tuesday that she had a double mastectomy.

Photograph by Amel Emric, AP

Marc Silver

National Geographic

Published May 15, 2013

Breast cancer is in the headlines: Angelina Jolie had a double mastectomy when she learned that she carries a gene that puts her at high risk for the disease. We spoke to experts Powel H. Brown and Marisa Weiss to learn more about the genetics of breast cancer.

Powel H. Brown is a breast medical oncologist and professor and chair of the department of clinical cancer prevention at the University of Texas MD Anderson Cancer Center in Houston.

What made scientists begin looking for a breast cancer gene?

The search started 20 years ago or so and was begun when it was noted that breast cancer can run in families. Some families have a very striking inheritance pattern where somebody's mother had breast cancer and their grandmother had breast cancer and two of their aunts had breast cancer and then another aunt had ovarian cancer—that's the kind of family history that suggests a cancer-causing gene mutation in the family.

This is called a cancer susceptibility syndrome. Another hallmark is having cancer at a very early age. So if you have a family history of a mother who got breast cancer at the age of 42, and a sister who got breast cancer at the age of 38, that's very unusual. In this country most breast cancer occurs on average after the age of 50.

But not every breast cancer is due to a gene?

There are two kinds of breast cancer: the common kind, which is called a sporadic kind, which most people get. It usually occurs over the age of 50. And the strongly inherited kind.

How many cancer-causing genes are there?

There are about 10 genes that can put you at risk for breast cancer. The two most common and famous are the BRCA genes: 1 and 2. They put you at risk for breast and ovarian cancer and for other cancers: BRCA2 carriers are at risk for pancreatic cancer, [and both] 1 and 2 have a slightly higher risk of melanoma.

Are other cancers genetically linked as well?

An inherited p53 gene mutation puts people at risk for breast cancer and also lung cancer, bone cancer, leukemia, and brain tumors. It shows up as extremely young breast cancer at the age of 21 or 23, leukemia and brain tumors and lung cancer in family members. That would point somebody to do genetic testing.

And what percentage of breast cancers are linked to a gene?

It's only about 5 to 10 percent—and probably 3 to 5 percent [are] BRCA1 or 2 associated.

Angelina Jolie had a double mastectomy to reduce her risk. But I understand there is still some risk that remains.

The bilateral mastectomy reduces the risk by 90 percent. Interestingly, it does not reduce the risk by 100 percent. Surgeons can't get every last breast cell. They try to remove everything, but there's a potential that a cell has been left behind. And it can turn into cancer. The other way it's possible [to have cancer after a double mastectomy] is if there is an undetectable breast cancer in the breast tissue that was removed—and it may already have spread.

The same is true for [removing] the ovaries. It reduces risk by 90 percent, not 100 percent. They can get all of the ovary cells, but the lining of the abdomen can turn into cancer and that looks like the same kind of cancer as ovarian cancer. But 90 percent risk reduction is the best we can do, and so many people choose that.

How do you screen for cancer in women who have had a double mastectomy or had ovaries removed?

They don't get screened with imaging tests, they get screened with a physical exam of their chest wall and their lymph glands. For the ovarian risk we use the CA 125 blood test to monitor them.

Even though only a small percentage of women carry the gene, every woman is at risk for breast cancer. Any advice?

Everyone should be aware of their risk and work with their health care professionals to come up with a plan to reduce their risk. For the average-risk person, breast cancer occurs something on the order of one in seven or one in eight women in this country. The average-risk person should have a healthy lifestyle with a healthy diet, low in red meat, high in chicken, fruit, fish, and vegetables. Alcohol also puts you at risk: As little as three glasses per week increases your risk of breast cancer.

Do we know how alcohol increases risk?

Alcohol clearly is a carcinogen. [Its connection] is much more clear with esophageal cancer. With breast cancer, I don't think we know.

Marisa Weiss is a breast cancer oncologist and founder and director of breastcancer.org. She is the author of Living Beyond Breast Cancer and Living Well Beyond Breast Cancer, co-authored with her mother, Ellen Weiss; Taking Care of Your "Girls": A Breast Health Guide for Girls, Teens, and In-Betweens, co-authored with her daughter, Isabel Friedman (2008); and 7 Minutes!: How to Get the Most From Your Doctor Visit (2007).

How are people responding to the news that Angelina Jolie was at risk for breast cancer?

I think it really shocked people. I think people expect that someone who looks so sexual and beautiful and young and fancy and with so much celebrity is immune or has some free pass.

It's also shocking to think she had a double mastectomy and reconstruction.

It's disturbing to think she had to go through this surgery. But saying she feels just as good, just as feminine, is encouraging to women. The fact is that reconstruction has come so far that a lot of women have an excellent result. They feel whole again. She's saying this gene abnormality is not going to define her. That's all positive.

How does a woman know if she is at risk for carrying one of the breast cancer genes?

[The risk is] based on personal and family history of breast and other related cancers. It depends on the pattern of the story that family history tells.

Does insurance cover genetic testing?

Usually you come in and give your family history [to a genetic counselor], which means the history of cancer on both mother's and father's side and age of diagnosis. If the family history sounds like there are multiple affected relatives at a young age or more than one cancer, that means higher risk. If there's a male with breast cancer in the family, that goes along with higher risk.

If your family history adds up like that, starts smelling like an inherited pattern, then you would qualify for genetic testing and the insurance company is likely to pay for it. But if the genetic counselor tells you it's a low risk, the counselor is not going to recommend testing.

Angelina Jolie had the BRCA1 gene.

Women with BRCA1 gene are more likely to have triple-negative breast cancer, which is a harder cancer to treat. If you're looking at an up to 87 percent risk, a mastectomy is not so radical. It makes a lot of sense. If you had a BRCA2 type of gene, you're more likely to have a hormone-receptor-positive breast cancer, a more treatable kind of malignancy. Not all those women choose mastectomy.

How do patients make the decision about treatment once they know they have a gene that puts them at risk?

It happens in steps. Genetic counseling takes time. And so people get used to the information over time, consider pros and cons of each option, and the genetic counselor and doctor will talk about a combination of strategies to lower risk.

Would a mastectomy to prevent cancer ever be appropriate if there isn't a genetic risk?

What I do is I always evaluate an individual person's risk. Sometimes there's a strong family history and no clear genetic abnormality. In that case, family history trumps genetics. What I mean by that is if you're looking at a family with a lot of cancer in it, and you can't find a gene to explain all the cancer, it may just be because you don't know the name of the gene and can't test for it. But something's going on.

And what do people then do if they are at risk by family history or genetics?

Some women come to you and say, "I'm a watch-and-wait kind of girl. I'm confident you'll have new discoveries sooner [rather] than later. I don't need to sacrifice my breasts right now. I'm prepared to be followed very carefully over time. I'll make changes in my life [to reduce risk]: diet, exercise, reproductive choices." But somebody else might say, "I'm a mother with young kids. I've got to be around for the long run. I am prepared to move ahead with any option likely to maximize my chances of never seeing cancer."

Could the women already have cancer and not know it?

For women who find out they have the breast cancer gene and who have what they believe to be a prophylactic mastectomy, about 10 to 15 percent of the time they find cancer in [the breast tissue] they didn't expect.

Editor's Note: Marc Silver is the author of Breast Cancer Husband: How to Help Your Wife (And Yourself) Through Diagnosis, Treatment, and Beyond and co-author of the new book My Parent Has Cancer and It Really Sucks: Real-Life Advice from Real-LIfe Teens.

4 comments
Paul Schietekat
Paul Schietekat

Nothing creates more mass hysteria than cancer. I don't whish for anybody to receive the news that they have found a tumour. However, I do feel that we should be more conscious about the triggers for cancer and its our own responsibility to do something about it. One of the most important is the exhaust of combustion processes, regardless the nature of the fuel. Any kind of exhaust from a combustion process contains toxic material and is carcinogenic. The other one is the oxygen overconsumption through these combustion processes. Without reforestation and the elimination of combustion processes, we just grab a pill to heal ourselves. Why just focus on sports and healthy food, while we continue to infect ourselves and others with toxic smoke. Smoking is a well known problem. Why don't we recognize the dangers of exhaust all the way?

The levels of CO2 reached 400ppmv recently. While many countries claim success stories on reducing these CO2 levels, not even a small reduction is shown on the Keeling Curve.
Why? Because we replaced the combustion of fossil fuel through other combustion processes using organic fuel. The second fuel remains oxygen, otherwise a combustion cannot take place and the exhaust of toxic materials remains.

Why can't we see what is happening? Are we continuing to pollute this planet to make shore that our children will have more and more cancers than we have today?

Brigitte Meier
Brigitte Meier

The more all these theories get hyped up, the more women get afraid that they might get afflicted with cancer, the more likely they will get cancer. A bit of toning down on the hysteria would go a long way to prevent at least some cancer. Tell women to sacrifice cancer and keep their body intact. I'm sure that if you kill yourself, you will be protected against all diseases, not just 90%. But does it make sense to do it? The same is true for all these non-sensical prophylactic mastectomies and removal of ovaries. Some years later the theories collapse, then way more harm will have been done than a chance of cancer. One way or another, you live until you die. 

Brian Howard
Brian Howard expert

Interesting read. This topic was a story line on Nip/Tuck: a woman who had a strong history of breast cancer in her family was freaked out by it and tried to convince the docs to remove her breasts for prevention.

They saw that she was mentally distressed and they declined to do the surgery. In a fit she then tried to remove her own breasts.

Laura Carrie
Laura Carrie

@Brigitte Meier When you watch 2/3 of every generation of your family die of variations of the same disease (including your ancestors who lived before DNA or the mechanisms for disease had even been discovered, and most certainly did not bring cancer on themselves by fearing it or expecting it to happen) you begin to realize that genetic predisposition is very real and doesn't go away if you just refuse to pay attention to it. Some people are more likely to be born with red hair or very large feet; some people are more likely to eventually develop cancer. It's just reality. Stress is certainly a contributing factor, but a lack of stress and a carefree attitude are hardly reassuring methods to combat this high a cancer risk. I've known since early childhood that I will probably get cancer because my family history makes it clear that I almost certainly have some of these genetic predispositions. Will I get prophylactic surgery? I don't know. But I AM getting more frequent screening, and I am much more careful to live a lifestyle that makes me less predisposed. Those choices - based on my awareness of my genetic makeup- may very well save my life, or at least give me a head start on fighting cancer if I get it. While these prophylactic procedures seem ridiculously extreme, it's also pretty extreme to watch a disease ravage your family time after time, stealing life, health, comfort, time, money, and the ability to fully be a parent, wife, friend or child from your mother, aunts, sisters and grandmothers (and the men too), generation after generation, and know it's probably in your future but just sit back and let it happen- especially if you do have young kids or other dependents. Your opinion changes pretty drastically each time a family member gathers everyone together and tells you they have cancer, and you all look around at each other and at their kids and say "oh dear God, not again", your minds all traveling back to the deathbed or hospital room of the last relative to make this announcement, your eyes resting a little longer on the children of that last relative or this one, desperately hoping through the tears that the next time you get together for Christmas you will all still be there and nobody else will have the same bad news. Every time you feel a new lump, or an almost-lump, or just a hormonal difference in breast tissue, your life almost stops until you can get to the doctor or until the MRI, mammogram or ultrasound machine is available. You try to live your life normally but you can't sleep, your mind is numb, you're not sure when to tell your family that you might have cancer (yet again) and you feel sick that you're hiding something so important from them. But because you don't want to drag them behind you on the roller-coaster of emotions every time this happens because you love them too much, you lie to them and say everything is normal, and then you pray that it will be nothing, because hearing that a loved one has been going through this alone is almost as hard as hearing the news itself and you don't want to have to say that to them. 

Nobody chooses this lightly. It is very much a case of choosing the lesser of two evils. These procedures are extreme but are not irrational, hyper-dramatic or paranoid; it's not so different from someone having all their large moles removed because the doctor thinks they look particularly likely to be cancerous. People are simply more attached to their breasts, ovaries, etc. than moles-as they should be-and there are certainly hormonal and other implications to altering the reproductive system. But appreciating the privilege of having intact breasts/ovaries and choosing to basically keep ticking time bombs within your own body-which is really what they might be, in these cases- in order to keep some non-essential body parts are two very different things. Considering preventative measures is not embracing paranoia or allowing yourself to spiral into an unnecessary panic that causes your body to spontaneously generate more cancer. It's being realistic and rational in choosing life, peace of mind, and a more certain future-for yourself and your family-in exchange for some fatty tissue and reproductive capacity. 

And which part of this is a "theory" that may collapse in the future? The theory that a cancer which attacks breast tissue is lessened if you don't HAVE breasts? That logic is pretty irrefutable.

Privileging an intact body over a secure, healthy future - especially after watching time and time again as cancer attacks your loved ones - is the real hysteria. When you understand the risks and the statistics, refuse to let your inherent attachment to every body part rule over your will to survive, and make the decision that you won't be a victim just because you're genetically unlucky, it's not being overreactive. You do "live until you die", but deliberately ignoring specific, changeable things that can hasten death and making no effort to protect your life is hardly appreciating the privilege of living in the first place. Although they involve pain and loss, not to mention the almost unfathomable strength of will required to voluntarily sacrifice a piece of yourself for the survival of the body as a whole, in these cases prophylactic surgeries are choosing life and health over some body parts that are not essential to survival. It's that simple.

Share

How to Feed Our Growing Planet

  • Feed the World

    Feed the World

    National Geographic explores how we can feed the growing population without overwhelming the planet in our food series.

See blogs, stories, photos, and news »

The Innovators Project

See more innovators »

Latest News Video

See more videos »

See Us on Google Glass

Shop Our Space Collection

  • Be the First to Own <i>Cosmos: A Spacetime Odyssey</i>

    Be the First to Own Cosmos: A Spacetime Odyssey

    The updated companion book to Carl Sagan's Cosmos, featuring a new forward by Neil deGrasse Tyson is now available. Proceeds support our mission programs, which protect species, habitats, and cultures.

Shop Now »