Women who carry a BRCA mutation are typically told that they have a 60 to 80 percent risk of developing breast cancer by age 70. A study in this week’s Journal of the American Medical Association suggests that this figure might be incorrect, and that women with a BRCA mutation are actually more likely to have a 36 to 52 percent risk of developing breast cancer by age 70.

Why the discrepancy? Researchers derived the 60-80 percent statistic from studies of families known to carry a BRCA mutation. (Often these were families who chose to be studied.) The new study was a population-based, case-control study that compared women who developed a second breast cancer in the opposite breast with women who had cancer in only one breast. The researchers began by looking at 2000 women with breast cancer. Within this group, there were 1394 women who had had breast cancer in one breast. Of these women, 73 (5.2%) had a BRCA mutation. There were also 704 women who had developed breast cancer in both breasts. In this group, 108(15.3%) carried a BRCA mutation.

The researchers then looked at breast cancer rates in all of these women’s first-degree relatives: their mothers, sisters, and daughters. This analysis revealed that although having a first-degree relative increased risk, the risk levels were not the same. Specifically, the researchers found that relatives of carriers who were diagnosed at age 35 or younger had a 52 percent chance of being diagnosed with breast cancer by age 70 and a 95 percent chance by age 80. In contrast, relatives of carriers who were diagnosed at age 45 or older had a 36 percent chance of being diagnosed with breast cancer by age 70 and a 44 percent chance by age 80.

This suggests, as the researchers point out in their article, that among BRCA carriers there are “additional unknown risk factors for breast cancer, which are more prevalent in the families of women diagnosed at a younger age, and in the families of women with contralateral breast cancer.” Finding out what these risk factors are will help us fine-tune risk estimates even further. It might also lead to new ways of preventing or treating breast cancer in these BRCA carriers.

I’ve always tried to stress that being high risk is not the same as being being destined to get the disease. It’s also clear that different women handle this high risk in different ways. Some choose to undergo more frequent screening with mammography and MRI to try to catch a cancer as early possible while others choose to reduce their risk by having their breasts and/or ovaries removed.

Will learning that their risk is 36 to 52 percent instead of 60 to 80 percent lead some women to change what risk-reduction options they choose? Perhaps. But there will also be some women who says that this news reinforces the decision they have made to have more frequent screening. And there will be others who say that while the risk might be lower, it is still way too high for them to not choose prophylactic mastectomy and oophorectomy.

Bottom-line: It will remain a personal decision whether a woman chooses to learn if she carries a BRCA mutation and, if she is tested, how she responds to the knowledge that she does.

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8 Responses to Risk Associated with BRCA Mutations

  1. sally says:

    wonder if there are other women out there with similar situation. 3 out of 4 women on mothers side(I’m the 4th)have been dx with bc premenopausally. Genetic counseling showed our family to be BRCA1 and 2 negative, but given another sibling group has alot of cancer, they suspect we might have a gene mutation that we just can’t test for yet…so estimated risk is 30%–too high for me….I’m trying to get insurance to pay for prophylactic mast and oopherectomy—harder when not BRCA positive. can anyone relate? have suggested other tests(PTEN, chek5) but results take over a year……

  2. ellenjay says:

    While it is true that being high risk does not mean being destined to get the disease, 36-52% does not seem like good odds when dealing with such a dasterdly disease. Especially with ovarian cancer which is so hard to detect at an early stage, even with surveillance.

    Being BRCA2 positive and diagnosed with BC last year at age 50, statistics are a moot point for me. I opted for bilateral mastectomy (one side prophylactic) and am scheduled for oopherectomy in a few weeks.

  3. BeauBeau says:

    I’m from 3 generations of Breast Cancer survivors. Our family carries the BRAC2 gene. 3 out of 5 of my family members had pre-menapausal bilateral breast cancer. The decision to have prophylatic mastectomies and oopherectomy (pre-vivor) didn’t seem like a choice. Fortunately, my insurance company paid for the surgeries based on family history. My BRAC2 mutation is not part of my medical history. At the time of my surgery (5 years ago) the statistics were presented as an 85% lifetime chance of developing the disease. Since that time, those statistics have changed – including this most recent report on this web site. Personally, the statistics were a moot point for me as well. My life had become a series of MRI’s, mammograms, ultra sounds and biopsy’s. I have not looked back on my decision. I pay little attention to the ever changing data. Unfortunately after being so pro-acitve I developed a disease called Alopecia Universalis (an auto immune disease that causes hair loss) however it led me to a career (designing scarves for women and girls with medical hair loss). The decision to have healthy breast tissue removed is personal – but I know it was the right choice for me.

  4. pberon says:

    At dinner tonite I was speaking with a woman who told me her sister was having bilateral mastectomy in two weeks in Los Angleles. She is BRCA positive.

    I asked her if she had been tested and she said no. At first I was astounded And then she explained her reasons for not wanting to know–and they made perfect sense.

    And then I came home and read this post. Once again I am humbled by the vast amount of opinions and facts and different ways to deal with difficult issues.

    Bravo to this wonderful site.
    Phil Beron, MD

  5. Dear Susan,
    I am highly skeptical of the basic genetic testing methods themselves, and of the foundational assumptions underlying them. Inheritance of a disorder within families is no proof this is “genetic”. The textbooks befuddle the entire matter by assuming “genetics” and “heredity” are one and the same thing, when they are not. I have met women whose family doctors were ordering up multiple mammograms every year, for all the women in a given family, and of course from this came radiologically-induced cancers within several generations of women, all seeing the same “family doctor”. In other cases, families of alcoholics or obesity or cigarette smoking, could produce similar inheritance factors unrelated to genetics. Even the chronic wearing of blood-circulation-reducing tight bras — some women wear them night and day — could produce the anoxia typical of cancers. And how many of the studies on these claimed “breast cancer genes” are structured so as to test for a fully null hypothesis, that is to say, for the absence of a genetic influence? How many false assumptions are built into such studies? You know, preventive penis amputation is a 100% cure for penile cancer. But the doctors would never in a million years consider that, with the same sadistic enthusiasm one sees among the “preventive mastectomy” advocates — and “enthusiasm” is fully at work, as I’ve seen and heard for myself in various interviews of such physicians AND their victim-patients. The whole matter of “feeling relieved” about the end of their sexual existence of the patient is at work. It carries a hint of the old Medieval priest, seeking to obiterate “sexual sin” from the landscape.

    Ask yourself, how different is this “preventive” breast amputation any different from what goes on in some woman-hating jungle tribe in Africa, where female genital mutilation exists — in both cases, the ordinary citizen would be extremely alarmed at anyone who would question the “wisdom” of what they do. Dissenters are considered “crazy” and are socially punished. I am sure right now you read this and maybe get angry — in which case, it proves my point that this is an emotion-driven phenomenon, one of hatred of the female, hatred of sexuality, and anger towards anyone who dares to question the foundational assumptions. There are numerous other examples from modern medicine, of junk-science claims merged with the surgeon’s scalpel, working to destroy a part of human health. For a few short examples: Just consider circumcisions of boys, now merged with the still unproven “infectious HIV” theory (more anger against the dissenter!), which has already been abused to justify denial of breastfeeding, c-section births, a sex-can-kill hysteria into the population, and now, mandatory circumcisions of boys! How much of that is “science” versus hatred of sexuality, dressed up as ‘science’? Look how the dissenters are emotionally attacked, no matter what their credentials or the considerable substance of their findings and argument. Surely you also know, how hysterectomies and other female mutilations were “medical fads” and still are. What deep emotional urges within the doctor, and patient, are satisfied by such alarming unnecessary sexual surgeries? Modern medicine of today, in some future age, is surely going to be considered as a period of unprecedented unscientific barbarism. And “preventive mastectomy” will be one of the clearest examples.

  6. vicki childress says:

    Dr. James Demeo…Kudos to you…I could not have said it better myself…About a year ago I was diagnosis with Breast Cancer DCIS, had a mastectomy and was encouraged to have a bilateral mastectomy….I also agreed to be tested for the BRCA gene and was positive…..I was at one of the lowest points in my life…going through menopause and having immense anxiety..Needless to say the breast cancer and the genetic testing only heightened my anxiety. I had a friend diagnosed with Ovarian Cancer the week I got my BRCA test back…which did not help my anxiety…Unfortunately, I succumbed to the recommendation to have the Total hysterectomy…I regret it ever since..I can only imagine how I have screwed up my body. I am 54..It was amazing how EASY it was to get the surgery…After a 15 minute “Sales pitch” it was just a matter of showing up for surgery and the deed was done. I was even Jaundice and the surgeon did not notice. Apparently her eyes were looking through her DaVinci Robot and not on the patient.
    I feel stupid for having let this happen. Yes, I did consent… but maybe what I needed was a constant dose of good sound advice and encouragement instead I was gutted….I am typically health oriented and knew about the misuse of surgery but was weak and fell into the scare tactic…..
    I hope someday I can forgive myself and will try to warn other women of this horrible attack on women…It is amazing that BRCA positive men are not encouraged to have prophylactic prostatectomies…..I agree our healthcare system preys on women. I wish I had been stronger.

  7. Theresia Brege says:

    Generally, hair loss in patches signifies alopecia areata. Alopecia areata typically presents with sudden hair loss causing patches to appear on the scalp or other areas of the body. If left untreated, or if the disease does not respond to treatment, complete baldness can result in the affected area, which is referred to as alopecia totalis.

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