Mary-Claire King was honored on Monday with the prestigious Lasker Award for Special Achievement in Medical Science “for bold, imaginative, and diverse contributions to medical science and human rights.”
In December 1990, King forever altered the path of breast cancer care when she published a study in Science announcing that she and her colleagues had identified what we now call BRCA1—an inherited mutation that increases risk for breast and ovarian cancer.
Now, showing that she continues to remain a bold voice, King has published two articles that again have the potential to alter breast cancer care. These articles, a study that appeared in the Proceedings of the National Academy of Sciences (PNAS) and a viewpoint published in the Journal of the American Medical Association, made headlines not only because King won the Lasker Award but because of what they suggest: that BRCA testing should become a routine part of medical care.
Is this a good idea?
According to the National Cancer Institute, BRCA1 and BRCA2 mutations account for about 20 to 25 percent of hereditary breast cancers and about 5 to 10 percent of all breast cancers.
A woman with one of these mutations has a greatly increased risk of developing breast cancer. About 12 percent of women in the general population will develop breast cancer by age 70. In contrast, about 55 to 65 percent of women with a BRCA1 mutation and 45 percent of women with a BRCA2 mutation will develop breast cancer by age 70 years. Their ovarian cancer risk is higher too. About 1.4 percent of women in the general population will develop ovarian cancer, compared to 39 percent of women who inherit a BRCA1 mutation and 11 to 17 percent of women who inherit a BRCA2 mutation.
What are these women’s options? They boil down to this: more screening--usually mammography alternating with MRI every six months, reducing risk by taking the drug tamoxifen for five years, prophylactic salpingo oophorectomy (removal of the fallopian tubes and ovaries, which reduces breast and ovarian cancer risk), and/or prophylactic mastectomy (removal of both breasts).
Currently, only women who have an extensive family history of breast and/or ovarian cancer are referred for genetic counseling and testing for the BRCA mutations. But King’s study of Israeli women, which was published in PNAS, showed that there were women without a family history who also tested positive for a BRCA mutation. This was what led to her call for universal screening.
To be sure, universal screening would identify women with a common BRCA mutation who would never have been referred for screening. However, does that mean it makes sense to do it? Men can also carry and pass on the BRCA mutation and men who have it are also at an increased risk for breast cancer. Would we test men too? Since it is inherited, if a mother and father are tested, there would be no need for their kids to be tested if the parents tested negative? Should we make BRCA mutations akin to blood type, widely known and shared?
And what about the other, less common mutations? Dr. King recommends not testing for them, but will that give women with a family history a false sense of security since they will test negative even though they may have a different mutation?
Also, genetic literacy is not currently all that high. It is possible that many people would think they were not at risk for breast cancer because they tested negative--which is not necessarily the case. Would that keep those women from being proactive about their breast health? And what would you do if you learned you had the mutation? Is breast cancer risk the same for someone who has the mutation and has a family history as it is for someone who has the mutation but no family history?
And what about the cost? As prevention, the Affordable Care Act requires that most insurers cover BRCA testing at no cost to women with a qualifying family history. So would women with a family history not have to pay while others would?
Clearly, there is a lot we would have to discuss and work out before we could suggest everyone be screened for the BRCA mutations. It is a provocative idea that needs to be thought out and publicly discussed.
Still, I remain intrigued by the fact that about half the women with a mutation and family history get breast cancer. Why not the other half? What is different between the two groups and can that give us a clue as to what causes breast cancer more widely?
Cutting off normal breasts and/or castration are crude approaches to prevention. If we focus on finding the cause of breast cancer, then we could eliminate the disease once and for all!