From a healthcare perspective, Angelina’s Jolie’s case is pretty clearcut, even if her personal decisions were fraught and complex. Her insurance presumably paid for her breast-cancer gene tests because her mother died of ovarian cancer.* When women like Jolie appear to be at higher than usual risk for breast cancer, their risk factors are punched into a mathematical model and out comes a magic number that helps us make health care decisions. A first-degree relative with breast cancer is pretty much a slam-dunk, and most insurance companies will pony up the cost for Myriad’s monopoly-priced diagnostic panel.
For the rest of us, figuring out risk is trickier. The standard breast-cancer model, the Gail model, tends to underestimate risk, and doesn’t take into account all sorts of well established risk factors such as obesity, alcohol consumption, exposure to radiation, use of hormone replacement therapy and family history of breast cancer in relatives more distantly related than a sister or mother. As a baseline, the average risk of U.S. women is 12.2 percent, or the risk of one in eight women getting breast cancer if they live through old age.
When my doctor used the Gail model, my risk was slightly higher than average, about 14 percent, but neither of us found that reassuring. That’s because I have two grandmothers and a great-grandmother who died of breast cancer or ovarian cancer, which is genetically related to breast cancer. My doctor referred me me to a genetic counselor, who ran a more sophisticated risk model called the Tyrer-Cruzick that upped my estimated risk to 19.8 percent. That’s two-tenths of a percent lower than the risk that triggers the use of “high-risk” detection tools like regular MRIs in addition to mammograms. Welcome to the gray zone of risk assessment. Both my counselor and I thought I should get tested for the BRCA genes, but my insurance carrier firmly disagreed. At over $3,000, Myriad’s test is too expensive for me and most other women to get, regardless of what they and their doctors may think.
So why didn’t I just cough up the money? Isn’t my health and life worth it? A couple of reasons. For one thing, I learned that our fear of breast cancer is clouded by misconceptions. We tend to think of breast cancer as a heritable disease, but in the vast majority of cases, it’s not. Straight hereditary factors only account for about 10 percent of all breast cancers. And while the BRCA genes are the well-known poster children of risk, they get more credit than they deserve. In families with histories of breast and ovarian cancer, about half do not have BRCA mutations at all.
Given my family history, I could have a genetic flaw like the one that originated on a BRCA2 gene in 16th century Iceland. Or my grandmothers could have inherited one of the 700 other distinct “founder effect” mutations on BRCA genes discovered in Dutch, German and Pakistani populations, among others. But it’s just as likely they had totally different genetic variants that can cause breast cancer, including TP53, PTEN, STK11/LKB1, CDH1, CHEK2, ATM, MLH1, and MSH2, or ones that are as yet undiscovered.
I decided to opt for a much cheaper panel that tested for several known genetic mutations, the dominant BRCA ones excluded thanks to Myriad’s DNA-grabbing patent. When that panel came back negative, I was relieved. Many companies offer these tests, including 23andMe, which does it for $99.
Using the models, tests and screens made me feel like I was doing something, but ultimately, they’re not terribly meaningful. It’s not even very helpful to know your magic risk number for breast cancer. Most women with lots of risk factors will never get breast cancer, and many without the big risk factors will get it nonetheless. In other words, many of the standard risk factors (early puberty, late menopause, obesity, older maternal age, obesity, smoking) are fairly useless. The reason is that we still don’t know really know what causes breast cancer. But at least most of us don’t have Jolie’s BRCA gene (it occurs in 1 in 500 people), and for that, we should be thankful.
Correction, May 14, 2013: This post originally stated that Angelina Jolie's mother died of breast cancer. She died of ovarian cancer.