Breast Density and High Hormone Levels: New Breast Cancer Risk Factors

PJ Hamel Health Guide
  • Last fall, research was published showing that women with dense breasts are more likely to be diagnosed with breast cancer–four times more likely, if you compare women with the densest breasts to women at the other end of the scale, with the least dense breasts. Now, a new study finds that women with dense breasts AND a high level of sex hormones – including estrogen and testosterone – are at a SIX times greater risk for breast cancer. And that’s significant.

    What does that term mean, “dense breasts”? Well, it’s pretty self-descriptive: it means breasts that are made up of more connective tissue than fat; more A cup than D cup. It’s a specific genetic condition in some women; but in most, it’s simply a body type. If you have dense breasts, you’re probably small-breasted; and you may have had trouble discerning lumps in your breasts because they feel lumpy and gnarly all the time anyway. About one in six women is characterized as having dense breasts.
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    Now, an August 1 report in the Journal of the National Cancer Institute details the results of the nine-year Nurses Health Study involving nearly 800 post-menopausal women. That study, conducted by researchers from Georgetown University Medical Center and Harvard Medical School, compared breast density and hormone levels in women with breast cancer against the same criteria in women who were cancer-free. And, not only did breast density signal a higher risk, as expected; hormone levels predicted a twofold increase in risk, and the combination of dense breasts and high levels of hormones predicted the aforementioned 6X risk.

    The study also noted a surprising finding: that hormone levels and breast density are not related. Lead author Celia Byrne, Ph.d., said that scientists had long believed the two were related; circumstantial evidence, such as the fact that a woman’s breasts grow when she’s pregnant (and producing more hormones) seemed compelling. “But that is not what our study showed,” said Byrne. “We have found that dense breasts are not a marker for higher hormone levels, or vice versa, and this tells us each increases breast cancer risk via a different biochemical pathway.”

    So, what can you do with this information? You might want to find out if you have dense breasts, which isn’t something you can determine for certain on your own. Next time you’re scheduled for a mammogram, contact your oncologist ahead of time, and ask if the radiologist can assess the density of your breasts from the mammogram, when he or she reads it. If you do have dense breasts, you might want to ask for a digital mammogram going forward, as that type of screening is more effective in women with higher breast density.

    And what about the high levels of hormones? Well, taking hormone replacement therapy is certainly a good way to raise your hormone levels–for better (relieving symptoms of menopause) or, in this case, for worse. In addition, being overweight increases your body’s production of estrogen; so do what you can to lose weight. There’s more to maintaining proper weight than just being happy with how you look in your clothes; you’ll also be chipping away at another factor that could lead to breast cancer, especially if you determine that you have dense breasts.
Published On: August 22, 2007