More younger women are getting breast cancer, and doctors are scrambling to understand why.
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| Breast cancer Ribbon |
Rates of breast cancer in women under 50 have increased more than 15% in the last two decades, a rise that is almost entirely driven by an increase in estrogen receptor-positive breast cancer (ER+), a tumor subtype that needs the hormone estrogen to grow and spread.
Estrogen receptor-positive breast cancer is the most common type among all age groups. Because this specific type of breast cancer is almost exclusively causing the spike in younger women, some doctors suspect the trend is related to more people in the U.S. getting their periods earlier and having their first baby later.
“Women are being exposed to more estrogen over their lifespans,” said Dr. Alexandra Thomas, a medical oncologist at Duke Health. “That’s probably a big piece of it, but we don’t know why we’re seeing earlier periods.”
Numerous factors are likely behind the increase — including obesity, alcohol consumption, genetics and some hormonal birth control.
“This work is still in the early stage,” said Dr. Adetunji Toriola, a molecular epidemiologist at Washington University’s Siteman Cancer Center. “But we do know from some of our previous work and the work of others that we know certain factors that may be responsible. We know that these reproductive factors can relate to breast cancers.” nbcnews.com
