How does menopausal hormone replacement therapy (HRT) affect breast cancer risk?

Updated: Sep 13, 2021
  • Author: Nicole K Banks, MD; Chief Editor: Richard Scott Lucidi, MD, FACOG  more...
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Although studies have been inconsistent, an emerging consensus appears to suggest that HT may slightly increase the risk for breast cancer. This risk is similar to that associated with natural late menopause, and it comes into effect after at least 5 years of continuous HT. [1] The lifetime risk of developing breast cancer significantly increases with current long-term HT when it is started in women aged 50 years or older (relative risk, 1.35). Such an effect is not seen in women who start HT early for premature menopause. This observation indicates that it is the duration of lifetime sex hormone exposure that is relevant.

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