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Menopausal hormone therapy and breast cancer

Research findings published in 2019 lend support to the view that the risk of hormone therapy for menopausal symptoms in women might be underestimated. There has been ongoing debate for years about whether there is a relation between invasive breast cancer and the use of hormones. The 2019 research findings provided evidence for associations with almost all types of therapy, including oral and transdermal oestrogens, combinations of oestrogens and progestogens, and tibolone.  A comprehensive meta-analysis of individual patient data of over 100,000 women with breast cancer from 24 prospective observational studies found an association between invasive breast cancer and hormone therapy which was likely to be causative. Calculations show that about 5% of the cases of invasive breast cancer in women might be explained by menopausal hormone therapy. The risk proved highest for oestrogen/progestogen combination therapies. In addition, the invasive breast cancer risk increases with the duration of use, and remains increased for years after cessation of the hormone therapy. It is also important to take into account that there is limited evidence for a clinically relevant effect of hormone therapy on menopausal symptoms, compared to placebo.

  • Doctors should be highly reticent about prescribing hormone therapy for menopausal symptoms.
  • Although the risk of invasive breast cancer is only slightly increased, this is hardly ever justified by the limited effects of hormone treatment.

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  • Frans M. Helmerhorst, prof. dr
  • Jan P. Vandenbroucke
  • Hein J.E.M. Janssens, dr, general practitioner