Research published in the Lancet has found that women taking hormone replacement therapy (HRT) to mitigate the symptoms of menopause for longer than a year have a significantly higher risk of breast cancer than menopausal women who have never taken HRT.
Breast cancer risk is twice as great if HRT is taken for more than five years and although the risk does decline once HRT is stopped, a heightened risk remains ten years after patients have stopped taking the therapies, compared to women who have never taken HRT.
The risk was seen in all types of HRT, except topical kinds, however, combined oestrogen-progestogen therapies caused the greatest breast cancer risk, compared to oestrogen alone.
Funded by Cancer Research UK and the Medical Research Council, the study used existing epidemiological evidence, both published and unpublished, from January 1992 until January 2018. It was conducted by researchers from the University of Oxford’s Nuffield Department of Population Health.
Co-author Professor Valerie Beral from the University of Oxford said: “Our new findings indicate that some increased risk persists even after stopping use of menopausal hormone therapy.
“Previous estimates of risks associated with use of menopausal hormone therapy are approximately doubled by the inclusion of the persistent risk after use of the hormones ceases.”
As a result of this study, the UK’s Medicines and Healthcare products Regulatory Authority (MHRA) has recommended that HRT only be prescribed where menopause affects the quality of life for the patient, and if it has to be prescribed, it should be the lowest does and for the shortest time possible.
MHRA Vigilance and risk management of medicines division deputy director Sarah Branch said:
“Women should be aware of this new information, so that it can be considered with the other risks and benefits of using HRT.
“The menopause can have unpleasant side effects and HRT products can be effective in helping to ease the symptoms.
“No medicine is completely without risk, but it is important for women to be able to make an informed decision about the risks and benefits that are appropriate for them.
“If you have any questions please talk to your healthcare professional.
“The MHRA is communicating this new evidence to patients and healthcare professionals.”