The Marion Gluck Clinic


Date: September 2019

The recent publication in The Lancet reports an increased risk of breast cancer with longer duration of HRT use, especially with combined HRT, and that this risk continues for longer than previously thought once HRT is stopped. Further details can be found here.

For many years, there has been a link between HRT and breast cancer risk. In 2015, NICE guidance stated that healthcare professionals should discuss these risks with women before starting on HRT.

The Lancet review is not a new forward-looking clinical trial, but instead a selection of 58 published and unpublished past studies, the earliest dating back to 1992. The increase in breast cancer reported from these studies, in simple terms, means that if a woman aged 50 takes the combined HRT and is followed up 20 years later, the breast cancer risk goes up from 6.3% to 8.3% (2% increase). In the same scenario on oestrogen only therapy, the risk goes up from 6.3% to 6.8% (0.5% increase).

The publication did not include licensed bio-identical (also known as body identical) HRT formulations containing micronised natural progesterone, which is also used in the customised BHRT that we prescribe.

Our general conclusions are as follows:

  • There is a slightly greater risk of breast cancer in women taking conventional HRT than previously thought, however the risks are low. Conventional HRT often includes ‘synthetic progestins’ which were the only form of progesterone included in the Lancet publication. In previous studies the breast cancer risk has been lower in women using the bioidentical form of progesterone (i).
  • At the Marion Gluck Clinic, we always take the safety of our patients extremely seriously and discuss all risk factors with them, taking into account family history, lifestyle and the impact menopause has had on them both physically and psychologically. Because we prescribe customised BHRT, the dose of HRT is always the lowest possible which gives the desirable symptom control. We also constantly monitor patients throughout their treatment, ensuring up-to-date breast cancer screening (mammograms), DEXA scans (to check bone density), pelvic ultra-sounds and blood tests to ensure the best outcomes.
  • The study also did not take into account the reported increased risk of breast cancer from lifestyle factors, such as smoking, alcohol and obesity.
  • Obesity still remains the greatest risk factor for breast cancer.Should you have any concerns or questions relating to this study, please contact the clinic.

i – Effects of estradiol with micronized progesterone or medroxyprogesterone acetate on risk markers for breast cancer in postmenopausal monkeys. Wood CE, Register TC, Lees CJ, Chen H, Kimrey S, Mark CJ. Breast Cancer Research and Treatment. 2007 Jan; 101(2):125–134.



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