06 Nov 2018

Oestrogen and Breast Cancer: Why some well-known facts aren’t facts

“The great tragedy of science - the slaying of a beautiful hypothesis by an ugly fact” Thomas Huxley Most of the population prefer simple solutions to complex problems that are easy to recall and have a superficial veneer of rational thinking.

The oestrogen/breast cancer nexus is one such favoured hypothesis. The more a woman is exposed to oestrogen the greater the risk of breast cancer ergo the treatment of cancer requires depriving the woman of the oestrogen that is feeding the cancer. There is now a second rank theory that these concerns are amplified in the aetiology and management of breast cancer that expresses the oestrogen receptor (ER+)

If only it was that easy! Here is a list of ugly facts.

  1. Oestrogen levels in the blood are highest in young women and lowest in old women but the incidence of breast cancer has the reverse correlation.
  2. In the days before tamoxifen was available advanced breast cancer was treated with high doses of oestrogen and many of these tumours melted away.
  3. Breast cancer during pregnancy, with its extended period of very high levels of oestrogen in the blood, has no impact on prognosis.
  4. It is thought that tamoxifen works as an anti-oestrogen yet the drug has the side effect of provoking uterine cancer because of its oestrogenic activity. The endocrinologists no longer know how it works so they call it a “selective oestrogen receptor modulator” (SERM)
  5. Women who have had a hysterectomy and require HRT can avoid the progesterone that is used to protect the lining of the uterus and simply have oestrogen (ERT)

ERT is associated with a reduction in the risk of breast cancer. http://cancerpreventionresearch.aacrjournals.org/content/4/5/633;

  1. The Women’s Health Initiative (WHI) trial that is quoted as the most compelling evidence for the link between HRT and breast cancer, was re-analysed and re-published in the Journal of the American Medical Association (JAMA) in 2017. This new publication completely reversed the findings of the initial publication yet received no publicity. (Only bad news gets published) http://cancerpreventionresearch.aacrjournals.org/content/4/5/633;

 I find it intolerable that we should have to carry on in ignorance about the benefits and risks of prescribing hormone replacement therapy to women who have had breast cancer.

There are occasions when the indications for hormone replacement therapy must take precedence over any theoretical objections. It is clearly inhumane when a woman who was already having to cope with the physical and psychological burden of breast cancer is then expected to accept, without relief, some of the serious effects of the menopause, which can include severe depression and suicide.

I published those words in the last paragraph in the Lancet 1994, yet still these women are allowed to suffer without the one treatment that might relieve their anguish.

I note that some anger has been expressed on Twitter following Avrum Bluming’s interview on Women’s hour on Wednesday. I think the anger was misdirected. It is outrageous that women are denied the evidence described above before making informed choices even to the extent of accepting uncertainty when their quality of life is being destroyed.

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