From John Ray's shorter notes

December 20, 2019

Some forms of hormone replacement therapy can LOWER breast cancer risk, research indicates

This is not a new finding but it is encouraging to see it replicated. For women with an intact womb there is no doubt that estrogen-only pills do increase womb (endometrial) cancer -- which tends to counteract their benefit for breast cancer.  What you gain on the swings, you lose on the roundabouts.

Taking a combination pill containing progesterone plus estrogen does however reduce all risks greatly, though there still is an elevation of risks compared with women who take nothing.  The elevation of risk is now however known to be very small so there is little reason for women not to take the combined pill.

Rather perversely, women who have had a hysterectomy are the big winners.  They can get all the benefits of estrogen pills (reduced heart disease etc) without having to worry about womb cancer

Certain forms of HRT actually protect women against breast cancer, researchers have shown.

After years of back-and-forth debate on the risks of hormone replacement therapy, new analysis suggests the type of treatment women use has a huge impact on cancer risk.

Scientists have found that in women who took the combined oestrogen-progestogen form of HRT the risk was raised by about 26 per cent compared with those who took a dummy pill. The combined form is the type of HRT taken by most women.

But the oestrogen-only form reduces breast cancer incidence by 24 per cent.

The study, based on 27,300 women in the US who were tracked for about 19 years after they started taking the pills, alters scientists’ understanding of the link between HRT and cancer.

Crucially, however, women are not able to pick and choose which type of HRT they select.

Oestrogen HRT is only an option for those who have had a hysterectomy – an operation to remove the womb. That is because oestrogen is known to increase the risk of womb cancer, so only women without a womb can safely take it.

But 60,000 undergo a hysterectomy every year in Britain and by the age of 60 one in five women have had the procedure, so tens of thousands of women could benefit from taking the oestrogen only drug.

Researcher Dr Rowan Chlebowski, of the University of California Los Angeles: ‘In contrast to decades of observational study findings... oestrogen alone significantly reduced breast cancer incidence and significantly reduced deaths from breast cancer, with these favourable effects persisting over a decade after discontinuing use.’

The findings were presented yesterday at the San Antonio Breast Cancer Symposium in Texas.

The menopause can cause depression, hot flushes, headaches and night sweats. HRT tackles these symptoms by providing hormones as the body stops producing them.

But many women go without the drugs because of fears it raises the risk of cancer of the breast, womb and ovaries.

The number taking HRT plummeted after studies published in the early 2000s raised fears of side effects, but in recent years research has suggested the risk may be overstated.

Dr Melanie Davies, consultant gynaecologist at University College London Hospitals, said: ‘This is high-quality research.’

But she added that the risk of taking the combined pill is now probably lower than that shown in the trial, because HRT has been improved to more closely match the hormones produced by the human body.


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