Yesterday saw some bold, but extremely misleading headlines about hormone replacement therapy (HRT) being “harmless”.

This unfortunate statement flies in the face of years of research showing that, while HRT is an effective short-term treatment for menopausal symptoms, it also carries risks – particularly an increased likelihood of developing breast and ovarian cancer.

For years, researchers around the world have been studying these risks, how they stack up, and how they change over time, to help women make an informed choice about taking HRT.

So where did yesterday’s headlines come from? What do UK experts make of the research underpinning them?

And what’s the best advice for women making decisions about HRT?

Small study

The headlines are based on the results of a study supported by drugs company Pfizer (who make HRT), which was presented at the American Society for Reproductive Medicine’s annual conference, and which have yet to be made public in a scientific journal.

According to reports in the media, the study involved 80 women who took HRT, and compared their risk of developing different types of cancer with 56 women who hadn’t used HRT .

These reports suggest the women used HRT for 14 years on average, and were monitored for 10 years to see if they developed problems. The researchers found that “women taking HRT were no more likely to develop breast cancer, heart disease or diabetes than any other women who did not take the treatment, the study found,” one newspaper reported.

The first thing to say, even without having seen the finer details of the research, is this is far too small a study to base health advice on.

Professor Valerie Beral of Oxford University runs the Cancer Research UK-funded Million Women Study – one of the largest studies to look into HRT’s risks.

She appeared on BBC Radio 4’s Today programme (listen here from 2hrs 50mins) to discuss the study’s findings.

International consensus

As Professor Beral told the BBC, “There are over 50 studies worldwide, that in total have studied several million women, and to base advice on the results of 80 women, even over 10 years is quite meaningless”

These studies show overwhelmingly that HRT has risks as well as benefits.

“Amongst the scientific community the evidence is really quite uncontroversial,” Beral said.

“It is very clear there’s an increased risk of cancer of the breast, cancer of the ovary, blood clots and strokes in women who have taken HRT, compared to women who have not.”


This, she said is why the regulatory bodies in the UK, US and Europe all say the same thing: “Women who want to take HRT if they have very severe menopausal symptoms, should do so for as short a time as possible.”

Serious concerns

As you might expect, we’re very concerned at the way such a small study has been presented to the public. We’ve issued a press release to journalists (which you can read here), and our chief executive has also written to the editor of the Daily Mirror about their decision to put the story on the newspaper’s front page:

Dear Lloyd Embley,

I am very concerned for women’s health following your front page story on Monday 19 October carrying the headline, “It’s official: HRT is NOT a danger to women as experts conclusively dismiss worries over safety.”

This is wrong and will cause irrevocable damage to women’s perception of HRT – a treatment which, if used for extended periods, is well known to increase the risk of several different cancers.

The news story was based on a study that, according to your story, looked at only 80 women. You cannot claim that HRT is safe on the basis of this very small study. Scientific discovery relies on many research studies in order to be able to identify the risks of any treatment.

Cancer Research UK has funded a study looking at a million women, which showed that taking HRT doubles their risk of developing breast cancer. We also know that it increases the risk of womb and ovarian cancer. However, the study concluded that the risk is lower for short term use.

The consensus of the international scientific community based on a large body of research is HRT increases the risk of breast cancer. They are dismayed by yesterday’s headlines and believe women may die as a result.

As a paper with huge influence and power to communicate health messages to the public, I would ask that you think more carefully about the reporting of your science and health.

I would be happy to discuss this with you further.

Yours sincerely,

Harpal. S. Kumar, Chief Executive, Cancer Research UK

So what should women do?

The evidence underpinning the benefits and risks of HRT didn’t arrive overnight – it has been accumulating for decades.

Women need to be aware that, as well as offering effective relief for menopausal symptoms, it also leads to more cases of breast and ovarian cancers, as well as strokes and blood clots. The risks and benefits will stack up differently for each woman, and whether or not to take HRT is clearly an individual choice.

And women need clear, evidence-based information to help them decide – not sensationalist headlines based on unpublished research.

– Fiona Osgun is a senior health information officer at Cancer Research UK

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