HRT breast cancer alert that led to thousands of women abandoning treatment was 'based on bad research'
By JR on Wednesday, January 18, 2012
I have been pointing this out for years
British research which linked HRT to breast cancer and led to hundreds of thousands of women abandoning the treatment was ‘unreliable and defective’, says a damning review.
It is almost ten years since the study – the largest of its kind – contributed to a worldwide scare about the safety of Hormone Replacement Therapy. It was one of three major pieces of research which undermined the confidence of women and doctors in the therapy.
As a result GPs were advised to prescribe it on a short-term basis only to combat menopausal symptoms such as hot flushes and night sweats. They were also told not to use it as a treatment for the bone thinning disease osteoporosis – which can lead to deadly fractures. An estimated one million women gave up HRT in Britain, halving the number using it.
Scientists at Cancer Research UK’s Epidemiology Unit at Oxford, who carried out the MWS, said HRT doubled the risk of breast cancer and blamed it for an extra 20,000 British cases over the decade.
However, the new review led by Professor Samuel Shapiro, a leading epidemiologist at Cape Town Medical School, South Africa, says the size of the study was irrelevant because the design was flawed and this skewed its findings. Professor Shapiro claims the study failed on a number of criteria accepted in good quality research.
For example, cancers detected within a few months of the study’s start would have already been present when women were enrolled, but these were not excluded and this skewed the findings.
Women in the study were contacted through breast screening – but this in itself would have increased the number already aware of lumps or pre-cancerous changes and led to a bias in higher numbers of cancers being detected.
A key criticism is the ‘biological implausibility’ of HRT promoting new cancers – and of this effect being ‘switched off’ within months of a woman stopping using it.
The researchers also said the name Million Women Study implies an authority beyond criticism or refutation. ‘Size alone does not guarantee that the findings are reliable,’ said the review. ‘HRT may or may not increase the risk of breast cancer, but the MWS does not establish that it does.’
The review, published in the Journal of Family Planning and Reproductive Health Care, is the final in a series looking at research linking HRT to breast cancer, which found flaws in two other major studies.
Review co-author Dr John Stevenson, consultant metabolic physician at Imperial College, London, and Royal Brompton Hospital London, said: ‘So much damage has been done by frightening women off HRT, in terms of reducing their quality of life, preventing bone loss and fractures and improving the risk of cardiovascular disease.
‘HRT is one of the cheapest treatments in medicine and we have yet to count the cost to the NHS because of women not having HRT.’
Professor Dame Valerie Beral, who led the Million Women Study, said the review authors were influenced by work as consultants to HRT manufacturers, and that 20 other studies had come to the same conclusion as MWS. [An "ad hominem" attack is about as weak a rejoinder as you get]