Generation of women ‘deprived of HRT over misinterpreted data linking hormone therapy with breast cancer’ – review

New critical review published of the Women’s Health Initiative study, which linked hormone therapy with the risk of breast cancer

Fresh criticism of the study that suggested a possible link between HRT and breast cancer two decades ago has been published in a leading journal.

The new paper, published in Menopause journal, further debunks the findings of the Women’s Health Initiative study (WHI). US medical oncologist Dr Avrum Bluming and colleagues say that if the WHI had been transparent about their findings around breast cancer, there would have been ‘minimal controversy, no confusion, and women’s health would not have suffered so dramatically over the ensuing decades.’

In 1993, the WHI began a clinical trial looking at the health effects of women taking oestrogen-only or combined HRT compared to a placebo. In 2002, researchers halted the part of the study looking at women taking both oestrogen and progesterone (two hormones that decline during the perimenopause onwards) early over concerns there were small increased risks of breast cancer, heart disease, strokes and blood clots. This led to confusion and concern from doctors and women worldwide, and in the UK women taking HRT fell sharply [1].

But even with the older versions of HRT, the WHI researchers have subsequently acknowledged that HRT is the most effective treatment for managing menopausal symptoms like hot flushes and that taking oestrogen alone reduces the risk of breast cancer by 23% and death by breast cancer by 40%.

Those involved with the study have continued to insist that there is a small increased risk of breast cancer for those taking oestrogen and progesterone.

But Dr Bluming and colleagues, in their Menopause article, argue:

• Combined HRT begun for women who had not had it before did not increase their risk of breast cancer, not even in those with a family risk of the condition 

• Even if the WHI risk was accepted, it would mean there would be one additional extra case of non-fatal breast cancer for every 1,000 women who took HRT. But there is no statistically significant risk between combined HRT and breast cancer when the data is properly interpretated using the rules set out by the study

‘A generation of women has been deprived of HRT largely as a result of this widely publicised misinterpretation of the data,’ the article says.

References

1. Women’s Health Concern (2022), ‘HRT: the history’
2. Bluming A.Z., Hodis H.N., Langer R.D. (2023), ‘‘Tis but a scratch’, Menopause, doi: 10.1097/GME.0000000000002267