Commonly used hormone replacement therapy can nearly triple the chance of breast cancer in women, a major study released on Tuesday has warned. Scientists at the Institute of Cancer Research (ICR) in London found menopausal women using the combined hormone replacement therapy (HRT) therapy, a combination of oestrogen and progestogen, were running a risk of 2.7 times greater than non-users.
“What we found is that the risks with combined HRT are larger than most of the literature would suggest,” said Anthony Swerdlow, professor of epidemiology at the ICR who led the research. The findings in the ‘British Journal of Cancer’ suggest that although 14 out of every 1,000 women will ordinarily develop the disease in their early 50s, the number would rise to 34 if they all took combined HRT.
This is an increase of 12 cases per 1,000 women on previous estimates, according to Breast Cancer Now, which helped to fund the study. In the UK, about a fifth of the 2 million women going through menopause are thought to be prescribed HRT after symptoms that include hot flushes, sweats, low mood and tiredness.
In the biggest of its kind study, which covered 39,000 women, scientists concluded that taking combined oestrogen and progestogen HRT for an average of five years almost tripled the risk of breast cancer. According to the study, the chance increased the longer the women took HRT, with those using it for 15 years having 3.3 times more chances of developing breast cancer.
It said that HRT is an individual choice but accurate information is essential. “Women need clear, evidence-based information to break through the conflicts of opinion about the menopause. For many women, any change in breast cancer risk is outweighed by the benefit on their quality of life,” said Heather Currie, chairperson of the British Menopause Society.