HRT risk ‘underestimated’ – study

The risks of hormone replacement therapy (HRT) may have been underestimated, experts have said.

Taking the treatment to combat the effects of the menopause could mean that women are 2.7 times more likely to develop breast cancer than those who are not, a new study found.

Women taking combined HRT are more likely to develop the disease, with risk increasing the longer it is used, the study found. The study, published in the British Journal of Cancer, found that those taking oestrogen plus progestogen HRT were 2.74 times more likely to develop breast cancer. And those who had been using the combined HRT for 15 or more years had a 3.27 times increased risk, the study found.

But once HRT-use ended the increased risk returned to normal levels, the authors stressed.

Those taking oestrogenonly HRT did not have an increased risk, they found. The findings were drawn from thousands of women taking part in the Breast Cancer Now Generations Study – a major study following more than 100,000 women for 40 years to investigate the causes of breast cancer.

Experts analysed data over six years from almost 40,000 menopausal women – 775 of whom developed breast cancer.

Research has shown that HRT increases the risk of breast and ovarian cancer, while links have also been made with stroke and heart attack.

But the authors of the latest study said previous studies could have underestimated the risk of breast cancer because they did not use updated information on women’s use of HRT over time and took into account when they actually began the menopause.

Earlier investigations may have underestimated the increased risk of breast cancer by up to 60%, the authors added.