A thousand British women may have died from ovarian cancer since 1991 because they had hormone replacement therapy (HRT).
The death toll estimate emerged from the biggest investigation of links between HRT and cancer ever undertaken.
New findings from the Million Women Study suggest that HRT use in the UK resulted in 1,300 extra cases of ovarian cancer between 1991 and 2005. Of these women, 1,000 died of the disease.
Previous results from the same study have linked HRT with an increased risk of breast and womb cancer.
The research indicates that a woman’s risk of suffering ovarian cancer returns to normal within a few years of giving up HRT.
To put the findings in perspective, they mean that over a period of five years there is likely to be one extra case of ovarian cancer among every 2,500 women receiving hormone replacement therapy. For every 3,300 women on HRT, there is estimated to be one additional death from ovarian cancer.
However the strength of the association between HRT and ovarian cancer has alarmed experts involved in the study.
Their leader, Professor Valerie Beral, Director of Cancer Research UK’s epidemiology unit at Oxford University, said: ‘The results of this study are worrying because they show that not only does HRT increase the risk of getting ovarian cancer, it also increases a woman’s risk of dying of ovarian cancer. This study, along with our previous research, clearly demonstrates the cancer risks of taking HRT.’
Ovarian cancer is the fourth most common female cancer in the UK. Each year about 6,700 women develop the disease and 4,600 die from it.
The Million Women Study, largely funded by Cancer Research UK, recruited 948,576 postmenopausal women, representing a quarter of all women aged 50 to 64 in the UK. Around a third of the women were undergoing HRT, and a further fifth had received it in the past.
© The Press Association, All rights reserved.