A statistically significant decline in breast cancer rates amongst Australian women aged over 50 years has been linked to a decrease in the use of hormone replacement therapy (HRT), according to new research by The Cancer Council NSW.
The research, published in the Medical Journal Australia, found that the use of HRT in Australia dropped, by 40 per cent from 2001 to 2003 following the US Women’s Health Initiative study, which highlighted HRT’s adverse effects. During the same period, there was a statistically significant seven per cent drop in breast cancer rates among women aged 50 and over, which is equivalent to 600 fewer cases of breast cancer among Australian women.
Dr Karen Canfell, lead author of this new Australian research said, “This research replicates recent findings from the US, which also showed a substantial decline in breast cancer attributed largely to declining use of HRT”.
Associate Professor Emily Banks at Australian National University, co-author of the study added, “To increase the reliability of our study, we ruled out breast cancer screening trends and other factors, including use of medication, as major contributors to this fall in breast cancer incidence in women 50 years and over.”
Dr Andrew Penman, CEO at The Cancer Council NSW believes these findings are positive, indicating that the decision of women and their health professionals to curtail the use of HRT has resulted in a substantial drop in breast cancer at population level.
“The correlation between the drop in breast cancer cases and HRT use is clear and its importance can’t be underestimated. This study’s findings are great news for women. They warrant further investigation to review all available evidence on HRT and its links with breast cancer,” said Dr Penman.
The Therapeutic Goods Administration recommends that HRT should only be used for menopausal symptoms and not for long-term prevention of any disease. Periodic re-evaluation of whether HRT should be discontinued is recommended at least every six months. This is because, in terms of serious disease, the overall harms of HRT outweigh the benefits. However, the National Health Survey of 2004-2005 found that whilst there were fewer users of HRT overall there remain a substantial minority of women who have been using HRT for five or more years.
“It appears that although women and GPs are taking heed of warnings on the long term dangers of HRT there is still potential for more women to reap the benefits of giving it up. Women with severe menopausal symptoms need to talk to their GP and decide whether they are willing to run the increased risk of breast cancer and other conditions.” Dr Penman said.