Fall In HRT Use Linked To Drop In Breast Cancer In Aussie Women

Main Category: Women's Health / Gynecology
Also Included In: Breast Cancer;  Endocrinology
Article Date: 02 Jun 2008 - 1:00 PST

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A rapid fall in the use of hormone replacement therapy (HRT) has largely been responsible for a recent reduction in invasive breast cancer among Australian women aged 50 years or older, according to a research paper published in the latest issue of Medical Journal of Australia.

Dr Karen Canfell, from the Cancer Council New South Wales' Cancer Epidemiology Research Unit, and her co-authors used Pharmaceutical Benefits Scheme data to analyse trends in annual prescribing of HRT. The researchers also looked at annual age-standardised breast cancer rates in Australian women between 1996 and 2003.

Dr Canfell said that HRT prescriptions increased during the first five years of the period they analysed, but then dropped by 40 per cent between 2001 and 2003.

"Breast cancer incidence rates in women aged 50 years and older, who comprise the majority of HRT users, increased up to 2001. But after 2001 incidence rates in this age group fell, corresponding to the drop in use of HRT. Incidence rates were significantly lower by 6.7 per cent in 2003 compared with 2001, equivalent to 600 fewer breast cancers." she said.

"By contrast, there was no change in breast cancer incidence among women younger than 50, who rarely use HRT."

The changes in breast cancer incidence among Australian women do not appear to be due to other factors considered by the authors, including participation in the national breast screening programme.

In 2002, the Women's Health Initiative released a report showing a significant increase in the risk of breast cancer, coronary heart disease, thrombosis and stroke among women using HRT. This US report, along with subsequent prescribing advice from drug regulatory authorities, has lead to a rapid and substantial drop in the use of HRT worldwide.

Co-author Associate Professor Emily Banks from the Australian National University said "Our analyses were designed to replicate, in an Australian setting, analyses carried out in the US, which also found a significant drop in breast cancer incidence among women aged 50 and over, but not in younger women."

"Many other studies have shown that the increased risk of breast cancer associated with HRT use is greatest when women are taking HRT, and that this risk falls soon after women stop taking HRT. The Australian figures support these findings. It is important for women to know that the adverse effects of HRT on breast cancer can go away after they stop taking HRT."

The Medical Journal of Australia is a publication of the Australian Medical Association

Medical Journal of Australia

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