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ADEC summary statement on HRT

16 April 2004

Following publicaton of the results of the oestrogen only arm of the WHI study, the ADEC has reviewed and updated its statement on use of HRT to include reference to the newly available information. This statement update should be read in conjunction with previous advice of the ADEC on this matter.

ADEC summary statement on the use of hormone replacement therapy following the cessation of the oestrogen only arm of the WHI study

16 April 2004

The ADEC notes the reported results from the oestrogen only arm of the large United States' WHI study. The US National Institute of Health (NIH) had previously issued a press statement around its concerns over the risk of stroke in oestrogen only users. In the study arm, oestrogen alone appears to increase the risk of stroke by 8/10,000 woman-years, similar to that seen in the combined oestrogen and progestogen arm of the study. No effect was seen on the incidence of coronary heart disease, the primary outcome under study, or in preventing colorectal cancer. Oestrogen alone, similar to combined oestrogen and progestogen, reduced the incidence of hip fractures.

In the oestrogen only arm, no increase in breast cancer risk was observed over almost seven years. Indeed a non-significant decrease was observed, however this does not prove that oestrogen does not cause breast cancer. Analysis of the study result indicates this could be a chance finding. It is also inconsistent with the results from other trials, where oestrogen alone was statistically significantly associated with an increase in breast cancer.

The Committee noted that the risk of heart disease in the oestrogen only arm of the WHI study was not apparently increased or decreased. The Women's Health Initiative Memory Study1 (WHIMS) showed an increased risk of probable dementia and/or mild cognitive impairment. There was a trend to the same outcome in the oestrogen only arm of the WHI Study.

The Steering Committee for the study reports that there was no overall benefit from the use of oestrogen alone and recommended that its use in disease prevention in post-menopausal women could not be justified. The Steering Committee concluded that it supported the US FDA view that oestrogen be used for treatment of menopause at the lowest possible dose for the shortest possible time.

The ADEC agrees that hormone replacement therapy remains an effective short-term treatment option for controlling the symptoms of the menopause. For each woman considering use of HRT, it is necessary that the benefits be weighed against the several risks that have been observed, including that of coronary heart disease within one year and breast cancer after more than one year of therapy. Periodic re-evaluation of whether HRT should be discontinued is recommended at not more than six monthly intervals. Hormone replacement therapy is not recommended for any long-term prevention of any disease, including the prevention of osteoporosis, as the potential harm may outweigh the potential benefits.

There is no TGA-approved indication for HRT in the treatment of osteoporosis and there are no large scale studies on the risk and benefit of HRT in women with established osteoporosis. The Committee is not able to make an evidenced-based recommendation for or against use in women with established osteoporosis.

Nevertheless, it is recognised that some women are currently taking long-term hormone replacement therapy for the treatment of osteoporosis. In this situation the risks now documented must be considered when reviewing an individual's circumstances as well as considering the benefits and risks of other therapies.

For younger women with premature menopause or hypogonadism, the benefits of hormone replacement therapy would be expected to be greater and the risks probably smaller than those reported recently in the WHI study and Million Women Study.

Women taking any form of hormone replacement therapy should discuss their circumstances with their doctors. The decision to continue HRT will depend on the individual's circumstances and should be regularly reviewed by patients with their doctors. HRT should not be used as a "lifestyle" choice or to prevent any disease.

References:

1. Shumaker, S A, Legault, C et al. JAMA 2003 289:2651-2662

Issued: 16th April 2004