HRT use still low after breast cancer link
31 March 2016
Hormone replacement therapy (HRT) has failed to shake off its bad reputation despite evidence showing it can be used safely, research suggests.
The proportion of Australian women in their 50s and 60s using HRT has remained below 15% during the past 10 years, a recent analysis has shown.
Use of HRT has halved from about 30% of women using it in the early 2000s, when a possible link with breast cancer was uncovered by the Women's Health Initiative study, to about 13% of Australian women using it in 2013.
The 2013 survey of more than 4000 Australian women aged 50-69 found that 13% currently used HRT — a similar figure to 2004/2005.
Combination HRT was the most common therapy type in women with an intact uterus, while oestrogen-only therapy was most popular among women who had had a hysterectomy.
According to Sydney gynaecologist and menopause expert Dr Michele Kwik, the ongoing fear surrounding HRT is largely unjustified.
"Since the Women's Health Initiative study, we've gone back through all the data and re-stratified all the women to try to work out whether the effects were real or not," she explained at a recent Australian Doctor education seminar.
Further analyses have revealed that the risk of developing breast cancer on HRT is low, especially if it is used for a short time, she said.
"The risk of breast cancer attributable to [HRT] is small and related to the duration of use, and the risk decreases after treatment is stopped."
Latest RANZCOG (Royal Australian and New Zealand College of Obstetricians and Gynaecologists) guidelines state that oestrogen-only HRT does not increase the risk of breast cancer and that combined HRT increases the risk of breast cancer only if it is used for more than 5 years.
One concern raised by the PLOS ONE study was that three-quarters of HRT users reported using the treatment for 5 years or more, corresponding to 9% of all Australian women aged 50-69.
"[This] is important because [HRT]-related risks, particularly the risk of developing breast cancer, increase with increasing duration of use," the authors wrote.
The analysis also showed that about 2% of women in their 50s and 60s were using ‘bioidentical hormone therapy' (BHT) — plant-derived hormone formulations that have the same structure as human hormones.
"BHT has been promoted as a more natural and safer alternative for relieving menopausal symptoms, but it has been noted that the safety and efficacy of compounded hormone products have not been extensively evaluated in large-scale randomised trials," the researchers said.