In line with todays media coverage on a study showing an increase of breast cancer to those taking HRT, Daisy Network still stands with our current opinion on the importance of HRT use for women with Premature Ovarian Insufficiency.
Daisy Network Statement on:
“Type and timing of menopausal hormone therapy and breast cancer risk: individual participant meta-analysis of the worldwide epidemiological evidence.” Collaborative Group on Hormonal Factors in Breast Cancer. The Lancet 29th August 2019
This study, published this week in the Lancet, is based on analysis of 108,647 postmenopausal women who had developed breast cancer. 51% had used HRT. The paper is not based on new data, but is amalgamation of many studies on HRT and breast cancer in order to provide larger numbers for analysis (called a meta-analysis). The study found an increased risk of breast cancer amongst users of HRT, both for estrogen-progestogen HRT and, to a lesser extent, estrogen only HRT.
Specifically relevant to women with Premature Ovarian Insufficiency (POI), the authors report that few women in the study had started MHT at ages 30–39 years, but among those who were still current users 15 years later, there was increased risk of breast cancer with oestrogen-progestogen and oestrogen-only preparations.
It is well recognised that menopausal HRT is associated with a small increased risk of breast cancer when used for more than 5 years in women who have menopause around the natural age. What this study adds is that it shows that the breast cancer risk remains increased for 10 years post discontinuation of HRT. In addition, the study suggests an increased risk from estrogen alone HRT, which is contrary to many previous studies. Risk of breast cancer is affected by many factors, this study also adds to the body of evidence suggesting that obesity is a great risk factor for breast cancer than HRT.
It is extremely important to note that this study did not assessing the more modern HRT preparations that are currently prescribed. For example only a very small number of women were using micronized progesterone and so conclusions could not be drawn for this this. Many of the preparations studied in this paper are no longer prescribed.
The study suggests that women who started HRT between the ages of 30-50 had an increased risk of breast cancer compared to postmenopausal women of the same age not using HRT. As most women age 30-50 are not postmenopausal – it would be more appropriate to compare the breast cancer incidence to age matched premenopausal controls.
Previous studies have suggested that women with POI or early menopause may have a 30% lower risk of breast cancer. By using HRT and replacing the hormones they are lacking, the risk of breast cancer returns to a level similar to if they hadn’t had an early or premature menopause.
Clearly the use of HRT needs to be individualised, weighing up your individual risks and benefits, however, taking in to account the multitude of other benefits of HRT in women with POI (symptom relief, bone, CV and cognitive function), HRT is still strongly recommended until at least the average age of menopause and we want to reassure women with POI who are currently using HRT.
Key points from the International Menopause Society statement:
- Much of the information regarding breast cancer risk and HRT reported in this paper is not new, although findings in relation to estrogen-only therapy do differ from those reported in the Women’s Health Initiative randomised trial. It is important to note that, because of when the data included in this report was collected, most of the MHT regimens were different from those currently recommended.
- This paper provides an important public health message about obesity and breast cancer risk.
- The reported effects of MHT for women who go through early menopause (before the age of 45 years) must be seen in the context of what is “normal” for women of this age.
- Potential breast cancer risk is one component of the benefit: risk analysis of MHT use for an individual woman which needs to include symptom severity and the potential beneficial effects of MHT on bone and cardiovascular health.
Please read this statement by the British Menopause Society for more information on the findings.