Breast cancer and HRT
Tuesday, 30 August 2016
When I ask women in my clinic why they are worried about taking HRT, the most common answer is their concern about the increased risk of breast cancer. Many women are very worried about this risk and it leads to much concern and confusion. There is evidence that taking combined HRT over the age of 51 years is associated with a small increased risk of breast cancer.
The findings of a study* published in the British Journal of Cancer this week have suggested that the increased risk of breast cancer among women taking the more common combined HRT in the longer term is slightly higher than previous studies have shown. This retrospective observational study has shown that there is a 2.74 times increased risk of developing breast cancer (or pre-invasive DCIS) for women using combined HRT for five years and also that this risk increases to around threefold with prolonged treatment – over 15 years. As shown with other studies, there was no increased risk of breast cancer seen for users of oestrogen only therapy. This increased risk returned to normal after stopping HRT.
However, there is no new cause for alarm. The results of this study are similar with other studies in that women who are only taking oestrogen (so those women who have had a hysterectomy) do not have an increased risk of breast cancer. There has never been a study to show there is an increased risk of dying from breast cancer when taking HRT.
It appears to be the type of progestogen that is important and the newer type of progestogen, micronised progesterone, was not mentioned in this study. It is so important for women to understand that there are so many other risk factors for breast cancer. These include being overweight or obese, being older, drinking alcohol and smoking.
The risk of developing breast cancer is actually greater if a woman is overweight than if she is taking HRT. The British Menopause Society and the International Menopause Society have also produced documents that agree with my views.
Women who are under 51 years of age taking HRT do not have any increased risk of breast cancer by taking HRT as they are simply taking hormones that their body would otherwise be making.
It is so important that a woman’s individual risk factors for breast cancer, and indeed other conditions, are clearly assessed and evaluated. The results of this study should not lead to women panicking about HRT and stopping any treatment they are on.
There is no need for the current NICE guidelines to change in view of this recent trial.
* Jones ME, et al. Menopausal hormone therapy and breast cancer: what is the true size of the increased risk? British Journal of Cancer advance online, publication 28 July 2016. DOI: 10.1038/bjc.2016.231