Unfortunately, due to a media frenzy and poorly reported women’s health initiative (WHI) study in the early 2000’s there has been a huge amount of controversy with regards to breast cancer and HRT that we just cannot shake off despite the evidence we have that there is no or very little risk depending on the type of HRT we use. Menopause is not formally taught in medical school or nursing training so many clinicians just don’t know this either.
When we look at breast cancer, we need to look at all factors that impact a women’s individual risks for breast cancer. This chart shows the background risk for all women ages 50-59 being diagnosed with breast cancer – 23 out of 1000. There is an increase of 4 women in 1000 (27) with combined HRT and combined oral contraceptives (that have a mix of oestrogen and progesterone).
As you can see here women who just have oestrogen HRT are not at increased risk of breast cancer.
The very small increased risk of breast cancer comes from the progesterone part of HRT not the oestrogen. There are different types of progesterone available that have different breast safety profiles. Taking combined HRT (oestrogen and synthetic progestogen), may be associated with a small risk of developing breast cancer however some studies show this risk is reduced if micronised progesterone (utrogestan) is used. We will mostly prescribe micronised progesterone as it has a much better breast safety profile. There is good evidence there is no increased risk of breast cancer with micronised progesterone.
The risk of breast cancer with any type of HRT is low; for comparison, the risk of breast cancer is greater in a woman who is obese or who drinks a moderate amount of alcohol. To highlight here: being obese and or having more than 2 units of alcohol a day increases risk of breast cancer more than the combined contraceptive pill or HRT.
