Risks of HRT
After reviewing the evidence base, the National Institute for Health and Care Excellence have made some recommendations:
- Risk of venous thromboembolism is higher if oral preparations of HRT are used
- If the transdermal route of HRT is used, there is no greater risk of venous thromboembolism compared with the baseline
- HRT with oestrogen alone carries no or reduced risk of coronary heart disease
- Combined HRT with oestrogen and progesterone carries little or no risk of coronary heart disease
- Oral oestrogen HRT gives a small increased risk of stroke (this does not apply to any transdermal HRT) – however this does not apply if started in women under the age of 60
- Oestrogen-only HRT has little or no increased risk of breast cancer
HRT containing oestrogen and progesterone can increase the risk of breast cancer (but not overall mortality) and the risk is maximal whilst on treatment and reduces once HRT is stopped - The risk of ovarian cancer is not fully understood but meta-analyses suggest that women who use HRT for 5 years from the age of 50 are at risk of approximately 1 case in every 1000 users and up to 1 excess death in that group
The British National Formulary has published tables that show the baseline risks of some of these conditions in the general population and the increased risk from using different types of HRT for different lengths of time as well that after stopping treatment.
This of course offers some advice for women with comorbidities in that:
- Those with or at high risk of breast cancer should be offered alternatives to HRT like antidepressants, vaginal moisturiser, lubricants, cognitive behavioural therapy, acupuncture and relaxation. They can also be referred to someone with an expertise in menopause
- Those at risk of venous thromboembolism should be given transdermal HRT or be referred to a haematologist for advice before initiation