The Women’s Health Initiative (WHI) study led to a significant reduction in prescribing Hormone Replacement Therapy (HRT) due to findings that older women (over 60) who started HRT had a slight increase in heart disease and strokes. There was also a slight increase in breast cancer risk, which contributed to HRT’s negative reputation.
Key Findings from the WHI Study
- Oestrogen Alone: Women who were on oestrogen alone (typically those who had a hysterectomy) did not experience an increase in breast cancer risk.
- Cancer and Fractures: The study found a decrease in bowel cancer and osteoporotic fractures in all groups. This is significant because fractures can increase mortality.
- Timing of HRT: For women who started HRT at the typical time (perimenopause/menopause), there was actually a slight reduction in heart disease and strokes.
Differences in HRT Usage
The WHI study highlighted that starting HRT later in life (which is rarely done in practice) has different risks and benefits compared to starting it at a younger age. It’s also important to note that the type of HRT used in the WHI study is not what we use today.
- Topical 17-beta Oestradiol: Unlike the oral oestrogen used in the WHI study, topical 17-beta oestradiol does not go through the liver and increase coagulation proteins, resulting in negligible or no increase in DVT risk and other thromboembolic risks.
- Micronized Progesterone: This form of progesterone has the same molecular structure as natural progesterone. Studies of up to five years have not shown an increased breast cancer risk with its use.
Current Recommendations and Considerations
Comparing the risks of a different type of HRT in older women long past menopause to the safer HRT commenced at menopause is not appropriate. HRT is still generally recommended for the treatment of menopause symptoms. Claims that it prevents dementia or should be used for primary heart disease prevention cannot be made based on current evidence.
- Breast Cancer: HRT is not recommended for women with a history of breast cancer as it increases the recurrence risk (similar to the risk associated with consuming two glasses of wine per day). However, topical vaginal oestrogen is generally safe but should be discussed with an oncologist first.
- Treatment Duration: The duration of HRT treatment is a contentious topic. While we do not have long-term safety data, some experts believe it could be continued indefinitely. Current guidelines, however, recommend using it for only a few years.
As a doctor, it’s important to discuss the risks and benefits with the patient and agree on a treatment plan together. 💛