Estrogen Replacement Therapy: Friend or Foe?
Menopause occurs when the ovaries stop making the hormones progesterone and estrogen. Estrogen replacement therapy (ERT) is treatment with estrogen alone. It’s used for women who no longer have a uterus. Hormone replacement therapy (HRT) replaces both hormones. It’s used for women who do have a uterus. The goal is to counter certain side effects of menopause. Those include:
- hot flashes
- night sweats
- vaginal dryness
It’s also used to reduce certain health risks that come with menopause. ERT has been used for more than 60 years. Still, its health risks and benefits are surrounded by controversy.
We know that HRT reduces the risk of osteoporosis. We also know it relieves many symptoms of menopause. But other things we thought we knew have now come into question.
There was a recent large study to evaluate the use of combined HRT. The researchers stopped the trial, though, before it was finished. They stopped it to alert participants that the overall health risks of HRT outweighed the benefits. They were particularly concerned about the risk of invasive breast cancer.
The study was sponsored by the Women’s Health Initiative. It involved more than 16,000 postmenopausal women who still had their uterus. The women were given either combined HRT or a placebo. Overall, the health risks were relatively small. But, the risks of invasive breast cancer, heart disease, stroke, and blood clots were higher among women taking HRT. The following chart shows the overall risks.
| HRT arm | Placebo arm | |
|---|---|---|
| Invasive breast cancer | 38/10,000 person years | 30/10,000 |
| Coronary heart disease | 37/10,000 | 30/10,000 |
| Stroke | 29/10,000 | 21/10,000 |
| Venous thromboembolism | 34/10,000 | 16/10,000 |
The vast majority of people taking HRT did not develop these side effects. But their risk for doing so was greater than in women taking placebo. Women in the HRT arm did have some decreased risks. They included a lower risk of colorectal cancer and of hip fracture.
| Colorectal cancer | 10/10,000 | 16/10,000 |
| Hip fracture | 10/10,100 | 15/10,000 |
The two groups had approximately the same risk for
- non-invasive breast cancers (DCIS, LCIS)
- endometrial cancer
- lung cancers
- other cancers
They also had about the same risk of death from coronary heart disease or breast cancer. Part of the reason there was no difference was the relatively short follow-up time of the study. These results may be different for women taking lower dosages of these medications, estrogen alone, or hormones with a transdermal patch.
This study and several other recent studies seem to agree that HRT should not be used to prevent heart disease in healthy women. Nor should it be used in women with existing heart disease.
Do the results show that no women should use HRT? Do they show that all women who are using it should stop? No. This study showed that the overall, absolute risks of HRT remain relatively small.
You need to work with your own doctor and genetic counselor. It’s important to map out your own personal risk for
- breast cancer
- colon cancer
- stroke
- blood clots
- heart disease
- osteoporosis
Then explore which personal risk factors (e.g. obesity, tobacco use, inactivity) you can alter to lower your disease risks. You should also weigh their own discomfort from hot flashes, night sweats, vaginal dryness and other menopausal symptoms. Then you can explore both hormonal and non-hormonal methods for reducing these symptoms. Then you’ll be able to make a personalized, informed decision about the menopausal therapy that is best for you.