Some types of endometrial cancer (EC) grow in response to high levels of a hormone called estrogen. These are known as hormone-sensitive or hormone-dependent cancers.
If your cancer is hormone-sensitive, your doctor might recommend a treatment called hormone therapy, also known as endocrine therapy. Hormone therapy works by changing the levels of certain hormones in your body to help slow down or stop the growth of the cancer.
How does hormone therapy work?
The hormone estrogen can act like fuel for some endometrial cancer cells, helping them grow and divide. Hormone therapy aims to take away that fuel or block its effects.
A common approach is to use a hormone called progesterone or drugs that act like progesterone, called progestins. These treatments counter the effects of estrogen.
Progestins work by attaching to special parts of the cancer cells, called progesterone receptors. By doing so, they block the effects of estrogen on cancer cell growth.
Types of hormone therapy
Progestins
These are synthetic hormones that mimic the effects of progesterone and are the main hormone treatment for endometrial cancer. Options include:
- Medroxyprogesterone (Provera®) – taken as pills or injections
- Megestrol (Megace®) – available as pills or liquid
- Levonorgestrel IUD (Mirena®) – a hormone-releasing device placed in the uterus, often used for women with early-stage cancer who want to keep their fertility
Other hormone-blocking drugs
Other medicines can also help. These include:
- Aromatase inhibitors, which lower estrogen production
- Tamoxifen and fulvestrant, which block estrogen from attaching to cancer cells
- CDK 4/6 inhibitors, which stop cancer cells from dividing
When might hormone therapy be a good option?
For advanced or recurrent cancer
Hormone therapy is often used when the cancer is in an advanced stage (stage 3 or 4) or when cancer comes back after other treatments. It’s also beneficial for women who would like to avoid or cannot tolerate chemotherapy.
For fertility preservation
Younger women with early-stage cancer sometimes choose hormone therapy to avoid a hysterectomy and keep the chance of getting pregnant later.
How effective is hormone therapy?
The effectiveness of hormone therapy is strongly linked to the presence or absence of hormone receptors on cancer cells. Patients whose tumors have progesterone receptors tend to respond better to treatment, with response rates between 37% and 55%, compared to only 8% to 12% in those without these receptors.
What are the possible side effects?
As with all therapies, you can experience several side effects from hormone therapy. Progestins can cause:
- Hot flashes and night sweats
- Weight gain due to water retention or increased appetite
- Worsening of depression
- Higher blood sugar, especially for women with diabetes
- In rare cases, blood clots
If you’re considering hormone therapy, your doctor can help weigh the benefits and risks based on your personal situation.
