Some breast cancers need female hormones (oestrogen and/or progesterone) to grow and reproduce. Hormones – particularly oestrogen – can encourage the growth of breast cancer that tests positive for hormone receptors. This type of breast cancer is called hormone receptor-positive breast cancer.
In most cases treatment for hormone-receptor-positive metastatic breast cancer will start with hormone-blocking therapy given in the form of oral tablets. This treatment aims to deprive the breast cancer cells of the hormones they need to grow.
Hormone-blocking therapy is designed to either lower the level of oestrogen in your body or stop the oestrogen from stimulating the cancer cells. Your doctor may recommend this treatment if your tumour is hormone receptor-positive.
Once started, each treatment is continued until it is no longer effective or side effects are sufficiently troublesome to prevent its use. Often a sequence of these treatments may control the cancer for a number of years.
There are also now several targeted therapies that can be added to extend the length of control by hormone-blocking therapies and improve outcomes. Treatment will usually start with hormone-blocking therapy (oral tablets) with or without one of the targeted therapies called CDK 4/6 inhibitors.
Occasionally, if there is concern that your cancer may cause serious problems for you in the near future, you may be advised that a course of chemotherapy should be given first to gain control of the cancer quickly. One example of this is if you have numerous symptoms from your cancer, liver metastases, or calcium levels above normal. Once chemotherapy is completed, people are usually able to proceed with hormone-blocking therapies.
Some of the hormone-blocking therapies available currently include:
Which hormone-blocking therapy is right for me?
The hormone-blocking treatment recommended for you will depend on a number of factors, including:
If you have had a hysterectomy, you may need a blood test to determine whether you are premenopausal or postmenopausal.
If your breast cancer was metastatic when you were first diagnosed (e.g. de novo metastatic breast cancer), the main factor influencing the choice of hormone-blocking therapy is whether you are premenopausal or postmenopausal. If you have been using hormone replacement therapy or a hormonal contraceptive, then this will need to be permanently stopped.
People taking hormone-blocking therapy for metastatic breast cancer may experience a range of side effects, including:
You may experience some or none of these side effects. Talk to your treating team about any side effects you experience as there are often ways to manage them.
Occasionally, you may need to stop a treatment because of side effects. In this case, there is usually another hormone-blocking therapy you can try.
Note: Hormone-blocking therapy is sometimes confused with “hormone replacement therapy” (HRT), but they are completely different treatments.
Let’s be Upfront about navigating a breast cancer diagnosis as an Aboriginal or Torres Strait Islander.
Let’s be Upfront about navigating relationships with your medical team.
Let’s be Upfront about living in a rural area following a breast cancer diagnosis.
Let’s be Upfront about living with metastatic breast cancer.
Let’s be upfront about the side effects of hormone-blocking therapies for the treatment of hormone receptor positive breast cancer.
Let’s be Upfront about living with metastatic breast cancer
*This article does not provide medical advice and is intended for informational purposes only.
Please consult a medical professional or healthcare provider if you're seeking medical advice, diagnoses, or treatment.