The Link Between Breast Cancer and HRT

Published: 07/06/2022

The link between breast cancer and HRT, the risk of getting breast cancer from HRT and how to identify the symptoms of breast cancer from HRT

Breast Cancer and HRT    

What are my chances of getting breast cancer from HRT?

Breast cancer is the most common female cancer in developed countries, but for most women (90% of the population) the risk of developing breast cancer is low over their lifetime. The small risk of developing breast cancer will increase slightly with age as most breast cancers (over 80%) are diagnosed in the over 50s. Genetic and lifestyle factors can also increase the risk.

In the general population, the risk of developing breast cancer in women aged between 50-59 is estimated to be about 22 to 24 per thousand women, whether they use HRT or not.

Your own personal risk will depend on your family history, for example if  a close relative has breast cancer or if there is a genetic risk.  If you smoke, drink alcohol, do not undertake physical exercise and are overweight or obese your risk will be higher.

Other factors for having an increased risk of developing breast cancer are starting periods early and having a late menopause, not having children, not having breastfed your child and use of hormonal contraception.

HRT and Breast Cancer

There are some factors which can affect the risk of breast cancer with HRT including the type of HRT, the age HRT is started, when and how long it is used for. This is explained in more detail below: 

Using oestrogen only HRT (if you have had a hysterectomy) is associated with little or no change in risk of developing breast cancer.

If you are under 50 and using HRT for early menopause your risk of developing breast cancer does not change.

If you start combined HRT after the age of 50 and use it for up to 5 years there appears to be no increased risk of developing breast cancer.

If you use combined HRT for more than 5 years from the age of 50 onwards your risk is increased slightly. It is estimated that around 4-6 additional women per 1000 might develop breast cancer, on top of the 22-24 women in the general population.  This means that out of every 1000 women, 970 will not develop breast cancer and approximately 30 women might.

Risk of breast cancer from HRT

Many women decide the benefits of HRT outweigh the risks. The risks however, cannot be taken in isolation and we all take risks every day.  For example in women that drink 4-6 units of alcohol per day, there will be an additional 8 cases of breast cancer per 100 women, this increases to 11 per 1000 women for those who consume 6 or more units of alcohol per day.  In obese women there are an additional 10 cases per 1000 of breast cancer, and an additional 4 per 1000 in overweight women.  These lifestyle risks of developing breast cancer are greater than that of using combined HRT.

As with any medication, the benefits and risks will vary between individuals.

It should be noted however, that if you have had breast cancer, it is very unlikely that you will be offered HRT.

This is the sixth in our series on Menopause. Check out our other articles to get a full understanding of what the Menopause means for many women.

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