Does hormone replacement therapy (HRT) increase the risk of cancer?

  • Hormone replacement therapy (HRT) slightly increases the risk of breast cancer, ovarian cancer, and sometimes womb cancer. But the risk is small.
  • HRT is an effective treatment for symptoms of menopause. For most people, the benefits of taking HRT outweigh the risks.
  • Your doctor can prescribe HRT and can help you make an informed choice about what is right for you.

 

What is HRT?

HRT is a treatment that can reduce symptoms of menopause by changing hormone levels in the body. Hormones are chemical messengers. They can affect things like growth, fertility, and mood. Menopause is a natural part of ageing where periods stop.

During menopause, the ovaries start to produce less of the hormone oestrogen. Most people who go through menopause will experience symptoms. These can last for months or years and can be uncomfortable, and have a big impact on daily life. HRT can help reduce them.  

You can learn more about HRT from the NHS. The main types of are:

  • Combined HRT, which has both oestrogen and progestogen
  • Oestrogen-only HRT

Tibolone is a medicine that is used in a similar way to HRT. There is little evidence available on tibolone and cancer. Your GP can give you more information about the different types of HRT and other ways to manage menopause symptoms.

Transgender men and transgender women may also use hormones to affirm their gender. There isn’t enough research yet about cancer risk associated with hormone therapies used in this way. You can find out more about gender-affirming hormone therapy from the NHS.

This webpage covers HRT used to treat menopause symptoms and cancer risk. We have separate information about HRT if you have, or have had, cancer. 

 

Does combined HRT increase the risk of cancer?

  • Breast cancer: combined HRT slightly increases the risk of breast cancer. This increased risk gets bigger the longer HRT is used. When HRT is stopped, the increased risk goes down over time. This takes longer, the longer that HRT was used. Combined HRT affects breast cancer risk more than oestrogen-only HRT. 
  • Ovarian cancer: combined HRT slightly increases the risk of ovarian cancer. When HRT is stopped, the increased risk starts to go back down.  
     
  • Endometrial (womb) cancer: combined HRT does not affect womb cancer risk.

There is not enough evidence on combined HRT and any other type of cancer. 

 

Does oestrogen-only HRT increase the risk of cancer?

Oestrogen-only HRT is usually only given to people who have had their womb removed (hysterectomy).

  • Breast cancer: oestrogen-only HRT slightly increases the risk of breast cancer. This increased risk gets bigger the longer HRT is used. When HRT is stopped, the increased risk starts to go back down. This takes longer the longer that HRT was used. 
     
  • Ovarian cancer: oestrogen-only HRT slightly increases the risk of ovarian cancer. When HRT is stopped, the increased risk starts to go back down. 
     
  • Endometrial (womb) cancer: oestrogen-only HRT increases the risk of womb cancer. This increased risk gets bigger the longer HRT is used, and may stay for some years after HRT is stopped. This is why it is usually only prescribed to people who are not at risk of womb cancer.

There is not enough evidence on oestrogen-only HRT and any other type of cancer.

 

Should I take HRT?

Cancer risk from HRT is small and depends on many different things. This includes the type of HRT used, how long someone takes it for, their age, and general health. The benefits of taking HRT will be different for each person too. Cancer risk is only part of the decision on whether to take HRT. Your doctor can help you make an informed choice on what is right for you.

Eating a healthy, balanced diet and being active may help with menopause symptoms. This can also help reduce your risk of cancer. Other things you can do to reduce your risk of cancer include: 

 

Hormone replacement therapy and the risk of endometrial cancer: A systematic review. Sjögren, L. Mørch, L. Løkkegaard, E. (2016) https://pubmed.ncbi.nlm.nih.gov/27451318/

Brown, K. F. et al. The fraction of cancer attributable to modifiable risk factors in England, Wales, Scotland, Northern Ireland, and the United Kingdom in 2015. Br. J. Cancer 118, 1130–1141 (2018). https://www.nature.com/articles/s41416-018-0029-6

IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Combined Estrogen-Progestogen Contraceptives and Combined Estrogen-Progestogen Menopausal Therapy. 100A (2018).

The Lancet. Type and timing of menopausal hormone therapy and breast cancer risk: individual participant meta-analysis of the worldwide epidemiological evidence. The Lancet (London, England). 394, 10204 p.1159-1168 (2019). https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)31709-X/fulltext

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