Hormone replacement therapy and risk of breast cancer: case-control study using CPRD

Hormone replacement therapy (HRT) is used to relieve adverse symptoms and reduce risk of chronic conditions in women going through menopause. There are different therapy types, which depend on the symptoms experienced by an individual. These include different types of hormones and different types of medicine (tables, patches, or creams). Although all these treatments are effective in managing menopausal symptoms, they have a rare, but serious side effect – an increased risk of breast cancer.

A recently issued guideline from the National Institute for Health and Care Excellence (NICE) stressed that research results from studies trying to estimate risk of developing breast cancer as a result of HRT are still not clear, and that the findings are not a good basis for decision-making by doctors or patients.

This study will investigate real-life use of HRT and risk of breast cancer from all types of HRT over a 20-year period (1998-2018). The data will be provided by more than 650 general practices in the UK. Patient confidentiality will be absolute because it is not possible to identify individuals from the database. We will use prescription records and also take into account patient characteristics and health conditions which might affect the risk of breast cancer to ensure that our results properly demonstrate the effects of the different therapies. We will look at the type of hormone (type of oestrogen or progesterone) and the type of medicine (tablets, patches or creams) to see which types of HRT appear to be safer.

The findings will provide much clearer, more detailed information for doctors and patients about breast cancer risks related to all types of HRT to help them in their decisions.

Amount awarded: £11 960