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. 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 and risks from all types of hormone therapy. 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. 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.
Objective: The study will investigate risks of incident breast cancer associated with different types of hormone replacement therapy (HRT). Methods: This will be a nested case-control study. Cases will be women with incident breast cancer diagnosed between 1990 and 2016, matched with up to 5 controls by age, sex, practice and calendar year. Cases will be determined using GP, ONS mortality and HES data. Analysis: Exposure to different HRTs will be defined as at least one prescription for that HRT excluding the year before the index date (date of diagnosis of breast cancer or equivalent date in matched controls). Conditional logistic regression will be used to assess the risks associated with different types of oestrogen and progesterone. The effects of duration, length of any gap since the last use and different application routes will be analysed for the most common types of hormones.
Incidence of breast cancer.
Yana Vinogradova - Chief Investigator - University of Nottingham
Yana Vinogradova - Corresponding Applicant - University of Nottingham
Carol Coupland - Collaborator - University of Nottingham
Julia Hippisley-Cox - Collaborator - University of Oxford
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Townsend Score