Dr Yee-Ming Cheung

The cardiometabolic effects of endocrine therapy

Dr Yee-Ming Cheung, University of Melbourne

2019 Health Professional Scholarship

Years funded: 2020-2022

Breast cancer accounts for 30% of all new cancers in Australian women each year. Oestrogen-receptor-positive (ER+) early stage breast cancer has a relatively good prognosis. Breast cancer and cardiovascular disease (CVD) share many risk factors such as obesity and diabetes. Postmenopausal women with breast cancer have a higher risk of CVD mortality than those in the general population. Women with breast cancer are exposed to chemotherapy and radiotherapy, which have independent cardiotoxic effects, therefore, making these women, a particularly higher risk group.

Endocrine therapies (ET) exert their cancer benefits by blocking oestradiol production and action. As a consequence, women are left in an oestradiol-deplete state. Oestradiol has been shown to have favourable associations with metabolic health. Therefore, we hypothesise that use of ET will lead to adverse cardio-metabolic effects. Given the population in which ET is being prescribed, any incremental impact of ET on CVD may have significant health implications for this population.

This research project will be a 12 month, prospective, controlled observational study investigating the effects of ET-related oestradiol depletion on body fat distribution, and other surrogate markers of cardio-metabolic health in postmenopausal women with ER+ breast cancer. Controls will be aged -matched postmenopausal women with ductal carcinoma in situ/women not requiring ET. This study will also investigate the potential mechanisms by which ET may be associated with CVD risk.

If ET is associated with CVD markers suggesting elevated risk, this may suggest a role in monitoring these factors as part of routine clinical care during ET. The collective results from these tests can provide clinicians with a means of stratifying each woman's CVD risk, enabling delivery of personalised care. This project will also provide a platform for subsequent interventional studies to investigate the clinical impact of risk factor modification.