Physical activity, sedentary behaviour and breast cancer: determining how type, domain, duration and intensity affect risk and prognosis

Exercise can reduce the risk of developing breast cancer, and improve survival amongst women diagnosed with the disease. Despite this knowledge, the majority of Australian women do not participate in sufficient exercise. Further, how the eight or nine hours of daily sitting time accumulated by Australian women affects their breast cancer risk is unknown. Given what we know about the biology of breast cancer, it is likely that sitting time also contributes to risk.

The proposed research will address two themes: breast cancer prevention, and breast cancer survivorship. Using data collected by existing studies I will examine how the type, duration, intensity and frequency of exercise and sitting time relate to breast cancer. A new study (part of a much larger project being undertaken by Cancer Council Victoria – the ABC Study) will collect accurate information on the exercise and sitting time patterns of approximately 1,000 postmenopausal women, by using small devices called accelerometers. This will help us to understand how exercise and sitting time affect breast cancer risk. Another new study will investigate whether the use of wearable activity monitors (such as the Fitbit®) can increase breast cancer survivors’ exercise and reduce their sitting time.

The proposed research will enable us to provide more specific advice to women about how much, and what type of, exercise they should be doing to prevent breast cancer, or to improve their survival after diagnosis. It will also allow us to give guidance on how much sitting is can be safely done each day.