The largest study of its kind conducted worldwide, and the first ever in Canada, the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial was a randomized controlled trial designed to examine how a one-year intervention of moderate-to vigorous-intensity exercise (45-minute sessions, 5 days per week) influences several intermediate endpoints for breast cancer, including mammographic density, endogenous estrogens, insulin levels, insulin-like growth factors, body composition, and physical fitness levels, in 320 postmenopausal women. One-year of follow-up after the exercise intervention was also conducted. An extension of the ALPHA Trial, the ALPHA Ancillary Study, examined endogenous androgens and biomarkers of obesity and inflammation, including adiponectin, C-reactive protein, insulin, leptin, TNF-α, and interleukin-6, which have recently been proposed as important biomarkers involved in the association of physical activity and breast cancer. An additional ancillary study recently funded to examine the role of oxidative stress, anti-oxidant enzymes and anti-inflammatory cytokines will provide additional evidence on other pathways that may explain how exercise influences breast cancer risk.
Co-Principal Investigator: Dr. K. Courneya