Exercise adherence in a randomized trial of exercise on aromatase inhibitor arthralgias in breast cancer survivors: the Hormones and Physical Exercise (HOPE) study

Up to 50 % of postmenopausal breast cancer survivors taking aromatase inhibitors (AIs) experience AI-associated arthralgias, or joint pain, which causes many to stop taking AIs and may inhibit exercise, despite known health benefits. We thus evaluated exercise adherence and factors associated with better exercise adherence in breast cancer survivors experiencing AI-induced arthralgia in the (HOPE) year long randomized controlled trial. We included 61 HOPE women randomized to exercise (150 min/week of moderate-intensity aerobic exercise and twice-weekly supervised strength training). Our main outcomes were aerobic exercise measured with daily activity logs, attendance at supervised exercise sessions, and changes in cardiorespiratory fitness, measured maximal oxygen consumption (VO(2)max). We examined means and standard deviations (SDs) for exercise adherence by demographic and medical characteristics and used the t test for mean differences. We also examined predictors of adherence using linear regression. On average, at the end of the year long trial, women reported 119 (SD 78) min/week of moderate-intensity aerobic exercise and participated in 70 % of supervised exercise training sessions. After adjustment for other factors that influence adherence, at 6 months postrandomization, only baseline VO(2)max was associated with higher aerobic exercise levels and at 12 months, only older age predicted better supervised exercise training attendance. Breast cancer survivors taking AIs and experiencing arthralgia are able to initiate and maintain a year long exercise program, regardless of other factors that influence activity levels. Breast cancer survivors can exercise at levels that have been shown to improve AI-associated arthralgia.