AbstractContextPhysical activity for women with early-stage breast cancer is well recognized for managing cancer-related symptoms and improving quality of life. While typically excluded from interventions, women with metastatic breast cancer may also benefit from physical activity. ObjectiveTo 1) determine the safety and feasibility of a physical activity program for women with metastatic breast cancer and 2) explore the efficacy of the program. MethodsFourteen women with metastatic breast cancer were randomized to either a control group or an 8-week home-based physical activity intervention comprising twice weekly supervised resistance training and an unsupervized walking program. ResultsThe recruitment rate was 93%. Adherence to the resistance and walking components of the program was 100% and 25%, respectively. No adverse events were reported. When mean change scores from baseline to postintervention were compared, trends in favor of the exercise group over the control group were observed for the Functional Assessment of Chronic Illness Therapy-Fatigue score (+5.6 ± 3.2 vs. −1.8 ± 3.9, respectively), VO 2max (+1.6 ml/kg/minute ±1.8 mL/kg/minute vs. −0.2 mL/kg/minute ±0.1 mL/kg/minute, respectively) and six-minute walk test (+40 m ± 23 m vs. −46 m ± 56 m, respectively). ConclusionA partially supervised home-based physical activity program for women with metastatic breast cancer is feasible and safe. The dose of the resistance training component was well tolerated and achievable in this population. In contrast, adherence and compliance to the walking program were poor. Preliminary data suggest a physical activity program, comprising predominantly resistance training, may lead to improvements in physical capacity and may help women to live well with their disease.