Level of physical activity and characteristics associated with change following breast cancer diagnosis and treatment

Objective: While the physical and psychosocial benefits of participating in physical activity (PA) during and following breast cancer treatment are well understood, less is known about rates and uptake of PA following diagnosis. This paper explores the levels and patterns of PA among women recently diagnosed with breast cancer and the factors associated with change in activity levels.

Methods: Using a population-based recruitment approach, PA levels of 287 breast cancer patients were assessed at 6, 12 and 18 months post-diagnosis using the Behavioral Risk Factor Surveillance System, and then converted to MET (metabolic equivalent task)-hours/week. Regression analyses were used to explore the correlates associated with change between 6 and 18 months post-diagnosis.

Results: Although more than 80% of women participated in PA at each testing phases, more than 50% were considered insufficiently active or sedentary according to national recommendations and less than one-third reported engagement in vigorous or strength activities. Mean change in total MET-hours/week between 6 and 18 months post-diagnosis was minor (mean=0.10, median=0.0), however individual changes were substantial (ranging from -100 to +174 MET-hours/week). Results are more encouraging for the lower threshold of 3+ MET-hours/week, which may be most relevant specifically for breast cancer outcomes.

Conclusions: Since the majority of women report insufficient levels of PA, there is a clear need for exercise interventions during and following breast cancer treatment. Few characteristics predict declines or improvements in PA levels, hence for optimal benefit, interventions should target the entire breast cancer population.