Maintenance of physical activity in breast cancer survivors after a randomized trial

The purpose of this study was to examine the longer-term effects of pedometers and print materials on changes in physical activity (PA) and health-related quality of life (HRQoL) in breast cancer survivors who participated in a 3-month behavior change intervention.

Breast cancer survivors (N = 377) were randomly assigned to receive either (a) a standard public health recommendation for PA (SR), (b) previously developed breast cancer-specific PA print materials (PM), (c) a step pedometer (PED), or (d) a combination of the two (COM). The primary endpoint was self-reported moderate/vigorous PA minutes per week at 6-month follow-up after the initial 3-month intervention period.

Seventy-one percent (266/377) of participants completed the 6-month follow-up assessment. According to intention-to-treat linear mixed-model analyses, self-reported moderate to vigorous PA increased by 9 min x wk(-1) in the SR group compared with 39 min x wk(-1) in the PM group (mean difference = 30 min x wk(-1); 95% CI = -44 to 104; P = 0.425), 69 min x wk(-1) in the PED group (mean difference = 60 min x wk(-1); 95% CI = -13 to 132; P = 0.107), and 56 min x wk(-1) in the COM group (mean difference = 47 min x wk(-1); 95% CI = -26 to 119; P = 0.210). The same pattern was observed for self-reported, brisk walking. No differences were found for HRQoL or fatigue.

Breast cancer-specific PM and PED did not maintain significantly higher PA or HRQoL at 6-month follow-up in breast cancer survivors, but the magnitude of the effect on PA (30-60 min x wk(-1)) was consistent with the immediate postintervention effect observed at the 3-month postintervention time point. Issues of power resulting from additional loss to follow-up may account for the failure to achieve statistical significance. Additional research with larger sample sizes and more complete follow-up is warranted.