Maintenance of Physical Activity in Breast Cancer Survivors after a Randomized Trial

Abstract

Purpose: 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 that participated in a three month behavior change intervention. Methods: 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 (min•wk) at six months follow-up after the initial three month-intervention period. Results: 71% (266/377) of participants completed the six-month follow-up assessment. Based on intention-to-treat linear mixed model analyses, self-reported moderate-to-vigorous PA increased by 9 min•wk in the SR group compared to 39 min•wk in the PM group (Mean difference=30 min•wk; 95% CI=-44 to 104; p=.425), 69 min•wk in the PED group (M difference=60 min•wk; 95% CI=-13 to 132; p=.107), and 56 min•wk in the COM group (M difference=47 min•wk; 95% CI=-26 to 119; p=.210). The same pattern was observed for self-reported brisk walking. No differences were found for HRQoL or fatigue. Conclusion(s): Breast-cancer specific print materials and pedometers did not maintain significantly higher PA or HRQoL at six months follow-up in breast cancer survivors but the magnitude of the effect on PA (30-60 min•wk) was consistent with the immediate postintervention effect observed at the three-month postintervention timepoint. 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.