ASPO Abstracts

Fit2Thrive: Optimization of a mHealth Physical Activity Promotion Intervention for Breast Cancer Survivors

Authors: Siobhan M. Phillips, Linda M. Collins, Payton Solk, Whitney Welch, Lisa Auster-Gussman, Juned Siddique, Frank J. Penedo, David Cella, Kerry S. Courneya, Ronald T. Ackermann, Jing Song, Madelyn Whitaker, Erin Cullather, Emily Izenman, & Bonnie Spring

Category: Survivorship & Health Outcomes/Comparative Effectiveness Research
Conference Year: 2021

Abstract Body:
Purpose: The benefits of moderate and vigorous physical activity (MVPA) for breast cancer survivors (BCS) are well established. Yet, most are insufficiently active. Most existing MVPA promotion interventions are resource- intensive and include numerous components delivered together simultaneously in a package. This makes it difficult to evaluate the relative importance of each component. Fit2Thrive used Multiphase Optimization Strategy (MOST) methodology to determine the effect of five remotely-delivered mobile health (mHealth) intervention components on MVPA in a nationwide sample of BCS. Methods: Breast cancer survivors [n=269;Mage=52.5(SD=9.9)] were given a core intervention (Fit2Thrive self- monitoring app and Fitbit) and were randomly assigned to five intervention components set to on/off in a factorial experiment: telephone support calls, deluxe Fit2Thrive app (i.e. goal-setting and newsfeed features), Fitbit buddy, online gym, and tailored text messages. The intervention was designed to increase BCS' MVPA to meet MVPA guidelines (i.e. ≥150 minutes/week). Fit2Thrive was delivered over 12-weeks, and MVPA was measured via accelerometry at baseline (T1), 12- (T2) and 24- (T3) weeks. Main effects and interaction effects for all components at each time point were examined using an intention to treat mixed-effects model. Results: Overall, BCS increased MVPA by 58.3 (95%CI=44.2-72.4;p<0.001) min/wk [MT1=94.8; MT2=153.1).There was a 26.6% increase in the percent of BCS meeting MVPA guidelines at T2 (T1=16.2%; T2=42.8%; p<0.001). Effects were maintained but attenuated at 24 weeks follow-up [MT3=121.9 min MVPA; 12.5% increase in BCS meeting MVPA guidelines; ps<0.001). While the "on” level of each component resulted in an increase in MVPA, none of these improvements was superior to the "off” levels for any component under consideration. Conclusions: Systematically testing the effect of each intervention component on MVPA suggests the Fit2Thrive self-monitoring app and Fitbit represent a promising, low-cost, scalable strategy for increasing MVPA in BCS in the short term. Future research should evaluate these components in a randomized trial and determine how to more effectively use technology to maintain MVPA.

Keywords: physical activity; optimizatoin; technology; cancer survivorship