Feasibility and acceptability of the Fit2Thrive mHealth physical activity promotion intervention components in breast cancer survivors.

Background: Most breast cancer survivors (BCS) are insufficiently active. mHealth moderate-to-vigorous physical activity (MVPA) interventions for BCS are highly scalable, but the feasibility and acceptability of specific intervention components are unknown.

Purpose: The purpose of this study is to examine the feasibility and acceptability of the Fit2Thrive MVPA promotion intervention components.

Methods: Using Multiphase Optimization Strategy methodology, inactive BCS [n = 269; Mage = 52.5; (SD ± 9.9)] received a core intervention (Fitbit + Fit2Thrive smartphone app) and were randomly assigned to receive zero to five components for 12 weeks: (i) support calls; (ii) deluxe app; (iii) text messages, (iv) online gym; and (v) Buddy. Feasibility was measured through study accrual, retention, and adherence rates. Acceptability was measured via post-program evaluations.

Results: Enrollment rates were high; 419 BCS expressed interest in the study, 348 (83%) passed screening, and 269 (77%) were randomized; 98% (n = 264) received the intervention. Retention was 94% at 12 weeks. Fitbits were worn on 93% of study days. Most reported using the app ≥5 days/week (67%), enjoyed using the Fitbit (79%), and were satisfied with their study experience (88%) and the Fit2Thrive app design (79%). Component adherence rates and acceptability varied by intervention component. Component-specific effects on MVPA goal adherence and overall acceptability ratings were significant for telephone support calls.

Conclusions: Findings indicate Fit2Thrive's feasibility and acceptability were high overall but may vary by component. Future work should refine and test components to maximize participant engagement, efficacy, and scalability.

Clinical Trial Information: The Clinical Trials Registration NCT03131440.