Feasibility, Usability, and Preliminary Effectiveness of an mHealth App to Promote Screening Behaviors Among High-Risk Populations for Breast Cancer: Randomized Controlled Pilot Study.

Abstract

Background: Breast cancer is a major public health challenge worldwide. Women at high risk for breast cancer are more likely to develop the disease; yet, screening participation remains. Mobile health interventions may improve breast health awareness and screening behaviors, but evidence in high-risk populations for breast cancer remains limited.

Objective: This study aimed to evaluate the feasibility, usability, and preliminary signals of potential effectiveness of the "Ruaikang" mobile health app, designed to support breast health awareness and engagement with early screening among high-risk populations for breast cancer.

Methods: In this pilot randomized controlled trial, eligible high-risk populations for breast cancer were randomly assigned (1:1) to a 4-week intervention using the "Ruaikang" app or a control group receiving standard breast cancer screening guidelines. Feasibility was assessed via recruitment and completion rates. Usability was measured using the System Usability Scale. Use data were collected through the app's back-end system. Preliminary effectiveness was assessed through changes in willingness to participate in breast cancer screening, screening knowledge, health beliefs, and self-efficacy at both the fourth (T1) and eighth (T2) weeks. Semistructured interviews were conducted with a purposive subsample of intervention participants to explore user experience and suggestions for improvement.

Results: Of 62 eligible women approached, 50 enrolled (recruitment rate 80.6%) and were randomized to intervention (n=25) and control (n=25) groups. In total, 19 participants in the intervention group completed the study (completion rate 76%), reflecting good feasibility. The mean usability score was 88.82 (SD 10.29), indicating high usability. Back-end use data showed that participants actively engaged during the intervention period. At T1, the intervention group showed preliminary signals of improvement in willingness to participate in breast cancer screening, screening knowledge, health beliefs, and self-efficacy, although these changes were less pronounced at T2. Qualitative interviews with 8 participants identified 2 core themes: "perceived value and acceptability of the app" and "system limitations and user-centered improvement needs." Participants highlighted that the app was easy to use and content-rich and provided actionable feedback for optimizing interactive features, navigation, and content depth.

Conclusions: The "Ruaikang" mobile health app demonstrated good feasibility and usability and provided preliminary signals of potential effectiveness in improving willingness to participate in breast cancer screening, screening knowledge, health beliefs, and self-efficacy among high-risk populations for breast cancer. Participants' feedback indicates that the app aligns with users' core needs and supports engagement with breast health information. Future work should refine the app based on user feedback and conduct larger-scale, longer-term randomized controlled trials to confirm and further validate the preliminary effectiveness observed.