ENABLE—App-Based Digital Capture and Intervention of Patient-Reported Quality of Life, Adverse Events, and Treatment Satisfaction in Breast Cancer: Protocol for a Randomized Controlled Trial - Thomas M Deutsch; Léa L Volmer; Manuel Feisst; Laura Bodenbeck; Kathrin Hassdenteufel; Lara Tretschock; Christiane Breit; Stefan Stefanovic; Armin Bauer; Carolin Anders; Lina Weinert; Tobias Engler; et al. (JMIR Research Protocols)