Methods
We recruited patients from four departments of oncology from 2019 to 2021. Inclusion criteria were locally advanced or metastatic BC, initiating chemo- or immunotherapy. Patients were randomized 1:1 between answering selected PRO-CTCAE questions electronically once weekly with a built-in alert-algorithm instructing patients of how to handle reported symptoms as a supplement to standard of care for handling of side effects (intervention arm (IA)) vs standard procedure for handling of side effects (control arm (CA)). No real-time alerts were sent to the clinic when PROs exceeded threshold values. Clinicians were prompted to view the completed PROs in the IA at each clinical visit. The co-primary clinical endpoints were hospital admissions and treatment completion rate. Secondary endpoints were overall survival (OS), quality of life (EORTC’s QLQ-C30 and QLQ-BLM30) and dose reductions.