ERBB2 and cancer: The aim of the Kaiser Permanente Cardiovascular Health Enhancement and Monitoring for Oncology (KP CHEMO) study was to determine the incidence, timing, and treatment-specific variation in CTRCD within an integrated US health system.<h4>Methods and results</h4>We conducted a retrospective cohort study of adult Kaiser Permanente Northern California (KPNC) members diagnosed with malignant tumours between 2012 and 2022 who received anthracyclines, human epidermal growth factor receptor (HER2) inhibitors, immune checkpoint inhibitors (ICIs), or tyrosine kinase inhibitors.