CARDIOCARE is a prospective observational parallel cohort study that is expected to enroll 750 elderly breast cancer patients. Twelve European oncology centres will participate in the research, including the Oncology Institute Ljubljana. Patients will be randomized into two groups (1:1), namely the control group and the group with appropriate supportive therapy. After enrollment into the study, patients will be evaluated for cardiotoxic effects of treatment, patients' intrinsic capacity, the quality of life, the workload of medical staff, and the cost-effectiveness of care that patients will receive. The research will collect clinical data, cardiac imaging results, biochemical and psychological biomarkers, metagenomics test results, and quality of life data at baseline and at several different pre-determined time points during the study. The study's primary aim is to examine the impact of various supportive behavioural and psychological interventions on intrinsic capacity and quality of life in breast cancer patients who may develop cardiotoxicity during treatment and thus improve their care. This study is funded by the European Commission and its coordinator is prof. Dimitrios Fotiadis, University of Ionannina, Greece.