Prospective multicentre study of patients with cutaneous metastases from breast cancer treated with electrochemotherapy

The study database contains the full set of raw data that served as the foundational material for the analyses and the final results reported in the published study (DOI: 10.1007/s10585-025-10350-5). This prospective multicentre dataset encompasses original clinical, pathological, treatment, and outcome information collected from patients with cutaneous and/or subcutaneous metastases from breast cancer, enrolled across multiple participating centres according to predefined inclusion criteria pertinent to this advanced disease setting. The raw data include patient demographics, tumour characteristics (e.g., receptor status, lesion size and number), details of prior systemic and locoregional therapies, specifics of the electrochemotherapy (ECT) procedures administered, and subsequent clinical outcomes such as objective response rates and progression metrics. These data reflect the real-world therapeutic context in which locoregional ECT was applied to patients with challenging cutaneous metastatic presentations and were essential to evaluate treatment efficacy across subgroups defined by molecular subtype (e.g., luminal A-like, luminal B-like, HER2-positive, triple negative) and lesion burden. All data were recorded in an anonymized format and subjected to systematic quality control, data cleaning, consistency checks, and validation prior to downstream statistical analyses. The resulting database thus represents the original, high-integrity information framework from which study variables and outcome measures were derived. It was used exclusively for research purposes and managed in compliance with ethical standards and applicable data protection regulations.