Efficacy and safety of electrochemotherapy in the treatment of cutaneous and sub-cutaneous recurrence from breast cancer: A single-center cohort study.

[BACKGROUND] Cutaneous and subcutaneous recurrence of breast cancer represents a challenging clinical scenario, particularly in patients previously treated with surgery, radiotherapy, and systemic therapies. Electrochemotherapy (ECT) combines electroporation with cytotoxic drug administration and has shown promising local control rates; however, evidence in breast cancer remains limited. This study aimed to evaluate the safety and efficacy of ECT in patients with breast cancer skin recurrence.

[METHODS] We conducted a single-center retrospective cohort study including patients with histologically confirmed breast cancer who developed cutaneous recurrence and were treated with ECT between January 2015 and December 2023. Tumor response was assessed according to RECIST 1.1 criteria. Overall survival (OS) was calculated from the date of the first ECT session to death or last follow-up. Survival analysis compared responders (complete or partial response) and non-responders (no response or progressive disease). Cox regression was used to identify prognostic factors.

[RESULTS] Nineteen patients were included. Eleven (57.9%) achieved a complete or partial response. Median OS for the entire cohort was 19 months. Responders had significantly longer OS compared to non-responders (20 vs 12 months; log-rank p = 0.002). Lack of response to ECT was the strongest negative prognostic factor (HR 6.59, 95% CI 1.72-25.29, p = 0.006). HER2 positivity was also associated with poorer survival (HR 10.67, 95% CI 1.32-86.30, p = 0.026). No grade ≥3 adverse events were observed.

[CONCLUSION] ECT appears to be a safe and effective local treatment for cutaneous breast cancer recurrence, providing meaningful local control and a potential survival benefit in responders. Larger prospective studies are warranted to confirm these findings.