Electrochemotherapy Following Surgical Cytoreduction for the Treatment of Recurrent Equine Sarcoids: A Retrospective Study of 23 Lesions

Despite the wide range of therapeutic options currently available for equine sarcoids, recurrence of these lesions remains a major clinical challenge. Consequently, the identification of effective strategies for the management of recurrent sarcoids remains an important objective in equine oncology. The aim of this retrospective study was to evaluate the clinical outcome of surgical cytoreduction combined with intraoperative electrochemotherapy in horses affected by recurrent equine sarcoids. Medical records of horses treated between July 2018 and August 2025 at the Veterinary Teaching Hospital of the University of Bologna were retrospectively reviewed. Data collected included signalment, lesion location, clinical subtype, lesion size, chemotherapeutic agent used, recurrence status, and follow-up duration. Fourteen horses presenting 23 recurrent sarcoid lesions met the inclusion criteria. Recurrence was evaluated at both the lesion and horse levels. Local tumour control was achieved in 16 of 23 lesions (69.6%). Recurrence was observed in 7 lesions, corresponding to a lesion-based recurrence rate of 30.4%, and in 5 of 14 horses (35.7%). Malignant and fibroblastic lesions showed higher recurrence rates than other clinical subtypes, whereas larger lesions tended to recur more frequently than smaller lesions. No significant differences were identified between cisplatin- and carboplatin-treated lesions. Surgical cytoreduction combined with intraoperative electrochemotherapy provided encouraging local tumour control in a population composed exclusively of recurrent sarcoids. This treatment protocol may represent a valuable therapeutic option for horses with local recurrence of sarcoids, although larger prospective studies are required to further define prognostic factors and long-term outcomes.