Raimondo Tornago

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.

Feline squamous cell carcinoma (SCC) is currently treated with surgery, radiation therapy and electrochemotherapy (ECT). Both the efficacy and/or safety of ECT were evaluated as a sole therapy with bleomycin to treat feline nasal planum SCC (npSCC). Sixty-one cats were enrolled. Local treatment response was evaluated as complete remission (CR), partial remission (PR) or stable disease (SD). Recurrence rate (RR), disease-free interval (DFI) and progression free survival (PFS) were calculated. A six-point scale was used for ECT toxicity. The median tumor size was 1.5 cm. CR was achieved in 65.6% of cases, PR in 31.1% and SD in 3.3%. The overall response rate was 96.7%, RR was 22.5%, median DFI was 136 days, and median PFS was 65.5 days. ECT toxicity was ≤2 in 51% of cats. Tumor recurrence/progression (p = 0.014) and local treatment response (PR: p < 0.001; SD: p < 0.001) influenced survival time. Cats with toxicity >2 showed a higher probability of tumor recurrence/progression. Tumor-related death was higher in cats with PR (p < 0.001) and recurrence/progression (p = 0.002), in ECT treatment with 1 Hz (p = 0.035) and 1200 V/cm (p = 0.011) or 1300 V/cm (p = 0.016). Tumor size influenced local treatment response (p = 0.008) and toxicity (p < 0.001). ECT is an effective treatment for feline npSCCs and should be considered as the first-line procedure for low-stage tumors.

Melanomas are rare in cats. The eye is the most commonly involved site, whereas few data are available about feline non-ocular melanomas (NOMs). Ki-67 thresholds with prognostic relevance have been established for canine melanomas, but not in cats. This study was undertaken to investigate the relationship between Ki-67 index, tumour characteristics, and clinical outcome in feline NOMs. Histologic samples were retrospectively reviewed. Amelanotic tumours were admitted upon immunohistochemical positivity for Melan A or S100. Evaluated parameters included morphological diagnosis, histotype, junctional activity, degree of pigmentation, vascular invasion, lymphocytic infiltrate, necrosis, mitotic count (MC) and Ki-67 index. Pigmented tumours were bleached before evaluation. Clinical and follow-up information were retrieved via telephone interviews with the referring veterinarians. Fifty tumours located in skin (n = 33) and mucosae (n = 17) were included. Forty-eight percent and 95% of amelanotic tumours (n = 21) stained positive for Melan A and S100, respectively. Most achromic tumours were mucosal (P < 0.001, Fisher’s exact test) and presented a spindle cell morphology (P = 0.002; Fisher’s exact test). MC and Ki-67 index were significantly correlated (P < 0.001; R = 0.67; Spearman’s rank correlation); median values were 15 (range, 0–153) and 28% (range, 1–78%), respectively. Both were significantly higher in spindle cell melanomas, in tumours lacking junctional activity and in poorly-pigmented tumours. Follow-up information was available for 33 cats (66%). Variables related with a poor clinical outcome included mucosal location, tumour size, spindle, balloon and signet ring cell histotypes, low pigmentation, MC > 5, Ki-67 > 20% and lack of treatment administration. On multivariable analysis, only tumour histotype and treatment retained prognostic significance. Although the majority of feline NOMs behave aggressively, Ki-67 index, together with other parameters, may contribute to prognostic assessment. Prospective studies on homogeneous populations are warranted to identify reliable threshold values for this marker.