Electrochemotherapy is effective in the treatment of early-stage feline cutaneous squamous cell carcinoma

Abstract

Objectives Feline cutaneous squamous cell carcinoma (cSCC) is a malignant tumour arising from squamous epithelium and accounts for 15% of all skin tumours, commonly involving the nasal planum, pinnae and eyelids. Electrochemotherapy (ECT) combines the application of short high-voltage electric pulses with intravenous or intralesional administration of cytotoxic agents to enhance the efficacy of chemotherapy. This study aimed to investigate the efficacy of ECT with intravenously administered bleomycin in the treatment of different stages of cSCC (T1–T4). Methods A total of 23 cats with cSCC located on the nasal planum (19/23), lip (1/23), eyelid (1/23), metacarpal pad (1/23) and temporal region (1/23) were included in this retrospective study. Cats were excluded if they did not have a histological or cytological diagnosis of cSCC or if records were incomplete. All cats were treated following a standard protocol with intravenous bleomycin before electroporation of cSCC lesions. Cats were staged according to the World Health Organization staging system: T1 (10/23), T2 (4/23), T3 (1/23) and T4 (8/23). Data on treatment adverse effects and response were collected. Results The median follow-up after initial treatment was 136 days (range 7–1763). Common adverse effects were local effects in 13/23 cats consisting of erythema, desquamation (dry/moist), ulceration and crusting. Complete response (CR) was achieved in 65.3% of cases, partial response in 13%, stable disease in 8.7% and progressive disease in 13%. Eight cats received a second ECT treatment, with 4/8 cats achieving CR after the second treatment. The overall response rate was 78.3%. The recurrence rate was 26.7%, with a disease-free interval of 466 days. Conclusions and relevance ECT is effective in treating T1 and T2 cSCC and can be considered a relevant treatment alternative for these cases.