This retrospective study examines the effects of electrochemotherapy (ECT) in client-owned dogs and cats with spontaneous squamous cell carcinomas (SCC) where conventional therapies were not acceptable to the owners.

ECT comprises the administration of a cytotoxic agent followed by the administration of brief high voltage electrical pulses to the tumour and margins (electroporation) to increase the uptake of the drug by up to 700 times in tumour cells.

The patients were 9 cats and 8 dogs with spontaneous SCC of the face, mouth or distal limb. None had any evidence of local or systemic metastasis as shown by lymph node examination and thoracic radiography. All tumours had been confirmed as SCC by histological or cytological examination. Informed consent of owners was obtained in all cases.

Surgical cytoreduction was performed in only one patient where the lesion was too large for ECT as sole therapy.

A single dose of electrochemotherapy using intravenous bleomycin was given in each case. Electroporation stimuli were provided by a Cytopulse PA4000 using Gehl array needle electrodes.

Two patients were euthanased before tumour response could be evaluated. Complete remissions were achieved in 84.6% of evaluable patients and partial responses in the remaining 15.4%. The complete remissions were maintained for the period of the study in all but one patient.

SCC of the face and oral cavity is a disease of primarily local morbidity and is, therefore, amenable to local therapies. In the distal limb it is more likely to metastasise. Standard therapies such as radical surgery and radiotherapy can have long-term effects on the patient. ECT provided remissions with a single treatment and with reduced cosmetic and functional effects compared to standard therapies. The lower costs involved in the therapy could allow its use in smaller centres than is possible with radiotherapy.