FIRST CLINICAL-TRIAL OF CAT SOFT-TISSUE SARCOMAS TREATMENT BY ELECTROCHEMOTHERAPY

Electrochemotherapy combines bleomycin and local electric pulses that allow cell permeabilization and free access of bleomycin to its intrac ellular target. We report the first veterinarian clinical trial of ele ctrochemotherapy in 12 cats with spontaneous large soft-tissue sarcoma s that suffered relapse after treatment with conventional therapies. P ermeabilizing electric pulses were delivered using external surface el ectrodes, as well as new needle-shaped electrodes that were designed t o be inserted in tumours for more effective treatment of several-centi metre-thick tumour nodules. The electric pulses were applied to the tu mours several times from 4 to 15-30 min after a bolus intravenous inje ction of 0.5 mg kg(-1) bleomycin. Tolerance to treatment was excellent without general side-effects. The cats showed local inflammatory reac tions for a few days and disease stabilization lasted from 2 weeks to 7 months. One partial regression was observed, and the general absence of nodule volume decrease can be explained by local fibrotic reaction s. Histological[ analysis of biopsies also revealed massive tumour cel l death. The cats' lifespan increased (p much less than 0.001), With a mean survival time of 6.1 months (maximum 18 months) compared with 0. 8 months (maximum 1.5 months) for a group of 11 untreated control cats displaying similar carcinological features. Electrochemotherapy is cl early effective as a salvage treatment for large spontaneous solid tum ours in adverse clinical situations and this is promising for future a pplications.