Abstract Introduction: Cancer affecting parenchymal organs in dogs and cats present a therapeutic challenge, particularly in cases of multiple lesions or locally advanced disease where surgery is not indicated and medical therapies offer limited response. Electrochemotherapy (ECT) facilitates bleomycin entry into cells through the formation of transient membrane pores, providing a precise drug delivery that enhances cytotoxic efficacy. The aim of this study was to report the safety and feasibility of ECT for the management of parenchymal tumors in both species. Materials and methods: Five patients (four dogs and one cat) diagnosed with hepatic or pancreatic cancer, for whom no therapeutic option was feasible, were included. Recorded variables included diagnosed pathology, clinical presentation, treatment duration, clinical response, and short-and long-term adverse effects. Bleomycin (15,000 IU/m2) was administered intravenously, followed by electric pulse application using a Biotex EPV200 electroporator (Argentina). Electric pulses (eight pulses of 100 μs, 1.000 V/cm, 5 kHz) were delivered to all lesions, planned preoperatively via computer tomography. Response was evaluated by ultrasonography at 30 and 60 days post-treatment. Results: Among the four dogs, three were diagnosed with multifocal hepatocellular carcinoma and one with insulinoma. Additionally, a cat was diagnosed with pancreatic adenocarcinoma. All cases were treated. Hepatic lesions were ≤3 cm, located in different lobes, with 2-3 nodules treated per patient. The insulinoma (2.66 x 0.88 cm) was located in the right pancreatic lobe, and the feline adenocarcinoma (2.15 x 1.63 x 1.89cm) was found i the pancreatic body in contact with the duodenum and the pancreaticoduodenal vein. All treatments were performed via laparotomy. A foldable needle electrode was used for hepatic lesions due to deeper access, while plate electrodes were selected for pancreatic tumors to ensure complete coverage. The mean treatment duration was 15 minutes from bleomycin infusion, with longer times for hepatic cases. All patients achieved a complete response: hepatic tumors by day 60, the feline pancreatic tumor showed a partial response at day 30, and a complete response by 6 months. Among hepatic cases, one showed transient liver enzyme elevation, and another case showed normalization of liver enzymes. For pancreatic cases, the specific pancreatic lipase was elevated post-treatment. All animals experienced mild to moderate pain, slightly prolonged in the cat. The dog with insulinoma resolved hypoglycemia but later developed diabetes mellitus requiring medical management, the only long-term adverse outcome observed. Conclusions: Electroporation-mediated bleomycin delivery represents a viable and safe option for the treatment of malignant parenchymal tumors. Further studies are needed to confirm these preliminary findings. Citation Format: Sergio Fernando Salgado, Andrea Hatsumi Bazan, Josmell David Mestanza, Nandi Ken Candela, Mitzi Westreicher, Micaela Vizquerra. Feasibility and safety of electroporation-enhanced bleomycin delivery for the treatment of parenchymal tumors in dogs and cats abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3034.
Salgado et al. (Fri,) studied this question.