Electrochemotherapy as an innovative drug delivery modality for local control of canine acanthomatous ameloblastoma

Introduction: Acanthomatous ameloblastoma is the most common odontogenic epithelial tumor in dogs. Block excision is the treatment of choice since marginal removal has a recurrence rate exceeding 90% within one year. Electrochemotherapy (ECT) enables intracellular delivery of bleomycin, inducing apoptotic cell death. The aim of this study was to evaluate efficacy, response and complications of ECT in canine ameloblastomas. Materials and Methods: Twelve dogs with histopathologically confirmed oral ameloblastoma were included. Of the lesions analyzed, nine were smaller than 2 cm and three were larger than 2 cm. All patients were treated with ECT in one or two sessions. In 11 of 12 cases, tooth extraction was required to optimize tumor access. Treatment was performed using an EPV-200 electroporator (Biotex, Argentina) with needle electrodes. Bleomycin was administered intravenously at a dose of 15000 IU/m 2 , eight minutes prior to delivering the electric pulses (train of eight 100 µs pulses, 1000 V/cm, 5000 Hz). Tumor response, recurrence and post treatment complications were recorded. Results: Seventy-five percent (9/12) of the lesions were smaller than 2 cm. A single ECT session was performed in 10 patients (8.3.3%), while the remaining two required a second session- one at 30 days and another at 95 days- based on the initial treatment response. Smaller lesion (<2cm) showed better response when the entire tumor was covered by the electric field. In 11 of 12 cases (91.6%) partial tooth removal was necessary to ensure complete exposure of the tumor and its origin. Clinical responses were complete in 83.3% (10/12), partial in 8.3% (1/12), and stable disease in 8.3% (1/12), with no cases of tumor progression during the follow- up. The main postoperative complications were local inflammation (100%) and mild to moderate pain (33.3%), both managed successfully with analgesic and anti-inflammatory therapy. Conclusions: Electrochemotherapy represents an effective and safe therapeutic alternative for the conservative management of canine ameloblastoma. Early detection and treatment are associated with higher complete response rates. Extraction of adjacent teeth improves treatment efficacy by enhancing electric field contact with the tumor tissue. Post treatment pain and inflammation control are essential to minimize complications and optimize recovery.