Surgical debulking and electrochemotherapy, including a tetrapolar single-needle electrode, are associated with clinical benefit in dogs with intranasal tumors

Objective: To evaluate the feasibility and preliminary clinical outcomes of surgical debulking combined with electrochemotherapy (ECT) using a multielectrode approach, including a tetrapolar single-needle electrode, in dogs with intranasal tumors. Methods: This retrospective observational study included client-owned dogs with intranasal tumors treated from 2017 through 2024 at a veterinary oncology referral center. Dogs were included if they underwent at least 1 surgical procedure combined with intraoperative bleomycin-based ECT using a multielectrode approach and had a minimum follow-up period of 2 months. Results: 12 dogs were included, and most had advanced local disease (83% stages T3 to T4). Epithelial tumors predominated (91%), mainly adenocarcinoma (42%). Clinical response was observed in all dogs, including complete clinical response in 75% and partial clinical response in 25%. Local progression was documented by CT in 5 dogs (42%). Repeat procedures were performed in 67% of dogs because of persistent clinical signs or tumor progression. The median progression-free interval was 492 days, and the median survival time was 694 days. Treatment-related adverse events were frequent but predominantly mild to moderate, including partial wound dehiscence (50%), crust formation (42%), infection (25%), and oronasal fistula (25%). No procedure-related deaths occurred. Conclusions: Surgical debulking combined with ECT using a multielectrode approach, including a tetrapolar single-needle electrode, was feasible and associated with clinical benefit in dogs with intranasal tumors. These findings support further prospective investigation of this approach for intranasal tumors in dogs. Clinical Relevance: This approach may represent a treatment option for dogs with locally advanced intranasal tumors, particularly when radiotherapy is unavailable.