Evaluation of the safety and feasibility of electrochemotherapy with intravenous bleomycin as local treatment of bladder cancer in dogs

Abstract Local treatment of canine urothelial carcinoma (UC) of the bladder is a challenge. More than 90% of cases arise as muscle-invasive tumors, with more than 50% developing on bladder sites with a difficult surgical approach often requiring radical procedures. This study aimed to evaluate the safety and feasibility of electrochemotherapy (ECT) with intravenous bleomycin (BLM) as selective local therapy for bladder UC. This prospective study included 21 dogs with spontaneous bladder UC. Neoplastic infiltration in the serosa layer was considered the main exclusion criterion. No patient died during ECT or in the immediate postoperative period, and no patient presented with suture dehiscence. Most dogs (19/21) developed mild adverse effects, whereas two dogs developed ureteral stenosis. Complete response (CR) was achieved in 62% of the dogs (13/21), while partial response (PR) was achieved in 24% (5/21). The mean survival and disease-free survival times were 420 and 405 days, respectively. Overall survival was significantly better in the patients who achieved CR. ECT was well-tolerated in dogs with UC, demonstrating its safety and feasibility. These data pave the way for new studies aimed at evaluating the effectiveness of ECT in canine bladder UC as a translational model for human disease.