Minimally invasive electrochemotherapy procedure for treating nasal duct tumors in dogs using a single needle electrode

Nasal cavity tumors are usually diagnosed late, when they already have infiltrated adjacent tissues thus requiring very aggressive treatments with serious side effects. Here we explore the use of electrochemotherapy, an electroporation-based tumor treatment with demonstrated effectiveness and minimum side effects. Its main limitation is the difficulty of reaching the tumor with an appropriate electric field, especially in the case of difficult to reach tumors, such as those located deep in the nasal duct. Here we overcome that limitation by means of the Single Needle Electrode, a minimally invasive device that can deliver an appropriate electric field with a simple procedure. For demonstrating the effectiveness of electrochemotherapy and the applicability of this electrode in nasal tumors, twenty-one canine patients with spontaneous tumors were selected, eleven were treated using the Single Needle Electrode with electrochemotherapy, and ten with surgery plus adjuvant chemotherapy as a control group, since is the best treatment option in our setting.  In the Single Needle Electrode group, 64% had a partial response, 27% achieved a complete response and 9% had a stable disease. This means that 91% of objective responses were obtained. The mean survival was 16.86 months (4-32 months, median 16.5 months), with a survival rate significantly higher (p=0.0008) when compared with control group. The only side effect observed was the inflammation of the treated nasal passage, which was very well controlled with corticosteroid therapy for one week. One year after the treatment, 60% of the patients of the Single Needle Electrode group vs 10% of the control group remain alive, and after the two-year follow-up, the survival rate was 30% and 0% respectively. Electrochemotherapy with the Single Needle Electrode can be safely used in dogs to treat nasal tumors with encouraging results.