Electrochemotherapy as a new treatment for prostate cancer in dogs

Abstract

BACKGROUND: Canine prostatic carcinoma (PC) is an uncommon neoplasia characterized by aggressive biological behavior. Treatment options include surgery (partial or total prostatectomy), radiation therapy (RT), and medical treatment [non-steroidal anti-inflammatory drugs (NSAIDs), chemotherapy, or tyrosine kinase inhibitors]. Electrochemotherapy (ECT) is a local treatment modality increasingly used in human and veterinary oncology. AIM: This retrospective multi-institutional study aimed to assess the safety, feasibility, and preliminary efficacy of ECT as a treatment for canine PC. METHODS: Dogs with cytologically or histologically confirmed PC treated with ECT as first-line therapy were included in this study. Dogs with distant metastases or those previously treated with surgery, RT, or chemotherapy were excluded. The clinical response was evaluated based on the improvement of clinical signs and reduction in tumor volume. Adverse effects, time to progression, and median survival time (MST) were recorded. RESULTS: Nine dogs were enrolled in this study. All but two dogs were neutered. Regional lymph node metastases were present in two patients (22%). Metastatic lymph nodes were treated concurrently with ECT in one patient. Three patients (33%) had a partial response, three (33%) had stable disease, 2 (22%) had progressive disease, and one had a complete response. The overall response rate, including complete and partial responses, was 44%. The median TTP was 74 days, and MST was 70 days. The treatment was well tolerated, with no observed local or systemic adverse effects. CONCLUSION: This preliminary study showed that ECT is a safe and well-tolerated local therapy, although survival outcomes were modest compared with those of surgery, RT, or medical treatment. Further controlled, prospective studies are needed to better define its role as a therapeutic option.