Palliative Intralesional Interleukin-2 Treatment in Dogs with Urinary Bladder and Urethral Carcinomas

Aim: The investigation of the influence of intralesional interleukin-2 (IL-2) on the clinical course and tumor progression in dogs suffering from urinary bladder and urethral carcinomas. Materials and Methods: Medical records of 25 dogs diagnosed with advanced transitional cell carcinomas (TCC) were retrospectively reviewed. In 14 dogs, intralesional IL-2 treatment was performed by transabdominal ultrasound-guided injection. Seven dogs underwent cytoreductive surgery, followed by IL-2 injection into the tumor bed. All dogs received long-term non-steroidal anti-inflammatory drugs. Results: Adverse effects associated with IL-2 treatment were not observed. At re-examination, 17 dogs showed marked clinical improvement and regression of tumor size. Four dogs were in complete remission. Conclusion: Intralesional IL-2 application is a safe and minimally-invasive palliative treatment option in dogs suffering from advanced transitional cell carcinoma when surgical cure is impossible. Prognosis depends on tumor localization and feasibility of concomitant cytoreductive surgery.