Abstract

Background:
Canine urinary bladder transitional cell carcinoma (TCC) is a locally invasive malignancy commonly associated with hematuria and progressive lower urinary tract signs. Although piroxicam is widely used as a medical treatment, tumor progression is frequently observed during follow-up. Additional therapeutic options are therefore needed for dogs with progressive disease.

Case Description:
Three dogs with BRAF-mutated urinary bladder TCC were treated with an autologous tumor antigen vaccine prepared from urine sediment. In Cases 1 and 2, vaccination was introduced after tumor progression during prolonged piroxicam treatment. In Case 3, vaccination and piroxicam were initiated concurrently at diagnosis. Serial ultrasonographic examinations were performed throughout follow-up. Case 1 showed tumor regression after vaccination and survived 949 days from diagnosis. Case 2 was followed for at least 1,196 days and maintained a relatively slow clinical course. Case 3 survived 502 days from diagnosis. No severe adverse events attributable to vaccination were observed in any dog.

Conclusion:
Autologous tumor antigen vaccination was safely administered in all three dogs. Although treatment efficacy cannot be determined from this uncontrolled case series, prolonged survival and acceptable tolerability were observed. Further investigation of individualized immunotherapeutic approaches for canine urinary bladder TCC is warranted.

Key words: Autologous tumor vaccine; BRAF mutation; Canine bladder cancer; Immunotherapy; Transitional cell carcinoma.