Factors Affecting Treatment Outcome of Canine Transmissible Venereal Tumor: A Retrospective Study

Canine transmissible venereal tumor (TVT) is a contagious neoplastic disease commonly seen in tropical and subtropical areas in the countries where the control of stray dog population is poor. This study aimed to summarize the current disease status and evaluate factors affecting treatment outcome to vincristine sulfate, which is the chemotherapeutic drug of choice. Studied factors were divided into three categories; general background (i.e. age, gender, breed), specific descriptions (i.e. tumor diameter, tumor site, season of the year), and treatment details (number of vincristine shots, meteorological parameters). One hundred and fifty-seven medical records were included with 100 achieved complete treatments and enrolled in the investigation of treatment outcome. Treatment outcome was classified as complete remission (CR) and partial remission (PR) at the eighth week of treatment. Moreover, the corresponding factors affecting number of vincristine shot to commit CR were evaluated. The age, gender and breed had no effect on treatment outcome or number of vincristine shots. The tumors at the genital area were prone to be recovered (CR) than the others (P = 0.08). The tumors with diameter >6 cm required higher number of vincristine shots than that of diameter <2 cm (P = 0.05). Moreover, there was a tendency that CR was observed with lower mean temperature at 60 days after enrolled (Temp60) and lower maximal temperature (MaxTemp60) than the PR cases (P = 0.08 and P = 0.07, respectively). These results may contribute to the prognosis of the treatment with vincristine sulfate particularly when the treatment is influenced by tumor site, tumor size, and climate.