Alternative vincristine treatment in dogs with transmissible venereal tumour

Introduction and aim - Canine transmissible venereal tumour (CTVT) is a neoplasm with unique features. Despite occasional spontaneous regression of the tumour, veterinarians often have to treat it by chemotherapy. This study aimed to evaluate a new bi-weekly vincristine treatment in comparison to the traditional weekly protocol for CTVT. Materials and methods - 30 dogs with CTVT were divided into two groups: 10 dogs in the control group A and 20 dogs in the experimental group B, treated with weekly and bi-weekly 0.025 mg/kg iv of vincristine sulphate respectively. All animals were monitored during treatment by gross evaluation of the tumour, cytology and haematic samples (CBC and hepatic profile). Therapy was suspended when neoplastic cells were no longer found in smears. Results and discussions - In group B, complete remission was obtained for all the dogs after 2.2 ± 0.3 administrations of vincristine. Regarding group A remission was obtained in 9 dogs after 3.6 ± 0.7 administrations. Only mild side effects were observed with no significant differences between groups. A bi-weekly vincristine regimen may be an alternative or elective treatment for CTVT, being successfully applied to animals in which weekly therapy is impractical. A bi-weekly schedule is advantageous for both owners and animals.