Combination vinblastine and palladia for high-grade and metastatic mast cell tumors in dogs.

High-grade and metastatic canine mast cell tumors carry a guarded prognosis because of their unpredictable biologic behavior. An ideal chemotherapy regime is yet to be established. The aim of this study was to review the efficacy and toxicity of combination vinblastine and toceranib for high-grade and metastatic mast cell tumors. Twenty-eight dogs were categorized with either high-grade, lymph node metastasis or Stage IV disease. Demographics, disease, and treatment variables were compared between categories (Kruskal-Wallis test for continuous data and Fisher's Exact test for categorical data). Survival times and progression-free intervals (PFI) were calculated and compared between groups (log rank test). The PFI was 310 d [95% confidence interval (CI): 155 to 1425] and overall survival was 373 d (95% CI: 226 to 1219). There was no difference between disease categories for PFI (P = 0.9) or survival (P = 0.5). The protocol was well-tolerated with increased liver enzyme activity and gastrointestinal toxicity most frequently observed. Progression-free intervals and survival times were similar in dogs with high-grade, metastatic and Stage IV disease.