Clinical evaluation of canine mast cell tumor treatment between combined vinblastine and prednisolone and single prednisolone

Thirty three dogs having cutaneous mast cell tumors (MCT) were divided into two groups; group 1 had 23 dogs that were treated with vinblastine and prednisolone and group 2 had 10 dogs that were treated with prednisolone. Evaluation of the 33 pre- and post-treated tissue samples was performed on their clinical stages, histopathological features, expression of proliferative markers such as argyrophilic nucleolar organizer regions (AgNORs), proliferative cell nuclear antigen (PCNA) and Ki-67 and clinical response. All cases were diagnosed as MCT grade II without post-treatment changes in histopathological grade. An increase of uniform nucleus, stroma but a decrease of cytoplasm, the number of visible nucleolus, intralesional vascularization, eosinophilic aggregation, and the mean of mitotic index (pretreatment = 1.6 cells/HPF, post-treatment = 1.1 cells/HPF) was observed in the post-treated samples of both groups. With regard to the clinical evaluation, 18 dogs (78.2%) were partially responsive and the rest (21.8%) were stable in group 1 while five dogs (50%) were partially responsive, three dogs (30%) were stable, and the remaining two dogs (20%) were progressive in group 2. The median survival time of the group 1 cases was 101 days and for the group 2 cases was 175 days. In addition, mean ± standard deviations of AgNORs (dots/cell), PCNA (%), and Ki-67 (%) were 1.83 ± 0.4, 18.67 ± 9.25, and 6.86 ± 7.23 in the pretreatment group 1 and 1.59 ± 0.3, 12.4 ± 7.15, and 1.9 ± 1.35 in the post-treatment group 1, respectively. Mean ± standard deviations of AgNORs, PCNA and Ki-67 were 1.83 ± 0.42, 18 ± 20.01 and 6.74 ± 5.42 in the pretreatment group 2 and 1.67 ± 0.28, 6.28 ± 5.59 and 2.3 ± 1.55 in the post-treatment group 2, respectively. All proliferative markers decreased differently statistically after treatment (P < 0.05). In conclusion, the MCT dogs treated with vinblastine and oral prednisolone and single oral prednisolone were shown to have a decrease in histopathological malignancy characteristics which included AgNORs, PCNA, Ki-67 indices.