CCNU, vinblastine and prednisone treatment for grade II dermal mast cell tumor in a Yorkshire terrier dog

An 11-year-old, castrated male Yorkshire terrier dog was presented with multiple plaques on right inguinal region. Grade II mast cell tumor was diagnosed. The dog was treated with Vinblastine and prednisone (PDS) initially. Because of poor response of the dog, CCNU was added for more aggressive treatment. After 5 weeks treatment of with CCNU, vinblastine and PDS, the lesion was improved. Moderate leukopenia was shown after 4 cycles of chemotherapy. The chemotherapy was re-administered since the patient recovered from the leukopenia. Though the same protocol was applied, no improvement of the lesion was observed. Moreover, the general body condition of the dog became worse and was euthanized by the owner's request. Necropsy was not permitted. The survival time was 330 days after start of the chemotherapy.