Adjuvant post-operative chemotherapy in bitches with mammary cancer

The survival time in a group of eight bitches with malignant mammary tumours given adjuvant post-operative chemotherapy was compared with survival in another group of eight bitches with mammary cancer which were treated by surgical excision alone. The same surgical procedure was used in both groups. All bitches had stage III disease according to the World Health Organization clinical staging system. Histologically, 10 of the bitches had complex carcinomas (carcinomatous mixed tumours), the remaining six bitches had carcinosarcomas. The chemotherapeutic protocol used was a combination of 5-fluorouracil (150 mg/m2 of body surface area) and cyclophosphamide (100 mg/m2) given on the same day, intravenously, every week for four consecutive weeks. Chemotherapy was started one week post-surgery. Selected haematological parameters (packed cell volume, white blood cell count, platelet count and differential white blood cell count) and serum biochemical parameters (alanine aminotransferase, alkaline phosphatase, blood urea nitrogen and creatinine) were measured before and during chemotherapy. Survival analysis indicated that the chemotherapeutic regimen had a positive influence on the disease-free interval and the survival time of the eight bitches (P < 0.05). Although leucocyte numbers were significantly decreased (P < 0.001) during chemotherapy, the mean leucocyte counts remained within normal limits. Temporary leukopenia was noted only in one bitch. Packed cell volume and alkaline phosphatase increased significantly (P < 0.05) but within normal limits. Creatinine was also increased significantly (P < 0.01) but the mean creatinine concentrations were within normal limits, although in half of the bitches the concentrations occasionally rose above normal.