Retrospective Evaluation of a Combination of Carboplatin and Bleomycin for the Treatment of Canine Carcinomas

SIMPLE SUMMARY: The safety of combined carboplatin and bleomycin chemotherapy treatment has never been assessed in dogs. Thirty dogs diagnosed with various types of carcinomas and treated with carboplatin and bleomycin chemotherapy were retrospectively evaluated. The treatment with carboplatin and bleomycin was well tolerated, with sixteen patients (53%) developing mild side effects. Gastrointestinal signs developed in thirteen (46%) of the dogs and hematological abnormalities in nine (30%). Objective response was observed in 24% of the cases (six partial responses) and 76% of cases achieved clinical benefit (partial response + stable disease). The combination of bleomycin and carboplatin appears safe and potentially effective for some types of carcinomas. ABSTRACT: Carboplatin is a chemotherapy agent widely used in veterinary oncology to treat various types of tumors including carcinomas. Carboplatin has previously been used in combination with 5-Fluoro uracil (5-FU) or gemcitabine for the treatment of various carcinomas. Bleomycin is a chemotherapy drug commonly used in humans, but its use has been uncommonly reported in dogs. The combination of carboplatin and bleomycin chemotherapy treatment has never been reported in dogs. Dogs diagnosed with carcinoma and treated with a combination of carboplatin and bleomycin, at a single veterinary referral center, were retrospectively evaluated. Thirty patients met the inclusion criteria. The dose of carboplatin ranged from 200–250 mg/m(2) (median 240 mg/m(2)) and the dose of bleomycin from 15–20 IU/m(2) (median 15 IU/m(2)). The treatment with carboplatin and bleomycin was well tolerated, with sixteen patients (53%) developing side effects. Thirteen patients (46%) developed gastrointestinal signs and nine dogs (30%) developed hematological abnormalities. The most common side effects were grade-1 hyporexia and grade-1 neutropenia. Grade-2 neutropenia was rarely observed, and only one patient developed grade-3 neutropenia. None of the dogs developed grade-4 adverse events, or required hospitalization, or died due to the treatment. No signs of chronic side effects, including pulmonary toxicity, were observed. Objective response was observed in 24% of the cases (six partial responses) and 76% of cases achieved clinical benefit (partial response+ stable disease). Clinical signs improved in 24 of the 30 cases (80%). The main aim of this study was to evaluate the safety of bleomycin and carboplatin in combination for the treatment of various types of carcinomas. The combination of bleomycin and carboplatin appears safe and potentially effective for some types of carcinomas. Larger prospective studies are needed to confirm the safety and efficacy of combined carboplatin and bleomycin.