• Open Access

Adjuvant Carboplatin and Gemcitabine Combination Chemotherapy Postamputation in Canine Appendicular Osteosarcoma


  • Dr McMahon is presently affiliated with Northwest Veterinary Specialists, 16756 SE, 82nd Drive, Clackamas, OR 97015. This work was completed at the following institutions: The Ohio State University (OSU), The University of Wisconsin—Madison (UW—Madison), and The New England Veterinary Oncology Group (NEVOG). Presented in part at the 29th Veterinary Cancer Society Conference, Austin, TX, October 2009.

Corresponding author: Cheryl London, DVM, PhD, Associate Professor, the Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1925 Coffey Road, Columbus, OH 43214; e-mail: london.20@osu.edu.


Background: Appendicular osteosarcoma (OSA), the most common bone tumor in dogs, is typically treated by amputation and adjuvant chemotherapy. Despite numerous efforts, the median survival time (MST) for dogs receiving a platinum compound, doxorubicin, or a combination of these remains at 8–12 months. Evidence from studies in mice suggests that gemcitabine has activity against OSA in vivo. Our preliminary work demonstrated that the addition of low-dosage (10 mM) gemcitabine to carboplatin resulted in synergistic inhibition of OSA cell viability in vitro.

Objective: The purpose of the following study was to determine whether the addition of low-dosage (2 mg/kg) gemcitabine to carboplatin chemotherapy in dogs with OSA after amputation would improve MST over carboplatin monotherapy.

Animals: Fifty dogs with histologically confirmed appendicular OSA.

Methods: Dogs were treated prospectively with amputation and up to 4 dosages of carboplatin and gemcitabine in combination every 3 weeks.

Results: The chemotherapeutic regimen was well tolerated with only 5 episodes of grade 3 or 4 hematologic toxicity. The median disease-free interval (DFI) was 203 days and the MST was 279 for all dogs in this study. The 1- and 2-year survival rates were 29.5 and 11.3%, respectively. Dogs with proximal humeral OSA had a shorter median DFI (P= .04) compared with dogs with OSA in other locations.

Conclusions and Clinical Importance: These results are comparable to those reported for carboplatin monotherapy indicating that the addition of gemcitabine to carboplatin in dogs with appendicular OSA does not appear to improve outcome.