Get access

The Impact of Pamidronate and Chemotherapy on Survival Times in Dogs with Appendicular Primary Bone Tumors Treated with Palliative Radiation Therapy


  • Michelle L. Oblak DVM,

    Corresponding author
    • Department of Clinical Studies, Ontario Veterinary College, Guelph, Canada
    Search for more papers by this author
  • Sarah E. Boston DVM, DVSc, Diplomate ACVS,

  • Geraldine Higginson MSc,

  • Steven G. Patten MSc,

  • Gabrielle J. Monteith BSc,

  • J. Paul Woods DVM, MS, Diplomate ACVIM (Oncology)

  • Funded in part by the Ontario Veterinary College Pet Trust Fund.

  • Presented in part at the ACVS Veterinary Symposium, Seattle WA, October 2010.

Corresponding Author

Michelle L. Oblak, DVM, Small Animal Clinic VTH, Ontario Veterinary College, University of Guelph, Guelph, ON N1G2W1, Canada




To assess survival times in dogs that received palliative radiation therapy (RT) alone, and in combination with chemotherapy, pamidronate, or both for primary appendicular bone tumors and determine whether the addition of these adjunctive therapies affects survival.

Study Design

Retrospective case series.


Dogs (n = 50) with primary appendicular bone tumors.


Dogs were divided into the following treatment groups: RT alone, RT + chemotherapy, RT+ pamidronate, and RT+ chemotherapy + pamidronate. Dogs were considered for analysis if they had a known euthanasia date or follow-up data were available for at least 120 days from the time of diagnosis. Survival time was defined as the time from admission to euthanasia. Cox proportional hazard models and Kaplan–Meier survival functions were used. A P value of less than .05 was considered significant.


Fifty dogs were considered for survival analysis. Median survival times (MSTs) were longest for dogs receiving RT and chemotherapy (307 days; 95% CI: 279, 831) and shortest in dogs receiving RT and pamidronate (69 days; 95% CI: 47, 112 days). The difference in MST between dogs who received pamidronate and those who did not in this population was statistically significant in a univariate (P = .039) and multivariate analysis (P = .0015). The addition of chemotherapy into any protocol improved survival (P < .001).


Chemotherapy should be recommended in addition to a palliative RT protocol to improve survival of dogs with primary appendicular bone tumors. When combined with RT ± chemotherapy, pamidronate decreased MST and should not be included in a standard protocol.