USE OF FORCE PLATE ANALYSIS TO EVALUATE THE EFFICACY OF EXTERNAL BEAM RADIATION TO ALLEVIATE OSTEOSARCOMA PAIN

Authors


  • Acknowledgement for assistance with statistical analyses: Durwood Marshall, Statistical & Research Computing, Specialist Tufts University Information Technology (UIT), Academic Technology, 16 Dearborn Road, Somerville, MA 02144.

  • "This study was supported through a grant from the Tufts Cummings School of Veterinary Medicine's Fund for Companion Animal Health.

  • Sarah Payne's current address is Sarah Payne, 393 Woods Lake Road, Greenville, SC 29607.

Address correspondence and reprint requests to Chieko Azuma, at the above address. E-mail: chieko.azuma@tufts.edu

Abstract

A standard of therapy for osteosarcoma includes amputation with or without adjuvant chemotherapy. There is a subset of dogs with osteosarcoma that are unsuitable for amputation. We evaluated kinetic variables in dogs with appendicular osteosarcoma treated with a single 8 Gy dose of radiation. Eighteen pet dogs with appendicular osteosarcoma received one 8 Gy fraction of palliative radiation on day 0. Force plate measurements and clinical assessments were made on days 0, 7, 14, and 21. Peak vertical forces (Fz) were recorded for each limb and a symmetric index (SI) was calculated. There were no significant changes in kinetic parameters after one 8 Gy dose of radiation therapy. Nine of these 18 dogs exhibited increased limb function at day 21 based on force plate analysis. Significant factors affecting Fz included gender and tumor location. There was a significant correlation between Fz and response to therapy based on SI at day 21. SI seems to be useful to objectively assess response in this mixed population of dogs. One 8 Gy fraction of radiation therapy alone did not reduce lameness associated with appendicular osteosarcoma, but a subset of dogs did have improved limb function after a single dose.

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