Pathologic fracture in dogs with suspected or confirmed osteosarcoma.

Objective: To evaluate clinical presentation of pathologic fractures associated with suspected or confirmed osteosarcoma in dogs and to assess treatment and survival times. Study design: Case series. Animals: Dogs (n=25) appendicular pathologic fracture. Methods: Medical records (January 1997-May 2008) of dogs with pathologic fracture associated with a suspected or confirmed osteosarcoma were reviewed. Dogs were included if they had radiographic evidence of a pathologic fracture and a presumptive or definitive diagnosis of osteosarcoma. Radiographic details, histopathology, and/or cytology findings were recorded. Overall median survival time (MST) and MST of treated dogs were calculated. Age, sex, breed, and other concurrent treatment were evaluated. Results: Rottweilers, Irish Wolfhounds, and Greyhounds were the most common breeds represented. Most dogs had minor trauma and 60% had lameness preceding the fracture. Most commonly, fractures were nondisplaced with minimal comminution. None of the dogs had radiographic evidence of pulmonary metastases at admission. Immediate (13 dogs; 52%) and delayed (4; 16%) euthanasia were performed. One dog was not treated and died 90 days after diagnosis. Three dogs (12%) were treated by amputation alone, 1 (4%) with amputation and chemotherapy, and 3 (12%) with internal fixation using an interlocking nail. Overall MST was 1 day (range, 0-623 days) and MST of treated dogs was 406.5 days. Histologic confirmation of osteosarcoma was available in all treated dogs and 6 euthanatized dogs. Conclusions: Treatment of pathologic fracture associated with presumptive osteosarcoma should be considered as an option to amputation or euthanasia if owners desire other options.