Osteosarcoma (OSA) is the most common primary bone tumor in dogs. Limb amputation remains standard treatment for local control; however, radiation therapy has become more common as availability has increased and targeting improved. A major challenge of any limb salvage technique is pathologic bone fracture.
This small retrospective study described the clinical features of 6 dogs with appendicular OSA managed by stereotactic radiosurgery (SRS; radiation therapy that focuses high-power energy on a small area of the body), adjuvant chemotherapy, and fracture fixation for secondary pathologic fractures. The mean time to fracture development after SRS was 6.25 months for the 4 cases that did not initially present with pathologic fractures. Five cases developed early postoperative surgical infections after fracture stabilization and required extended antimicrobial therapy and/or wound debridement. Implant failure occurred in 50% of cases; 2 revisions and 1 amputation were required. When morbidity was controlled, subjective limb function was good in all cases, despite intermittent lameness. The overall survival ranged from 364–897 days, with metastatic disease developing in 4 of 6 cases; 1 dog was lost to follow-up.