Figure 2 (
A) Radiograph of a distal radial osteosarcoma. Centered at the distal metaphysis of the radius, there is evidence of permeative and moth-eaten lysis. There is also concurrent ill-defined periosteal proliferation consistent with an aggressive bone lesion. (
B) CT scan of distal radial osteosarcoma in the same patient. Coronal view of limb in bone window. There is more evidence of geographic bone lysis and evidence of periosteal proliferation. Consistent with an aggressive bone lesion. (
C) Bone scan of the distal radial osteosarcoma in the same patient. Note the increased uptake of radiopharmaceutical in the distal radius of the patient (
arrow).
Osteosarcoma (OSA) is the most common primary bone tumor in dogs.5 Unfortunately, most cases are not cured with surgery because of the high risk for metastatic disease.5
Patients should be staged for gross metastasis to lung or another bone before surgery (Figure 2). Staging methods vary depending on clinician preference, but 3-view thoracic radiographs and/or thoracic CT and bone scan are recommended.6 Limb amputation is the most commonly performed surgical treatment; major benefits include removal with wide margins of the tumor, removal of the source of pain, and removal of potential for ongoing metastasis.
Related Article: Canine Osteosarcoma: Part 1
In some cases, another surgical option may be limb salvage, which is most commonly performed in the distal radius and involves the surgical removal of the affected bone. The defect is most commonly bridged using an endoprosthesis (ie, a metal implant with a bone plate extending from the metacarpals to the proximal radius). Although the limb is usually preserved, the rate of complications (eg, infection, local recurrence, implant failure) is extremely high.7 Limb salvage should only be considered when amputation is not an option for medical reasons (eg, a patient with significant concurrent orthopedic or neurological disorders). There are cases in which a client will not accept amputation and limb salvage is considered; client education in these cases is critical.