Bone cancer (osteosarcoma or OSA) is a malignant tumour which usually affects the limb bones. Unfortunately, by the time a dog has symptoms the cancer has often already metastasised, most commonly to the lungs. It is listed as the cause of death of approximately 20-24% of Wolfhounds.
The causes of OSA are poorly understood, but are likely to be both polygenic (an inherited tendency) and environmental. Areas of previous injury or infection may be more prone to the disease.