Osteosarcoma is a common type of bone cancer that develops from cells of the bones in domestic dogs and cats. It is fairly rare in other species. There are other types of cancer that can form from bone, including chondrosarcoma, fibrosarcoma and hemangiosarcoma. However, osteosarcoma is by far the most common primary bone cancer in dogs. Primary bone cancer/tumors are those that are caused specifically by overgrowth of bone cells. They are different from secondary bone tumors, which form from cells of other organs or tissues and then metastasize – or spread – to bone.
Osteosarcoma initially involves the uncontrolled or out-of-control growth of osteoblasts - immature cells that are the building blocks for mature bone. When a dog has osteosarcoma, osteoblasts multiply without any of the constraints that normally control bone growth. As a result, abnormal bone forms in the affected areas, causing hard, swollen, painful masses. In dogs, osteosarcoma often develops near the joints of the legs. These are the elbow and wrist (carpus) in the front legs, and the knee (hock) and ankle (tarsus) in the hind legs. Osteosarcoma is malignant, which means that it progressively worsens over time and ultimately will be fatal. This type of cancer usually spreads very quickly in dogs, especially from bone to the lungs. Even when cancerous cells migrate from the bone and multiply in other areas of a dog’s body, the condition is still considered to be osteosarcoma, or primary cancer of the bone. Large and giant breed dogs develop osteosarcoma much more frequently than do smaller breeds.
The most common sites of osteosarcoma in dogs are the long bones of the legs. This particular form of cancer frequently occurs in the upper long bone of the front leg that connects the shoulder to the elbow, or in one of the two lower long bones of the front leg that connect the elbow to the wrist. These bones are called the humerus, and the radius and ulna, respectively. Other common sites of osteosarcoma
Osteosarcoma frequently affects the upper or lower long bones of a dog’s front legs. These are called the humerus, and the radius and ulna, respectively. The long bones of the rear legs can be affected, as well; these are the femur, tibia and fibula. The jaw and other facial bones, as well as the ribs and vertebrae, can also be subject to osteosarcoma. The first sign of osteosarcoma usually is a slight but progressive limp
Osteosarcoma is preliminarily diagnosed on the basis of a dog’s history, a thorough physical examination and X-rays (radiographs) of the suspected affected areas of bone. If osteosarcoma is present, the X-ray films will show aggressive bony lesions characterized by a moth-eaten, ragged appearance. Osteosarcoma is a very aggressive form of cancer. It almost always spreads quickly through the blood stream and lodges in remote places in the dog’s body – especially in the lungs. This
The goals of treating a dog that has osteosarcoma are to relieve pain and prolong the pet’s disease-free quality of life for as long as realistically possible. Because osteosarcoma tends to spread rapidly, it should be taken very seriously and treated aggressively. The lungs are often one of the first places that osteosarcoma migrates to. X-rays (radiographs) of a dog’s chest may be recommended before it is placed under anesthesia to undergo surgery, in order