Osteosarcoma is the most common primary bone tumor in dogs (85 – 98% of all primary bone tumors). Large breed dogs are most commonly affected, including Scottish Deerhound, Rottweiler, Irish Wolfhound, Saint Bernard, Great Dane, Doberman, German Shepherd, and Golden Retriever. Age distribution of the disease in dogs is biphasic, with a peak at 1-2 years and another peak at 8-10 years. Primary tumors are most commonly found in the appendicular skeleton (fore and hind limbs). Most common sites include the distal radius (forearm), proximal humerus, distal femur, and the proximal or distal tibia. A diagnosis is made based on radiographic (x-ray) findings of the affected bone, and fine needle aspirate or biopsy of the boney lesion. Appendicular OSA is a highly malignant tumor as 75-90% of dogs will develop distant metastases. The most common site for metastasis is the lungs, however, with aggressive treatment (surgery and chemotherapy) it is more common to see boney metastasis. Treatment options include palliative care (pain management) and more definitive therapies that involve combinations of either surgery or radiation and chemotherapy. Median survival times for palliative pain management, either via oral analgesics or radiation therapy, are 107 days and 122-313 days respectively. Surgery alone (typically amputation) has a median survival time of 101-175 days, while surgery with adjunctive chemotherapy extends survival time to roughly one year.
OSA in people is typically seen in children and teens, although it can occur at any age. It accounts for about 2% of childhood cancers. Similar to dogs, OSA in people often occurs in long bones and is more often seen in taller individuals. Treatment involves surgery, chemotherapy and/or radiation. With current treatment options, the average 5-year survival rate is roughly 70%.