Dog Bone Cancer - Osteosarcoma

Canine osteosarcoma, or dog bone cancer, is the most common type of cancer in dogs, according to the College of Veterinary Medicine at North Carolina State University. Though common, osteosarcoma is currently not a preventable disease. It is also rarely detected in the early stages. In about 95 percent of dogs suffering from osteosarcoma, the cancer has already metastasized or spread to other parts of the body upon being diagnosed. However, with proper, successful treatment, dogs with osteosarcoma may live anywhere from one to four years after receiving treatment.

  1. Causes

    • Unfortunately, the exact cause of canine osteosarcoma is not known. Veterinarians do know that there are several factors at work: Genetic changes, environmental causes and biological reasons. According to Dr. Rowan J. Milner of the University of Florida, the dog's inherited genes, its exposure to certain environmental triggers like radiation, and biological causes -- such as acquiring certain viruses -- may mutate normal bone cells into cancerous ones.

    Risk Factors

    • Some dogs are at a higher risk of developing bone cancer than others. Large and giant-breed dogs are more susceptible to osteosarcoma; examples of dogs that tend to develop osteosarcoma include Great Danes, St. Bernards, golden retrievers, Labrador retrievers, Rottweilers and boxers. Age is also a risk factor; the older the dog, the greater its chance of getting bone cancer. Less significant risk factors include being male, being spayed or neutered, being a chronic sufferer of bone infections and having surgical implants.

    Signs and Symptoms

    • The most common symptom that a dog suffering from osteosarcoma exhibits is bone pain. Lameness or limping on the limb that is affected also points to the possibility of osteosarcoma. In addition, dogs in later stages of the cancer may exhibit swelling and warmth right over the affected bone. Other signs that a dog is suffering from bone cancer include weight loss and loss of appetite.

    Diagnosis

    • While there are signs that may point to a dog having bone cancer, the only way veterinarians know for sure that a dog is suffering from osteosarcoma and not another disease is by performing certain diagnostic tests. Vets will take X-rays of the affected limb and the lungs, to see if the cancer has metastasized beyond the limbs. If there is any doubt that the dog has bone cancer, the vet will perform a biopsy on the tumor; after the pathologist analyzes the biopsy, the diagnosis can be confirmed. Complete blood counts and urine tests may also be ordered when diagnosing a dog of osteosarcoma.

    Treatment

    • Treating bone cancer in dogs involves a combination of several approaches. According to the College of Veterinary Medicine at North Carolina State University, the main goals when treating canine osteosarcoma are to alleviate pain, to remove the tumor and to slow down the spread of cancer to other parts of the body. Vets generally recommend amputation of the affected limb to remove the tumor. An alternative to amputation is radiation therapy, which helps relieve pain and decreases inflammation and swelling of the tumor. After the amputation or radiation therapy, the dog typically undergoes chemotherapy treatment, which prevents or delays metastasis, therefore extending the life expectancy of the dog.