Causes

• The cause of canine osteosarcoma is unknown but may be due to genetics, trauma or injury, foreign objects (metal implants) and chemical carcinogens.
  
  

Symptoms

• Symptoms of appendicular osteosarcoma may include swelling, pain in the joint and lameness. Dogs suffering from cranial or vertebral osteosarcoma may have neurological issues while mandibular (lower-jawbone) osteosarcomas may cause difficulty with swallowing.
  
  

Diagnosis

• A physical exam and various tests will be used to rule out other causes of lameness, neurological issues or swallowing difficulties. To confirm canine osteosarcoma, an X-ray and biopsy are necessary.
  
  

Treatment

• Appendicular osteosarcoma requires amputation of the affected limb. For other forms of osteosarcoma, there may be chemotherapy, surgical removal of affected bones, pain management and radiation therapy.
  
  

Prognosis

• Due to the high rate of metastasis of canine osteosarcomas, many dogs are dealt a poor prognosis. A variety of factors will determine each dog's individual prognosis and include age, severity of cancer and whether metastasis has occurred.