What is osteosarcoma?

For ease of understanding, you will find many of the medical terms defined in red text at the end of a sentence. The term that is being defined will be underlined.

Osteogenic Sarcoma or Osteosarcoma (OSA) is commonly known as bone cancer. The term "osteo  means of or relating to the bones. "Sarcoma  is defined as a usually malignant tumor arising from connective tissue (bone or muscle etc.); one of the four major types of cancer. Simply put, cancer is a break down of the immune system.

OSA is the most common primary bone tumor in dogs. (An abnormal growth of tissue resulting from uncontrolled, progressive multiplication of cells and serving no physiological function)These tumors develop most frequently in the long bones of limbs and less commonly in the bones of the spinal column or skull. OSA is highly aggressive and has a high metastatic rate - most often spreading to the lungs. (A secondary cancerous growth formed by transmission of cancerous cells from a primary growth located elsewhere in the body) OSA of the limbs is called appendicular Osteosarcoma (Of or relating to an appendage and especially a limb) OSA develops deep within the bone and becomes progressively more painful as it grows outward and the bone is destroyed from the inside out. Obvious swelling becomes evident as the tumor grows and normal bone is replaced by tumorous bone. The tumorous bone is not as strong as normal bone and can cause the bone to be weakened to the point of spontaneously fracturing. This type of broken bone is called a pathological fracture. (Altered or caused by disease) Without treatment, most dogs will be euthanized within one to two months due to uncontrollable pain.
General Statistics

OSA is estimated to occur in 8 - 10,000 dogs per year in the United States, and it is highly malignant. (Tending to infiltrate, metastasize, and terminate fatally )

Cancerous lesions of the bone present most commonly between 2-8 years of age, with 7 years being the average age for presentation

According to the bone tumor database at the Animal Cancer Center at Colorado State University, 98% of 1,273 appendicular primary bone tumors diagnosed in dogs were OSA.

Osteosarcoma can develop in any bone but the limbs account for 75-85% of affected bones. The front legs are affected twice as often as the hind legs.

Giant breeds have a greater risk for developing Osteosarcoma, and males have a slightly higher risk than females for this form of cancer.

With local disease control alone (amputation or limb sparing), the 1 year survival rate is les than 10%, and most patients succumb to pulmonary metastasis.
(Relating to or affecting the lungs)
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