Metastatic osteosarcoma is commonly referred to simply as osteosarcoma, which is a type of cancer that is formed in osteoblasts. The "metastatic" adjective refers to the disease's ability to spread to other parts of the body. Osteosarcoma is known as the most common form of bone cancer.
Osteoblasts are bone cells instrumental in forming the bones of the body. More specifically, they form bone tissue by producing a soft, organic substance called osteoid. Osteosarcoma occurs when the osteoblasts begin to form into malignant tumors.
There are three stages of osteosarcoma. Metastatic osteosarcoma is classified as Stage II or Stage III osteosarcoma, which are considered the more advanced stages of the disease. The lungs constitute the most common site for metastasis of the disease.
There is no known cause of osteosarcoma. Some researchers, however, have tried to link the bone cancer to fluoride. Other researchers have theorized that radiotherapy, which is actually a form of cancer treatment, may be a cause of osteosarcoma.
Osteosarcoma tends to occur in the long bones of the body, most especially the bones that form the arms and legs. This includes the humerus, ulna, radius, femur and fibula. With children, however, the tumors commonly develop around the patella, or knee cap. In some cases, osteosarcoma occurs in the pelvis.
Other common sites include the abdomen and chest, where it can develop in the soft tissue of organs in these locations. This is typically a sign of metastatic osteosarcoma. Children and young adults, particularly males, are more likely to develop osteosarcoma than other groups. Symptoms of the bone cancer include swelling and pain around a bone, and easy bone fractures.
Osteosarcoma is typically diagnosed using imaging techniques such as x-ray, computed tomography (CT) scan or magnetic resonance imaging (MRI). Also, oncologists perform a biopsy, which involves removing and testing cells or tissues for the presence of disease. Once discovered, they treat the disease by combining chemotherapy and surgery, with certain factors such as age and overall health of the patient, size and location of the tumor, and stage of the disease taken into account.
Prognosis for metastatic osteosarcoma depends on when the disease is detected. The sooner it is diagnosed, the greater the prognosis. Overall, though, the prognosis for metastatic osteosarccoma — or Stage II and Stage III osteosarcoma — is much poorer than the cancer at Stage I. At its earliest stage, patients can expect up to a 90 percent chance of survival with wide resection of the tumors. By comparison, patients with metastatic osteosarcoma have a 30 percent overall chance of survival.