There are two main types of bone cancer, primary and metastatic bone cancers.  Metastatic bone cancer is one of the most common cancer diagnosis in the United States.  Cancers from other organs, such as breast cancer, prostate cancer, lung cancer, etc, can cause metastatic bone cancer in their late stages.  Compare to metastatic bone cancer, primary bone cancers are relatively rare and account for less than 0.2% of all cancers.  In 2002, approximately 2,400 new cases of primary bone cancers were diagnosed in the United States, and about 50% of these bone cancer patients died from this disease. 

Metastatic Bone Cancer

The most common type of bone cancer is the cancer that has spread to the bone from other organs. It is called metastatic bone cancer or malignant bone metastases.  The cancer did not start in the bone and cancer cells usually traveled from other organs via bloodstream to the bone. A typical example is when advanced prostate cancer spreads to the bones.  The cells of the cancer (usually adenocarcinoma) look like prostate cancer cells, not bone cancer cells, even after they are relocated in the bones. 

Please refer to our Bone Metastases document if you are interested in reading more about metastatic bone cancer.

Primary Bone Cancers

Most bone cancers are called sarcomas.  There are several types of primary bone cancers.  The exact cause of bone cancer is unknown, although multiple risk factors of bone cancers have been discovered.  Common risk factors related to bone cancer include history of bone tumor or malignancy, multiple exostoses (overgrowths of bone tissue), radiation, genetic mutation, injury, Paget’s disease, etc. However, most patients with bone cancers do not have any apparent risk factors, and most people with such risk factors never develop bone cancer.

The name of the different types of bone cancers are based on the cells forming the cancer and location of the bone or surrounding tissue involved. 

Osteogenic sarcoma: Osteogenic sarcoma (also called osteosarcoma) is the most common primary cancer that develops in bone.  Approximately 35% of primary bone cancer cases are osteosarcoma.  It is a malignancy developed from the cells that produce bone matrix.  Osteosarcoma most commonly develops in arms, legs and pelvis, but usually at the edge or metaphysis of the long bone.

Osteosarcoma is more common in males than females.  It often occurs in children and adolescents, although approximately 10% of cases develop in patients in their 60’s and 70’s.

Based on the histology appearance, osteosarcoma can be sub-classified into high-grade, intermediate-grade, and low-grade diseases.  Treatment of the disease and prognosis after therapy is closely associated to the grade of the disease.   Patients with low-grade tumors are usually treated with complete resection only without chemotherapy.  Prognosis for patients with low-grade osteosarcoma is excellent, and the 5-year survival rate is more than 85%.  High-grade tumors should be completely removed surgically, and post-surgical systemic chemotherapy is generally required.   Almost all pediatric osteosarcoma cases are high-grade.  The prognosis of pediatric patients is much better than elderly patients.  After complete surgical resection and aggressive chemotherapy, the 5-year survival rate for young patients with high-grade osteosarcoma is about 75%.

Osteosarcoma can extend to the nearby tissues and spread beyond the original location (i.e., primary site) to the lungs, other organs, or other bones through the bloodstream.

Chondrosarcoma:  Chondrosarcoma is the second most common primary bone malignancy.  It is a cancer of cartilage cells.  Unlike osteosarcoma, chondrosarcoma is uncommon in patients younger than 20, and men and women are equally affected. Chondrosarcoma is associated with osteochondroma, a benign tumor of cartilage and bone.  Chondrosarcoma may occur in any part of the skeletal system, but it usually occurs in arms, legs, and pelvis.

Giant cell tumor of bone: Only about 10% of the giant cell bone tumors are malignant and may spread to other part of the body.  Ninety percent of this type of bone tumor is benign and requires local treatment only.  However, local recurrence after surgery is common for the benign form of giant cell bone tumor.   These tumors typically affect the long bones (arm or leg bones) of young and middle-aged patients.  Typically, radiotherapy and systemic chemotherapy are not used for the treatment of this tumor.

Ewing’s Sarcoma: Dr. James Ewing first described Ewing’s sarcoma in 1921.  Ewing’s sarcoma is usually a pediatric malignancy because it is more common in children and adolescents and uncommon in adults.  Ewing’s sarcoma may occur in any part of the skeleton but usually arise in the long bones of the arms and lets.  For more information, please refer to the Ewing’s Sarcoma document of the National Cancer Institute.

Multiple Myeloma: The cancer cells involved in multiple myeloma are plasma cells, not bone or cartilage cells.  Multiple myeloma is a malignancy of the bone marrow and is always a systemic disease.  Rarely, it can start as a solitary lesion in a single bone, but spread of the disease to multiple bony areas is inevitable.  Multiple myeloma is usually treated with chemotherapy or palliative radiotherapy for bone destruction.  For more information, please refer to the Multiple Myeloma Directory of the Cancer Information Network.

Benign Bone Tumors: Not all bone tumors are cancerous.  Benign bone tumors are usually localized diseases and do not metastasize to other organs.  Commonly diagnosed benign bone tumors include osteoma, osteoblastoma, osteochondroma, osteroid osteoma, and hemangioma.  These tumors are not life threatening and are generally cured by surgery; however, some of them are associated with the development of bone malignancy and are considered as risk factors of bone cancers.

Published by The Cancer Information Network on 12/29/2002