Bone and connective tissue neoplasms, which include bone and joint sarcomas, myelomas, and soft tissue sarcomas, are uncommon when compared with other cancers and with other musculoskeletal conditions, accounting for about 2.4% of annual cancer cases between 2010 and 2014 (approximately 50,000 cases). This share is higher than the 2.2% reported for 2006 to 2010, and the 1.9% for 2002 to 2006. Estimated cases for 2017 were slightly lower, at 46,000 cases, but represented 2.7% of all new cancer cases. The annual average number of new bone and joints cancer cases, excluding myeloma and soft tissue, reported between 2010 and 2014 was 4,126 cases, with an average of 1,440 deaths from bone and joints cancer each year. Estimates for 2017 are 3,260 new cases and 1,550 deaths. Data cited is from the Surveillance Epidemiology and End Results (SEER) program of the National Cancer Institute and is used to illustrate the burden of bone and connective tissue neoplasms. (Reference Table 6A.A.1.0 PDF CSV, Table 6A.A.1.3.1 PDF CSV; and Table 6A.A.1.4.1 PDF CSV)

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Cancers of Bones and Joints

The three most common primary cancers of bones and joints are osteosarcoma, chondrosarcoma, and Ewing sarcoma. Together they account for more than 80% of true primary bone and joint cancers. The ages at which these cancers most often occur vary. Osteosarcoma, a malignant bone tissue tumor commonly found near the growing end of the long bones, is the most common, and occurs most frequently in teens and young adults. Ewing sarcoma, a tumor often located in the shaft of long bones and in the pelvic bones, occurs most frequently in children and youth. Chondrosarcoma, a sarcoma of malignant cartilage cells, often occurs as the result of malignant degeneration of pre-existing cartilage cells within bone, including enchondromas (a benign tumor), and is primarily found among middle age and older adults. However, the majority of enchondromas never undergo malignant change; therefore, the routine resection of benign enchondromas is unwarranted. (Reference Table 6A.B.1.1 PDF CSV, Table 6A.B.1.2 PDF CSV, Table 6A.B.1.3 PDF CSV, and Table 6A.B.1.4 PDF CSV)

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Of the three, chondrosarcoma has the best prognosis, while Ewing sarcoma is generally considered to have the worst prognosis, followed closely by osteosarcoma. However, this perception is largely due to the greater tendency for osteosarcomas to present as high-grade tumors and for chondrosarcomas to present as low-grade tumors. When analyzed by stage, a recent survivorship analysis of a prior cohort of patients in the NCDB PUF database revealed similar survivorship rates for low-grade chondrosarcoma compared to low-grade osteosarcoma, and similar survivorship rates for Ewing sarcoma and high-grade osteosarcoma. By definition, all cases of Ewing sarcoma are high-grade, the most aggressive category of cancer, with full potential to metastasize and bring about death. High-grade chondrosarcoma has a worse prognosis when compared to high grade osteosarcoma and Ewing sarcoma.1

In the current NCDB analysis, only 4% of osteosarcomas are of Grade 1, the lowest grade, whereas 48% of chondrosarcoma are Grade 1. Therefore, chondrosarcomas have a higher proportion of low-grade cases than the other two bone and joint cancers, which accounts for its overall higher survival rate and the perception that it is not be as lethal. Conversely, 2% of all chondrosarcomas with histologic grading were reported as Grade 4, whereas 40% of osteosarcomas were reported as being in the most aggressive Grade 4 category. (Reference Table 6A.B.1.8 PDF CSV)

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A fourth type of cancer is myeloma, a malignant primary tumor of the bone marrow formed from a type of bone marrow cells called plasma cells (the cells that manufacture antibodies). Although not classified as a bones and joint cancer, it typically causes extensive changes or damage to the bone structure itself, causing fractures, pain, and hypercalcemia (a condition in which the calcium level in blood is above normal, which can weaken bones, create kidney stones, and interfere with how the heart and brain work). Because of the associated bone destruction, myeloma is generally included in analysis of bone cancers. Myeloma usually involves multiple bones simultaneously. The isolated single-bone version of myeloma is called plasmacytoma, but virtually all cases of isolated plasmacytoma evolve into full-fledged multiple myeloma within 5 to 10 years after diagnosis of the plasmacytoma. Like leukemia and lymphoma, myeloma is more properly considered a primary cancer of the hematopoietic bone marrow (stem cells that give rise to other blood cells.). However, leukemia and lymphomas generally are not considered primary bone cancers, presumably because of the lower likelihood of structural bone destruction and associated complications. Non­Hodgkin's lymphomas, however, as well as myelomas, warrant some consideration in a report on the burden of musculoskeletal diseases due to the frequency of bone destruction and pathological fractures requiring operative intervention.

Description of Cancers of Bones and Joints

The reader is referred to the data tables 6A.B.1.1 thru 6A.B.1.9 for a more robust appreciation of these tumors. These tables show the latest NCDB demographic and survivorship analyses of bone and joint cancers, providing additional understanding of the demographics, age distribution, anatomic distribution, nature, treatment and prognosis of these sarcomas and their treatments and results.

Adamantinoma: A rare bone cancer, making up less than 1% of all bone cancers. It almost always occurs in the bones of the lower leg and involves both epithelial and osteofibrous tissue. It generally has a favorable prognosis.

Angiosarcoma: A cancer that forms from cells that are in the lining of blood vessels and lymph vessels. It often affects the skin and may appear as a bruise-like lesion that grows over time. The disease most commonly occurs in the skin, breast, liver, spleen, and deep tissue. It typically has an aggressive course and a poor prognosis.

Chondroblastoma – malignant: Chondroblastoma is a rare, usually benign, tumor of cartilaginous origin. It typically arises in the epiphysis of a long bone. Malignant chondroblastomas, which may occur many years after the original lesion, are extremely rare. Our analysis of the NCDB database reveals a usually good prognosis, with 95% survivorship at 5 years. Establishing the diagnosis in such rare and unusual cases is challenging at best. (Reference Table 6A.B.1.1 PDF CSV)

Chondrosarcoma: A bone cancer that develops from cartilage cells. Cartilage is the specialized, gristly connective tissue that is on the ends of bones with articulating joints that cushion the bone ends and allow motion over its smooth lubricated surfaces. Primitive cartilage is present in adults and the tissue from which most bones develop. Chondrosarcoma develops primarily in the pelvis, scapulae, chest bones, long bones, and spine.

Chordoma: A rare type of slow growing cancerous tumor that can occur anywhere along the spine, from the base of the skull to the tailbone. It derives from the notochord, an embryonic tissue generally considered to be the precursor to intervertebral disc tissue.

Ewing sarcoma: A cancerous tumor that grows in the bones or in the tissue around bones (soft tissue)—often the legs, pelvis, ribs, arms, or spine. Ewing sarcoma can spread to the lungs, bones, and bone marrow.

Fibrosarcoma: A malignant tumor consisting of fibroblasts (connective tissue cells that produce the collagen found in scar tissue) that may occur as a mass in the soft tissues or may be found in bone.

Giant cell tumor of bone - malignant: A relatively uncommon tumor of bone characterized by the presence of multinucleated giant cells (osteoclast-like cells). Malignancy in giant-cell tumor is uncommon and occurs in about 2% of all cases. However, if malignant degeneration does occur, it is likely to metastasize to the lungs. It often arises in sites of previously treated benign giant cell tumors that were treated with radiation therapy.

Hemangioendothelioma: A rare type of vascular tumor that affects the epithelial cells which line the inside of blood vessels. Epithelioid hemangioendothelioma tumors most commonly affect the soft tissues, liver, lungs, and bones.

Leiomyosarcoma: A type of soft tissue sarcoma that develops in muscle, fat, blood vessels, or any of the other tissues that support, surround, and protect the organs of the body. Leiomyosarcoma is one of the more common types of soft tissue sarcoma to develop in adults.

Malignant fibrous histiocytoma: Most often more recently classified as pleomorphic undifferentiated sarcoma, malignant fibrous histiocytoma (MFH) also can be listed as plasmosphic sarcoma not otherwise specified (PS-NOS). It also was often formerly known as a type of fibrosarcoma. It is historically considered the most common type of soft tissue sarcoma. It has an aggressive biological behavior and a poor prognosis, and primarily affects the extremities.

Neoplasm - malignant: The term "malignant neoplasm" means that a tumor is cancerous. When diagnosed it may mean further testing is needed to identify the specific type of cancer or sarcoma.

Osteosarcoma: The most common type of cancer that starts in the bones. The cancer cells in these tumors look like early forms of bone cells that normally help make new bone tissue, but the bone tissue in an osteosarcoma is not as strong as that of normal bones. Therefore, affected bones are subject to pathologic fracture (fractures caused by bone weakened due to underlying disease). Without proper treatment, osteosarcome is fatal.

Primitive peripheral neuroectodermal tumor: Primitive neuroectodermal tumors (PNETs) are a group of highly malignant tumors composed of small round cells of neuroectodermal origin that affect soft tissue and bone. PNETs exhibit great diversity in their clinical manifestations and pathologic similarities with other small round cell tumors. Peripheral primitive neuroectodermal tumors (pPNETs) are tumors derived from tissues outside the central and autonomic nervous system.

Sarcoma (NOS): A usually aggressive malignant mesenchymal cell tumor most commonly arising from muscle, fat, fibrous tissue, bone, cartilage, and/or blood vessels that is not otherwise specified (NOS).

• 1. Ward WG, Corey RM, Swett K. Does Histologic Diagnosis Really Determine Prognosis – An NCDB Analysis of Osteosarcoma, Chondrosarcoma and Ewing Sarcoma. Paper presented at the North America Musculoskeletal Tumor Society Annual Meeting, San Francisco, CA, October 5, 2013. Manuscript under preparation.