Bone sarcomas are extremely rare and account for only 0.2% of all cancers in the United States. Approximately 3,000 people are diagnosed each year.
Endorsed and supported in part by SARC and the NCCN Foundation, the National Comprehensive Cancer Network® recently published NCCN Guidelines for Patients® Bone Cancer.
Below are some specific types of bone sarcomas:
This is a very rare tumor of cells that are associated with bone formation in a process that may be similar to the cells responsible for forming teeth. The latter cells can form cancers of the lower jaw more than the upper jaw, termed ameloblastoma. Adamantinoma nearly always affects the tibia, and is treated with surgery. Rare cases can travel elsewhere in the body, at which point chemotherapy is used to increase survival rates.
Chordoma is a tumor that appears very similar to the fetal cells that form the new spine, the notochord. The relationship to development of the bone while the fetus is growing in the uterus is hard to understand, since tumors of this sort typically only arise in people over 50. It typically occurs at the base of the skull, or in the sacrum (the very base of the spine in the pelvis), where surgical removal is often not possible. This is one tumor that can respond to radiation designed to cure even tumors that are not surgically removable, and is a tumor for which treatment with proton-beam radiation may be better than other forms of radiation therapy. Though there are no approved drugs to treat chordoma, some drugs approved for other cancers can be used for people with recurrences of their chordoma.
Conventional chondrosarcoma can be a difficult tumor to treat. It often arises in older patients, and often in the pelvis. As a result, people with multiple medical diagnoses are put in the position of requiring a very large operation with a high risk of post-operative complications, with subsequent loss of function. For chondrosarcomas that arise in other sites, surgery can be less risky and represents the standard of care. There is often a significant risk of tumor recurrence where it started.
People with metastatic disease often do not respond well to chemotherapy. Grade 1 chondrosarcomas almost never metastasize and are now called “atypical cartilaginous tumor”, Grade 2 chondrosarcomas have only a 10-15% risk of metastasis, and grade 3 chondrosarcomas have a two-thirds or higher risk of metastasis. As a result, some people with grade 3 chondrosarcomas are treated with adjuvant chemotherapy. A version of chondrosarcoma called clear-cell chondrosarcoma has an intermediate risk of metastasis, but treatment is typically surgery alone.
This more aggressive version of chondrosarcoma typically occurs in adolescence and in people over age 60. It shows features of both chondrosarcoma and a less differentiated tumor, such as UPS (undifferentiated pleomorphic sarcoma), which does not show even a hint of relatedness to the chondrosarcoma. This version of chondrosarcoma has a high risk of recurrence, even greater than that of grade 3 conventional chondrosarcoma (described above).
This rare bone tumor shows a mixture of aggressive small round blue cells mixed with more typical lower-grade chondrosarcoma. It usually affects people between 15 and 30, and has a high risk of recurrence. The benefit of chemotherapy is not known, though chemotherapy is often used. The typical chemotherapy drugs that are used in the adjuvant setting (or metastatic setting, for that matter) are the drugs used for Ewing sarcoma and similar sarcomas.
Conventional Osteogenic Sarcoma
Osteogenic sarcoma (also called osteosarcoma) is the most common tumor of bone. Approximately 1,000 cases of osteogenic sarcoma are seen in the United States each year. A second peak of incidence of osteosarcoma occurs in the eighth decade of life, typically associated with Paget bone disease. Osteosarcoma typically affects adolescents and generally occurs in bones around the knee joint, though any bone of the body can be affected. Treatment typically involves chemotherapy and surgery to try to achieve the best cure rate. Standard drugs include doxorubicin and cisplatin in adults and the same two drugs with high-dose methotrexate in children, adolescents, or young adults.
Recurrences typically occur in the lungs. Surgical removal of lung metastases from a primary osteosarcoma is a standard of care when there is a small number of lung nodules that can be removed safely, and can be associated with a 30-35% cure rate. Osteosarcomas occur commonly in familial syndromes associated with sarcoma, such as Li-Fraumeni syndrome (involving a mutation in the p53 gene), retinoblastoma (involving a mutation in the Rb gene), and Rothmund-Thomson syndrome.
Parosteal Osteogenic Sarcoma
Parosteal osteosarcoma is a low-grade osteosarcoma of bone that grows from the surface of the bone without lifting off the surface connective tissue of bone (periosteum). It occurs by far most often along the posterior, distal femur in the third decade of life. Treatment for this rare form of osteosarcoma is usually surgery alone, although if there are aggressive features such as dedifferentiation or if a high-grade component is seen, chemotherapy is added to treatment.
This is the third-most-common sarcoma of bone and second most common in children. The same tumor occurs in the soft tissue of adults more than it occurs in bone. There are fewer than 600 cases a year in the United States. Without chemotherapy, the cure rate is at best 10%, but with chemotherapy, a cure rate of up to 75% in children and 50-60% in adults is seen. Surgery and radiation are also commonly used as treatment for the primary tumor to achieve the highest possible cure rate. Ewing sarcomas can appear in any site of the body. When they recur, it is most commonly in the lungs and bones.
Giant-Cell Tumor (GCT) of Bone
Giant-cell tumor of bone typically occurs between ages 20 and 40, and has a unique appearance under the microscope. It typically occurs in the knee or lower spine. It is treated by scraping out the tumor and treating the tumor cavity with cement (which heats up and destroys tumor tissue) or with liquid nitrogen (freezing and thawing the tumor in place, often killing remaining cells). A bone graft is often used to try to reconstruct the area. In some cases, the tumor can be removed as one piece without damaging other tissues, and in these cases a bone graft may be performed as well. Conventional giant-cell tumors have a risk of recurrence where they start and have a low but real possibility of metastasis to the lungs. Giant-cell tumors must be differentiated from aneurysmal bone cysts. For giant-cell tumors of bone that have recurred, the new agent denosumab can delay further recurrence, though it is not believed to be curative by itself.
Sarcomas of Bone That Arise More Commonly in Soft Tissue
These are other sarcomas that typically occur in soft tissue in adults and can also occur in bone. They include undifferentiated pleomorphic sarcoma (UPS), fibrosarcoma, leiomyosarcoma, and angiosarcoma, among others. Please see the similar section under Soft Tissue Sarcomas for details. While leiomyosarcoma of bone is typically treated with surgery alone, many physicians treat UPS of bone like other osteogenic sarcomas, using chemotherapy and surgery as the main treatments.