sarcoma

[sahr-koh-muh]

sarcoma, highly malignant tumor arising in connective- and muscle-cell tissue. It is the result of oncogenes (the cancer causing genes of some viruses) and proto-oncogenes (cancer causing genes in human cells). It may affect bone, cartilage, blood vessels, lymph nodes, and skin. See cancer; neoplasm.

The Columbia Electronic Encyclopedia Copyright © 2004.
Licensed from Columbia University Press

Sarcoma

A sarcoma (from the Greek 'sarx' meaning "flesh") is a cancer of the connective or supportive tissue (bone, cartilage, fat, muscle, blood vessels) and soft tissue. This is in contrast to carcinomas, which are of epithelial origin (breast, colon, pancreas, and others).

Classification

Sarcomas are given a number of different names, based on the type of tissue from which they arise. For example, osteosarcoma arises from bone, chondrosarcoma arises from cartilage, and leiomyosarcoma arises from smooth muscle. Sarcomas strike people in all age ranges, but they are very rare, accounting for only 1% of all cases of cancer. Soft tissue sarcomas, such as leiomyosarcoma, chondrosarcoma, and gastrointestinal stromal tumor (GIST), are more common in adults than in children. GIST is the most common form of sarcoma, with approximately 3000-3500 cases per year in the United States. This should be compared with breast cancer, with approximately 200,000 cases per year in North America. Bone sarcomas, such as osteosarcoma and Ewing's sarcoma, are more common in children than in adults. These tumors most commonly strike adolescents and young adults between the ages of 12 and 25. In addition to being named based on the tissue of origin, sarcomas are also assigned a grade, such as low grade or high grade. Low grade sarcomas are usually treated surgically, although sometimes radiation therapy or chemotherapy are used. High grade sarcomas are more frequently treated with chemotherapy. Since these tumors are more likely to undergo metastasis (spreading to distant sites), these tumors are treated more aggressively. Childhood sarcomas are almost always treated with a combination of surgery and chemotherapy, and radiation is frequently used as well. The recognition that childhood sarcomas are sensitive to chemotherapy has dramatically improved the survival of patients. For example, in the era before chemotherapy, long term survival for patients with localized osteosarcoma was only approximately 20%, but now has risen to 60-70%.