| Sarcoma | |
|---|---|
| Classification and external resources | |
| ICD-O: | M8800/3 |
| MeSH | D012509 |
A sarcoma (from the Greek sarx meaning "flesh") is a cancer that arises from transformed cells in one of a number of tissues that develop from embryonic mesoderm.[1] Thus, sarcomas include tumors of bone, cartilage, fat, muscle, vascular, and hematopoietic tissues. (This is in contrast to carcinomas, which originate from epithelial cells and thus give rise to more common malignancies, such as breast, colon, and lung cancer.)
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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, liposarcoma arises from fat, and leiomyosarcoma arises from smooth muscle.
In addition to being named based on the tissue of origin, sarcomas are also assigned a grade (low, intermediate, or high) based on the presence and frequency of certain cellular and subcellular characteristics associated with malignant biological behavior. Low grade sarcomas are usually treated surgically, although sometimes radiation therapy or chemotherapy are used. Intermediate and high grade sarcomas are more frequently treated with a combination of surgery, chemotherapy and/or radiation therapy.[2] Since higher grade tumors are more likely to undergo metastasis (invasion and spread to locoregional and distant sites), they are treated more aggressively. The recognition that many 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%.[3]
(ICD-O codes are provided where available.)
Surgery is important in the treatment of most sarcomas.[4] Limb sparing surgery, as opposed to amputation, can now be used to save the limbs of patients in at least 90% of extremity tumor cases.[5] Additional treatments, including chemotherapy and radiation therapy, may be administered before and/or after surgery.[6] Chemotherapy significantly improves the prognosis for many sarcoma patients, especially those with bone sarcomas.[7] Treatment can be a long and arduous process, lasting about a year for many patients, but the process is necessary in order to cure the disease.[8]
Sarcomas are quite rare with only 15,000 new cases per year in the United States.[13] Sarcomas therefore represent about one percent of the 1.5 million new cancer diagnoses in that country each year,[14] and are well below the US's orphan disease threshold of 200,000 cases per year.
Gastrointestinal stromal tumor (GIST) is the most common form of sarcoma, with approximately 3,000-3,500 cases per year in the United States.[15]
Sarcomas affect people of all ages. Approximately 50% of bone sarcomas and 20% of soft tissue sarcomas are diagnosed in people under the age of 35.[16] Some sarcomas, such as leiomyosarcoma, chondrosarcoma, and gastrointestinal stromal tumor (GIST), are more common in adults than in children. Most high-grade bone sarcomas, including Ewing's sarcoma and osteosarcoma, are much more common in children and young adults.
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