Sarcoma

A sarcoma (from the Greek 'sarx' meaning "flesh") is a general term describing a malignant neoplasm, or cancer, that arises from transformed connective tissue cells,^[1] such as bone, cartilage, and fat cells, which originate from embryonic mesoderm.^[2]

This is in contrast to carcinomas, which are of epithelial origin (breast, colon, pancreas, and others). However, due to an evolving understanding of tissue origin, the term "sarcoma" is sometimes applied to tumors now known to arise from epithelial tissue.^[3] The term soft tissue sarcoma is used to describe tumors of soft tissue,^[4] which includes elements that are in connective tissue, but not derived from it (such as muscles and blood vessels).

Classification

Tissue

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.

Grade

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.^[5] 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%.^[6]

Types

(ICD-O codes are provided where available.)

• Askin's Tumor (8803/3)
• Botryodies
• Chondrosarcoma (9220/3-9240/3)
• Ewing's (9260/3) - PNET (9473/3)
• Malignant Hemangioendothelioma (9130/3)
• Malignant Schwannoma (9560/3-9561/3)
• Osteosarcoma (9180/3-9190/3)
• Soft tissue sarcomas, including:
  • Alveolar soft part sarcoma (9581/3)
  • Angiosarcoma (9120/3)
  • Cystosarcoma Phyllodes
  • Dermatofibrosarcoma (8832/3-8833/3)
  • Desmoid Tumor (8821/1-8822/1)
  • Desmoplastic small round cell tumor (8806/3)
  • Epithelioid Sarcoma (8804/3)
  • Extraskeletal chondrosarcoma (9220/3)
  • Extraskeletal osteosarcoma (9180/3)
  • Fibrosarcoma (8810/3)
  • Hemangiopericytoma (9150)
  • Hemangiosarcoma (9120/3)
  • Kaposi's sarcoma (9140/3) --> Note that Kaposi's sarcoma is not a true sarcoma as it derives from epithelial cells
  • Leiomyosarcoma (8890/3-8896/3)
  • Liposarcoma (8850/3-8858/3)
  • Lymphangiosarcoma (9170-9175)
  • Lymphosarcoma
  • Malignant fibrous histiocytoma (8830/3)
  • Neurofibrosarcoma (9540/3)
  • Rhabdomyosarcoma (8900-8920)
  • Synovial sarcoma (9040/3-9043/3)

Treatment

• Liposarcoma treatment consists of surgical resection, with chemotherapy not being used outside of the experimental setting. Adjuvant radiotherapy may also be used after surgical excision for liposarcoma.^[7]
• Rhabdomyosarcoma is treated with surgery, radiotherapy, and/or chemotherapy.^[8] Five-year survival is 50% for most rhabdomyosarcoma patients.^[9]
• Osteosarcoma is treated with surgical resection of as much of the cancer as possible, often along with neoadjuvant chemotherapy.^[10]

Epidemiology

Sarcomas are rare, with only 15,000 new cases per year in the United States.^[11] Sarcomas therefore represent about one percent of the 1.5 million new cancer diagnoses in that country each year,^[12] 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.^[13]

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.^[14] 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.

References

External links

• Sarcoma at the Open Directory Project