Sarcoma

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 connective tissue cells.[1] These cells originate from embryonic mesoderm, or middle layer,[2] which forms the bone, cartilage, and fat tissues.

This is in contrast to carcinomas, which originate in the epithelium. The epithelium lines the surface of structures throughout the body, and is the origin of cancers in the breast, colon, pancreas.

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).

Contents

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.)

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

  1. ^ sarcoma at Dorland's Medical Dictionary.
  2. ^ MeSH Sarcoma
  3. ^ Bukawa H, Kawabata A, Murano A, et al. (August 2007). "Monophasic epithelial synovial sarcoma arising in the temporomandibular joint". Int J Oral Maxillofac Surg 36 (8): 762–5. doi:10.1016/j.ijom.2007.02.014. PMID 17433623. http://linkinghub.elsevier.com/retrieve/pii/S0901-5027(07)00105-1. 
  4. ^ "Soft Tissue Sarcoma Home Page - National Cancer Institute". http://www.cancer.gov/cancertopics/types/soft-tissue-sarcoma/. 
  5. ^ Buecker, P (2005). "Sarcoma: A Diagnosis of Patience". ESUN 2 (5). http://sarcomahelp.org/learning_center/patience.html. Retrieved 2009-04-15. 
  6. ^ Longhi A, Errani C, De Paolis M, Mercuri M, Bacci G (Oct 2006). "Primary bone osteosarcoma in the pediatric age: state of the art". Cancer Treat Rev. 32 (6): 423–36. doi:10.1016/j.ctrv.2006.05.005. PMID 16860938. 
  7. ^ http://emedicine.medscape.com/article/1102007-treatment
  8. ^ http://www.childrenshospital.org/az/Site1068/mainpageS1068P0.html
  9. ^ http://www.acor.org/ped-onc/diseases/rhabdo.html
  10. ^ http://emedicine.medscape.com/article/1256857-treatment
  11. ^ Borden EC, Baker LH, Bell RS, et al. (Jun 2003). "Soft tissue sarcomas of adults: state of the translational science". Clin Cancer Res. 9 (6): 1941–56. PMID 12796356. http://clincancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=12796356. 
  12. ^ http://www.cancer.org/docroot/STT/content/STT_1x_Cancer_Facts__Figures_2009.asp?from=fast
  13. ^ Tran T, Davila JA, El-Serag HB (Jan 2005). "The epidemiology of malignant gastrointestinal stromal tumors: an analysis of 1,458 cases from 1992 to 2000". Am J Gastroenterol 100 (1): 162–8. doi:10.1111/j.1572-0241.2005.40709.x. PMID 15654796. 
  14. ^ Darling, J (2007). "A Different View of Sarcoma Statistics". ESUN 4 (6). http://sarcomahelp.org/sarcoma_statistics.html. Retrieved 2009-04-15. 

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http://en.wikipedia.org/w/index.php?title=Sarcoma

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