Causes of Sarcoma

“What we know about the causes of sarcoma”

By Logan G. Spector, Ph.D. Department of Pediatrics – University of Minnesota

Sarcomas are cancers of connective tissues like muscle, bone, and fat. Many different types of sarcoma exist, which are generally either bone or soft tissue sarcomas. All sarcomas are rare, regardless of the type. For instance, the incidence of all soft tissue sarcomas combined is 5 cases per 100,000 people per year(1). Unlike most other types of cancer, an appreciable fraction of sarcomas occur in children 0-19 years of age(2-4). Most osteosarcomas, Ewing’s sarcomas, and rhabdomyosarcomas occur in children, in fact, while tumors like leiomyosarcomas occur mainly among adults. The occurrence of sarcomas also varies according to sex and race, as well as by age.

Very little is known about what causes sarcomas, primarily because they are so rare. It is difficult to assemble enough cases into a study of useful size and often diverse types of sarcoma, which may have different causes, have to be lumped together. The rarity of sarcoma also means that most investigations use a retrospective study design, asking about exposures in the past, which is not always a reliable method.

As with most other types of cancer, inherited genetic predisposition is known to cause some sarcomas(5). For instance, osteosarcomas and soft-tissue sarcomas occur much more frequently among people with Li-Fraumeni syndrome, which involves inherited gene mutations. However, sarcomas associated with familial syndromes are a small portion of the total.

A few environmental causes are known for particular types of sarcoma. In particular, human herpesvirus 8 (HHV-8) is an established risk factor for Kaposi’s sarcoma, especially in the presence of a suppressed immune system such as occurs in the Acquired Immunodeficiency Syndrome (AIDS)(6). High doses of radiation also cause sarcomas (and many other types of cancer), although this kind of exposure is so rare that few cancers are attributable to it (7, 8). Chemotherapy for childhood cancer, in addition to high-dose therapeutic radiation, can also increase the risk of sarcoma(9, 10). Apart from the factors mentioned above there are no other established risk factors, although many have been investigated(11).

Risk Factor Summary – Bone Sarcomas

Osteosarcoma

Known risk factorsFactors for which evidence is suggestive but not conclusiveFactors for which evidence is limited or inconsistent
Male sexHeightDrinking water fluoridation
Li-Fraumeni syndromeAge at pubertyBroken bones
Hereditary retinoblastomaViruses
Rothmund-Thomson syndrome
Werner syndrome
Bloom syndrome
Paget’s disease (in adults)
High-dose radiation
Chemotherapy

Ewing's Sarcoma

Known risk factorsFactors for which evidence is suggestive but not conclusiveFactors for which evidence is limited or inconsistent
Caucasian racePrior herniaDrinking water fluoridation
Male sexFarm residenceViruses

Risk Factor Summary - Soft Tissue Sarcomas

Known risk factorsFactors for which evidence is suggestive but not conclusiveFactors for which evidence is limited or inconsistent
Li-Fraumeni syndromeDioxinTobacco use
Werner syndromeVinyl chloride (angiosarcoma only)Marijuana use
Bloom syndromeObesityViruses
High-dose radiation
Chemotherapy
HHV-8 (Kaposi’s sarcoma only)

References

1. Toro JR, Travis LB, Wu HJ, et al. Incidence patterns of soft tissue sarcomas, regardless of primary site, in the surveillance, epidemiology and end results program, 1978-2001: An analysis of 26,758 cases. Int J Cancer 2006;119:2922-30.

2. Bleyer A, O’Leary M, Barr R, et al. eds. Cancer Epidemiology in Older Adolescents and Young Adults 15 to 29 Years of Age, Including SEER Incidence and Survival: 1975-2000. Bethesda, MD: National Cancer Institute, 2006.

3. Ries LA, Smith MA, Gurney JG, et al. Cancer Incidence and Survival among Children and Adolescents: United States SEER Program 1975-1995. Bethesda, MD: National Cancer Institute, SEER Program, 1999no. 99-4649).

4. Wu XC, Chen VW, Steele B, et al. Cancer incidence in adolescents and young adults in the United States, 1992-1997. J Adolesc Health 2003;32:405-15.

5. Hecht F. Familial cancer syndromes: catalog with comments. Cytogenet Genome Res 2007;118:222-8.

6. Iscovich J, Boffetta P, Franceschi S, et al. Classic kaposi sarcoma: epidemiology and risk factors. Cancer 2000;88:500-17.

7. Fry SA. Studies of U.S. radium dial workers: an epidemiological classic. Radiat Res 1998;150:S21-9.

8. Ron E. Cancer risks from medical radiation. Health Phys 2003;85:47-59.

9. Hawkins MM, Wilson LM, Burton HS, et al. Radiotherapy, alkylating agents, and risk of bone cancer after childhood cancer. J Natl Cancer Inst 1996;88:270-8.

10. Jenkinson HC, Winter DL, Marsden HB, et al. A study of soft tissue sarcomas after childhood cancer in Britain. Br J Cancer 2007;97:695-9.

11. Schottenfeld D, Fraumeni JF eds. Cancer Epidemiology and Prevention. New York: Oxford University Press, 2006.