An updated review of the epidemiology of soft tissue sarcoma.

17 Incidence Soft tisssue sarcoma (SST) represents a heterogenous group of tumor diseases orginating from connective tissue accounting for less than 1 % of all malignant tumors in Sweden. With increasing age there is an increase in incidence (National Board of Health). Comprehensive reviews of the epidemiology of soft tissue sarcoma have previously been published (Tucker et al. 1982, Zahm and Fraumeni 1997 and Olsson 1999). The heterogenity of sarcoma types and the rarity of cases have hampered etiologically oriented studies. When excluding Kaposi sarcoma the incidence of other soft tissue sarcomas have not dramatically increased in developed western countries. Becasue of the inherent difficulty in classifying SST inter national variations and geographic patterns have not been evaluated in a meaningful way. Risk factors of SST are thus only partly known. Risk factors include a family history of cancer/ soft tissue sarcoma, certain genetic syndromes, exposure to ionizing irradiation, and exposure to certain chemicals such as vinyl chloride. Other factors associated with SST development include longstanding lymphedema, exposure to Thorotrast, arsenical pesticides and medications, herbicides, immunosuppressive drugs, alkylating agents, androgen-anabolic steroids, human immunodefi ciency virus, and exposure to human herpes virus type 8 (Zahm and Fraumeni 1997 and Olsson 1999). Further a tissue trauma has been discussed as a possible risk factor. Studies from our own group has suggested that oral contraceptive use is partly protective for STS in women (Olsson et al.