[Incidence of malignant soft tissue tumors (sarcomas) after previous radiotherapy].

The causal agent for sarcomas is mostly unknown. Unlike solid epithelial carcinomas, the correlation to the exposition to carcinogenic agents is unknown. Besides hereditary neurofibromatosis ("Recklinghausen"), radiation therapy has been reported to induce malignant tumors. In this retrospective study during the last 10 years we observed that in 7 of 356 (approximately 2%) patients treated for sarcomas in our Department of Surgery, the sarcoma was located in the area where radiation therapy had been given earlier for another primary malignant tumor. The interval between this radiation therapy and the diagnosis of sarcoma was 9 to 30 years, corroborated by findings in the literature based on approximately 100 radiation-induced tumors. The median survival time after diagnosis of sarcoma was 3 years. Because radiation therapy is often used in the treatment of malignant tumors this late complication is a clinically relevant problem in long-time survival.