Not all sarcomas developed in irradiated tissue are necessarily radiation-induced – Spectrum of disease and treatment characteristics

BackgroundSarcomas in irradiated tissue (SITs) are often considered with second cancers, although they usually present distinct dose–response, genetic and clinical patterns. The contribution of radiation in SIT development is likely, but remains unproven in many cases.Materials and methodsWe reviewed the literature for published data on SITs.ResultsSITs incidence ranged between 0.03% and 0.2%. Median latency was 15 years. Angiosarcoma was the second most common subtype after undifferentiated sarcomas of malignant fibrous histiocytoma (MFH). C-Myc overexpression can be used to identify radiation-induced angiosarcoma, and a recently described transcriptomic signature of genes involved in chronic oxidative stress and mitochondrial dysfunction may indicate radiation causality. Osteosarcomas were often associated with genetic predisposition. Five-year survival rates rarely exceeded 30% because the therapeutic possibilities were often limited by the first cancer. Chemotherapy response may differ from that of de novo sarcomas.ConclusionSITs present different characteristics from non-sarcomatoid second cancers. Reporting of SIT cases and the establishment of tissue and serum banks is necessary to better understand and validate the recently discovered radiation signature.