Systemic treatment options for radiation-associated sarcomas.

Sarcomas are rare malignant tumors that develop from mesenchymal tissue. Most sarcomas are idiopathic, however, a significant minority develops as a consequence of prior radiation exposure. Although the absolute risk of developing a radiation-associated sarcoma is small, these tumors represent significant clinical challenges. For recurrent, unresectable or metastatic disease, the standard treatment is systemic chemotherapy. Radiation-associated sarcomas tend to be undifferentiated sarcomas, angiosarcomas, or leiomyosarcomas, which are variably sensitive to chemotherapy. The best general approach is to treat each radiation-associated sarcoma as one would its sporadic histologic counterpart. There are limited data to guide the best treatment for radiation-associated sarcoma, therefore, the standard chemotherapy options are reasonable choices. These include doxorubicin, ifosfamide, gemcitabine, docetaxel, and pazopanib. Patients with radiation-associated sarcomas may have received prior anthracyclines to treat antecedent malignancies such as breast cancer or lymphoma. Thus, if additional doxorubicin cannot be used, liposomal doxorubicin is a reasonable substitute. More prospective research is needed on how radiation-associated sarcomas respond to systemic therapy. Future clinical trials of new agents in sarcoma should identify and include patients with radiation-associated sarcoma.