Osteosarcoma after radiotherapy for prostate cancer.

Postradiation sarcomas are long-term complications of radiation treatment of various forms of cancer. Osteosarcoma, specifically, occurring in patients with a history of prostate cancer is rare; but with high-dose radiotherapy now an accepted standard of care for localized prostate adenocarcinoma, it should be considered in the clinical setting of patients presenting with potential remote disease relapse. We describe an osteosarcoma of the pubic ramus in a patient previously treated 10 years prior with radiation therapy for prostate cancer. Because of the long latency period, the appearance of lytic bone lesions with soft tissue components in pelvic bony structures may mimic recurrent/metastatic prostate adenocarcinoma. The prognosis of patients developing osteosarcoma after radiotherapy for prostate cancer is similar to other radiation-induced osteosarcomas occurring in the axial skeleton, with a 50% overall mortality within the first year after diagnosis.