Radiation-induced sarcoma after radiation therapy for prostate adenocarcinoma

Radiation therapy is widely used for prostate cancer, but radiation-induced sarcomas have been rarely reported.

A 77-year-old Japanese male was diagnosed with prostate cancer and received a combined androgen blockade and radiation therapy (total dose of 76 Gy). Five years after the radiation therapy, testicular pain and dysuria appeared. Computed tomography showed a soft tissue dense mass with invasion to the right subpubic ramus and prostate, mainly to the perineum. A needle biopsy revealed the pathological features of high-grade sarcoma. The patient was diagnosed with radiation-induced sarcoma based on the cancer's occurrence in the vicinity of the radiation field.

Although irradiation is one of the important treatments for prostate cancer, the risk of radiation-induced malignancy should be considered.