Postradiation prostatic sarcoma: de novo carcinogenesis or dedifferentiation of prostatic adenocarcinoma?

Postradiation sarcoma (PRS) of the prostate is rare. We describe the second case associated with brachytherapy for adenocarcinoma and review the literature on prior cases of PRS as well as carcinosarcoma, a dedifferentiated form ofadenocarcinoma that may be confused with true prostate sarcoma. It is clear that radiation to the prostate confers a significantly increased risk for subsequent sarcoma, although not within the prostate. Because many of the reported cases of PRS were admixed with adenocarcinoma and had relatively short latency periods, we conclude that these cases of PRS ofthe prostate are, in fact, carcinosarcoma. Therefore, with only one case reported following therapeutic irradiation, PRS of the prostate is extremely rare.