Effects of radiation on the normal prostate gland.

Prostate cancer is one of the commonest tumours of adult males. It shows a range of biological behaviour: many tumours are discovered incidentally; others will kill by producing widespread metastatic disease. Despite the fact that radiation is frequently used in the treatment of a range of pelvic lesions, including adenocarcinoma of the prostate itself, studies on the morphological changes in the normal prostate gland after irradiation are limited. This seems particularly surprising following the increasing use of needle biopsy specimens to assess the prostate. Patients who receive pelvic irradiation often suffer from lower urinary tract symptoms such as frequency and dysuria and it is possible that these may be related to prostatic and/or periprostatic injury. We therefore investigated the prostate glands removed at cystoprostatectomy for transitional cell carcinomas of the bladder which had received radiotherapy pre-operatively. The changes were compared to control prostatic tissue from transurethral resection specimens for benign myoadenomatous hyperplasia. We found a range of inflammatory, fibrotic and reactive cytological features, including many of the changes seen in benign hyperplasia, but these were significantly more exaggerated in the post-radiation group. In addition intraprostatic vascular and neural changes were prominent. This study documents radiation-induced changes throughout the normal prostate gland and neighbouring soft tissue and has particular importance in current pathological practice with the increasing and widespread use of needle biopsies in the diagnosis and follow-up of prostate cancer.