Morphology of treatment-related changes in the prostate and prostatic cancer

Nonsurgical therapeutic options for prostatic diseases are divided into androgen action-related, with androgen action inhibition (AAI), or androgen action-unrelated strategies, such as radiotherapy (RT). AAI, achieved by numerous medications with antiandrogen activity, is used for prostatic hyperplasia and carcinoma. Treatment mostly affects secretory epithelial cells, with consequent reduction in prostate volume and diminished amount of cancer. Histologically, AAI changes the morphologic appearance of benign prostatic glands, prostatic intraepithelial neoplasia, and cancer, as well as prostatic stroma. The effects of most AAI drugs are similar, although variable in intensity. Expression of some diagnostic immunohistochemical markers can decline after longtime treatment, requiring careful interpretation of staining results. Patterns of tissue injury after RT for prostate cancer differ from those after AAI. While irradiation has a profound effect on benign prostatic glands, it does not affect immunohistochemistry, which retains its diagnostic value. In order to make a reliable diagnosis in needle biopsies of treated prostate cancer, uropathologists should have all the relevant information on treatment modalities and their duration. As treatment affects the morphology of prostate cancer, Gleason grading is unreliable and therefore not recommended. An overview of treatment effects caused by AAI and RT is herein presented, with discussion on their importance in everyday practice.