Histopathological changes induced by therapies in the benign prostate and prostate adenocarcinoma.

The effect of androgen deprivation and other hormonal therapies, radiation therapy, thermal ablation therapies, chemotherapy, and other systemic treatments is evident in the histology of non-neoplastic and neoplastic human prostate gland. Androgen deprivation may be achieved with: a. orchidectomy, b. exogenous oestrogen administration, c. drugs with the capacity to deplete the hypothalamus of luteinizing hormone-releasing hormone, d. antiandrogens administration: drugs, which block the conversion of testosterone to its active form of 5-alpha dihydrotestosterone (i.e. finasteride, dutasteride), and drugs which block the androgen receptor on individual cells (i.e. flutamide). Androgen deprivation therapies cause atrophy of non-neoplastic and neoplastic prostatic epithelium, as the result of apoptosis, and are mainly used as a palliative measure in metastatic prostate cancer or as neoadjuvant or adjuvant treatment, in clinically localized prostate cancer. Morphological tumour regression may complicate the recognition and grading of treated carcinomas in radical prostatectomy specimens. Radiation therapy may be applied in the form of external beam, interstitial implantation (brachytherapy), or a combination, as a mainstay or adjuvant (external beam) treatment in localized prostate cancer. The primary effect is the damage of endothelial cells, which cause ischemia that leads to atrophy. The difficulty of post-radiation prostate needle biopsy interpretation includes the distinction of treatment effect in normal prostatic tissue from recurrent or residual tumour. Histological changes after thermal ablation mainly include lesions observed in prostatic infarcts due to periurethral coagulative type necrosis of variable volume. The correlation between the histopathological effects of the above therapies and their clinical significance is not absolutely clear.