Biological effect of neoadjuvant androgen-deprivation therapy assessed on specimens from radical prostatectomy: a systematic review.

INTRODUCTION: Androgen-deprivation therapy (ADT) administered in neoadjuvant setting before radical prostatectomy (RP) represents an ideal in vivo human model to test the efficacy of hormonal treatments in prostate cancer (PCa). This review summarizes the findings from published studies specifically focused on the biological effects of ADT assessed on specimens from RP. The aim is to provide a base of knowledge that might be used to design future studies on neoadjuvant therapy for PCa.

EVIDENCE ACQUISITION: A systematic review of the literature was performed according to the PRISMA statements. Search protocol identified published studies including a detailed analysis on specimen from RP to assess the biological effects of neoadjuvant ADT. In November 2017, Medline, Embase, and Scopus databases were searched using the terms "neoadjuvant" AND ("hormone therapy" OR "androgen deprivation therapy") AND "prostate cancer" in the "Title/Abstract" fields. Effects of ADT were classified according to four pathways - suppression of cellular proliferation, induction of apoptosis, alteration of immune response and onset of hormonal refractoriness - and relative markers of response were identified.

EVIDENCE SYNTHESIS: From 1856 papers initially retrieved, 19 studies were finally selected and included into the present review. ADT was constituted by luteinizing hormone-releasing hormone (LH-RH) agonist alone in two, peripheral anti-androgen alone in one, both in 10, abiraterone acetate in one, unspecified in five. According to the above-mentioned four pathways, the following markers of response were identified: transcription of the oncogene TMPRSS2:ERG, translation of Aurora-A, coding of β1C integrin gene, translation of Ki-67, expression of nerve growth factors TrkA and p75NGFR, anti-angiogenic activity and micro-vessel density were involved into suppression of proliferation; mRNA transcription of bcl-2, expression of cleaved caspase-3 and translation of insulin growth factor binding protein 3, into induction of apoptosis; expression of IL-7 gene, programmed death-ligand 1, and increase of intra-prostatic T-cell population were related to alteration of immune response; finally, expression of heat shock protein 27 and de-differentiation of PCa to neuroendocrine cells, influenced the onset of hormonal refractoriness.

CONCLUSIONS: Despite a potential high interest, unexpectedly, only 19 heterogeneous studies investigated the effects of ADT through the analysis of specimens from RP. The present review summarizes the available evidences on this topic showing that ADT interferes on PCa at different levels that can be investigated by specific biological markers.