Impact of age on the biochemical failure and androgen suppression after radical prostatectomy for prostate cancer in chilean men

Aim: The aim of this study was to determine the association of age with the clinicopathological findings, phenotypic expression of circulating prostate cells (CPCs) and micrometastasis, biochemical failure and effect of androgen blockade after radical prostatectomy for prostate cancer in Chilean men. Methods: This is a prospective, observational, single-center study of Chilean men who underwent radical prostatectomy. Three months after surgery, the peripheral blood was collected to analyze the biochemical failure by measuring prostate-specific antigen (PSA) levels in the serum. The blood and bone marrow were collected to detect the presence of CPCs and the bone marrow micrometastasis by checking the expression of PSA, human epidermal growth factor receptor 2 (HER-2), and matrix metalloproteinase 2 (MMP-2) using standard immunocytochemistry. The clinicopathological findings, phenotypic expression of CPCs and micrometastasis, biochemical failure and effect of androgen blockade were analyzed for association with age. Results: In total, 120/338 (36.6%) of patients were ≥ 70 years (older men). A higher frequency of biochemical failure occurred in older men with negative surgical margins, a Gleason score ≥ 8, and pT3 tumors compared to patients < 70 years of age (younger men). The expression of HER-2 and MMP-2 was higher in CPCs and micrometastasis in older men. After androgen blockade, the expression of HER-2 and MMP-2 was similar in both groups. With androgen blockade, more younger men became micrometastasis negative (49% vs. 15%) while more older men became castrate resistant (83% vs. 43%). Conclusion: After radical prostatectomy, the older men with pathological features of Gleason score ≥ 8, pT3 tumors, and positive extracapsular extension had higher frequency of biochemical failure and the presence of CPCs. The treatment of androgen blockade was less successful to suppress the disease relapse in the older men than that in the younger man.