Objectives: To evaluate associations of preoperative total prostate specific antigen (PSA) to free testosterone (FT), the PSA/FT index ratio, with features of pathology prostate cancer (PCA) and to investigate its prognostic potential in clustering the PCA population. Patients and methods: After excluding criteria, the records of 220 patients who underwent radical prostatectomy (RP) were retrospectively reviewed. Serum samples of PSA, total testosterone (TT) and FT were collected at 8.00 A.M., one month after biopsies and before RP. The PSA/FT ratio was computed in the population of patients who were clustered in groups according to ranking intervals of the PSA/FT ratio which identified at least 4 clusters which were coded as A, B, C, and D. The independent associations of the PSA/FT index ratio were assessed by statistical methods and a two-sided P < 0.05 was considered to indicate statistical significance. Results: TT correlated to FT which was a significant predictor of PSA in the population of patients who were subsequently clustered, according to increasing interval values of the PSA/FT index ratio, in groups that showed a stronger linear association of FT with PSA. The PSA/FT index ratio significantly associated with pathology features of prostate cancer such as pathology Gleason score (pGS), invasion of the seminal vesicles (pT3b), proportion of positive cores (P+) and proportion of cancer involving the volume of the prostate. In the population of patients, TT, PSA/FT index ratio and P+ independently associated with pGS ≥ 7 and pT3b; moreover, the odds ratio (OR) of the PSA/FT index ratio resulted 9.11 which was stronger than TT (OR = 1.11) and P+ (OR = 8.84). In the PCA population, TT, PSA/FT index ratio and P+ also independently associated with pT3b PCA; interestingly, the OR of PSA/FT index resulted 54.91 which was stronger than TT (OR = 1.31) and P+ (26.43). Conclusions: Preoperative PSA/FT index ratio is an independent strong factor which directly associates with aggressive features of pathology PCA; moreover, it might express prognostic potential for clustering the patient population in risk classes. Confirmatory studies are required.
Simultaneous determination of free and total prostate-specific antigen by a magnetic particle-based time-resolved fluoroimmunoassay
