To explore the role of percent free-prostate specific antigen(PSA) on the differentiation between benign and malignant prostatic diseases in patients with serum total PSA levels between 4.0 and 10.0 ng/ml. Forty-three out of the 221 screened men who had total PSA levels between 4.0 and 10.0 ng/ml were retrospectively enrolled into this study. in addition to digital rectal examination(DRE), transrectal ultrasonography(TRUS), and total PSA, they received either TRUS-guided biopsies(n=27) or transurethral resection of the prostate (TUR-P) (n=16). All sample sera were then stored at -70 °C after the initial measurement of total PSA levels using an immunoenzymometric assay(Tandem-E®, Hybritech). Thereafter, all stored sera were quantified for free-PSA levels and total PSA levels using a different radioimmunometric assay(PSA-RJACT, CIS). Two values of percent free-PSA were obtained for each individual by dividing the same free-PSA level by 2 different total PSA values as measured by 2 different assays. Among the 43 patients, there were 34(79.1%) patients with benign prostatic hyperpla-sia(BPH), 5(11.6%) with prostatitis, and 4(9.3%) with prostate cancer(PC). Using these 2 different total PSA assays, the percent free-PSA in patients with BPH, prostatitis, and PC were 28.0%±12.2%, 23.6%±9.1%, 8.7%±1.3% (FPSA-RJACT/Tandem-E®) and 29.6%±13.1%,28.5%±13.1%, 9.7%±1.1% (FPSA-RJACT/PSA-RIACT), respectively. Patients with PC had significantly lower values of percent free-PSA (less than 12%) while those with either BPH or prostatitis had values greater than l2%(p values, 0.015 and 0.003, unpaired t-test). In contrast, the percent free-PSA values were not statistically different between BPH and prostatitis patients in both assays (p=0. 44, unpaired t-test). Besides, the correlation between the 2 values of percent free-PSA was good(r2 =0.90), based on 2 different assays for total PSA levels. Our study implies that percent free-PSA can help differentiate prostate cancer from benign prostatic diseases, and thus greatly reducing unnecessary biopsies. There is no need to measure the total PSA levels again while determining the percent free-PSA.
Objective: To evaluate the prognostic value of changes in prostate-specific antigen (PSA) on the outcome of patients with metastatic prostate cancer treated with androgen ablation.
Patients and Methods: We analyzed 6 pretreatment clinicopathological and 5 posttreatment PSA parameters in 39 advanced prostate cancer patients receiving androgen ablation. Their ages ranged from 50 to 84 (mean, 67.8) years, and they were regularly followed up for 12 to 96 (mean, 27.9) months.
Results: Univariate analysis revealed that (1) a patient's age of ＞65 years, (2) a PSA drop to ≤4ng/ml within 3 months (i.e., a return to normal), (3) a PSA nadir value of ＜1ng/ml, and (4) a duration of PSA of ≤4ng/ml of longer than 12 months were 4 significant prognostic indicators for the disease-specific overall survival (p＜0.05), whereas the pretreatment PSA value, PSA half-life, and PSA doubling time were not. Further analysis with the multivariate Cox proportional hazard models revealed that a duration of PSA normalization of longer than 12 months was the strongest indicator of a favorable outcome. Moreover, patients with a PSA nadir value of ＜1ng/ml had significant longer normalization periods but not PSA doubling times compared to those who had a PSA nadir value of between 1 and 4ng/ml.
Conclusions: Results of this study reveal that (1) an age of ≥65 years, (2) a drop in the PSA value to ≤4ng/ml within 3 months, (3) a PSA nadir value of ＜1ng/ml, and (4) a PSA normalization duration of ＞12 months were the 4 significant prognostic parameters of metstatic prostate cancer patients treated with androgen ablation. In general, the lower the PSA nadir value a patient is able to achieve the longer the PSA normalization period and eventually a better disease-specific survival he may enjoy.
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