Percent Free Prostate Research Articles

OPTIMAL PREDICTORS OF PROSTATE CANCER ON REPEAT PROSTATE BIOPSY: A PROSPECTIVE STUDY OF 1,051 MEN

We compare the ability of total prostate specific antigen (PSA), percent free PSA, PSA density and transition zone PSA density to predict the outcome of repeat prostatic biopsy in men with serum total PSA 4 to 10 ng./ml. who were diagnosed with benign prostatic hyperplasia after initial biopsy. In this prospective study 1,051 men with total PSA 4 to 10 ng./ml. underwent transrectal ultrasound guided sextant biopsy with 2 additional transition zone biopsies. In 254 subjects biopsy specimens were also obtained from suspicious areas identified during transrectal ultrasound and digital rectal examination. All subjects with biopsy specimens negative for prostate cancer underwent repeat biopsy 6 weeks after initial biopsy. The ability of total PSA, percent free PSA, PSA density and transition zone PSA density to improve the diagnostic power of PSA testing was assessed with univariate and multivariate analyses as well as receiver operating characteristics (ROC) curves. Initial biopsy was positive (prostate cancer) in 231 and negative (benign prostatic hyperplasia) in 820 of the 1,051 subjects. Prostate cancer was detected on repeat biopsy in 10% of subjects (83 of 820) with negative initial biopsy. Percent free PSA and transition zone PSA density were the most accurate predictors of prostate cancer in these subjects. At a cutoff of 30% percent free PSA would have detected 90% of cancers (sensitivity) and eliminated 50% of unnecessary repeat biopsies (specificity). Sensitivity and specificity of transition zone PSA density at a cutoff of 0.26 ng./ml./cc was 78% and 52%, respectively. ROC curve analysis also showed that percent free PSA was a significantly better predictor of repeat biopsy results than total PSA, PSA density and transition zone PSA density. The area under the ROC curve was 74.5% for percent free PSA, 69.1% for transition zone PSA density, 61.8% for PSA density and 60.3% for total PSA. At least 10% of patients with negative initial prostatic biopsy results will be diagnosed with prostate cancer on repeat biopsy. Percent free PSA and transition zone PSA density enhance the specificity of PSA testing compared to total PSA or PSA density when determining which patients should undergo repeat biopsy. Repeat biopsy should be performed in patients with percent free PSA less than 30% or transition zone PSA density 0.26 ng./ml./cc or greater. In our study percent free PSA was the most accurate predictor of prostate cancer in repeat biopsy specimens.

Clinical Evaluation of Percent Free Prostate–Specific Antigen Using the AxSYM System in the Best Analytical Scenario

Objective: Percent free prostate–specific antigen (PSA) is a promising tool for prostate cancer (CaP) diagnosis. However, its diagnostic performances have not yet been established. The present study was carried out with the aim of evaluating percent free PSA in the most favourable analytical conditions.Materials and Methods: Eighty–eight patients affected by newly diagnosed, untreated, primary CaP, and 169 cases with biopsy–confirmed, untreated, benign prostatic hypertrophy (BPH) were prospectively enrolled. Abbott AxSYM total and free PSA were measured by the same technician using the same instrument and the same reagent batch.Results: Percent free PSA was more effective than total PSA in differential diagnosis between CaP and BPH in every evaluated dose range of total PSA. In cases with total PSA >4 μg/l, percent free PSA could have reduced by about 50% the rate of unnecessary biopsies with a probably still acceptable 93% cancer detection rate. The likelihood of CaP after the determination of percent free PSA was in fact higher than 50% using cut–off points which provide low sensitivity values (i.e. 58% in men aged 50–59 years).Conclusions: Percent free PSA is superior to total PSA in distinguishing primary CaP from BPH in patients with total PSA between 2 and 30 μg/l and in reducing the rate of unnecessary biopsies in men with total PSA higher than 4 μg/l. However, percent free PSA should be cautiously interpreted in decision making in individual patients since post–test probability is relatively low in men aged 50–70 years.

Comparison of Percent Free Prostate Specific Antigen and Prostate Specific Antigen Density as Methods to Enhance Prostate Specific Antigen Specificity in Early Prostate Cancer Detection in Men With Normal Rectal Examination and Prostate Specific Antigen Between 4.1 and 10 ng./ml.

Comparison of Percent Free Prostate Specific Antigen and Prostate Specific Antigen Density as Methods to Enhance Prostate Specific Antigen Specificity in Early Prostate Cancer Detection in Men With Normal Rectal Examination and Prostate Specific Antigen Between 4.1 and 10 ng./ml.

Comparison of Percent Free Prostate Specific Antigen and Prostate Specific Antigen Density as Methods to Enhance Prostate Specific Antigen Specificity in Early Prostate Cancer Detection in Men With Normal Rectal Examination and Prostate Specific Antigen Between 4.1 and 10 ng./ml.

Purpose We analyzed the behavior of prostate specific antigen (PSA) density and percent free PSA to enhance the specificity of PSA in the early diagnosis of prostate cancer in men with normal digital rectal examination and PSA serum level between 4.1 and 10 ng./ml. Materials and Methods PSA serum level, PSA density and percent free PSA were analyzed in 74 men with normal digital rectal examination and PSA serum level between 4.1 and 10 ng./ml. All men underwent systematic prostate biopsy, and the diagnosis was benign prostate hyperplasia in 52 and prostate cancer in 22. Furthermore, we determined the decrease in unnecessary biopsies and the cancer detection rate using 0.10 versus 0.15 as cut points for PSA density, and 20 versus 25 as cut points for percent free PSA. Results In patients with benign prostatic hyperplasia and prostate cancer, respectively, the median PSA level was 6.7 and 7.0 ng./ml. (p >0.05), median prostate volume was 50 and 37 cc (p <0.04), median PSA density was 0.14 and 0.19 (p <0.007) and median percent free PSA was 18.9 and 10.1 (p <0.005). Using PSA density cut points of 0.15 and 0.10, the decrease in negative biopsies was 53.8 and 36.5% with a sensitivity of 86.4 and 90.9%, respectively. However, using percent free PSA cut points of 20 and 25, the decrease in negative biopsies was 36.5 and 26.9% with a sensitivity of 77.3 and 95.5%, respectively. Conclusions Although both methods could minimize unnecessary biopsies in men with normal digital rectal examination and PSA serum level between 4.1 and 10 ng./ml., the percent free PSA was more cost-effective since transrectal ultrasound was not required. In this small series of symptomatic patients a percent free PSA cut point of 25 could detect at least 95% of prostate cancers and decrease 26.9% of negative biopsies.

Biological Variation of Total, Free and Percent Free Serum Prostate Specific Antigen Levels in Screening Volunteers

Biological Variation of Total, Free and Percent Free Serum Prostate Specific Antigen Levels in Screening Volunteers