http://repub.eur.nl/res/aut/21338/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/39441/ 2013-03-22T00:00:00Z Purpose: Reported prostate specific antigen values may differ substantially among assays using Hybritech® or WHO standardization. The Beckman Coulter® Prostate Health Index and [-2]proPSA are newly approved serum markers associated with prostate cancer risk and aggressiveness. We studied the influence of assay standardization on these markers. Materials and Methods: Prostate specific antigen, percent free prostate specific antigen and [-2]proPSA were measured using Hybritech calibration in 892 men from a prospective, multicenter study undergoing prostate biopsy. We calculated the Prostate Health Index using the equation, ([-2]proPSA/free prostate specific antigen) × sqrt(P)SA. Index performance characteristics for prostate cancer detection were then determined using recalculated WHO calibration prostate specific antigen values. Results: The median Prostate Health Index was significantly higher in men with prostate cancer than in those with negative biopsies using WHO values (47.4 vs 39.8, p <0.001). The index offered improved discrimination of prostate cancer detection on biopsy (AUC 0.704) compared to percent free or total prostate specific antigen using the WHO calibration. Conclusions: The Prostate Health Index can be calculated using Hybritech or WHO standardized assays. It significantly improved prediction of the biopsy outcome over that of percent free or prostate specific antigen alone. http://repub.eur.nl/res/pub/34872/ 2012-01-01T00:00:00Z http://repub.eur.nl/res/pub/34880/ 2012-01-01T00:00:00Z Context: Prostate cancer screening is highly controversial, including the age to begin prostate-specific antigen (PSA) testing. Several studies have evaluated the usefulness of baseline PSA measurements at a young age. Objective: Review the literature on baseline PSA testing at a young age (≤60 yr) for the prediction of prostate cancer risk and prognosis. Evidence acquisition: PubMed was searched for English-language publications on baseline PSA and prostate cancer for the period ending April 2011. Evidence synthesis: In most published series, median PSA levels in the general male population range from approximately 0.4 to 0.7 ng/ml in men in their 40s and from approximately 0.7 to 1.0 ng/ml in men in their 50s. Evidence from both nonscreening and screening populations has demonstrated the predictive value of a single baseline PSA measurement for prostate cancer risk assessment. Specifically, men with baseline PSA levels above the age-group-specific median have a greater risk of prostate cancer diagnosis during the next 20-25 yr. Additional studies confirmed that higher baseline PSA levels at a young age are also associated with a greater risk of aggressive disease, metastasis, and disease-specific mortality many years later. Conclusions: Baseline PSA measurements at a young age are significant predictors of later prostate cancer diagnosis and disease-specific outcomes. Thus baseline PSA testing may be used for risk stratification and to guide screening protocols. http://repub.eur.nl/res/pub/25907/ 2011-05-01T00:00:00Z Purpose: Prostate specific antigen and free prostate specific antigen have limited specificity to detect clinically significant, curable prostate cancer, leading to unnecessary biopsy, and detection and treatment of some indolent tumors. Specificity to detect clinically significant prostate cancer may be improved by [-2]pro-prostate specific antigen. We evaluated [-2]pro-prostate specific antigen, free prostate specific antigen and prostate specific antigen using the formula, ([-2]pro-prostate specific antigen/free prostate specific antigen × prostate specific antigen1/2) to enhance specificity to detect overall and high grade prostate cancer. Materials and Methods: We enrolled 892 men with no history of prostate cancer, normal rectal examination, prostate specific antigen 2 to 10 ng/ml and 6-core or greater prostate biopsy in a prospective multi-institutional trial. We examined the relationship of serum prostate specific antigen, free-to-total prostate specific antigen and the prostate health index with biopsy results. Primary end points were specificity and AUC using the prostate health index to detect overall and Gleason 7 or greater prostate cancer on biopsy compared with those of free-to-total prostate specific antigen. Results: In the 2 to 10 ng/ml prostate specific antigen range at 80% to 95% sensitivity the specificity and AUC (0.703) of the prostate health index exceeded those of prostate specific antigen and free-to-total prostate specific antigen. An increasing prostate health index was associated with a 4.7-fold increased risk of prostate cancer and a 1.61-fold increased risk of Gleason score greater than or equal to 4 + 3 = 7 disease on biopsy. The AUC of the index exceeded that of free-to-total prostate specific antigen (0.724 vs 0.670) to discriminate prostate cancer with Gleason 4 or greater + 3 from lower grade disease or negative biopsy. Prostate health index results were not associated with age and prostate volume. Conclusions: The prostate health index may be useful in prostate cancer screening to decrease unnecessary biopsy in men 50 years old or older with prostate specific antigen 2 to 10 ng/ml and negative digital rectal examination with minimal loss in sensitivity. http://repub.eur.nl/res/pub/17729/ 2009-01-01T00:00:00Z Aim: To examine the potential clinical implications of the recalibration of total prostate-specific antigen (PSA) and free PSA (fPSA) assays to the World Health Organization (WHO) standard materials. Material and methods: Data from 1098 patients with or without clinically detected prostate cancer (PCa) from four independent cohort studies were compared using commercial assays calibrated to the traditional Hybritech® PSA (PSA-Hyb) and fPSA (fPSA-Hyb) standards and to the WHO 96/670 (PSA-WHO) and 96/668 (fPSA-WHO) standards. The Access® Immunoassay System (Beckman Coulter, Inc.) was used in all studies. Results: All studies showed 20% to 25% lower PSA and fPSA test results with the WHO-standardized assays. No significant change in %fPSA (fPSA/ PSA × 100) was observed. Continuing to use the traditional clinical PSA cutoffs obtained with the Hybritech standard after changing to the PSA-WHO standard could result in up to one-third of prostate cancer cases being missed. Conclusions: Manufacturers should fully inform laboratories about a calibration change and its clinical impact. Laboratory reports for PSA measurements should indicate the assay's manufacturer and which calibration standard was used to avoid misleading information concerning PCa risk. http://repub.eur.nl/res/pub/17898/ 2009-01-01T00:00:00Z Aim: To examine the potential clinical implications of the recalibration of total prostate-specific antigen (PSA) and free PSA (fPSA) assays to the World Health Organization (WHO) standard materials. Material and methods: Data from 1098 patients with or without clinically detected prostate cancer (PCa) from four independent cohort studies were compared using commercial assays calibrated to the traditional Hybritech® PSA (PSA-Hyb) and fPSA (fPSA-Hyb) standards and to the WHO 96/670 (PSA-WHO) and 96/668 (fPSA-WHO) standards. The Access® Immunoassay System (Beckman Coulter, Inc.) was used in all studies. Results: All studies showed 20% to 25% lower PSA and fPSA test results with the WHO-standardized assays. No significant change in %fPSA (fPSA/ PSA × 100) was observed. Continuing to use the traditional clinical PSA cutoffs obtained with the Hybritech standard after changing to the PSA-WHO standard could result in up to one-third of prostate cancer cases being missed. Conclusions: Manufacturers should fully inform laboratories about a calibration change and its clinical impact. Laboratory reports for PSA measurements should indicate the assay's manufacturer and which calibration standard was used to avoid misleading information concerning PCa risk.