Distribution of serum prostate-specific antigen in healthy Korean men: influence of ethnicity

Age-Adjusted Reference Values for Prostate Specific Antigen - A Systematic Review and Meta-Analysis

OBJECTIVES

To systematically evaluates the evidence on ethnic differences in age-adjusted reference values of PSA.

MATERIALS AND METHODS

In concordance with the Preferred Reporting Items for Systematic Review and Meta-analysis statement, a review of English articles using Medline, Embase and Cochrane databases, from inception to December 2019 was conducted. Studies that reported the PSA upper reference value as 95th percentile of the cohort distribution, in healthy men aged 40 to 79, were included. Methodological quality was assessed with a modified version of the Agency for Healthcare Research and Quality checklist for cross-sectional studies.

RESULTS

Forty-three studies examining 325,514 participants were included in the analysis. These were published between 1993 and 2018. Majority were prospective observational studies and reported the reference values in ten-year age intervals. Only five reports directly compared ethnic differences in PSA values. Due to missing data, six studies were not considered in the quantitative synthesis. For the remainder (37/43), heterogeneity in PSA reference values was considerable (Higgin's index = 99.2%), with age and ethnicity being the sole identified significant contributors. Accordingly, the pooled upper limits for PSA reference values were 2.1, 3.2, 4.9 and 6.5 ng/ml for men in their 40 s, 50 s, 60 s, and 70 s, respectively.

CONCLUSION

Moderate quality evidence suggest that upper PSA reference limits increased with age and significant ethnic differences were present.

Prostate cancer screening in Europe and Asia

Prostate cancer (PCa) is the second most common cancer among men worldwide and even ranks first in Europe. Although Asia is known as the region with the lowest PCa incidence, it has been rising rapidly over the last 20 years mostly due to the introduction of prostate-specific antigen (PSA) testing. Randomized PCa screening studies in Europe show a mortality reduction in favor of PSA-based screening but coincide with high proportions of unnecessary biopsies, overdiagnosis and subsequent overtreatment. Conclusive data on the value of PSA-based screening and hence the balance between harms and benefits in Asia is still lacking. Because of known racial variations, Asian countries should not directly apply the European screening models. Like in the western world also in Asia, new predictive markers, tools and risk stratification strategies hold great potential to improve the early detection of PCa and to reduce the worldwide existing negative aspects of PSA-based PCa screening.

Could Magnetic Resonance Imaging Help to Identify the Presence of Prostate Cancer Before Initial Biopsy? The Development of Nomogram Predicting the Outcomes of Prostate Biopsy in the Chinese Population

PURPOSE

This study was designed to investigate the effectiveness of magnetic resonance imaging (MRI) in diagnosing prostate cancer (PCa) and high-grade prostate cancer (HGPCa) before transrectal ultrasound (TRUS)-guided biopsy.

METHODS

The clinical data of 894 patients who received TRUS-guided biopsy and prior MRI test from a large Chinese center was reviewed. Based on Prostate Imaging Reporting and Data System (PI-RADS) scoring, all MRIs were re-reviewed and assigned as Grade 0-2 (PI-RADS 1-2; PI-RADS 3; PI-RADS 4-5). We constructed two models both in predicting PCa and HGPCa (Gleason score ≥ 4 + 3): Model 1 with MRI and Model 2 without MRI. Other clinical factors include age, digital rectal examination, PSA, free-PSA, volume, and TRUS.

RESULTS

PCa and HGPCa were present in 434 (48.5 %) and 218 (24.4 %) patients. An MRI Grade 0, 1, and 2 were assigned in 324 (36.2 %), 193 (21.6 %) and 377 (42.2 %) patients, which was associated with the presence of PCa (p < 0.001) and HGPCa (p < 0.001). Particularly in patients aged ≤55 years, the assignment of MRI Grade 0 was correlated with extremely low rate of PCa (1/27) and no HGPCa. The c-statistic of Model 1 and Model 2 for predicting PCa was 0.875 and 0.841 (Z = 4.2302, p < 0.001), whereas for predicting HGPCa was 0.872 and 0.850 (Z = 3.265, p = 0.001). Model 1 exhibited higher sensitivity and specificity at same cutoffs, and decision-curve analysis also suggested the favorable clinical utility of Model 1.

CONCLUSIONS

Prostate MRI before biopsy could predict the presence of PCa and HGPCa, especially in younger patients. The incorporation of MRI in nomograms could increase predictive accuracy.

Efficacy of Repeated Transrectal Prostate Biopsy in Men Younger Than 50 Years With an Elevated Prostate-Specific Antigen Concentration (>3.0 ng/mL): Risks and Benefits Based on Biopsy Results and Follow-up Status

PURPOSE

Prostate cancer is rare in men younger than 50 years. Digital rectal examination (DRE) and measurement of prostate-specific antigen (PSA) concentrations are standard screening methods for detecting prostate cancer. We retrospectively investigated the risks and benefits of repeated transrectal ultrasonography-guided prostate needle biopsies in relation to the follow-up status of men younger than 50 years with a consistently high PSA concentration (>3.0 ng/mL).

MATERIALS AND METHODS

During the period from January 2000 through February 2013, we reviewed patient's ages, dates of procedures, DRE results, frequencies of biopsies, results of the biopsies, periods of follow-up, PSA concentrations, and prostate volumes in Chonbuk National University Hospital records. We conducted telephone interviews in patients who did not undergo regular follow-up.

RESULTS

The mean age of the patients was 44.7 years, and the mean PSA concentration was 8.59 ng/mL (range, 3.04-131 ng/mL) before biopsy. The PSA concentration was significantly different (p<0.001) between the patients with prostate cancer and those with benign prostatic hyperplasia (BPH). Nineteen patients underwent repeated prostate biopsy; however, in only one patient did the pathologic findings indicate a change from BPH to prostate cancer. We identified several complications after transrectal biopsy through an evaluation of follow-up data.

CONCLUSIONS

All patients with benign prostatic disease based on their first biopsy were shown to have benign disease based on all repeated biopsies (15.83%), except for one patient; however, several complications were noted after biopsy. Therefore, the risks and benefits of repeated biopsy in young patients should be considered because of the low rate of change from benign to malignant disease despite continuously high PSA concentrations (>3.0 ng/mL).

Mobile application-based Seoul National University Prostate Cancer Risk Calculator: development, validation, and comparative analysis with two Western risk calculators in Korean men

Objectives

We developed a mobile application-based Seoul National University Prostate Cancer Risk Calculator (SNUPC-RC) that predicts the probability of prostate cancer (PC) at the initial prostate biopsy in a Korean cohort. Additionally, the application was validated and subjected to head-to-head comparisons with internet-based Western risk calculators in a validation cohort. Here, we describe its development and validation.

Patients and Methods

As a retrospective study, consecutive men who underwent initial prostate biopsy with more than 12 cores at a tertiary center were included. In the development stage, 3,482 cases from May 2003 through November 2010 were analyzed. Clinical variables were evaluated, and the final prediction model was developed using the logistic regression model. In the validation stage, 1,112 cases from December 2010 through June 2012 were used. SNUPC-RC was compared with the European Randomized Study of Screening for PC Risk Calculator (ERSPC-RC) and the Prostate Cancer Prevention Trial Risk Calculator (PCPT-RC). The predictive accuracy was assessed using the area under the receiver operating characteristic curve (AUC). The clinical value was evaluated using decision curve analysis.

Results

PC was diagnosed in 1,240 (35.6%) and 417 (37.5%) men in the development and validation cohorts, respectively. Age, prostate-specific antigen level, prostate size, and abnormality on digital rectal examination or transrectal ultrasonography were significant factors of PC and were included in the final model. The predictive accuracy in the development cohort was 0.786. In the validation cohort, AUC was significantly higher for the SNUPC-RC (0.811) than for ERSPC-RC (0.768, p<0.001) and PCPT-RC (0.704, p<0.001). Decision curve analysis also showed higher net benefits with SNUPC-RC than with the other calculators.

Conclusions

SNUPC-RC has a higher predictive accuracy and clinical benefit than Western risk calculators. Furthermore, it is easy to use because it is available as a mobile application for smart devices.

Differences in prostate cancer detection between Canadian and Saudi populations

Few studies have addressed racial differences in prostate cancer (PCa) detection between Western and Arabian countries, although PCa has a significantly lower prevalence in Arabic populations compared to Western populations. Therefore, an explanation of this difference is lacking. Serum prostate-specific antigen (PSA) is a valuable marker used to select patients who should undergo prostate biopsies, although the manner in which it is used may require adjustments based on the ethnic population in question. We investigated racial differences in the PCa detection rate between Canadian and Saudi populations. A retrospective analysis was performed of data collected prospectively over 5 consecutive years in urology clinics at the McGill University Health Center (MUHC) and King Saud University Hospital (KSUH). Men who had high (>4'ng/mL) or rising PSA levels and a negative digital rectal examination were eligible. A total of 1403 Canadian and 414 Saudi patients were evaluated for the study; 717 and 158 men, median age 64 and 68 years, were included in the MUHC and KSUH cohorts, respectively, P<0.0001). Median serum PSA, prostate volume, and PSA density values were 6.1'ng/mL, 47.3 g, and 0.12'ng·mL⁻¹·g⁻¹, respectively, for MUHC patients and 5.2'ng/mL, 64.5'g, and 0.08'ng·mL⁻¹·g⁻¹, respectively, for KSUH patients (P<0.0001, t-test followed by one-way ANOVA). In addition, the KSUH group had a significantly lower PCa detection rate among patients younger than 60 years of age and with PSA values <10'ng/mL.

Nomograms to predict the pathological stage of clinically localized prostate cancer in Korean men: comparison with western predictive tools using decision curve analysis

OBJECTIVES

To develop and evaluate nomograms to predict the pathological stage of clinically localized prostate cancer after radical prostatectomy in Korean men.

METHODS

We reviewed the medical records of 2041 patients who had clinical stages T1c-T3a prostate cancer and were treated solely with radical prostatectomy at two hospitals. Logistic regressions were carried out to predict organ-confined disease, extraprostatic extension, seminal vesicle invasion, and lymph node metastasis using preoperative variables and resulting nomograms. Internal validations were assessed using the area under the receiver operating characteristic curve and calibration plot, and then external validations were carried out on 129 patients from another hospital. Head-to-head comparisons with 2007 Partin tables and Cancer of the Prostate Risk Assessment score were carried out using the area under the curve and decision curve analysis.

RESULTS

The significant predictors for organ-confined disease and extraprostatic extension were clinical stage, prostate-specific antigen, Gleason score and a percent positive core of biopsy. Significant predictors for seminal vesicle invasion were prostate-specific antigen, Gleason score and percent positive core, and those for lymph node metastasis were prostate-specific antigen and percent positive core. The area under the curve of established nomograms for organ-confined disease, extraprostatic extension, seminal vesicle invasion and lymph node metastasis were 0.809, 0.804, 0.889 and 0.838, respectively. The nomograms were well calibrated and externally validated. These nomograms showed significantly higher accuracies and net benefits than two Western tools in Korean men.

CONCLUSION

This is the first study to have developed and fully validated nomograms to predict the pathological stage of prostate cancer in an Asian population. These nomograms might be more accurate and useful for Korean men than other predictive models developed using Western populations.

Characteristics of baseline PSA and PSA velocity in young men without prostate cancer: Racial differences

BACKGROUND

Baseline prostate specific antigen (PSA) and PSA velocity used to stratify subsequent prostate cancer risk in young men may not directly applicable to all populations. We sought to compare the baseline PSA and PSA velocity among ethnic groups.

PATIENTS AND METHODS

Chinese, African-American (AA), and Caucasian-American (CA) men aged ≤50 years old without prostate cancer were used to identify baseline PSA and PSA velocity. The differences of baseline PSA and PSA velocity between races were assessed. The important cutoffs of baseline PSA and PSA velocity were used to stratify patients among races.

RESULTS

Four thousand two hundred six Chinese, 997 AA, and 2,030 CA were included. The rates of baseline PSA of ≥1.0, ≥2.5, and ≥4.0 ng/ml was 24.4%, 4.2%, and 2.1% in Chinese, 30.7%, 5.2%, and 1.8% in AA, 29.7%, 5.3%, and 2.8% in CA, respectively. The rates of PSA velocity of ≥0.35, ≥0.75, and ≥1.0 ng/ml/year was 6.0%, 3.1%, and 2.6% in Chinese, 5.3%, 2.3%, and 1.7% in AA, 5.4%, 3.5%, and 3.3% in CA, respectively. Chinese had a lower baseline PSA and higher PSA velocity as compared to AA and CA. Baseline PSA and PSA velocity in AA had no statistical differences as compared to CA.

CONCLUSIONS

The distributions of baseline PSA and PSA velocity in young men among Chinese, AA, and CA races are different. These characteristics shall be taken into account when using these variables to stratify risk of prostate cancer in young men.

Optimal baseline prostate-specific antigen level to distinguish risk of prostate cancer in healthy men between 40 and 69 years of age

The present study evaluated optimal baseline prostate-specific antigen (PSA) level at different ages in order to determine the risk of developing prostate cancer (CaP). We analyzed 6,651 Korean men, aged 40-69 yr. The serum PSA levels for these men were measured at one institute from 2000 to 2004 and were determined to be between 0-4 ng/mL. Patients were divided into 4 groups of 25th-percentile intervals, based on initial PSA level. Of these, the group with an increased risk was selected, and the optimal value was determined by the maximal area under a receiver-operating characteristic curve within the selected group. The risk of CaP diagnosis was evaluated by Cox regression. The mean follow-up period was 8.3 yr. CaP was detected in 27 of the 6,651 subjects. CaP detection rate was increased according to age. The optimal PSA value to distinguish the risk of CaP was 2.0 ng/mL for 50- to 69-yr-olds. Patients with a baseline PSA level greater than the optimal value had a 27.78 fold increase in the prostate cancer risk. Baseline PSA values are useful for determining the risk of developing CaP in Korean men for 50- and 69-yr-old. We suggest that PSA testing intervals be modified based on their baseline PSA levels.

Age-specific reference ranges of serum prostate-specific antigen in Iraqi men

BACKGROUND

Different races have their own reference ranges of serum prostate-specific antigen (PSA) because of the influence of geographical and ethnic differences. In this study we determined the distribution of serum PSA levels in Iraqi men with no prostate cancer, to our knowledge the first such study from Iraq.

SUBJECTS AND METHODS

From January 2003 to May 2004, in a prospectively designed study, we included 130 Iraqi men aged 20-79 years. The criteria of an elevated PSA level, abnormal ultrasonography results and/or abnormal findings on a digital rectal examination were used to exclude patients from the study. Ethnicity was not recorded, as Iraq has a multi-ethnic status. The results were analysed using descriptive statistics, statistical tables, the arithmetic mean, standard error, standard deviation, and by two extremes.

RESULTS

The PSA values in different age groups (20-29, 30-39, 40-49, 50-59 and 60-79) were, respectively, ⩾0.55 to ⩽1.3, ⩽1.6, ⩽2.0, ⩽4.6 and ⩽4.8 ng/mL. There was a significant increase between the third and fourth group, and all these results were significant at P < 0.001, with the last being more significant.

CONCLUSION

Serum PSA measurements should be standardized according to country and ethnic groups. Our result of a PSA maximum at 4.8 ng/mL is slightly more than the international standard threshold of 4.0 ng/mL.

Association of Polymorphisms in the Prostate-Specific Antigen (PSA) Gene Promoter with Serum PSA Level and PSA Changes after Dutasteride Treatment in Korean Men with Benign Prostatic Hypertrophy

Purpose

Studies of genetic variation in the prostate-specific antigen (PSA) gene have improved the diagnostic accuracy of PSA for diagnosing prostate diseases in Caucasians. However, the reference ranges and pharmacokinetics of PSA differ significantly according to race. Therefore, we evaluated the association between genetic variations in the PSA promoter area and benign prostatic hyperplasia (BPH) phenotypes in Korean BPH patients.

Materials and Methods

One hundred twenty-one men were enrolled. The initial serum PSA level, prostate size, and PSA changes at 3 months after treatment with dutasteride were determined. We amplified the promoter region of the PSA gene (nucleotide positions -158 to -356 and -5217 to -5429) and sequenced the products.

Results

Three relatively well characterized single-nucleotide polymorphisms (SNPs; rs3760722, rs266867, and rs266868), six uncharacterized SNPs (rs17554958, rs266882, rs4802754, rs2739448, rs2569733, and rs17526278), and one novel SNP (nucleotide position -5402) were found. There were no statistically significant correlations between any of the SNPs of the PSA promoter area and age-adjusted prostate sizes, initial PSA levels, or PSA variations after 3 months of dutasteride treatment.

Conclusions

SNPs in the PSA promoter area were not associated with BPH phenotypes. We could not predict serum PSA changes after dutasteride treatment on the basis of PSA promoter genotype in Korean patients with BPH.

Preoperative nomograms for predicting extracapsular extension in Korean men with localized prostate cancer: a multi-institutional clinicopathologic study

We developed a nomogram to predict the probability of extracapsular extension (ECE) in localized prostate cancer and to determine when the neurovascular bundle (NVB) may be spared. Total 1,471 Korean men who underwent radical prostatectomy for prostate cancer between 1995 and 2008 were included. We drew nonrandom samples of 1,031 for nomogram development, leaving 440 samples for nomogram validation. With multivariate logistic regression analyses, we made a nomogram to predicts the ECE probability at radical prostatectomy. Receiver operating characteristic (ROC) analyses were also performed to assess the predictive value of each variable alone and in combination. The internal validation was performed from 200 bootstrap re-samples and the external validation was also performed from the another cohort. Overall, 314 patients (30.5%) had ECE. Age, Prostate specific antigen (PSA), biopsy Gleason score, positive core ratio, and maximum percentage of biopsy tumor were independent predictors of the presence of ECE (all P values <0.05). The nomogram predicted ECE with good discrimination (an area under the ROC curve of 0.777). Our nomogram allows for the preoperative identification of patients with an ECE and may prove useful in selecting patients to receive nerve sparing radical prostatectomy.

Outcome of Prostate Biopsy in Men Younger than 40 Years of Age with High Prostate-Specific Antigen (PSA) Levels

Purpose

Prostate cancer is rarely diagnosed in men younger than 40 years of age. At present, the available data show a low rate of cancer detection from prostate-specific antigen (PSA) screening of this group of young men. We analyzed the outcome of prostate biopsy results in patients of this age group with a high PSA.

Materials and Methods

Between October 1997 and August 2008, a total of 81 men less than 40 years of age were referred from the Health Care Promotion Center as the result of elevated PSA levels. Six men with prostatitis were excluded. The remaining 75 men were asymptomatic and had normal findings on the digital rectal examination (DRE) and were selected to have a transrectal ultrasound-guided prostate biopsy for suspected prostate cancer. The patients with sustained high PSA levels underwent repeat biopsies.

Results

The median age of the 75 men was 33 years (range, 26-40 years) and the mean PSA level was 6.57 ng/ml (range, 4.32-13.45 ng/ml). The results of the primary biopsy was 1 (1.3%) case of prostate cancer, 70 cases (93%) with benign tissue, 2 cases (2.6%) with inflammation, and 1 case each (1.3%) with high grade intraepithelial neoplasia (HGPIN) and atypical small acinar proliferation (ASAP). Of the 10 men who underwent a second biopsy, all had benign findings. Three of the men who underwent a third biopsy all had benign tissue findings.

Conclusions

The prostate cancer detection rate in young men less than 40 years of age with high PSA levels and normal DREs was very low. Repeat biopsy for sustained high PSA levels in young men less than 40 years of age may not be indicated.

Clinical and pathological characteristics of screen-detected versus clinically diagnosed prostate cancer in Nanjing, China

Previous studies have suggested that implementation of PSA screening in China is of crucial importance. This study compared clinical and pathological characteristics of screen-detected and clinically diagnosed prostate cancers and evaluated the effectiveness of PSA screening for early detection of prostate cancer in Nanjing. Between July 2004 and December 2005, 8,562 men aged ≥ 50 years were included for PSA screening. Participants with serum PSA ≥ 4.0 ng/ml were recommended for transrectal ultrasonography (TRUS)-guided prostate needle biopsy (TRNB). During the same period, 82 consecutive clinically diagnosed prostate cancers were included as controls. The clinical and pathological features of the screened versus clinically diagnosed cancers were evaluated. A total of 719 (8.4%) of screened men had PSA levels ≥ 4.0 ng/ml. Biopsy was performed in 295 men, and 58 prostate cancers were detected. The biopsy rate, positive predictive value (PPV), and detection rate were 41.0, 19.7, and 0.68%, respectively. More screened patients were found with PSA levels <20 ng/ml (55.2 vs. 22.4%, P < 0.001), Gleason scores <7 (60.3 vs. 34.1%, P = 0.002), organ-confined tumors (87.9 vs. 26.8%, P < 0.001), and opportunities for radical prostatectomy (50.0 vs. 18.3%, P < 0.001) than that in clinically diagnosed patients. PSA screening is effective for early detection of prostate cancer in Chinese elderly men. Favorable PSA levels, Gleason scores, clinical stages, and chances for radical prostatectomy are associated with PSA screening. Further studies are needed to evaluate the effect of screening on treatment outcomes and mortality of prostate cancer in Chinese.

Body mass index influences prostate-specific antigen in men younger than 60 years of age

OBJECTIVES

Prostate-specific antigen (PSA) levels can be affected by many factors. Body mass index (BMI) is suspected to influence PSA levels, but the associations are controversial. The aim of this study was to examine whether PSA levels were affected by BMI and age in Koreans.

METHODS

We evaluated the association between BMI and PSA in a group of 8640 Korean men (aged 40-79 years) without prostate cancer who received a general health checkup. Eligible men were classified into age groups spanning 10 years. BMI was categorized as normal (BMI <22.9), overweight (BMI 23.0-24.9), obese (BMI 25.0-29.9), and very obese (BMI > or =30) according to the re-defined World Health Organization (WHO) criterion for the Asia Pacific Region. PSA levels were stratified by age and BMI category.

RESULTS

Prostate-specific antigen levels decreased with increasing BMI (P trend <0.001). However, the inverse correlations between PSA and BMI were significant only among men 40-59 years old (P trend <0.05, respectively). BMI showed no significant associations with PSA in 60-79 years old (P trend >0.05, respectively).

CONCLUSIONS

Our study demonstrates that increased BMI is associated with decreased PSA levels only in men younger than 60 years of age. When determining whether to carry out prostate biopsy as part of early prostate cancer detection, obesity should be considered as a factor associated with reduced PSA in healthy young men (<60 years old) with marginal PSA levels.

Nomograms for the prediction of pathologic stage of clinically localized prostate cancer in Korean men

We analyzed the prostate cancer data of 317 Korean men with clinically localized prostate cancer who underwent radical prostatectomy at Asan Medical Center between June 1990 and November 2003 to construct nomograms predicting the pathologic stage of these tumors, and compared the outcome with preexisting nomograms. Multinomial log-linear regression was performed for the simultaneous prediction of organ-confined disease (OCD), extracapsular extension (ECE), seminal vesicle invasion (SVI) and lymph node metastasis (LNM) using serum prostate-specific antigen (PSA), Gleason score and clinical stage. Nomograms representing percent probabilities were constructed and compared with those presented by Partin et al. by calculating areas under the receiver operating characteristics (ROC) curves. Median serum PSA at surgery was 10.8 ng/mL, and median biopsy Gleason score was 7. Overall OCD, ECE, SVI and LNM rates were 59.6%, 20.5%, 11.7% and 8.2%, respectively, and areas under the curves were 0.724, 0.626, 0.662, and 0.794, respectively. Pathologic stage of localized prostate cancer in Korean men may be predicted using the Partin table, with acceptable accuracy for OCD and LNM, but less so for ECE and SVI.

Comparison of total prostate-specific antigen and derivative levels in a screening population of black, white, and Korean-American men

Numerous studies have assessed serum total PSA (tPSA) levels among different races. We extended the serum biomarker profiling using prostate-specific antigen (PSA) derivatives in age-matched screening populations that included white, black, and Korean-American patients. The median ages were 61 years for white and black patients and 63 years for Korean-American patients. Serum samples from 70 men in each ethnic group were analyzed using 3 different tPSA assays (Tosoh AIA 600II, Bayer Immuno-1, Roche Elecsys 2010). The percentage of free PSA (fPSA) was measured directly by Roche Elecsys 2010 immunoassay and then calculated from complexed PSA (cPSA) and tPSA results determined with the Bayer Immuno-1. The percentage of cPSA was determined using cPSA and tPSA assayed by the Immuno-1 method. Statistical analyses included nonparametric Kruskal-Wallis and analysis of variance (ANOVA) evaluations. There were no differences noted in the tPSA values based on ANOVA among the 3 races irrespective of the assay platform methodology employed. Also, the PSA derivatives, percentages of fPSA and cPSA, evaluated using the Kruskal-Wallis test, showed no significant differences for either derivative assayed on 2 different assay platforms among the 3 groups. In a contemporary screening population comparing tPSA, percentage of fPSA, and percentage of cPSA levels in 3 races, there were no significant differences identified among the groups.

Ethnic differences in distribution of serum prostate-specific antigen: a study in a healthy chinese male population

OBJECTIVES

To evaluate the normal distribution of serum prostate-specific antigen (PSA) levels in healthy Chinese men, because, until recently, studies conducted to establish normal serum PSA values have not involved a Chinese population.

METHODS

Between September 1999 and December 2001, 1096 healthy Chinese men aged 23 to 85 years, who had undergone a routine health examination, were recruited to this study. All underwent detailed clinical examinations, including serum PSA determination and digital rectal examination. All men with abnormal digital rectal examination findings and/or an abnormal serum PSA level (greater than 4.0 ng/mL) underwent transrectal ultrasound-guided sextant biopsy.

RESULTS

The median serum PSA concentration was 0.50 ng/mL (95th percentile 1.20) for men 23 to 29 years old (n = 77); 0.55 ng/mL (95th percentile 1.21) for men 30 to 39 years old (n = 189); 0.54 ng/mL (95th percentile 1.23) for men 40 to 49 years old (n = 233); 0.82 ng/mL (95th percentile 2.35) for men 50 to 59 years old (n = 177); 0.93 ng/mL (95th percentile 3.20) for men 60 to 69 years old (n = 265); and 1.17 ng/mL (95th percentile 3.39) for men 70 years old or older (n = 155). The serum PSA concentration correlated with age (P <0.001), with an increase of approximately 1.1% annually. No change occurred in the median serum PSA value and 95th percentile in men younger than 50 years old; a gradual increase was observed in men older than 50 years. In those 50 years old or older, the median and 95th percentile serum PSA values for Chinese men were significantly lower than those for other races and even for other Asian men.

CONCLUSIONS

These findings further confirm that the serum PSA level correlates with age. Moreover, the distribution and cutoff value of the serum PSA level differs along ethnic lines. In addition, our findings raise the question of whether lowering the PSA cutoff may enhance the detection of cancer in Chinese men who have the lowest prostate cancer rate.