Total, free, and complexed prostate-specific antigen levels among US men, 2007-2010

Association between patient ethnicity and prostate cancer diagnosis following a prostate-specific antigen test: a cohort study of 730,000 men in primary care in the UK

BACKGROUND

Black men have higher prostate-specific antigen (PSA) levels and higher prostate cancer incidence and mortality than White men, while Asian men tend to have lower prostate cancer incidence and mortality than White men. Much of the evidence comes from the USA, and information from UK populations is limited.

METHODS

This retrospective cohort study used data on patients registered at general practices in England contributing to the Clinical Practice Research Datalink (CPRD) Aurum dataset. Those eligible were men aged 40 and over with a record of ethnicity and a PSA test result recorded between 2010 and 2017 with no prior cancer diagnosis. The aim was to assess the incidence of prostate cancer following a raised PSA test result in men from different ethnic groups. Additionally, incidence of advanced prostate cancer was investigated. Cancer incidence was estimated from multi-level logistic regression models adjusting for potential confounding factors.

RESULTS

730,515 men with a PSA test were included (88.9% White). Black men and men with mixed ethnicity had higher PSA values, particularly for those aged above 60 years. In the year following a raised PSA result (using age-specific thresholds), Black men had the highest prostate cancer incidence at 24.7% (95% CI 23.3%, 26.2%); Asian men had the lowest at 13.4% (12.2%, 14.7%); incidence for White men was 19.8% (19.4%, 20.2%). The peak incidence of prostate cancer for all groups was in men aged 70-79. Incidence of prostate cancer diagnosed at an advanced stage was similar between Black and White men.

CONCLUSIONS

More prostate cancer was diagnosed in Black men with a raised PSA result, but rates of advanced prostate cancer were not higher in this group. In this large primary care-based cohort, the incidence of prostate cancer in men with elevated PSA levels increases with increasing age, even when using age-adjusted thresholds, with Black men significantly more likely to be diagnosed compared to White or Asian men. The incidence of advanced stage prostate cancer at diagnosis was similar for Black and White men with a raised PSA result, but lower for Asian men.

Ethnic differences in prostate-specific antigen levels in men without prostate cancer: a systematic review

INTRODUCTION

Black men are twice as likely to be diagnosed with prostate cancer than White men. Raised prostate-specific antigen (PSA) levels can indicate an increased risk of prostate cancer, however it is not known whether PSA levels differ for men of different ethnic groups.

METHODS

PubMed and Embase were searched to identify studies that reported levels of PSA for men of at least two ethnic groups without a prostate cancer diagnosis or symptoms suggestive of prostate cancer. An adaptation of the Newcastle-Ottawa scale was used to assess risk of bias and study quality. Findings were stratified into the following broad ethnic groups: White, Black, Asian, Hispanic, and Other. Data were analysed in a narrative synthesis due to the heterogeneity of reported PSA measures and methods in the included studies.

RESULTS

A total of 654 197 males from 13 studies were included. By ethnicity, this included 536 201 White (82%), 38 287 Black (6%), 38 232 Asian (6%), 18 029 Pacific Island (3%), 13 614 Maori (2%), 8 885 Hispanic (1%), and 949 Other (<1%) men aged ≥40 years old. Black men had higher PSA levels than White men, and Hispanic men had similar levels to White men and lower levels than Black men.

CONCLUSIONS

Black men without prostate cancer have higher PSA levels than White or Hispanic men, which reflects the higher rates of prostate cancer diagnosis in Black men. Despite that, the diagnostic accuracy of PSA for prostate cancer for men of different ethnic groups is unknown, and current guidance for PSA test interpretation does not account for ethnicity. Future research needs to determine whether Black men are diagnosed with similar rates of clinically significant prostate cancer to White men, or whether raised PSA levels are contributing to overdiagnosis of prostate cancer in Black men.

Five-gene signature associating with Gleason score serve as novel biomarkers for identifying early recurring events and contributing to early diagnosis for Prostate Adenocarcinoma

Background: Compared to non-recurrent type, recurrent prostate adenocarcinoma (PCa) is highly fatal, and significantly shortens the survival time of affected patients. Early and accurate laboratory diagnosis is particularly important in identifying patients at high risk of recurrence, necessary for additional systemic intervention. We aimed to develop efficient and accurate diagnostic and prognostic biomarkers for new PCa following radical therapy. Methods: We identified differentially expressed genes (DEGs) and clinicopathological data of PCa patients from Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas (TCGA) repositories. We then uncovered the most relevant clinical traits and genes modules associated with PCa prognosis using the Weighted gene correlation network analysis (WGCNA). Univariate Cox regression analysis and multivariate Cox proportional hazards (Cox-PH) models were performed to identify candidate gene signatures related to Disease-Free Interval (DFI). Data for internal and external cohorts were utilized to test and validate the accuracy and clinical utility of the prognostic models. Results: We constructed and validated an accurate and reliable model for predicting the prognosis of PCa using 5 Gleason score-associated gene signatures (ZNF695, CENPA, TROAP, BIRC5 and KIF20A). The ROC and Kaplan-Meier analysis revealed the model was highly accurate in diagnosing and predicting the recurrence and metastases of PCa. The accuracy of the model was validated using the calibration curves based on internal TCGA cohort and external GEO cohort. Using the model, patients could be prognostically stratified in to various groups including TNM classification and Gleason score. Multivariate analysis revealed the model could independently predict the prognosis of PCa patients and its utility was superior to that of clinicopathological characteristics. In addition, we fund the expression of the 5 gene signatures strongly and positively correlated with tumor purity but negatively correlated with infiltration CD8+ T cells to the tumor microenvironment. Conclusions: A 5 gene signatures can accurately be used in the diagnosis and prediction of PCa prognosis. Thus this can guide the treatment and management prostate adenocarcinoma.

Systematic review and meta-analysis of the associations between body mass index, prostate cancer, advanced prostate cancer, and prostate-specific antigen

PURPOSE

The relationship between body mass index (BMI) and prostate cancer remains unclear. However, there is an inverse association between BMI and prostate-specific antigen (PSA), used for prostate cancer screening. We conducted this review to estimate the associations between BMI and (1) prostate cancer, (2) advanced prostate cancer, and (3) PSA.

METHODS

We searched PubMed and Embase for studies until 02 October 2017 and obtained individual participant data from four studies. In total, 78 studies were identified for the association between BMI and prostate cancer, 21 for BMI and advanced prostate cancer, and 35 for BMI and PSA. We performed random-effects meta-analysis of linear associations of log-PSA and prostate cancer with BMI and, to examine potential non-linearity, of associations between categories of BMI and each outcome.

RESULTS

In the meta-analyses with continuous BMI, a 5 kg/m2 increase in BMI was associated with a percentage change in PSA of - 5.88% (95% CI - 6.87 to - 4.87). Using BMI categories, compared to normal weight men the PSA levels of overweight men were 3.43% lower (95% CI - 5.57 to - 1.23), and obese men were 12.9% lower (95% CI - 15.2 to - 10.7). Prostate cancer and advanced prostate cancer analyses showed little or no evidence associations.

CONCLUSION

There is little or no evidence of an association between BMI and risk of prostate cancer or advanced prostate cancer, and strong evidence of an inverse and non-linear association between BMI and PSA. The association between BMI and prostate cancer is likely biased if missed diagnoses are not considered.

Establishment of reference intervals for serum [-2]proPSA (p2PSA), %p2PSA and prostate health index in healthy men

Background

Prostate cancer (PCa) is the second most common cancer among men worldwide. Recent research has identified [-2]proPSA (p2PSA), %p2PSA and prostate health index (phi) as new biomarkers for the early diagnosis and grading of PCa. However, few studies have used these parameters in a healthy population. In this study, we aimed to establish reference intervals (RIs) for p2PSA, %p2PSA and phi in healthy men based on age stratification.

Methods

Between April 2016 and March 2018, healthy subjects were recruited. Healthy men were then stratified into four age groups: <40 years, 40-49 years, 50-59 years and ≥60 years. Total PSA (tPSA), free PSA (fPSA), %fPSA, p2PSA, %p2PSA and phi were measured and RIs were established for p2PSA, %p2PSA and phi.

Results

In total, 732 healthy men were used for analysis. The RIs of phi were 9.77-48.44 for <40 years of age, 9.85-65.28 for 40-49 years of age, 9.98-39.72 for 50-59 years of age and 8.16-40.76 for ≥60 years of age. The reference values at the age of 40-49 years were generally higher than those at ≥60 years of age.

Conclusions

Age-specific RIs for p2PSA, %p2PSA and phi were established in this study. This first set of established RIs will be invaluable for physicians to make precise medical decisions and carry out appropriate medical interventions.

Dual-color magnetic-quantum dot nanobeads as versatile fluorescent probes in test strip for simultaneous point-of-care detection of free and complexed prostate-specific antigen

Simultaneous detection of free and complexed prostate-specific antigen (f-PSA and c-PSA) is critical to the prostate cancer (PCa) diagnostic accuracy for clinical samples with PSA values in the diagnostic gray zone between 4 and 10 ng mL^-1. Herein, red and green magnetic-quantum dot nanobeads (MQBs) with superior magnetic property and high luminescence were fabricated via polyethyleneimine-mediated electrostatic adsorption of numerous quantum dots onto superparamagnetic Fe₃O₄ magnetic cores, and were conjugated with f-PSA antibody and c-PSA antibody, respectively, as versatile fluorescent probes in test strip for immune recognition, magnetic enrichment, and simultaneous detection of f-PSA and c-PSA analytes in complex biological matrix with t-PSA antibody on the test line. A low-cost and portable smartphone readout device with an application was also developed for the imaging of dual-color test strips and data processing. This assay can simultaneously detect f-PSA and c-PSA with the limits of detection of 0.009 ng mL^-1 and 0.087 ng mL^-1, respectively. Clinical serum samples of PCa and benign prostatic hyperplasia patients were evaluated to confirm the clinical feasibility. The results suggest that the proposed dual-color MQBs-based fluorescent lateral flow immunoassay is a promising point-of-care diagnostics technique for the accurate diagnosis of PCa even in resource-limited settings.

Prostate-Specific Antigen Trends Predict the Probability of Prostate Cancer in a Very Large U.S. Veterans Affairs Cohort

If prostate-specific antigen (PSA) trends help identify elevated prostate cancer (PCa) risk, they might provide early warning of progressing cancer for further evaluation and justify annual testing. Our objective was to determine whether PSA trends predict PCa likelihood. A biopsy cohort of 361,657 men was obtained from a Veterans Affairs database (1999–2012). PSA trends were estimated for the 310,458 men with at least 2 PSA tests prior to biopsy. Cancer tumors may grow exponentially with cells doubling periodically. We hypothesized that PSA from prostate cancer grows exponentially above a no cancer baseline. We estimated PSA trends on that basis along with five descriptive variables: last PSA before biopsy, growth rate in PSA from cancer above a baseline, PSA variability around the trend, number of PSA tests, and time span of tests. PSA variability is a new variable that measures percentage deviations of PSA tests from estimated trends with 0% variability for a smoothly increasing trend. Logistic regression models were used to estimate relationships between the probability of PCa at biopsy and the trend variables and age. All five PSA trend variables and age were significant predictors of prostate cancer at biopsy (p < 0.0001). An overall logistic regression model achieved an AUC of 0.67 for men with at least 4 tests over at least 3 years, which was a substantial improvement over a single PSA (AUC 0.58). High probability of PCa was associated with low PSA variability (smooth trends), high PSA, high growth rate, many tests over a long time-span and older age. For example, at 4.0 PSA the probability of cancer is 32% for 1 PSA test and increases to 68% for 8 tests over 7 years with smooth, fast growth (0% variability and 50% exponential growth). Our results show that smooth, fast exponential growth in PSA above a baseline predicts an increased probability of PCa. The probability increases as smooth (low variability) trends are observed for more tests over a longer time span, which makes annual testing worth considering. Worrisome PSA trends might be used to trigger further evaluation and continued monitoring of the trends—even at low PSA levels.

Simultaneous determination of free and total prostate-specific antigen by a magnetic particle-based time-resolved fluoroimmunoassay

OBJECTIVES

In this paper, a novel, sensitive and rapid method to simultaneously determine the free and total prostate-specific antigen (fPSA and tPSA) in serum by combining a time-resolved fluoroimmunoassay (TRFIA) and immunomagnetic separation was described.

METHODS

The new approach uses magnetic particles as an immobilization matrix and means of separation, whereas the luminescent europium (Eu) and samarium (Sm) chelates are used as probes. The proposed method was evaluated via a single-step, sandwich-type TRFIA immunoassay of tPSA and fPSA as model analytes in serum.

RESULTS

A new one-step method to simultaneously detect fPSA and tPSA in less than 15 minutes was built up with the detection limits 0.006 ng/mL for fPSA and 0.05 ng/mL for tPSA. The assay ranges for fPSA and tPSA were both 0.5-100 ng/mL, whereas the average recovery of those two obtained by our original mode were 95.9% and 95.3%, respectively. The present new TRFIA method carrying larger reproducibility, higher recovery, and sensitive specificity was demonstrated to be widely acceptable.

CONCLUSIONS

This simultaneous determination method containing a fast and sensitive approach can be put into an important position to screening large quantities of specimen, and be commonly applied to the clinical determination of fPSA and tPSA in human serum.