Racial differences in prostate-specific antigen levels and prostate-specific antigen densities in patients with prostate cancer

Prostate Cancer, Race, and Health Disparity: What We Know

ABSTRACT

Prostate cancer (PCa) in African American men is one of the most common cancers with a great disparity in outcomes. The higher incidence and tendency to present with more advanced disease have prompted investigators to postulate that this is a problem of innate biology. However, unequal access to health care and poorer quality of care raise questions about the relative importance of genetics versus social/health injustice. Although race is inconsistent with global human genetic diversity, we need to understand the sociocultural reality that race and racism impact biology. Genetic studies reveal enrichment of PCa risk alleles in populations of West African descent and population-level differences in tumor immunology. Structural racism may explain some of the differences previously reported in PCa clinical outcomes; fortunately, there is high-level evidence that when care is comparable, outcomes are comparable.

Genetic Contributions to Prostate Cancer Disparities in Men of West African Descent

Prostate cancer (PCa) is the second most frequently diagnosed malignancy and the second leading cause of death in men worldwide, after adjusting for age. According to the International Agency for Research on Cancer, continents such as North America and Europe report higher incidence of PCa; however, mortality rates are highest among men of African ancestry in the western, southern, and central regions of Africa and the Caribbean. The American Cancer Society reports, African Americans (AAs), in the United States, have a 1.7 increased incidence and 2.4 times higher mortality rate, compared to European American's (EAs). Hence, early population history in west Africa and the subsequent African Diaspora may play an important role in understanding the global disproportionate burden of PCa shared among Africans and other men of African descent. Nonetheless, disparities involved in diagnosis, treatment, and survival of PCa patients has also been correlated to socioeconomic status, education and access to healthcare. Although recent studies suggest equal PCa treatments yield equal outcomes among patients, data illuminates an unsettling reality of disparities in treatment and care in both, developed and developing countries, especially for men of African descent. Yet, even after adjusting for the effects of the aforementioned factors; racial disparities in mortality rates remain significant. This suggests that molecular and genomic factors may account for much of PCa disparities.

Glucocorticoids Induce Stress Oncoproteins Associated with Therapy-Resistance in African American and European American Prostate Cancer Cells

Glucocorticoid receptor (GR) is emerging as a key driver of prostate cancer (PCa) progression and therapy resistance in the absence of androgen receptor (AR) signaling. Acting as a bypass mechanism, GR activates AR-regulated genes, although GR-target genes contributing to PCa therapy resistance remain to be identified. Emerging evidence also shows that African American (AA) men, who disproportionately develop aggressive PCa, have hypersensitive GR signaling linked to cumulative stressful life events. Using racially diverse PCa cell lines (MDA-PCa-2b, 22Rv1, PC3, and DU145) we examined the effects of glucocorticoids on the expression of two stress oncoproteins associated with PCa therapy resistance, Clusterin (CLU) and Lens Epithelium-Derived Growth Factor p75 (LEDGF/p75). We observed that glucocorticoids upregulated LEDGF/p75 and CLU in PCa cells. Blockade of GR activation abolished this upregulation. We also detected increased GR transcript expression in AA PCa tissues, compared to European American (EA) tissues, using Oncomine microarray datasets. These results demonstrate that glucocorticoids upregulate the therapy resistance-associated oncoproteins LEDGF/p75 and CLU, and suggest that this effect may be enhanced in AA PCa. This study provides an initial framework for understanding the contribution of glucocorticoid signaling to PCa health disparities.

Clarifying the PSA grey zone: The management of patients with a borderline PSA

INTRODUCTION

Prostate specific antigen is a marker for prostate cancer and a key diagnostic tool, yet when to refer patients with a borderline PSA is currently unclear. This review describes how to assess a patient with borderline PSA and provides an algorithm for management.

METHODS

Current literature on reference values, factors affecting PSA, indications for referral, non-invasive investigations and the role of MRI were reviewed. Medline and EMBASE were searched using MeSH terms.

RESULTS

The literature suggests that a PSA of over 1.5 ng/mL should be used as a cut-off to consider further testing for all age groups. There is strong evidence to show that adjuncts are useful when interpreting PSA results, most notably percentage free PSA and proPSA. Considerable weighting should also be given to the ERSPC risk calculator when deciding when to refer. Multi-parametric MRI is valuable in closely examining suspicious lesions to reduce the number of negative biopsies. MRI fusion biopsy (TRUS, transrectal ultrasonography or transperineal) should be considered over standard TRUS biopsy to detect more clinically significant disease.

CONCLUSIONS

Management of borderline PSA is not straightforward. A cut-off of 1.5 ng/mL should be used in conjunction with digital rectal exam, risk calculation and PSA adjuncts. Imaging and biopsy should utilise mpMRI to achieve improved diagnosis of clinically significant prostate cancer, with fewer unnecessary investigations.

The role of an abnormal prostate-specific antigen level and an abnormal digital rectal examination in the diagnosis of prostate cancer: A cross-sectional study in Qatar

Objective

To investigate the role of an abnormal prostate-specific antigen (PSA) level and abnormal findings on a digital rectal examination (DRE) in the detection of prostate cancer in men in Qatar.

Patients and methods

Between June 2008 and September 2012, 651 patients had a transrectal ultrasonography-guided biopsy of the prostate (TRUSBP) at our centre. The indications for a biopsy were a high PSA level (>4 ng/mL), or an abnormal DRE result. Patients were assessed by a thorough history, clinical examination and routine laboratory investigations. Data, including age, DRE findings, TRUS findings, total PSA level, prostate volume and the pathology results, were evaluated.

Results

The mean (SD) age of the 651 patients was 64.1 (7.4) years. Prostate cancer was detected in 181 men (27.8%), benign prostatic hyperplasia in 275 (42.2%) and prostatitis in 236 (36.4%). The sensitivity and specificity for detecting prostate cancer were 93.9% and 8.5% for an abnormal PSA level (>4 ng/mL), 46.1% and 84.7% for abnormal DRE findings, and 95% and 30.2% for the two combined. Using a receiver operating characteristics curve, a PSA threshold of 7.9 ng/mL had a sensitivity of 56.6% and specificity of 52.8%. When a PSA threshold of 7.9 ng/mL was used in combination with abnormal DRE findings, the overall accuracy was 76.9%.

Conclusion

The PSA threshold level of 7.9 ng/mL, determined by this analysis, has a higher likelihood of detecting prostate cancer in men in Qatar. However, it failed to detect cancer in substantially many men with statistically significant disease.

Race, genetic West African ancestry, and prostate cancer prediction by prostate-specific antigen in prospectively screened high-risk men

"Race-specific" prostate-specific antigen (PSA) needs evaluation in men at high risk for prostate cancer for optimizing early detection. Baseline PSA and longitudinal prediction for prostate cancer were examined by self-reported race and genetic West African (WA) ancestry in the Prostate Cancer Risk Assessment Program, a prospective high-risk cohort. Eligibility criteria were age 35 to 69 years, family history of prostate cancer, African American race, or BRCA1/2 mutations. Biopsies were done at low PSA values (<4.0 ng/mL). WA ancestry was discerned by genotyping 100 ancestry informative markers. Cox proportional hazards models evaluated baseline PSA, self-reported race, and genetic WA ancestry. Cox models were used for 3-year predictions for prostate cancer. Six hundred forty-six men (63% African American) were analyzed. Individual WA ancestry estimates varied widely among self-reported African American men. Race-specific differences in baseline PSA were not found by self-reported race or genetic WA ancestry. Among men with > or =1 follow-up visit (405 total, 54% African American), 3-year prediction for prostate cancer with a PSA of 1.5 to 4.0 ng/mL was higher in African American men with age in the model (P = 0.025) compared with European American men. Hazard ratios of PSA for prostate cancer were also higher by self-reported race (1.59 for African American versus 1.32 for European American, P = 0.04). There was a trend for increasing prediction for prostate cancer with increasing genetic WA ancestry. "Race-specific" PSA may need to be redefined as higher prediction for prostate cancer at any given PSA in African American men. Large-scale studies are needed to confirm if genetic WA ancestry explains these findings to make progress in personalizing prostate cancer early detection.

Correlation between serum prostate-specific antigen and alpha-1-antitrypsin in men without and with prostate cancer

Prostate specific antigen (PSA) is frequently used for prostate cancer (PCa) screening, but serum levels are also increased by prostate inflammation. Elevations in serum levels of alpha1-antitrypsin (ATT), a marker of inflammation, in cancer patients are well documented. However, an association between PSA and ATT has never been investigated. The authors, therefore, measured serum acute phase proteins (APPs) ATT, alpha1-acid glycoprotein, C-reactive protein, and alpha1-antichymotrypsin in 174 men without and 34 with newly diagnosed untreated PCa (38-80 years old). As expected, men with PCa had higher mean PSA levels than those without PCa (P < 0.00001). Men with PCa and those without PCa but with PSA >2 ng/mL (n = 68) had significantly higher ATT concentrations than those without these conditions (n = 106) (mean +/- SEM g/L): 1.94+/-0.083, 1.92+/-0.066, 1.25+/-0.043, respectively; p <0.005). Interestingly, African-American men without PCa (n=111) had higher ATT levels than Caucasian men (n=63) (1.565+/-0.045 g/l versus 1.395+/-0.056 g/l; p <0.005); and differences persisted in men with PSA >2 ng/ml (2.094+/-0.07 g/l versus 1.593 for all0.095 g/l; p<0.0002). There were no differences among groups in the levels of other APP. ATT showed the strongest correlation with PSA (r = 0.346 to 0.395; p <0.001) than any other APP (r < or =0.245). Our data suggest that men with PCa have higher ATT levels than those without PCa; and African-American men without PCa have higher ATT levels than Caucasian men. The possible implications of elevated ATT levels in African-American men on the risk of PCa are discussed.

Focus groups in the design of prostate cancer screening information for Hispanic farmworkers and African American men

PURPOSE/OBJECTIVES

To gain a better understanding of men's everyday concerns as part of formative research for creating relevant prostate cancer screening education; to describe methods and processes used to conduct community-based focus groups.

SETTING

Community-based settings in catchment areas surrounding Tampa, FL.

SAMPLE

8 community-based focus groups: a total of 71 Hispanic farmworkers and African American men.

METHODS

Focus group discussions were tape-recorded, transcribed, and analyzed for identification of emergent themes.

MAIN RESEARCH VARIABLES

General life and health priorities, prostate cancer knowledge, screening attitudes, cancer beliefs, and learning preferences.

FINDINGS

Major themes among African American men were importance of work, family, and faith. Major themes among Hispanic farmworkers were importance of family, employment, education of children, and faith. A common issue that surfaced among most men was that a cancer diagnosis was considered to be a death sentence. Preferred learning methods included use of cancer survivors as spokespeople, interactive group education, and the provision of easy-to-understand information. Issues of trust, respect, and community involvement were key to the successful conduct of focus groups among ethnically diverse groups.

CONCLUSIONS

Study findings have important implications for the content of information developed for prostate cancer education materials and media.

IMPLICATIONS FOR NURSING

Insights gained from focus group methodology can help nurses and other healthcare professionals design and develop appropriate prostate cancer education tools for use in community-based prostate cancer screening programs.

Comparison of the predictive accuracy of serum prostate specific antigen levels and prostate specific antigen density in the detection of prostate cancer in Hispanic-American and white men

PURPOSE

The Hispanic-American population is the fastest growing in the United States. Although many studies have looked at the performance of prostate specific antigen (PSA) in the detection of prostate cancer in white and black men, few have looked at it in relation to Hispanic men. The objective of this study was to compare the performance of PSA and PSA density (PSAD) in the detection of prostate cancer in Hispanic and white men.

MATERIALS AND METHODS

A total of 404 consecutive Hispanic and 341 consecutive white men with elevated serum PSA and/or abnormal digital rectal examination underwent transrectal ultrasound with lesion directed and systematic peripheral zone biopsies from 1996 to 2001 at a single institution by 2 investigators (ETG, MCB). Before biopsy all patients underwent volume measurements of the entire prostate. Of these patients 242 Hispanic and 255 white men had a total PSA between 2.5 and 10 ng/ml. Serum PSA and calculated PSAD were compared between the positive and negative biopsy groups, and between Hispanic and white men.

RESULTS

Of the 242 Hispanic and 255 white men 85 (35.1%) and 63 (24.7%) had cancer, respectively (p = 0.0147). There was no significant difference in age among the groups. There was no significant difference in median PSA between Hispanic and white men, or white men with malignant versus benign disease. There was a significant difference in median PSA in Hispanic men with malignant versus benign disease (6.3 vs 5.2 ng/ml, p = 0.0072). For PSAD there was a significant difference between Hispanic men with malignant versus benign disease (0.17 vs 0.12, p <0.0001) and white men with malignant versus benign disease (0.13 vs 0.11, p = 0.0019). Overall there was a difference in PSAD between positive and negative biopsy groups, and there was a significant difference in PSAD between Hispanic and white men (0.13 vs 0.11, p <0.0001).

CONCLUSIONS

This study shows for the first time that at similar levels of total PSA, PSAD is higher in Hispanic than in white men. Furthermore, these data show that while PSA was able to discriminate between malignant versus benign disease in Hispanic men, it was not able to do so in white men. Given the large number of patients in this series perhaps different PSAD cutoffs need to be defined for Hispanic men. Further study in this area is warranted.

Predictors of extracapsular extension and positive margins in African American and white men

OBJECTIVE

Radical retropubic prostatectomy (RRP) pathology from African American (AA) and White men from 1988 to 1999 was examined to determine if the pre-treatment factors PSA, clinical stage, biopsy grade, age at surgery, and year of surgery (YOS) were predictive of extracapsular extension (ECE) and positive margins for each ethnic group.

METHODS

Clinical and pathologic data was collected on 179 AA and 548 white men undergoing RRP from 1988 to 1999 at a tertiary military medical facility. Logistic regression with multivariate analysis was used to determine which pre-operative data-points were predictive of pathologic ECE and positive margins for each ethnic group.

RESULTS

PSA, biopsy grade, age, and YOS (more recent years had better surgical pathology) were predictive of ECE for AA and white men. PSA, biopsy grade, and YOS were predictive of positive margins for AA men, while PSA and YOS were predictive of positive margins for white men. PSA continues to be a strong predictor of ECE and positive margins for both AA and white men. However, we describe for the first time, YOS being predictive of ECE and positive margins for both AA and White men, using multivariate regression analysis.

CONCLUSION

This is thought to be reflective of the improving public awareness of prostate cancer that has occurred during the PSA-era, resulting in patients participating in screening programs and being diagnosed earlier. Close follow-up of these patients is warranted to determine if the improved pathologic stage of those patients treated more recently translates into improved disease-specific mortality.

Prostate-specific antigen testing accuracy in community practice

BACKGROUND

Most data on prostate-specific antigen (PSA) testing come from urologic cohorts comprised of volunteers for screening programs. We evaluated the diagnostic accuracy of PSA testing for detecting prostate cancer in community practice.

METHODS

PSA testing results were compared with a reference standard of prostate biopsy. Subjects were 2,620 men 40 years and older undergoing (PSA) testing and biopsy from 1/1/95 through 12/31/98 in the Albuquerque, New Mexico metropolitan area. Diagnostic measures included the area under the receiver-operating characteristic curve, sensitivity, specificity, and likelihood ratios.

RESULTS

Cancer was detected in 930 subjects (35%). The area under the ROC curve was 0.67 and the PSA cutpoint of 4 ng/ml had a sensitivity of 86% and a specificity of 33%. The likelihood ratio for a positive test (LR+) was 1.28 and 0.42 for a negative test (LR-). PSA testing was most sensitive (90%) but least specific (27%) in older men. Age-specific reference ranges improved specificity in older men (49%) but decreased sensitivity (70%), with an LR+ of 1.38. Lowering the PSA cutpoint to 2 ng/ml resulted in a sensitivity of 95%, a specificity of 20%, and an LR+ of 1.19.

CONCLUSIONS

PSA testing had fair discriminating power for detecting prostate cancer in community practice. The PSA cutpoint of 4 ng/ml was sensitive but relatively non-specific and associated likelihood ratios only moderately revised probabilities for cancer. Using age-specific reference ranges and a PSA cutpoint below 4 ng/ml improved test specificity and sensitivity, respectively, but did not improve the overall accuracy of PSA testing.

Screening for prostate cancer in African Americans

African American men are known to have a higher risk of developing prostate cancer. Historically, African American men have presented at a higher stage and had a worse outcome from the disease than non-African American men. There is an ongoing debate whether this disparity is due to biologic, environmental, or behavioral factors, or a combination of these factors. Furthermore, lack of access to care is implicated. Despite this debate, there is emerging data that African American men and their families are receptive to education and early detection. Encouraging data from the military, Veteran's Administration, and private sector suggest that African American men can have a similar outcome to non-African American men if diagnosed early and treated effectively. Early detection efforts depend on prostate-specific antigen (PSA) testing. This article discusses various options for using the PSA test to more effectively screen African American men. In general, testing starting at age 40 is recommended using an upper limit of normal for PSA at 2.0 to 2.5 ng/mL for men between 40 and 49 years of age. In older men, maintaining this lower PSA threshold is reasonable to optimize curable cancer; however, published guidelines of 0 to 4.0, 0 to 4.5, and 0 to 5.5 ng/mL in African American men in their 50s, 60s, and 70s, respectively, are also recognized to balance the sensitivity and specificity of testing. Population-based prospective clinical trials of African American men are needed to further fine-tune the use of PSA in early detection, and to assess whether screening will improve the disease-specific mortality of prostate cancer in the population.