Molecular basis for prostate cancer racial disparities

Advances in the understanding of androgen receptor structure and function and in the development of next-generation AR-targeted therapeutics

Androgen receptor (AR) and its ligand androgens are important for development and physiology of various tissues. AR and its ligands also play critical role in the development of various diseases, making it a valuable therapeutic target. AR ligands, both agonists and antagonists, are being widely used to treat pathological conditions, including prostate cancer and hypogonadism. Despite AR being studied widely over the last five decades, the last decade has seen striking advances in the knowledge on AR and discoveries that have the potential to translate to the clinic. This review provides an overview of the advances in AR biology, AR molecular mechanisms of action, and next generation molecules that are currently in development. Several of the areas described in the review are just unraveling and the next decade will bring more clarity on these developments that will put AR at the forefront of both basic biology and drug development.

Prostate cancer metastasis and health disparities: a systematic review

BACKGROUND

Prostate cancer (PCa), one of the most prevalent malignancies affecting men, significantly contributes to increased mortality rates worldwide. While the causative death is due to advanced metastatic disease, this occurrence disproportionately impacts men of African descent compared to men of European descent. In this review, we describe potential mechanisms underlying PCa metastases disparities and current treatments for metastatic disease among these populations, differences in treatment outcomes, and survival rates, in hopes of highlighting a need to address disparities in PCa metastases.

METHODS

We reviewed existing literature using databases such as PubMed, Google Scholar, and Science Direct using the following keywords: "prostate cancer metastases", "metastatic prostate cancer disparity", "metastatic prostate cancer diagnosis and treatment", "prostate cancer genetic differences and mechanisms", "genetic differences and prostate tumor microenvironment", and "men of African descent and access to clinical treatments". The inclusion criteria for literature usage were original research articles and review articles.

RESULTS

Studies indicate unique genetic signatures and molecular mechanisms such as Epithelial-Mesenchymal Transition (EMT), inflammation, and growth hormone signaling involved in metastatic PCa disparities. Clinical studies also demonstrate differences in treatment outcomes that are race-specific, for example, patients of African descent have a better response to enzalutamide and immunotherapy yet have less access to these drugs as compared to patients of European descent.

CONCLUSIONS

Growing evidence suggests a connection between a patient's genetic profile, the prostate tumor microenvironment, and social determinants of health that contribute to the aggressiveness of metastatic disease and treatment outcomes. With several potential pathways highlighted, the limitations in current diagnostic and therapeutic applications that target disparity in PCa metastases warrant rigorous research attention.

Survival Outcomes by Race and Ethnicity in Veterans With Nonmetastatic Castration-Resistant Prostate Cancer

Importance

Racial and ethnic disparities in prostate cancer are poorly understood. A given disparity-related factor may affect outcomes differently at each point along the highly variable trajectory of the disease.

Objective

To examine clinical outcomes by race and ethnicity in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC) within the US Veterans Health Administration.

Design, Setting, and Participants

A retrospective, observational cohort study using electronic health care records (January 1, 2006, to December 31, 2021) in a nationwide equal-access health care system was conducted. Mean (SD) follow-up time was 4.3 (3.3) years. Patients included in the analysis were diagnosed with prostate cancer from January 1, 2006, to December 30, 2020, that progressed to nmCRPC defined by (1) increasing prostate-specific antigen levels, (2) ongoing androgen deprivation, and (3) no evidence of metastatic disease. Patients with metastatic disease or death within the landmark period (3 months after the first nmCRPC evidence) were excluded.

Main Outcomes and Measures

The primary outcome was time from the landmark period to death or metastasis; the secondary outcome was overall survival. A multivariate Cox proportional hazards model, Kaplan-Meier estimates, and adjusted survival curves were used to evaluate outcome differences by race and ethnicity.

Results

Of 12 992 patients in the cohort, 826 patients identified as Hispanic (6%), 3671 as non-Hispanic Black (28%; henceforth Black), 7323 as non-Hispanic White (56%; henceforth White), and 1172 of other race and ethnicity (9%; henceforth other, including American Indian or Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, unknown by patient, and patient declined to answer). Median time elapsed from nmCRPC to metastasis or death was 5.96 (95% CI, 5.58-6.34) years for Black patients, 5.62 (95% CI, 5.11-6.67) years for Hispanic patients, 4.11 (95% CI, 3.96-4.25) years for White patients, and 3.59 (95% CI, 3.23-3.97) years for other patients. Median unadjusted overall survival was 6.26 (95% CI, 6.03-6.46) years among all patients, 8.36 (95% CI, 8.0-8.8) years for Black patients, 8.56 (95% CI, 7.3-9.7) years for Hispanic patients, 5.48 (95% CI, 5.2-5.7) years for White patients, and 4.48 (95% CI, 4.1-5.0) years for other patients.

Conclusions and Relevance

The findings of this cohort study of patients with nmCRPC suggest that differences in outcomes by race and ethnicity exist; in addition, Black and Hispanic men may have considerably improved outcomes when treated in an equal-access setting.

Immunologic Assessment of Tumors from a Race-matched Military Cohort Identifies Mast Cell Depletion as a Marker of Prostate Cancer Progression

Elucidating the cellular immune components underlying aggressive prostate cancer, especially among African American (AA) men who are disproportionately affected by this disease compared with Caucasian American (CA) men, will support more inclusive precision medicine treatment strategies. We aimed to evaluate which immune-related genes and cell types are differentially expressed in AA tumors and how immunobiology impacts prostate cancer progression. We purified nucleic acid from tumor biopsies, obtained following radical prostatectomy, from 51 patients (AA = 26, CA = 25). Gene expression was measured using the NanoString platform from which we estimated immune cell abundances and assessed differences between groups based on clinicopathologic data. Product-limit estimates determined associations with biochemical recurrence (BCR)-free and metastasis-free survival. DVL2 and KLRC2 were significantly upregulated in CA tumors and were also associated with worse disease progression. No significant differences in immune cell abundances by race were observed. Highly significant reductions in abundances of mast cells versus tumor-infiltrating lymphocytes (TIL) were found in men with high-grade pathologies and in men who later developed metastases. Low ratios of mast cells versus TILs were associated with worse BCR-free survival and metastasis-free survival. Although estimated immune cell abundances were not different by race, we identified genes involved in metabolism and natural killer cell functions that were differentially expressed between AA and CA tumors. Among the entire cohort, depletion of mast cells within prostatectomy tumors was characteristic of advanced disease and susceptibility to disease progression.

Significance

Our findings demonstrate that there are immune-related genes and pathways that differ by race. Impaired intratumoral cellular immune composition, especially for TIL-normalized mast cells, may be vital in predicting and contributing to prostate cancer disease progression.

Transcriptome Analysis Identifies Tumor Immune Microenvironment Signaling Networks Supporting Metastatic Castration-Resistant Prostate Cancer

Prostate cancer (PCa) is the second most common cause of cancer death in American men. Metastatic castration-resistant prostate cancer (mCRPC) is the most lethal form of PCa and preferentially metastasizes to the bones through incompletely understood molecular mechanisms. Herein, we processed RNA sequencing data from patients with mCRPC (n = 60) and identified 14 gene clusters (modules) highly correlated with mCRPC bone metastasis. We used a novel combination of weighted gene co-expression network analysis (WGCNA) and upstream regulator and gene ontology analyses of clinically annotated transcriptomes to identify the genes. The cyan module (M14) had the strongest positive correlation (0.81, p = 4 × 10-15) with mCRPC bone metastasis. It was associated with two significant biological pathways through KEGG enrichment analysis (parathyroid hormone synthesis, secretion, and action and protein digestion and absorption). In particular, we identified 10 hub genes (ALPL, PHEX, RUNX2, ENPP1, PHOSPHO1, PTH1R, COL11A1, COL24A1, COL22A1, and COL13A1) using cytoHubba of Cytoscape. We also found high gene expression for collagen formation, degradation, absorption, cell-signaling peptides, and bone regulation processes through Gene Ontology (GO) enrichment analysis.

Investigating miR-9 as a mediator in laryngeal cancer health disparities

Background

For several decades, Black patients have carried a higher burden of laryngeal cancer among all races. Even when accounting for sociodemographics, a disparity remains. Differentially expressed microRNAs have been linked to racially disparate clinical outcomes in breast and prostate cancers, yet an association in laryngeal cancer has not been addressed. In this study, we present our computational analysis of differentially expressed miRNAs in Black compared with White laryngeal cancer and further validate microRNA-9-5p (miR-9-5p) as a potential mediator of cancer phenotype and chemoresistance.

Methods

Bioinformatic analysis of 111 (92 Whites, 19 Black) laryngeal squamous cell carcinoma (LSCC) specimens from the TCGA revealed miRNAs were significantly differentially expressed in Black compared with White LSCC. We focused on miR-9-5 p which had a significant 4-fold lower expression in Black compared with White LSCC (p<0.05). After transient transfection with either miR-9 mimic or inhibitor in cell lines derived from Black (UM-SCC-12) or White LSCC patients (UM-SCC-10A), cellular migration and cell proliferation was assessed. Alterations in cisplatin sensitivity was evaluated in transient transfected cells via IC50 analysis. qPCR was performed on transfected cells to evaluate miR-9 targets and chemoresistance predictors, ABCC1 and MAP1B.

Results

Northern blot analysis revealed mature miR-9-5p was inherently lower in cell line UM-SCC-12 compared with UM-SCC-10A. UM -SCC-12 had baseline increase in cellular migration (p < 0.01), proliferation (p < 0.0001) and chemosensitivity (p < 0.01) compared to UM-SCC-10A. Increasing miR-9 in UM-SCC-12 cells resulted in decreased cellular migration (p < 0.05), decreased proliferation (p < 0.0001) and increased sensitivity to cisplatin (p < 0.001). Reducing miR-9 in UM-SCC-10A cells resulted in increased cellular migration (p < 0.05), increased proliferation (p < 0.05) and decreased sensitivity to cisplatin (p < 0.01). A significant inverse relationship in ABCC1 and MAP1B gene expression was observed when miR-9 levels were transiently elevated or reduced in either UM-SCC-12 or UM-SCC-10A cell lines, respectively, suggesting modulation by miR-9.

Conclusion

Collectively, these studies introduce differential miRNA expression in LSCC cancer health disparities and propose a role for low miR-9-5p as a mediator in LSCC tumorigenesis and chemoresistance.

Health inequity drives disease biology to create disparities in prostate cancer outcomes

Prostate cancer exerts a greater toll on African American men than on White men of European descent (hereafter referred to as European American men): the disparity in incidence and mortality is greater than that of any other common cancer. The disproportionate impact of prostate cancer on Black men has been attributed to the genetics of African ancestry, to diet and lifestyle risk factors, and to unequal access to quality health care. In this Review, all of these influences are considered in the context of the evolving understanding that chronic or recurrent inflammatory processes drive prostatic carcinogenesis. Studies of inherited susceptibility highlight the contributions of genes involved in prostate cell and tissue repair (BRCA1/2, ATM) and regeneration (HOXB13 and MYC). Social determinants of health appear to accentuate these genetic influences by fueling prostate inflammation and associated cell and genome damage. Molecular characterization of the prostate cancers that arise in Black versus White men further implicates this inflammatory microenvironment in disease behavior. Yet, when Black and White men with similar grade and stage of prostate cancer are treated equally, they exhibit equivalent outcomes. The central role of prostate inflammation in prostate cancer development and progression augments the impact of the social determinants of health on disease pathogenesis. And, when coupled with poorer access to high-quality treatment, these inequities result in a disparate burden of prostate cancer on African American men.

Overall and progression-free survival of Afro-Caribbean men with metastatic castration-resistant prostate cancer (mCRPC)

INTRODUCTION

Several studies in the Caucasian population have shown the benefit of using docetaxel, abiraterone, or enzalutamide for patients with metastatic prostate cancer at the castration-resistant stage (mCRPC). However, there are no strong data for men of African ancestry. The objective of this study was to estimate the overall and progression-free survival of patients according to these treatments at the mCRPC stage.

PATIENTS AND METHODS

This was a monocentric retrospective study that consecutively included 211 men with mCRPC between June 1, 2009 and August 31, 2020. The primary end point was overall survival (OS). The secondary end point was progression-free survival. Kaplan-Meier survival and Cox proportional hazard analyses were performed.

RESULTS

The present study included 180 patients for analyses. There was no difference in OS (log-rank test = 0.73), with a median follow-up of 20.7 months, regardless of the treatment administered in the first line. Men with mCRPC who received hormonotherapy (abiraterone or enzalutamide) showed better progression-free survival than those who received docetaxel (log-rank test = 0.004), with a particular interest for abiraterone hazard ratio (HR) = 0.51 (95% confidence interval: 0.39-0.67). The patient characteristics were similar, except for bone lesions, irrespective of the treatment administered in the first line. After univariate then multivariate analysis, only World Health Organization status and metastases at diagnosis were significantly associated with progression.

CONCLUSION

Our results suggest the use of hormonotherapy (abiraterone or enzalutamide) with a tendency for abiraterone in first line for men with African ancestry at the mCRPC stage.

Coexpression network analysis identified lncRNAs-mRNAs with potential relevance in African ancestry prostate cancer

AIM

This study aims to investigate similarities and differences using lncRNA and mRNA coexpression network analysis in African ancestry (AA) and European ancestry (EA) among prostate cancer (PCa) patients.

METHODS

We performed weighted gene coexpression network analysis of the expression from 49 of AA and 49 of EA to identify lncRNAs-mRNAs.

RESULTS

27 lncRNAs and 36 mRNAs were highly expressed in patients of AA. Two mRNAs and their antisense lncRNAs were expressed. Additionally, seven mRNAs were DE or coexpressed and had an impact on survival.

CONCLUSION

We present a list of lncRNAs and mRNAs that were DE and coexpressed when comparing patients of AA and EA, and these data are a resource for future studies to understand the role of lncRNAs.

In Situ Analysis of N-Linked Glycans as Potential Biomarkers of Clinical Course in Human Prostate Cancer

Prostate cancer is the most common cancer in men worldwide. Despite its prevalence, there is a critical knowledge gap in understanding factors driving disparities in survival among different cohorts of patients with prostate cancer. Identifying molecular features separating disparate populations is an important first step in prostate cancer research that could lead to fundamental hypotheses in prostate biology, predictive biomarker discovery, and personalized therapy. N-linked glycosylation is a cotranslational event during protein folding that modulates a myriad of cellular processes. Recently, aberrant N-linked glycosylation has been reported in prostate cancers. However, the full clinical implications of dysregulated glycosylation in prostate cancer has yet to be explored. Herein, we performed direct on-tissue analysis of N-linked glycans using matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) from tissue microarrays of over 100 patient tumors with over 10 years of follow-up metadata. We successfully identified a panel of N-glycans that are unique between benign and prostate tumor tissue. Specifically, high-mannose as well as tri-and tetra-antennary N-glycans were more abundant in tumor tissue and increase proportionally with tumor grade. Further, we expanded our analyses to examine the N-glycan profiles of Black and Appalachian patients and have identified unique glycan signatures that correlate with recurrence in each population. Our study highlights the potential applications of MALDI-MSI for digital pathology and biomarker discovery for prostate cancer. IMPLICATIONS: MALDI-MSI identifies N-glycan perturbations in prostate tumors compared with benign tissue. This method can be utilized to predict prostate cancer recurrence and study prostate cancer disparities.

Clinical Outcomes and Racial Disparities in Metastatic Hormone-Sensitive Prostate Cancer in the Era of Novel Treatment Options

BACKGROUND

Docetaxel (DOC) and abiraterone (ABI) in the upfront setting have separately improved clinical outcomes for metastatic hormone-sensitive prostate cancer (mHSPC), but there are no studies comparing drug efficacies or the influence of racial disparities.

MATERIALS AND METHODS

We performed a retrospective multicenter review from Winship Cancer Institute at Emory University and Georgia Cancer Center for Excellence at Grady Memorial Hospital (2014-2020) for patients with mHSPC treated with either upfront DOC or ABI. Outcomes evaluated were overall survival (OS), progression-free survival (PFS), and prostate-specific antigen complete response (PSA CR).

RESULTS

A total of 168 patients were included, consisting of 92 (54.8%) Black patients and 76 (45.2%) non-Black patients (69 White and 7 Asian or Hispanic). Ninety-four (56%) received DOC and 74 (44%) received ABI. Median follow-up time was 22.8 months with data last reviewed June 2020. For OS, there was no significant difference between ABI versus DOC and Black versus non-Black patients. For PFS, DOC was associated with hazard ratio (HR) 1.7 compared with ABI for all patients based on univariate association and HR 2.27 compared with ABI for Black patients on multivariable analysis. For PSA CR, Black patients were less likely to have a CR (odds ratio [OR] = 0.27).

CONCLUSION

ABI and DOC have similar OS with a trend toward better PFS for ABI in a cohort composed of 54% Black patients. Racial disparities were observed as prolonged PFS for Black patients treated with ABI, more so compared with all patients, and less PSA CR for Black patients. A prospective trial comparing available upfront therapies in a diverse racial population is needed to help guide clinical decision-making in the era of novel treatment options.

IMPLICATIONS FOR PRACTICE

Overall survival is similar for abiraterone and docetaxel when used as upfront therapy in metastatic hormone-sensitive prostate cancer in a cohort composed of 54% Black patients. There is a trend towards improved progression-free survival for abiraterone in all patients and Black patients. Non-Black patients were more likely to achieve prostate-specific antigen (PSA) complete response regardless of upfront therapy.

A review of new hormonal therapies for prostate cancer in black men: is there enough data?

BACKGROUND

Prostate cancer among black men is known to have specific molecular characteristics, especially the androgen receptor or enzymes related to the androgen metabolism. These targets are keys to the action of new hormonal therapies. Nevertheless, literature has a lack of data regarding black men. We aimed to gather the available literature data on new hormonal therapies among black populations.

METHODS

We conducted a literature review from the PubMed / MEDLINE database until October 2020. All clinical studies of new hormonal therapies and black populations, regardless of methodology, were included.

RESULTS

Four studies provided data on new hormonal therapies in black populations. Three studies reported a PSA decline in black patients treated with Abiraterone, higher in black men than in white men. Overall survival also appears to be higher in black patients treated with Abiraterone only or first.

CONCLUSION

Few articles have evaluated the effectiveness and safety of use of these treatments among black populations. The first results seem to show that Abiraterone can provide a benefit in overall survival in black populations. Prospective studies are needed to answer these questions in the future.

MYC DNA Methylation in Prostate Tumor Tissue Is Associated with Gleason Score

Increasing evidence suggests a role of epigenetic mechanisms at chromosome 8q24, an important cancer genetic susceptibility region, in prostate cancer. We investigated whether MYC DNA methylation at 8q24 (six CpG sites from exon 3 to the 3′ UTR) in prostate tumor was associated with tumor aggressiveness (based on Gleason score, GS), and we incorporated RNA expression data to investigate the function. We accessed radical prostatectomy tissue for 50 Caucasian and 50 African American prostate cancer patients at the University of Maryland Medical Center, selecting an equal number of GS 6 and GS 7 cases per group. MYC DNA methylation was lower in tumor than paired normal prostate tissue for all six CpG sites (median difference: −14.74 to −0.20 percentage points), and we observed similar results for two nearby sites in The Cancer Genome Atlas (p < 0.0001). We observed significantly lower methylation for more aggressive (GS 7) than less aggressive (GS 6) tumors for three exon 3 sites (for CpG 212 (chr8:128753145), GS 6 median = 89.7%; GS 7 median = 85.8%; p-value = 9.4 × 10⁻⁴). MYC DNA methylation was not associated with MYC expression, but was inversely associated with PRNCR1 expression after multiple comparison adjustment (q-value = 0.04). Findings suggest that prostate tumor MYC exon 3 hypomethylation is associated with increased aggressiveness.

Psychosocial Stress, Glucocorticoid Signaling, and Prostate Cancer Health Disparities in African American Men

Recent advances in our understanding of racial disparities in prostate cancer (PCa) incidence and mortality that disproportionately affect African American (AA) men have provided important insights into the psychosocial, socioeconomic, environmental, and molecular contributors. There is, however, limited mechanistic knowledge of how the interplay between these determinants influences prostate tumor aggressiveness in AA men and other men of African ancestry. Growing evidence indicates that chronic psychosocial stress in AA populations leads to sustained glucocorticoid signaling through the glucocorticoid receptor (GR), with negative physiological and pathological consequences. Compelling evidence indicates that treatment of castration-resistant prostate cancer (CRPC) with anti-androgen therapy activates GR signaling. This enhanced GR signaling bypasses androgen receptor (AR) signaling and transcriptionally activates both AR-target genes and GR-target genes, resulting in increased prostate tumor resistance to anti-androgen therapy, chemotherapy, and radiotherapy. Given its enhanced signaling in AA men, GR-together with specific genetic drivers-may promote CRPC progression and exacerbate tumor aggressiveness in this population, potentially contributing to PCa mortality disparities. Ongoing and future CRPC clinical trials that combine standard of care therapies with GR modulators should assess racial differences in therapy response and clinical outcomes in order to improve PCa health disparities that continue to exist for AA men.

Racial disparities, cancer and response to oxidative stress

At the intersection of genetics, biochemistry and behavioral sciences, there is a largely untapped opportunity to consider how ethnic and racial disparities contribute to individual sensitivity to reactive oxygen species and how these might influence susceptibility to various cancers and/or response to classical cancer treatment regimens that pervasively result in the formation of such chemical species. This chapter begins to explore these connections and builds a platform from which to consider how the disciplines can be strengthened further.

Self-reported Black race predicts significant prostate cancer independent of clinical setting and clinical and socioeconomic risk factors

INTRODUCTION AND OBJECTIVE

Studies have linked Black race to prostate cancer (CaP) risk but most fail to account for established risk factors such as 5-ARI use, prostate volume, socioeconomic status, and hospital setting. We assess whether Black race remains associated with CaP and Gleason ≥3 + 4 CaP, after adjusting for clinical setting and socioeconomic and clinical factors at prostate biopsy, with a focus on men aged 40-54 years, who may be excluded from current screening guidelines.

METHODS

We recruited 564 men age 40-79 undergoing initial prostate biopsy for abnormal PSA or digital rectal examination (DRE) from three publicly funded and two private hospitals from 2009-2014. Univariate and multivariate analyses examined the associations between hospital type, race, West African Ancestry (WAA), clinical, and sociodemographic risk factors with CaP diagnosis and Gleason ≥3 + 4 CaP. Given changes in CaP screening recommendations, we also assess the multivariate analyses for men aged 40-54.

RESULTS

Black and White men had similar age, BMI, and prostate volume. Black men had higher PSA (8.10 ng/mL vs. 5.63 ng/mL) and PSA density (0.22 ng/mL/cm³ vs. 0.15 ng/mL/cm³, all p < 0.001). Blacks had higher frequency of CaP (63.1% vs. 41.5%, p<0.001) and Gleason ≥3+4 CaP relative to Whites in both public (27.7% vs 11.6%, p<0.001) and private (48.4% vs 21.6%, p = 0.002) settings. In models adjusted for age, first degree family history, prostate volume, 5-ARI use, hospital type, income, marital and educational status, Black race was independently associated with overall CaP diagnosis (OR = 2.13, p = 0.002). There was a significant multiplicative interaction with Black race and abnormal DRE for Gleason ≥3 + 4 CaP (OR = 2.93, p = 0.01). WAA was not predictive of overall or significant CaP among Black men. Black race (OR = 5.66, p = 0.02) and family history (OR = 4.98, p = 0.01) were independently positively associated with overall CaP diagnosis for men aged 40 to 54.

CONCLUSIONS

Black race is independently associated with CaP and Gleason ≥3+4 CaP after accounting for clinical and socioeconomic risk factors including clinical setting and WAA, and has a higher odds ratio of CaP diagnosis in younger men. Further investigation into optimizing screening in Black men aged 40 to 54 is warranted.

Androgen metabolism genes in prostate cancer health disparities

For men in the United States, prostate cancer is common, and newly diagnosed cases of prostate cancer outnumber those of all other cancer types. For prostate cancer, there are racial disparities between Caucasian Americans and African Americans. Androgens and androgen metabolism may be involved in these disparities as well as in the initiation and progression of prostate cancer. Here, we analyzed, in the Cancer Genome Atlas (TCGA) database, the mRNA expression of genes involved in androgen metabolism in prostate cancer based on the patient's race. The results revealed that expressions of UGT2B15 and CYP3A5 are higher but that SRD5A2, CYP17A1, HSD3B2, and AKR1C3 are lower in African American prostate cancers than in those of Caucasian Americans. These genes may relate to the racial disparities associated with prostate cancer. However, the evidence require validation and functional analysis.

Race and risk of metastases and survival after radical prostatectomy: Results from the SEARCH database

BACKGROUND

Black race is associated with prostate cancer (PC) diagnosis and poor outcome. Previously, the authors reported that black men undergoing radical prostatectomy (RP) in equal-access hospitals had an increased risk of biochemical disease recurrence (BCR), but recurrences were equally aggressive as those occurring in white men. The authors examined the association between race and long-term outcomes after RP.

METHODS

Data regarding 1665 black men (37%) and 2791 white men (63%) undergoing RP were analyzed. Using Cox models, the authors tested the association between race and BCR, BCR with a prostate-specific antigen (PSA) doubling time <9 months (aggressive disease recurrence), metastases, PC-specific death, and overall death.

RESULTS

At a median follow-up of 102 months, 1566 men (35%) developed BCR, 217 men (5%) experienced aggressive disease recurrence, 193 men (4%) developed metastases, and 1207 men (27%) had died, 107 of whom (2%) died of PC. White men were older and had a lower preoperative PSA level, a lower biopsy and pathological grade group, and more capsular penetration but less seminal vesicle invasion and positive surgical margins versus black men (all P<.05). Black men were found to have a more recent surgery year (P<.001). On univariable analysis, black race was associated with increased BCR (P = .003) and reduced overall death (P = .017). On multivariable analysis, black race was not found to be associated with BCR (hazard ratio [HR], 1.07; P = .26), aggressive recurrence (HR, 1.14; P = .42), metastasis (HR, 1.24; P = .21), PC-specific death (HR, 1.03; P = .91), or overall death (HR, 1.03; P = .67).

CONCLUSIONS

Among men undergoing RP at equal-access centers, although black men were found to have an increased risk of BCR, they had similar risks of aggressive disease recurrence, metastasis, and PC-specific death compared with white men, and the risk of BCR was found to be similar after controlling for risk parameters. Longer follow-up is needed to confirm these findings. Cancer 2017;123:4199-4206. © 2017 American Cancer Society.