Deconstructing, Addressing, and Eliminating Racial and Ethnic Inequities in Prostate Cancer Care.

CONTEXT: Men of African ancestry have demonstrated markedly higher rates of prostate cancer mortality than men of other races and ethnicities around the world. In fact, the highest rates of prostate cancer mortality worldwide are found in the Caribbean and Sub-Saharan West Africa, and among men of African descent in the USA. Addressing this inequity in prostate cancer care and outcomes requires a focused research approach that creates durable solutions to address the structural, social, environmental, and health factors that create racial disparities in care and outcomes. OBJECTIVE: To introduce a conceptual model for evaluating racial inequities in prostate cancer care to facilitate the development of translational research studies and interventions. EVIDENCE ACQUISITION: A collaborative review of literature relevant to racial inequities in prostate cancer care and outcomes was performed. Existing literature was used to highlight various components of the conceptual model to inform future research and interventions toward equitable care and outcomes. EVIDENCE SYNTHESIS: Racial inequities in prostate cancer outcomes are driven by a series of structural and social determinants of health that impact exposures, mediators, and outcomes. Social determinants of equity, such as laws/policies, economic systems, and structural racism, affect the inequitable access to environmental and neighborhood exposures, in addition to health care access. Although the incidence disparity remains problematic, various studies have demonstrated parity in outcomes when social and health factors, such as access to equitable care, are normalized. Few studies have tested interventions to reduce inequities in prostate cancer among Black men. CONCLUSIONS: Worldwide, men of African ancestry demonstrate worse outcomes in prostate cancer, a phenomenon driven largely by social factors that inform biologic, environmental, and health care risks. A conceptual model was presented that organizes the many factors that influence prostate cancer incidence and mortality. Within that framework, we must understand the current state of inequities in clinical prostate cancer practice, the optimal state of what equitable practice would be, and how achieving equity in prostate cancer care balances costs, benefits, and harms. More robust characterization of the sources of prostate cancer inequities should inform testing of ambitious and innovative interventions as we work toward equity in care and outcomes. PATIENT SUMMARY: Men of African ancestry demonstrate the highest rates of prostate cancer mortality, which may be reduced through social interventions. We present a framework for formalizing the identification of the drivers of prostate cancer inequities to facilitate the development of interventions and trials to eradicate them.

DNA Repair Pathways and Their Association With Lethal Prostate Cancer in African American and European American Men.

Background: Altered DNA damage response (DDR) has emerged as an important mechanism for the development of aggressive prostate cancer among men of European ancestry but not other ancestry groups. Because common mechanisms for aggressive disease are expected, we explored a large panel of DDR genes and pathways to demonstrate that DDR alterations contribute to development of aggressive prostate cancer in both African American and European American men. Methods: We performed a case-case study of 764 African American and European American men with lethal or indolent prostate cancer treated at 4 US hospitals. We calculated carrier frequencies of germline pathogenic or likely pathogenic sequence variants within 306 DDR genes, summarized by DDR pathway, and compared lethal cases against indolent cases using 2-sided Fisher's exact tests. Secondary analysis examined if carrier frequencies differed by ancestry. Results: Lethal cases were more likely to carry a pathogenic sequence variant in a DDR gene compared with indolent cases (18.5% vs 9.6%, P = 4.30 × 10-4), even after excluding BRCA2 (14.6% vs 9.6%, P = .04). The carrier frequency was similar among lethal cases of African (16.7% including and 15.8% excluding BRCA2) and lethal cases of European (19.3% including and 14.2% excluding BRCA2) ancestry. Three DDR pathways were statistically significantly associated with lethal disease: homologous recombination (P = .003), Fanconi anemia (P = .002), and checkpoint factor (P = .02). Conclusions: Our findings suggest that altered DDR is an important mechanism for aggressive prostate cancer not only in men of European but also of African ancestry. Therefore, interrogation of entire DDR pathways is needed to fully characterize and better define genetic risk of lethal disease.

Pro-inflammatory cytokines and chemokines initiate multiple prostate cancer biologic pathways of cellular proliferation, heterogeneity and metastasis in a racially diverse population and underlie the genetic/biologic mechanism of racial disparity: Update.

Pro-inflammatory cytokine and chemokines genes drive prostate cancer progression and metastasis: molecular mechanism update and the science that underlies racial disparity. comprehensive review article. Isaac J. Powell, S. Chinni, S.S. Reddy, Alexander Zaslavsky, Navnath Gavande Introduction: In 2013 we reported that with the use of bioinformatics and ingenuity pathway network analysis we were able to identify functional driver genes that were differentially expressed among a large population of African American men (AAM) and European American men (EAM). Pro-inflammatory cytokine genes were found to be more interactive and more expressed among AAM and have been found to be functional drivers of aggressive prostate cancer (CaP) and aggressiveness in other solid tumors. We examined these genes and biological pathways initiated by these cytokines in primary CaP tissue. Method We unravel the gene network and identified biologic pathways that impacted activation of the androgen receptor, mesenchymal epithelial transition (invasion) and chemokines associated with metastasis in the CaP tissue from 639 radical prostatectomy specimens. Results Biologic pathways identified by unraveling pro-inflammatory genes from our network, more expressed among AAM compared to EAM, were tumor necrosis factor (TNF), IL1b, IL6, and IL8. IL6 and IL8 are downstream of TNF activity and are known activators of androgen receptor and through mediators promote CaP cell proliferation. TNF and IL1b mediate tumor cell invasiveness through the activation of MMP (matrix metalloproteinase) which down regulates E-Cadherin to initiate epithelial mesenchymal transition which allows cells to become invasive in the microenvironment. Ultimately our network analysis indicates that TNF and IL1b activate CXCR4 receptor on CaP cells, which facilitates metastatic progression reportedly by binding to CXCL12 on lipid rafts and tumor implantation in the bone marrow. Conclusion Our retrospective biologic mechanistic model reveals a set of pro-inflammatory cytokines and chemokines that drive CaP aggressiveness, tumor heterogeneity, progression and metastasis. A prospective multi-institutional study needs to be conducted for clinical validation as well consideration of targeted therapy.

The extrema of circulating miR-17 are identified as biomarkers for aggressive prostate cancer.

MicroRNAs (miRNAs) constitute short non-coding RNAs that can post-transcriptionally modulate the expression of many oncogenes and tumor suppressor genes engaged in key cellular processes. Deregulated serum miRNA signatures have been detected in various solid cancers including prostate cancer, suggesting that circulating miRNAs could function as non-invasive biomarkers of tumor emergence and progression. To determine whether serum miRNA expression levels are different between patients with aggressive and non-aggressive prostate cancer, we analyzed a panel of miRNAs from the blood of African American (AA) prostate cancer patients using a new recursive partitioning method that allows hypothesis testing of each split. We observed that both extrema of circulating miR-17, i.e. upregulation and downregulation, are associated with aggressive prostate cancer. A similar effect was observed in tumor samples from a separate dataset representing a different population of prostate cancer patients and in AA prostate cancer samples from the TCGA. The dual effect is consistent with the contradictory findings on the role of miR-17 in prostate cancer progression, whereby it controls important oncogenic and tumor-suppressive genes.

Risk of Becoming Lost to Follow-up During Active Surveillance for Prostate Cancer.

Active surveillance (AS) has emerged as the preferred management strategy for many men with prostate cancer (PC); however, insufficient longitudinal monitoring may increase the risk of poor outcomes. We sought to determine rates of patients becoming lost to follow-up (LTFU) and associated risk factors in a large AS cohort. The Michigan Urologic Surgery Improvement Collaborative (MUSIC) maintains a prospective registry of PC patients from 44 academic and community urology practices. Over a 6-yr period (2011-2017), we identified patients managed with AS. LTFU was defined as any 18-mo period where no pertinent surveillance testing was entered in the registry. With a median surveillance period of 32 mo, the estimated 2-yr LTFU-free probability calculated by Kaplan-Meier method was 90% (95% confidence interval [CI]=89-92%). Both African American race (hazard ratio [HR]: 2.77, 95% CI=1.81-4.24) and Charlson comorbidity index ≥1 (HR: 1.55, 95% CI=1.08-2.23) were independently associated with increased risk of LTFU. There was variability in rates of estimated 2-yr LTFU-free survival across MUSIC practices, ranging from 52% (95% CI=21-100%) to 99% (95% CI=97-100%), with a median of 96% (interquartile range: 94-98%), although this did not reach statistical significance (p=0.076). These data reveal opportunities for urology practices to identify systems to reduce rates of LTFU and improve the long-term safety of AS. PATIENT SUMMARY: With a median observation period of 32 mo, an estimated 10% of patients will be lost to follow-up at the 2 yr time point while on AS. African American men and generally unhealthy patients were at increased risk, and there was variability from one urology practice to another. There is ample opportunity to improve the quality of the performance of AS.

A study of circulating microRNAs identifies a new potential biomarker panel to distinguish aggressive prostate cancer.

Prostate cancer is one of the most common cancers in men worldwide. Currently available diagnostic and prognostic tools for this disease, such as prostate specific antigen, suffer from lack of specificity and sensitivity, resulting in over- and misdiagnosis. Hence, there is an urgent need for clinically relevant biomarkers capable of distinguishing between aggressive and nonaggressive forms of prostate cancer to aid in stratification, management and therapeutic decisions. To address this unmet need, we investigated the patterns of expression of a panel of 68 plasma-derived microRNAs (miRNAs) in a cohort of African American (AA) and European American (EA) prostate cancer patients (n = 114). miRNA qPCR results were analyzed using in-depth statistical methods, and a bioinformatics analysis was conducted to identify potential targets of the differentially expressed miRNAs. Our data demonstrate that a new previously unreported circulating miRNA signature consisting of a combination of interacting miRNAs (miR-17/miR-192) and an independent miRNA (miR-181a) are capable of segregating aggressive and nonaggressive prostate cancer in both AA and EA patients. The interacting miRNAs outperformed independent miRNAs in identifying aggressiveness. Our results suggest that these circulating miRNAs may constitute novel biomarkers of prostate cancer aggressiveness in both races and warrant further investigation.

Exome Sequencing of African-American Prostate Cancer Reveals Loss-of-Function ERF Mutations.

African-American men have the highest incidence of and mortality from prostate cancer. Whether a biological basis exists for this disparity remains unclear. Exome sequencing (n = 102) and targeted validation (n = 90) of localized primary hormone-naïve prostate cancer in African-American men identified several gene mutations not previously observed in this context, including recurrent loss-of-function mutations in ERF, an ETS transcriptional repressor, in 5% of cases. Analysis of existing prostate cancer cohorts revealed ERF deletions in 3% of primary prostate cancers and mutations or deletions in ERF in 3% to 5% of lethal castration-resistant prostate cancers. Knockdown of ERF confers increased anchorage-independent growth and generates a gene expression signature associated with oncogenic ETS activation and androgen signaling. Together, these results suggest that ERF is a prostate cancer tumor-suppressor gene. More generally, our findings support the application of systematic cancer genomic characterization in settings of broader ancestral diversity to enhance discovery and, eventually, therapeutic applications.Significance: Systematic genomic sequencing of prostate cancer in African-American men revealed new insights into prostate cancer, including the identification of ERF as a prostate cancer gene; somatic copy-number alteration differences; and uncommon PIK3CA and PTEN alterations. This study highlights the importance of inclusion of underrepresented minorities in cancer sequencing studies. Cancer Discov; 7(9); 973-83. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 920.

REVEL: An Ensemble Method for Predicting the Pathogenicity of Rare Missense Variants.

The vast majority of coding variants are rare, and assessment of the contribution of rare variants to complex traits is hampered by low statistical power and limited functional data. Improved methods for predicting the pathogenicity of rare coding variants are needed to facilitate the discovery of disease variants from exome sequencing studies. We developed REVEL (rare exome variant ensemble learner), an ensemble method for predicting the pathogenicity of missense variants on the basis of individual tools: MutPred, FATHMM, VEST, PolyPhen, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP, SiPhy, phyloP, and phastCons. REVEL was trained with recently discovered pathogenic and rare neutral missense variants, excluding those previously used to train its constituent tools. When applied to two independent test sets, REVEL had the best overall performance (p < 10-12) as compared to any individual tool and seven ensemble methods: MetaSVM, MetaLR, KGGSeq, Condel, CADD, DANN, and Eigen. Importantly, REVEL also had the best performance for distinguishing pathogenic from rare neutral variants with allele frequencies <0.5%. The area under the receiver operating characteristic curve (AUC) for REVEL was 0.046-0.182 higher in an independent test set of 935 recent SwissVar disease variants and 123,935 putatively neutral exome sequencing variants and 0.027-0.143 higher in an independent test set of 1,953 pathogenic and 2,406 benign variants recently reported in ClinVar than the AUCs for other ensemble methods. We provide pre-computed REVEL scores for all possible human missense variants to facilitate the identification of pathogenic variants in the sea of rare variants discovered as sequencing studies expand in scale.

Considering race and the potential for ERG expression as a biomarker for prostate cancer.

Genomic rearrangement and overexpression of the ERG oncogene (also known as v-ets avian erythroblastosis virus E26 oncogene homolog) is estimated to occur at a rate of 40-50% in prostate cancer. Early evidence suggests that ERG overexpression may be associated with disease progression, and the utilization of ERG levels as a biomarker for prostate cancer is being strongly considered. However, the evidence is incomplete because it relies on studies that primarily focused on men of European ancestry, giving little consideration to African-American men even though African-American men bear a greater disease burden in the form of significantly greater incidence and worse outcomes. In this perspective article we bring to light the issue that the potential use of ERG expression as a biomarker is yet to be solidly established and may have limited utility or varied applicably for African-American men as compared with European-American men.

Reducing prostate cancer racial disparity: evidence for aggressive early prostate cancer PSA testing of African American men.

BACKGROUND: There is continuing controversy about prostate cancer testing and the recent American Urological Association guidelines. We hypothesize that the reduction and elimination of racial survival disparity among African American men (AAM; high-risk group) compared with European American men (EAM; intermediate-risk group) during the PSA testing era compared with the pre-PSA era strongly supports the use of PSA testing in AAM. METHODS: We used Surveillance, Epidemiology, and End Results (SEER) data to investigate relative survival disparities between AAM and EAM. To evaluate pre-PSA testing era, we selected malignant first primary prostate cancer in AAM and EAM, all stages, diagnosed during 1973-1994. To evaluate relative survival disparities in the current PSA testing era, we selected malignant first primary local, regional, and distant stage prostate cancers diagnosed during 1998-2005 to calculate 5-year relative survival rates. RESULTS: Age-adjusted 5-year relative survival of prostate cancer diagnosed during 1973-1994 in the national SEER data revealed significantly shorter survival for AAM compared with EAM (P < 0.0001). The SEER-based survival analysis from 1995 to 2005 indicated no statistical difference in relative survival rates between AAM and EAM by year of diagnosis of local, regional, or distant stage prostate cancer. CONCLUSION: We conclude that the elimination of prostate cancer racial disparity of local, regional, and metastatic prostate cancer relative survival in the current PSA testing era compared with pre-PSA era as an endpoint to test PSA efficacy as a marker for prostate cancer diagnosis is evidence for aggressive testing of AAM. IMPACT: Evidence for screening AAM.

Minireview: the molecular and genomic basis for prostate cancer health disparities.

Despite more aggressive screening across all demographics and gradual declines in mortality related to prostate cancer (PCa) in the United States, race disparities persist. For African American men (AAM), PCa is more often an aggressive disease showing increased metastases and greater PCa-related mortality compared with European American men. The earliest research points to how distinctions are likely the result of a combination of factors, including ancestry genetics and lifestyle variables. More recent research considers that cancer, although influenced by external forces, is ultimately a disease primarily driven by aberrations observed in the molecular genetics of the tumor. Research studying PCa predominantly from European American men shows that indolent and advanced or metastatic prostate tumors have distinguishing molecular genomic make-ups. Early yet increasing evidence suggests that clinically distinct PCa from AAM also display molecular distinctions. It is reasonable to predict that further study will reveal molecular subtypes and various frequencies for PCa subtypes among diverse patient groups, thereby providing insight as to the genomic lesions and gene signatures that are functionally implicated in carcinogenesis or aggressive PCa in AAM. That knowledge will prove useful in developing strategies to predict who will develop advanced PCa among AAM and will provide the rationale to develop effective individualized treatment strategies to overcome disparities.

Genes associated with prostate cancer are differentially expressed in African American and European American men.

BACKGROUND: Despite more aggressive screening across all demographics and gradual declines in mortality related to prostate cancer (PCa) in the United States, disparities among populations persist. A substantial proportion of African American men (AAM) have a higher overall incidence, earlier age of onset, increased proportion of clinically advanced disease, and increased bone metastases and mortality from PCa compared to European American men (EAM). Limited early evidence indicates that underlying causes for disparities may be observed in tumor-specific gene expression programs. METHODS: This study used microarray-based methods to measure expression levels for 517 genes that were previously associated with PCa in archived formalin-fixed paraffin embedded (FFPE) specimens; testing the hypothesis that gene expression features of functional consequence to cancer distinguish PCa from AAM and EAM. A t test was conducted comparing AAM to EAM expression levels for each probe on the array. RESULTS: Analysis of 639 tumor samples (270 AAM, 369 EAM) showed that 95 genes were overexpressed specifically in PCa from AAM relative to EAM and 132 were overexpressed in PCa from EAM relative to AAM. Furthermore, systems-level analyses highlight the relevant signaling pathways and functions associated with the EAM- or AAM-specific overexpressed gene sets, for example, inflammation and lipid metabolism. CONCLUSIONS: Results here bring further understanding to the potential for molecular differences for PCa in AAM versus EAM. IMPACT: The results support the notion that therapeutic benefits will be realized when targeted treatments are designed to acknowledge and address a greater spectrum of PCa subtypes and molecular distinctions.

Improved overall survival trends of men with newly diagnosed M1 prostate cancer: a SWOG phase III trial experience (S8494, S8894 and S9346).

PURPOSE: Frequent prostate specific antigen testing for screening and monitoring prostate cancer has led to significant stage migration. We evaluated whether overall survival in hormone naïve patients with metastatic prostate cancer has improved during the era of prostate specific antigen use. We also assessed whether any patient subsets benefited differentially during this period. MATERIALS AND METHODS: We compared overall survival in 3 sequential phase III trials of 3,096 men with hormone naïve, metastatic prostate cancer who received similar androgen deprivation therapy, including 2 trials performed before the prostate specific antigen era (S8494 and S8894) and the other done during this era (S9346). Overall survival was adjusted for patient and disease risk factors in the latter 2 trials. Subgroups were evaluated by interactions of risk factors with trial. RESULTS: Median overall survival was 30 months in S8494, 33 months in S8894 and 49 months in S9346. Adjusting for risk factors, there was a 22% lower risk of death in S9346 than in S8894 (HR 0.78, 95% CI 0.70, 0.87, p <0.001). The improvement in overall survival was greater in black American men (test of interaction p = 0.008). In S8494 and S8894 median survival for black men was 27 months, and 34 and 35 months for nonblack men, respectively. This racial difference disappeared in S9346 with overall survival of 48 and 49 months in black and nonblack men, respectively. CONCLUSIONS: Adjusting for risk factors, overall survival was significantly improved in the post-prostate specific antigen era trial. However, it cannot be concluded that this was attributable only to prostate specific antigen monitoring. Black men now have overall survival comparable to that of white men. Current estimates of survival should be used to design new trials in this population.

Ten-year follow-up of neoadjuvant therapy with goserelin acetate and flutamide before radical prostatectomy for clinical T3 and T4 prostate cancer: update on Southwest Oncology Group Study 9109.

OBJECTIVE: To update the results with 10-year data of a phase II prospective trial of neoadjuvant hormonal therapy with goserelin acetate and flutamide followed by radical prostatectomy for locally advanced prostate cancer (SWOG 9109). The optimal management for clinical stage T3 and T4 N0,M0 prostate cancer is uncertain. MATERIALS AND METHODS: Sixty-two patients with clinical stage T3 and T4 N0,M0 prostate cancer were enrolled. Cases were classified by stage T3 vs T4 and by volume of disease (bulky >4 cm and nonbulky ≤ 4 cm). RESULTS: Fifty-five of 61 eligible patients completed the trial with radical prostatectomy after neoadjuvant androgen deprivation therapy (ADT). The median preoperative prostate-specific antigen value was 19.8 ng/mL, and 67% of patients had a Gleason score of ≥ 7. Among 41 patients last known to be alive, median follow-up is 10.6 years (range 5.1-12.6). In all, 38 patients have had disease progression (30/55, 55%) or died without progression (8/55, 15%) for a 10-year progression-free survival (PFS) estimate of 40% (95% CI 27-53). Median PFS was 7.5 years, and median survival has not been reached. The 10-year overall survival (OS) estimate is 68% (95% CI 56-80). CONCLUSIONS: In this small, prospective phase II study, neoadjuvant hormonal therapy with goserelin acetate and flutamide followed by radical prostatectomy achieves long-term PFS and OS comparable with alternative treatments. This approach is feasible and may be an alternative to a strategy of combined radiation and ADT.

The precise role of ethnicity and family history on aggressive prostate cancer: a review analysis.

Review analysis of prostate cancer among men of sub-Saharan West African descent in comparison to other ethnicities and men with a family history of prostate cancer.