Evidence supports a faster growth rate and/or earlier transformation to clinically significant prostate cancer in black than in white American men, and influences racial progression and mortality disparity

Race-Related Differences in Sipuleucel-T Response among Men with Metastatic Castrate-Resistant Prostate Cancer

Sipuleucel-T is an autologous cellular immunotherapy that targets prostatic acid phosphatase (PAP) and is available for treatment of men with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC). In this single-arm, two-cohort, multicenter clinical study, potential racial differences in immune responses to sipuleucel-T in men with mCRPC were explored. Patients' blood samples were obtained to assess serum cytokines, humoral responses, and cellular immunity markers before and after treatment. Baseline cumulative product parameters (total nucleated and CD54+ cell counts and CD54 upregulation) were evaluated. IgM titers against the immunogen PA2024, the target antigen PAP, prostate-specific membrane antigen (PSMA) and prostate-specific antigen (PSA) were quantified by ELISA. Cytotoxic T-lymphocyte activity was determined by ELISpots, and cytokine and chemokine concentrations were determined by Luminex.Twenty-nine African American (AA) men and 28 non-African American (non-AA) men with mCRPC received sipuleucel-T. Baseline total nucleated cell count, CD54+ cell count, CD54 expression, and cumulative product parameters were higher in non-AA men. Although PSA baseline levels were higher in AA men, there were no racial differences in IgM antibody and IFNγ ELISpots responses against PA2024, PAP, PSA, and PSMA before and after treatment. Expression of co-stimulatory receptor ICOS on CD4+ and CD8+ T cells, and the levels of Th1 cytokine granulocyte-macrophage colony-stimulating factor and chemokines CCL4 and CCL5, were significantly higher in AA men before and/or after treatment. Despite no difference in the overall survival, PSA changes from baseline were significantly different between the two races. The data suggest that immune correlates in blood differ in AA and non-AA men with mCRPC pre- and post-sipuleucel-T.

SIGNIFICANCE

Our novel findings of higher expression of co-stimulatory receptor ICOS on CD4+ and CD8+ T cells in African American patients with metastatic castrate-resistant prostate cancer (mCRPC) prior and post-sipuleucel-T suggest activation of CD4+ and CD8+ T cells. The data indicate that racial differences observed in these and other immune correlates before and after sipuleucel-T warrant additional investigation to further our understanding of the immune system in African American men and other men with mCRPC.

Race has no impact on prostate cancer-specific mortality, when comparing patients with similar risk of other-cause mortality: An analysis of a population-based cohort

BACKGROUND

Other-cause mortality (OCM) can serve as a surrogate for access-to-care. The authors sought to compare prostate cancer-specific mortality (PCSM) in Black versus White men matched based on their calculated OCM risk.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for Black and White men diagnosed with prostate cancer between 2004 to 2009, to collect long-term follow-up. A Cox regression was used to calculate the OCM risk using all available covariates. This calculated OCM risk was used to construct a 1:1 propensity score matched (PSM) cohort. Then, a competing-risks multivariable tested the impact of race on PCSM.

RESULTS

A total of 94,363 patients were identified, with 19,398 Black men and 74,965 White men. The median (IQR) follow-up was 11.3 years (9.8-12.8). In the unmatched-cohort at 10-years, PCSM and OCM were 5.5% versus 3.5% and 13.8% versus 8.4% in non-Hispanic Black (NHB) versus non-Hispanic White (NHW) patients (all p < .0001). The standardized mean difference was <0.15 for all covariates, indicating a good match. In the matched cohort at 10-years, OCM was 13.6% and 10.0% in NHB versus NHW (p < .0001), whereas the PCSM was 5.3% versus 4.7% (p < .01). On competing-risks multivariable analysis on PCSM, Black men had a hazard ratio of 1.08 (95% confidence interval, 0.98-1.20) compared to White men with a p = .13.

CONCLUSIONS

The results of this study showed similar PCSM in Black and White patients, when matched with their calculated OCM risk. This report is the first to indicate at a population-based level that race has no impact on PCSM.

PLAIN LANGUAGE SUMMARY

Prostate cancer is a very common cancer among men and it is associated with health disparities that disproportionately impact Black men compared to White men. There is an on-going discussion of whether disparities between these two groups stem from genetic or environmental factors. This study sought to examine if matching based on overall health status, a proxy for the impact of social determinants of health, mitigated significant differences in outcomes. When matched using risk of death from any cause other than prostate cancer, Black and White men had no significant differences in prostate cancer death.

Genetic and biological drivers of prostate cancer disparities in Black men

Black men with prostate cancer have historically had worse outcomes than white men with prostate cancer. The causes of this disparity in outcomes are multi-factorial, but a potential basis is that prostate cancers in Black men are biologically distinct from prostate cancers in white men. Evidence suggests that genetic and ancestral factors, molecular pathways involving androgen and non-androgen receptor signalling, inflammation, epigenetics, the tumour microenvironment and tumour metabolism are contributing factors to the racial disparities observed. Key genetic and molecular pathways linked to prostate cancer risk and aggressiveness have potential clinical relevance. Describing biological drivers of prostate cancer disparities could inform efforts to improve outcomes for Black men with prostate cancer.

Genetic ancestry and radical prostatectomy findings in Hispanic/Latino patients

Background

African ancestry is a known factor associated with the presentation and aggressiveness of prostate cancer (PC). Hispanic/Latino populations exhibit varying degrees of genetic admixture across Latin American countries, leading to diverse levels of African ancestry. However, it remains unclear whether genetic ancestry plays a role in the aggressiveness of PC in Hispanic/Latino patients. We explored the associations between genetic ancestry and the clinicopathological data in Hispanic/Latino PC patients from Colombia.

Patients and methods

We estimated the European, Indigenous and African genetic ancestry, of 230 Colombian patients with localized/regionally advanced PC through a validated panel for genotypification of 106 Ancestry Informative Markers. We examined the associations of the genetic ancestry components with the Gleason Grade Groups (GG) and the clinicopathological characteristics.

Results

No association was observed between the genetic ancestry with the biochemical recurrence or Gleason GG; however, in a two groups comparison, there were statistically significant differences between GG3 and GG4/GG5 for European ancestry, with a higher mean ancestry proportion in GG4/GG5. A lower risk of being diagnosed at an advanced age was observed for patients with high African ancestry than those with low African ancestry patients (OR: 0.96, CI: 0.92-0.99, p=0.03).

Conclusion

Our findings revealed an increased risk of presentation of PC at an earlier age in patients with higher African ancestry compared to patients with lower African ancestry in our Hispanic/Latino patients.

Updated prevalence of latent prostate cancer in Chinese population and comparison of biopsy results: An autopsy-based study

Prostate cancer detected by autopsy is named latent prostate cancer. As the repertoire of clinical prostate cancer, latent cancer may better reflect the disease burden. Unlike clinical prostate specimens, which are obtained exclusively from biopsy-positive cases, prostate specimens obtained through autopsy provide information on biopsy-negative cases, helping calculate the true sensitivity of prostate biopsy. From 2014 to 2021, we collected autopsy specimens of the prostate from body donors in China and performed transperineal and transrectal biopsies on specimens before step-sectioning and pathological measurements. We found that the crude prevalence of latent prostate cancer in middle-aged and elderly men was 35.1% (81/231), which was higher than previous estimates for Chinese populations. The overall per-patient sensitivities of transperineal and transrectal biopsies were not significantly different (33.3% vs. 32.1%, p = 0.82), but the two approaches differed in preferential sampling area along the proximal-distal axis of the prostate. Transperineal biopsy had a higher sensitivity for detecting clinically significant lesions in the distal third (34.7% vs. 16.3%, p = 0.02) and distal half (30.6% vs. 18.1%, p = 0.04), while transrectal biopsy had a higher sensitivity for lesions in the proximal half (25.0% vs. 13.9%, p = 0.046). Both transperineal and transrectal methods of biopsy missed most small lesions (<0.1 mL) and 35.3% (6/17) of large lesions (>0.5 mL). In conclusion, the prevalence of latent prostate cancer in China has increased over the past 2 decades. Systematic transperineal and transrectal methods of biopsy had comparable sensitivities but had different preferential sampling areas. Both approaches miss one-third of large lesions.

Linking African ancestral substructure to prostate cancer health disparities

Prostate cancer (PCa) is a significant health burden in Sub-Saharan Africa, with mortality rates loosely linked to African ancestry. Yet studies aimed at identifying contributing risk factors are lacking within the continent and as such exclude for significant ancestral diversity. Here, we investigate a series of epidemiological demographic and lifestyle risk factors for 1387 men recruited as part of the multi-ethnic Southern African Prostate Cancer Study (SAPCS). We found poverty to be a decisive factor for disease grade and age at diagnosis, with other notably significant PCa associated risk factors including sexually transmitted diseases, erectile dysfunction, gynaecomastia, and vertex or complete pattern balding. Aligned with African American data, Black ethnicity showed significant risk for PCa diagnosis (OR = 1.44, 95% CI 1.05-2.00), and aggressive disease presentation (ISUP ≥ 4: OR = 2.25, 95% CI   1.49-3.40). New to this study, we demonstrate African ancestral population substructure associated PCa disparity, observing increased risk for advanced disease for the southern African Tsonga people (ISUP ≥ 4: OR = 3.43, 95% CI   1.62-7.27). Conversely, South African Coloured were less likely to be diagnosed with aggressive disease overall (ISUP ≥ 3: OR = 0.38, 95% 0.17-0.85). Understanding the basis for PCa health disparities calls for African inclusion, however, lack of available data has limited the power to begin discussions. Here, focusing on arguably the largest study of its kind for the African continent, we draw attention to the contribution of within African ancestral diversity as a contributing factor to PCa health disparities within the genetically diverse region of southern Africa.

Symptom appraisal and help seeking in males with symptoms of possible prostate cancer: a qualitative study with an ethnically diverse sample in London

BACKGROUND

Prostate cancer mortality in Black males is disproportionately high. This problem may be overcome by reducing delays in the pathway to diagnosis, particularly those occurring before initial medical help seeking. A greater understanding of symptom appraisal and help seeking could support the development of targeted interventions for improving early presentation among Black males.

AIM

To provide an in-depth understanding of males' pre-consultation experiences following the onset of symptoms of possible prostate cancer, identifying both general trends as well as potential differences that may exist between Black and White males.

DESIGN AND SETTING

Qualitative study of 18 males (nine Black, nine White) in London, UK, who had recently seen their GP with urinary symptoms, erectile dysfunction, or haematuria.

METHOD

Semi-structured interviews from a previous multi-methods study of primary care use by males with symptoms of possible prostate cancer were analysed using thematic framework analysis.

RESULTS

Symptoms were often interpreted by patients as unimportant. Most delays occurred due to the absence of reasons to seek help, which, in Black males, often stemmed from poor awareness of prostate cancer. This lack of awareness could have been a consequence of their reluctance to seek health information and discuss health issues with others in their social network. Friends and relatives played an important role in symptom appraisal and help seeking.

CONCLUSION

Cognitive biases, cultural stigmas, and everyday interpersonal interactions should be important areas at which to target strategies seeking to reduce delays and improve early presentation in males with possible prostate cancer, particularly Black males.

Effect of type of definitive treatment on race-based differences in prostate cancer-specific survival

BACKGROUND

Racial and ethnic disparities in prostate cancer (PCa) mortality are partially mediated by inequities in quality of care. Intermediate- and high-risk PCa can be treated with either surgery or radiation, therefore we designed a study to assess the magnitude of race-based differences in cancer-specific survival between these two treatment modalities.

METHODS

Non-Hispanic Black (NHB) and non-Hispanic White (NHW) men with localized intermediate- and high-risk PCa, treated with surgery or radiation between 2004 and 2015 in the Surveillance, Epidemiology and End Results database were included in the study and followed until December 2018. Unadjusted and adjusted survival analyses were employed to compare cancer-specific survival by race and treatment modality. A model with an interaction term between race and treatment was used to assess whether the type of treatment amplified or attenuated the effect of race/ethnicity on prostate cancer-specific mortality (PCSM).

RESULTS

15,178 (20.1%) NHB and 60,225 (79.9%) NHW men were included in the study. NHB men had a higher cumulative incidence of PCSM (p = 0.005) and were significantly more likely to be treated with radiation than NHW men (aOR: 1.89, 95% CI: 1.81-1.97, p < 0.001). In the adjusted models, NHB men were significantly more likely to die from PCa compared with NHW men (aHR: 1.18, 95% CI: 1.03-1.35, p = 0.014), and radiation was associated with a significantly higher odds of PCSM (aHR: 2.10, 95% CI: 1.85-2.38, p < 0.001) compared with surgery. Finally, the interaction between race and treatment on PCSM was not significant, meaning that no race-based differences in PCSM were found within each treatment modality.

CONCLUSIONS

NHB men with intermediate- and high-risk PCa had a higher rate of PCSM than NWH men in a large national cancer registry, though NHB and NHW men managed with the same treatment achieved similar PCa survival outcomes. The higher tendency for NHB men to receive radiation was similar in magnitude to the difference in cancer survival between racial and ethnic groups.

Analysis of evolutionary dynamics and clonal architecture in prostate cancer

The extent to which clinical and genomic characteristics associate with prostate cancer clonal architecture, tumor evolution, and therapeutic response remains unclear. Here, we reconstructed the clonal architecture and evolutionary trajectories of 845 prostate cancer tumors with harmonized clinical and molecular data. We observed that tumors from patients who self-reported as Black had more linear and monoclonal architectures, despite these men having higher rates of biochemical recurrence. This finding contrasts with prior observations relating polyclonal architecture to adverse clinical outcomes. Additionally, we utilized a novel approach to mutational signature analysis that leverages clonal architecture to uncover additional cases of homologous recombination and mismatch repair deficiency in primary and metastatic tumors and link the origin of mutational signatures to specific subclones. Broadly, prostate cancer clonal architecture analysis reveals novel biological insights that may be immediately clinically actionable and provide multiple opportunities for subsequent investigation.

Statement of significance

Tumors from patients who self-reported as Black demonstrate linear and monoclonal evolutionary trajectories yet experience higher rates of biochemical recurrence. In addition, analysis of clonal and subclonal mutational signatures identifies additional tumors with potentially actionable alterations such as deficiencies in mismatch repair and homologous recombination.

Genomic, epigenomic, and transcriptomic signatures of prostate cancer between African American and European American patients

Prostate cancer is the second most common cancer in men in the United States, and racial disparities are greatly observed in the disease. Specifically, African American (AA) patients have 60% higher incidence and mortality rates, in addition to higher grade and stage prostate tumors, than European American (EA) patients. In order to narrow the gap between clinical outcomes for these two populations, genetic and molecular signatures contributing to this disparity have been characterized. Over the past decade, profiles of prostate tumor samples from different ethnic groups have been developed using molecular and functional assays coupled with next generation sequencing or microarrays. Comparative genome-wide analyses of genomic, epigenomic, and transcriptomic profiles from prostate tumor samples have uncovered potential race-specific mutations, copy number alterations, DNA methylation, and gene expression patterns. In this study, we reviewed over 20 published studies that examined the aforementioned molecular contributions to racial disparities in AA and EA prostate cancer patients. The reviewed genomic studies revealed mutations, deletions, amplifications, duplications, or fusion genes differentially enriched in AA patients relative to EA patients. Commonly reported genomic alterations included mutations or copy number alterations of FOXA1, KMT2D, SPOP, MYC, PTEN, TP53, ZFHX3, and the TMPRSS2-ERG fusion. The reviewed epigenomic studies identified that CpG sites near the promoters of PMEPA1, RARB, SNRPN, and TIMP3 genes were differentially methylated between AA and EA patients. Lastly, the reviewed transcriptomic studies identified genes (e.g. CCL4, CHRM3, CRYBB2, CXCR4, GALR1, GSTM3, SPINK1) and signaling pathways dysregulated between AA and EA patients. The most frequently found dysregulated pathways were involved in immune and inflammatory responses and neuroactive ligand signaling. Overall, we observed that the genomic, epigenomic, and transcriptomic alterations evaluated between AA and EA prostate cancer patients varied between studies, highlighting the impact of using different methods and sample sizes. The reported genomic, epigenomic, and transcriptomic alterations do not only uncover molecular mechanisms of tumorigenesis but also provide researchers and clinicians valuable resources to identify novel biomarkers and treatment modalities to improve the disparity of clinical outcomes between AA and EA patients.

Racial Differences in Androgen Receptor (AR) and AR Splice Variants (AR-SVs) Expression in Treatment-Naïve Androgen-Dependent Prostate Cancer

Androgen receptor splice variants (AR-SVs) contribute to the aggressive growth of castration-resistant prostate cancer (CRPC). AR-SVs, including AR-V7, are expressed in ~30% of CRPC, but minimally in treatment-naïve primary prostate cancer (PCa). Compared to Caucasian American (CA) men, African American (AA) men are more likely to be diagnosed with aggressive/potentially lethal PCa and have shorter disease-free survival. Expression of a truncated AR in an aggressively growing patient-derived xenograft developed with a primary PCa specimen from an AA patient led us to hypothesize that the expression of AR-SVs could be an indicator of aggressive growth both in PCa progression and at the CRPC stage in AA men. Tissue microarrays (TMAs) were created from formalin-fixed paraffin-embedded (FFPE) prostatectomy tumor blocks from 118 AA and 115 CA treatment-naïve PCa patients. TMAs were stained with AR-V7-speicifc antibody and with antibodies binding to the N-terminus domain (NTD) and ligand-binding domain (LBD) of the AR. Since over 20 AR-SVs have been identified, and most AR-SVs do not as yet have a specific antibody, we considered a 2.0-fold or greater difference in the NTD vs. LBD staining as indication of potential AR-SV expression. Two AA, but no CA, patient tumors stained positively for AR-V7. AR staining with NTD and LBD antibodies was robust in most patients, with 21% of patients staining at least 2-fold more for NTD than LBD, indicating that AR-SVs other than AR-V7 are expressed in primary treatment-naïve PCa. About 24% of the patients were AR-negative, and race differences in AR expression were not statistically significant. These results indicate that AR-SVs are not restricted to CRPC, but also are expressed in primary PCa at higher rate than previously reported. Future investigation of the relative expression of NTD vs. LBD AR-SVs could guide the use of newly developed treatments targeting the NTD earlier in the treatment paradigm.

Carcinoembryonic Antigen, Carbohydrate Antigen 19-9, Cancer Antigen 125, Prostate-Specific Antigen and Other Cancer Markers: A Primer on Commonly Used Cancer Markers

Cancer markers are molecules produced by cancer cells which may serve to identify the presence of cancer. Cancer markers can be differentiated as serum-based, radiology-based and tissue-based, and are one of the most important tools in diagnosing, staging and monitoring of treatment of many cancers. The most used cancer markers are serum cancer markers due to its relative ease and lower cost of testing. However, serum cancer markers have poor mass screening utilization due to poor positive predictive value. Several markers such as prostate-specific antigen (PSA), beta-human chorionic gonadotropin (B-hCG), alpha-fetoprotein (AFP), and lactate dehydrogenase (LDH) are used to aid in diagnosis of cancer in cases of high suspicion. Serum markers such as carcinoembryonic antigen (CEA), AFP, carbohydrate antigen 19-9 (CA 19-9), and 5-hydroxyindoleacetic acid (5-HIAA) play a significant role in assessing disease prognosis as well as response to treatment. This work reviews the role of some of the biomarkers in the diagnosis and treatment of cancer.

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.

Substantial Gleason reclassification in Black men with national comprehensive cancer network low-risk prostate cancer - A propensity score analysis

BACKGROUND

Emerging evidence suggests that a subset of Black men with National Comprehensive Cancer Network (NCCN) low-risk prostate cancer (PCa) may harbor high volume and genomically aggressive disease. However, limited, and ambiguous research exist to evaluate the risk of extreme Gleason reclassification in Black men with low-risk PCa.

METHODS

This retrospective cohort study included 45,674 low-risk PCa patients who underwent prostatectomy and were not on active surveillance, from National Cancer Database (NCDB). A propensity score matched-pair design was employed, and the final cohort was limited to 1:1 matched 12,340 patients. Gleason score reclassification was used as primary endpoint. As such, any migration to pathologic Gleason score ≥7(3 + 4) was identified as overall, whereas migration to ≥7(4 + 3) was defined as extreme reclassification. A conditional Poisson regression model was used to estimate the risk of reclassification. Whereas spline model was used to estimate the impact of increasing time to treatment as a non-linear function on Gleason reclassification between race group.

RESULTS

Upon matching there were no differences in the baseline characteristics between race groups. In a matched cohort, higher proportion of low-risk Black men (6.6%) reported extreme reclassification to pathologic Gleason score than White men (5.0%), p < 0.001. In a conditional Poisson regression model adjusted for time to treatment, the risk of overall (RR = 1.09, 95% CI, 1.05-1.13, p < 0.001) and extreme (RR = 1.30, 95% CI, 1.12-1.50, p = 0.004) reclassification was significantly higher in Black men as compared to their White counterpart. In spline model, the probability of Gleason reclassification in Black men was elevated with increasing time to treatment, especially after 180 days (53% vs. 43% between Black and White men).

CONCLUSION

Risk of Gleason score reclassification is disparately elevated in Black men with low-risk PCa. Furthermore, time to treatment can non-linearly impact Gleason reclassification in Black men.

Effect of chemotherapy in metastatic prostate cancer according to race/ethnicity groups

BACKGROUND

No North-American study tested the survival benefit of chemotherapy in de novo metastatic prostate cancer according to race/ethnicity. We addressed this void.

METHODS

We identified de novo metastatic prostate cancer patients within the Surveillance, Epidemiology, and End Results database (2014-2015). Separate and specific Kaplan-Meier plots and Cox regression models tested for overall survival differences between chemotherapy-exposed versus chemotherapy-naïve patients in four race/ethnicity groups: Caucasian versus African-American versus Hispanic/Latino vs Asian. Race/ethnicity specific propensity score matching was applied. Here, additional landmark analysis was performed.

RESULTS

Of 4232 de novo metastatic prostate cancer patients, 2690 (63.3%) were Caucasian versus 783 (18.5%) African-American versus 504 (11.8%) Hispanic/Latino versus 257 (6.1%) Asian. Chemotherapy rates were: 21.3% versus 20.8% versus 21.0% versus 20.2% for Caucasians versus African-Americans versus Hispanic/Latinos versus Asians, respectively. At 30 months of follow-up, overall survival rates between chemotherapy-exposed versus chemotherapy-naïve patients were 61.5 versus 53.2% (multivariable hazard ratio [mHR]: 0.76, 95 confidence interval [CI]: 0.63-0.92, p = 0.004) in Caucasians, 55.2 versus 51.6% (mHR: 0.76, 95 CI: 0.54-1.07, p = 0.11) in African-Americans, 62.8 versus 57.0% (mHR: 1.11, 95 CI: 0.73-1.71, p = 0.61) in Hispanic/Latinos and 77.7 versus 65.0% (mHR: 0.31, 95 CI: 0.11-0.89, p = 0.03) in Asians. Virtually the same findings were recorded after propensity score matching within each race/ethnicity group.

CONCLUSIONS

Caucasian and Asian de novo metastatic prostate cancer patients exhibit the greatest overall survival benefit from chemotherapy exposure. Conversely, no overall survival benefit from chemotherapy exposure could be identified in either African-Americans or Hispanic/Latinos. Further studies are clearly needed to address these race/ethnicity specific disparities.

68Ga-PSMA-11 PET/CT Initial Staging in Black and White South African Males with ISUP Grade Group 1 and 2 Prostate Adenocarcinoma

Prostate adenocarcinoma (PCa) is a leading cause of mortality. Black males with high-risk PCa have a poorer prognosis compared to white males. Patients with International Society of Urological Pathology (ISUP) Grade Group (GG) 1 and 2 PCa have little potential for metastases post radical prostatectomy. ⁶⁸Gallium prostate specific membrane antigen (⁶⁸Ga-PSMA) PET/CT imaging for metastatic PCa is superior to conventional imaging in staging high-risk PCa. No strong evidence is available to support imaging low-risk patients. We aimed to evaluate the value of ⁶⁸Ga-PSMA PET/CT in black and white South African (BSA and WSA) males with GG1 and 2 PCa at initial staging. We evaluated 25 WSA and 123 BSA males. The image findings were correlated with prostate specific antigen (PSA). PSA levels significantly correlated with both primary tumor and whole-body PSMA-tumor volume (PSMA-TV) and were higher in BSA males. No differences were noted in the occurrence of metastases; however, PSA, seminal vesicle invasion and black race predicted metastases. Our findings suggest higher PSMA expression and tumor burden in BSA with histologically low-risk PCa, and future research with immunohistochemistry evaluation will be essential to confirm these findings.

Prostate Cancer in the Caribbean: A Baseline Assessment of Current Practices and Potential Needs

Afro-Caribbean men have a higher risk of prostate cancer than any other population of men in the world. However, the Caribbean is composed of a heterogenous group of healthcare systems located on small islands which makes population-based studies difficult to conduct and interpret. The aim of this review is to compile previously published data on the state of prostate cancer in Caribbean men and to highlight potential healthcare needs that can be addressed by public health efforts. We reviewed three databases and identified relevant papers that were subsequently searched by the authors. Peer-reviewed studies published in the English language after 2010 with a focus on prostate cancer diagnosis, management, and outcomes of Caribbean men were prioritized. Afro-Caribbean men were found to have a higher incidence and mortality rate compared to their counterparts. Misperception about the disease, lack of regional guidelines, and poor access to care are compounding factors that result in worse outcomes for these men compared to high-income nations. Urologists and oncologists in the region, while well-trained, are limited in number and in most cases do not offer newer treatment modalities. Overall, only a few island nations have cancer registries, and there remains a significant need for more population-based studies to assess guideline adherence and outcomes. Until further research and investment in the region is made, the disparity between the care received by Afro-Caribbean men and their counterparts will likely remain.

A network-based integration for understanding racial disparity in prostate cancer

Compared to Caucasians (CAs), African Americans (AAs) have a higher rate of incidence and mortality in prostate cancer and are prone to be diagnosed at later stages. To understand this racial disparity, molecular features of different types, including gene expression, DNA methylation and other genomic alterations, have been compared between tumor samples from the two races, but led to different disparity associated genes (DAGs). In this study, we applied a network-based algorithm to integrate a comprehensive set of genomic datasets and identified 130 core DAGs. Out of these genes, 78 were not identified by any individual dataset but prioritized and selected through network propagation. We found DAGs were highly enriched in several critical prostate cancer-related signaling transduction and cell cycle pathways and were more likely to be associated with patient prognosis in prostate cancer. Furthermore, DAGs were over-represented in prostate cancer risk genes identified from previous genome wide association studies. We also found DAGs were enriched in kinase and transcription factor encoding genes. Interestingly, for many of these prioritized kinases their association with racial disparity did not manifest from the original genomic/transcriptomic data but was reflected by their differential phosphorylation levels between AA and CA prostate tumor samples. Similarly, the disparity relevance of some transcription factors was not reflected at the mRNA or protein expression level, but at the activity level as demonstrated by their differential ability in regulating target gene expression. Our integrative analysis provided new candidate targets for improving prostate cancer treatment and addressing the racial disparity problem.

Racial disparities in prostate cancer: A complex interplay between socioeconomic inequities and genomics

The largest US cancer health disparity exists in prostate cancer, with Black men having more than a two-fold increased risk of dying from prostate cancer compared to all other races. This disparity is a result of a complex network of factors including socioeconomic status (SES), environmental exposures, and genetics/biology. Inequity in the US healthcare system has emerged as a major driver of disparity in prostate cancer outcomes and has raised concerns that the actual incidence rates may be higher than current estimates. However, emerging studies argue that equalizing healthcare access will not fully eliminate racial health disparities and highlight the important role of biology. Significant differences have been observed in prostate cancer biology between various ancestral groups that may contribute to prostate cancer health disparities. These differences include enhanced androgen receptor signaling, increased genomic instability, metabolic dysregulation, and enhanced inflammatory and cytokine signaling. Immediate actions are needed to increase the establishment of adequate infrastructure and multi-center, interdisciplinary research to bridge the gap between social and biological determinants of prostate cancer health disparities.

A Bone Scan Is Valuable for Primary Staging of Newly Diagnosed Prostate Cancer in a Low-Resource Setting (Nigeria)

Objective

There is a paucity of information on bone scanning for prostate cancer from low-resource countries. This study evaluated the role of bone scan in the primary staging of newly diagnosed prostate cancer in one such setting.

Methods

A retrospective analysis of 126 men with newly diagnosed prostate cancer undergoing an initial staging bone scan between January 2017 and December 2020 was carried out at a regional nuclear medicine center in Nigeria. Bone scan results were analyzed according to age, serum level of baseline prostate-specific antigen (PSA), and Gleason score. Equivocal scans and patients with no Gleason score or baseline PSA were excluded from the analysis. p < 0.05 was said to be significant statistically.

Results

Of 111 patients (aged 38-84 years, median 66 years), who met the inclusion criteria, 26 (23%) men had evidence of bony metastases as shown by a positive bone scan. Higher PSA levels and Gleason scores were associated with an increased risk of a positive bone scan, p < 0.001. No patient with a PSA level < 20 ng/mL and a Gleason score of < 7 had a positive bone scan.

Conclusion

The role of bone scanning in staging newly diagnosed prostate cancer patients in Nigeria is consistent with global reports. Our study confirms that a bone scan finding is well associated with the risk classification using PSA and Gleason score in our population.

Racial Differences in Prostate Cancer Characteristics and Cancer-Specific Mortality: An Overview

Racial differences of prostate cancer incidence and mortality among Asian, Black, and Caucasian men have been known, however, comprehensive update of this topic is not yet reported. In the present review, an overview of the racial differences in prostate cancer characteristics and cancer-specific mortality is collected and reviewed. Regarding racial differences of incidence and mortality, surprising differences in the incidence of prostate cancer are seen among different populations around the world, with some countries having rates that are 60 to 100 times higher than others. African-American men have a higher incidence of prostate cancer, higher prostate cancer mortality, and are diagnosed with prostate cancer at a younger age than Caucasian American men. Furthermore, race is gaining attention as an important factor to consider for planning active surveillance for localized prostate cancer, especially among African-Americans. In addition, the causes of these differences are being elucidated by genomic profiling. Determinants of racial disparities are multifactorial, including socioeconomic and biologic factors. Although race-specific differences in prostate cancer survival estimates appear to be narrowing over time, there is an ongoing need to continue to understand and mitigate racial factors associated with disparities in health care outcomes.

Predicting Cancer-Specific Survival Among Patients With Prostate Cancer After Radical Prostatectomy Based on the Competing Risk Model: Population-Based Study

Introduction: We aimed to develop an easy-to-use individual survival prognostication tool based on competing risk analyses to predict the risk of 5-year cancer-specific death after radical prostatectomy for patients with prostate cancer (PCa).

Methods: We obtained the data from the Surveillance, Epidemiology, and End Results (SEER) database (2004–2016). The main variables obtained included age at diagnosis, marital status, race, pathological extension, regional lymphonode status, prostate specific antigen level, pathological Gleason Score. In order to reveal the independent prognostic factors. The cumulative incidence function was used as the univariable competing risk analyses and The Fine and Gray's proportional subdistribution hazard approach was used as the multivariable competing risk analyses. With these factors, a nomogram and risk stratification based on the nomogram was established. Concordance index (C-index) and calibration curves were used for validation.

Results: A total of 95,812 patients were included and divided into training cohort (n = 67,072) and validation cohort (n = 28,740). Seven independent prognostic factors including age, race, marital status, pathological extension, regional lymphonode status, PSA level, and pathological GS were used to construct the nomogram. In the training cohort, the C-index was 0.828 (%95CI, 0.812–0.844), and the C-index was 0.838 (%95CI, 0.813–0.863) in the validation cohort. The results of the cumulative incidence function showed that the discrimination of risk stratification based on nomogram is better than that of the risk stratification system based on D'Amico risk stratification.

Conclusions: We successfully developed the first competing risk nomogram to predict the risk of cancer-specific death after surgery for patients with PCa. It has the potential to help clinicians improve post-operative management of patients.

Identification and Characterization of Key Differentially Expressed Genes Associated With Metronomic Dosing of Topotecan in Human Prostate Cancer

Repetitive, low-dose (metronomic; METRO) drug administration of some anticancer agents can overcome drug resistance and increase drug efficacy in many cancers, but the mechanisms are not understood fully. Previously, we showed that METRO dosing of topotecan (TOPO) is more effective than conventional (CONV) dosing in aggressive human prostate cancer (PCa) cell lines and in mouse tumor xenograft models. To gain mechanistic insights into METRO-TOPO activity, in this study we determined the effect of METRO- and CONV-TOPO treatment in a panel of human PCa cell lines representing castration-sensitive/resistant, androgen receptor (+/−), and those of different ethnicity on cell growth and gene expression. Differentially expressed genes (DEGs) were identified for METRO-TOPO therapy and compared to a PCa patient cohort and The Cancer Genome Atlas (TCGA) database. The top five DEGs were SERPINB5, CDKN1A, TNF, FOS, and ANGPT1. Ingenuity Pathway Analysis predicted several upstream regulators and identified top molecular networks associated with METRO dosing, including tumor suppression, anti-proliferation, angiogenesis, invasion, metastasis, and inflammation. Further, the top DEGs were associated with increase survival of PCa patients (TCGA database), as well as ethnic differences in gene expression patterns in patients and cell lines representing African Americans (AA) and European Americans (EA). Thus, we have identified candidate pharmacogenomic biomarkers and novel pathways associated with METRO-TOPO therapy that will serve as a foundation for further investigation and validation of METRO-TOPO as a novel treatment option for prostate cancers.

Comparison of Characteristics, Follow-up and Outcomes of Active Surveillance for Prostate Cancer According to Ethnicity in the GAP3 Global Consortium Database

BACKGROUND

Studies of active surveillance (AS) for prostate cancer (PCa) have focussed predominantly on Caucasian populations. Little is known about the experience of Asian men, while suitability for men of African descent has been questioned.

OBJECTIVE

To compare baseline characteristics, follow-up, and outcomes for men on AS for PCa, according to ethnicity.

DESIGN SETTING AND PARTICIPANTS

The study cohort included 13 centres from the GAP3 consortium that record ethnicity (categorised broadly as Caucasian/white, African/Afro-Caribbean/black, Asian, mixed/other, and unknown). Men with biopsy grade group >2, prostate-specific antigen (PSA) >20 ng/ml, T stage ≥cT3, or age >80 yr were excluded.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Clinical characteristics, follow-up schedules, outcome status, and reasons for discontinuation were compared across ethnic groups. Risk of upgrading, potential disease progression (grade group ≥3 or T stage ≥3), suspicious indications (any upgrading, number of positive cores >3, T stage ≥cT3, PSA >20 ng/ml, or PSA density >0.2 ng/ml/cc²), and conversion to treatment were assessed using mixed-effect regression models.

RESULTS AND LIMITATIONS

The eligible cohort (n = 9158) comprised 83% Caucasian men, 6% men of African descent, 5% Asian men, 2% men of mixed/other ethnicity, and 4% men of unknown ethnicity. Risks of suspicious indicators (hazard ratio = 1.27; 95% confidence interval [CI] 1.12-1.45), upgrading (odds ratio [OR] = 1.40; 95% CI 1.14-1.71), and potential progression (OR = 1.46; 95% CI 1.06-2.01) were higher among African/black than among Caucasian/white men. Risk of transitioning to treatment did not differ by ethnicity. More Asian than Caucasian men converted without progression (42% vs 26%, p < 0.001). Heterogeneity in surveillance protocols and racial makeup limit interpretation.

CONCLUSIONS

This multinational study found differences in the risk of disease progression and transitioning to treatment without signs of progression between ethnic groups. Further research is required to determine whether differences are due to biology, sociocultural factors, and/or clinical practice.

PATIENT SUMMARY

This international study compared prostate cancer active surveillance outcomes by ethnicity. Risks of upgrading and disease progression were higher among African than among Caucasian men. Transitioning to treatment without progression was highest among Asian men. Understanding of these differences requires further investigation.

Experiences of UK African-Caribbean prostate cancer survivors of discharge to primary care

Objective: Black men are three times more likely to develop prostate cancer (PCa), to do so at a younger age and to experience a more aggressive form than White men. This study aims to understand the experiences of African-Caribbean men with respect to their discharge to primary care following successful PCa treatment and the challenges associated with survivorship.Design: Eight African-Caribbean men, who had been successfully treated for PCa, were recruited through the charity BME Cancer Communities. They participated in a focus group, which took place on the premises of the charity and was audio-recorded. The recording was transcribed and the data were analysed employing thematic analysis.Results: Three overarching themes were developed: Discharge - misconceptions and uncertainties; Survivorship - challenges and ways of coping; Black men and PCa: real and potential discrimination. Participants expressed concerns regarding the lack of information and clarity about what discharge meant, the quality of follow-up care, especially the levels of specialist knowledge among GPs, and the impact of side-effects, particularly erectile dysfunction (ED). Participants linked ED with stereotypes of Black male sexuality, particularly in relation to difficulties of expressing their emotions and psychological distress. African-Caribbean men face particular challenges in dealing with the side-effects of treatment for PCa, which are linked to socially-constructed ideas of masculinity.Conclusion: There needs to be a greater focus in primary care on understanding these issues and providing individualised culturally-sensitive care. In particular, GPs should be aware of sensitivities concerning help-seeking related to culturally-mediated understandings of masculinity.

Primary care use by men with symptoms of possible prostate cancer: A multi-method study with an ethnically diverse sample in London

OBJECTIVE

The objective of this study is to investigate primary care use by men with recent onset of lower urinary tract symptoms (LUTS) to identify differences in presentation and investigation that may explain ethnic inequality in prostate cancer outcomes.

METHODS

This is a multi-method study of men presenting LUTS to primary care. Two hundred seventy-four men completed a self-administered questionnaire, and 23 participated in face-to-face interviews. Regression analyses investigated ethnic differences in (a) the period between symptom onset and first primary care presentation (patient interval) and (b) the interval between first primary care presentation and investigation with prostate-specific antigen (PSA) and digital rectal examination (DRE). Interview data were analysed using thematic analysis.

RESULTS

Half (144, 53%) reported a solitary first symptom, although multiple first symptoms were also common, particularly in Asian and Black men. There was no difference between ethnicities in patient interval or time from presentation to investigation. However, Asian men were offered less PSA testing (odds ratio 0.39; 95% confidence interval 0.17-0.92; p = 0.03). Qualitative data revealed ethnic differences in general practitioners' offer of DRE and PSA testing and highlighted limitations in doctor-patient communication and safety netting.

CONCLUSION

Our study showed only small differences in primary care experiences, insufficient to explain ethnic inequalities in prostate cancer outcomes.

Small Extracellular Vesicle-Derived microRNAs Stratify Prostate Cancer Patients According to Gleason Score, Race and Associate with Survival of African American and Caucasian Men

Simple Summary

Novel biomarkers are needed to guide prognosis and treatment of aggressive forms of prostate cancer (PCa). In this study, small extracellular vesicles (sEVs)-derived microRNAs (miRs) are used to predict aggressive phenotypes and ancestral background of PCa patients. Two cohorts was used to study the diagnostic and prognostic utility of sEV-associated miRs in predicting aggressive forms of PCa in African American (AA) and Caucasian (CA) men. In training cohort, miR profiling was performed and top-ranked sEV-associated miRs were then validated in two independent confirmatory cohorts comprising 150 plasma samples. Results revealed that sEV-associated miR-6068 and miR-1915-3p were enriched in PCa patients compared to healthy subjects. sEV-associated miR-6716-5p and miR-3692-3p distinguished AA from CA men and low from high Gleason score. However, miR-1915-3p was the only studied miR associated with longer recurrence-free survival as independent prognostic marker.

Abstract

The utility of small extracellular vesicles (sEVs)-derived microRNAs (miRs) to segregate prostate cancer (PCa) patients according to tumor aggressiveness and ancestral background has not been fully investigated. Thus, we aimed to determine the diagnostic and prognostic utility of sEV-associated miRs in identifying aggressive PCa in African American (AA) and Caucasian (CA) men. Using a training cohort, miR profiling was performed on sEVs isolated from plasma of PCa patients. Top-ranked sEV-associated miRs were then validated in 150 plasma samples (75 AA and 75 CA) collected from two independent cohorts; NIH (n = 90) and Washington University (n = 60) cohorts. Receiver operating characteristic (ROC) curve, Kaplan–Meier and Cox proportional hazards regression were used to assess these miRs as clinical biomarkers. Among nine top-ranked sEV-associated miRs, miR-6068 and miR-1915-3p were enriched in sEVs collected from PCa patients compared to healthy volunteers. Moreover, miR-6716-5p and miR-3692-3p segregated AA from CA men and low from high Gleason score (GS), respectively. Upregulation of sEV-associated miR-1915-3p, miR-3692-3p and miR-5001-5p was associated with improved survival time, and only miR-1915-3p was associated with longer recurrence-free survival (RFS) as an independent prognostic marker. Taken together, we identified novel sEV-associated miRs that can differentiate PCa patients from normal, AA from CA and high from low GS and predicts RFS.

Emerging role of multiparametric magnetic resonance imaging in identifying clinically relevant localized prostate cancer

PURPOSE OF REVIEW

To explore the recent advances and utility of multiparametric magnetic resonance imaging (mpMRI) in the diagnosis and risk-stratification of prostate cancer.

RECENT FINDINGS

Low-risk, clinically insignificant prostate cancer has a decreased risk of morbidity or mortality. Meanwhile, patients with intermediate and high-risk prostate cancer may significantly benefit from interventions like radiation or surgery. To appropriately risk stratify these patients, MRI has emerged as the imaging modality in the last decade to assist in defining prostate cancer significance, location, and biologic aggressiveness. Traditional 12-core transrectal ultrasound-guided biopsy is associated with over-detection, and ultimately over-treatment of clinically insignificant disease, and the under-detection of clinically significant disease. Biopsy accuracy is improved with MRI-guided targeted biopsy and with the use of standardized risk stratification imaging score systems. Cancer detection accuracy is further improved with combined biopsy techniques that include both systematic and MRI-targeted biopsy that aid in detection of MRI-invisible lesions.

SUMMARY

mpMRI is an area of expanding innovation that continues to refine the diagnostic accuracy of prostate biopsies. As mpMRI-targeted biopsy in prostate cancer becomes more commonplace, advances like artificial intelligence and less invasive dynamic metabolic imaging will continue to improve the utility of MRI.

Race, Age, Gender, and Insurance Status: A Comparative Analysis of Access to and Quality of Gastrointestinal Cancer Care

BACKGROUND

Socioeconomics, demographics, and insurance status play roles in healthcare access. Considering the limited resources available, understanding the relative impact of disparities helps prioritize programs designed to overcome them. This study evaluates gastrointestinal cancer care disparity by comparing the impact of different patient factors across oncologic care metrices.

METHODS

A multi-institutional prospectively maintained cancer database was reviewed retrospectively for gastrointestinal cancers (esophagus, stomach, liver, pancreas, colorectal, and hepato-pancreato-biliary) from 2007 to 2017 to assess quality of care provided. Quality of care was defined by clinical course following national guidelines for the respective cancer. This included surgical intervention, chemotherapy, palliative care, and minimal delay to treatment/diagnosis. Logistic regression was used to adjust for confounders and identify factors associated with quality of care. Kaplan-Meier survival curves were compared using log-rank test.

RESULTS

One thousand seventy-two patients were identified. Survival improved in patients with private insurance compared to government-funded options [median overall survival (mOS) 57.8 vs. 21.2 months; P < .001]. Private insurance also correlated with earlier stage at diagnosis [stages I-II = 50.9% vs. 37.5%, stages III-IV = 37.7% vs. 49.1%, P < .001], increased chemotherapy use [44.2% vs. 37.1%, P < .001], and more surgical intervention [62.4% vs. 48.8%, P < .001]. Outcomes were inferior for Black Americans, including trend towards lower rate of surgical treatment [42% vs. 54%, P = .058] and worse survival in private insurance carriers [mOS 7.8 vs. 57.8 months, P = .021] and those with early stage disease [mOS 39.2 vs. 81.5 months, P = .045] compared to White counterparts.

CONCLUSIONS

Insurance status has the strongest impact on the quality of gastrointestinal oncologic care with negative synergistic negative effect of race for Black Americans. While governmental programs aim to improve equality of care, there remains significant disparity compared to private insurance. Moreover, private insurance doesn't correct disparity for Black Americans, suggesting the need to address racial imbalances in cancer care.

A Review of Research on Disparities in the Care of Black and White Patients With Cancer in Detroit

Racial disparities in cancer incidence and outcomes are well-documented in the US, with Black people having higher incidence rates and worse outcomes than White people. In this review, we present a summary of almost 30 years of research conducted by investigators at the Karmanos Cancer Institute's (KCI's) Population Studies and Disparities Research (PSDR) Program focusing on Black-White disparities in cancer incidence, care, and outcomes. The studies in the review focus on individuals diagnosed with cancer from the Detroit Metropolitan area, but also includes individuals included in national databases. Using an organizational framework of three generations of studies on racial disparities, this review describes racial disparities by primary cancer site, disparities associated with the presence or absence of comorbid medical conditions, disparities in treatment, and disparities in physician-patient communication, all of which contribute to poorer outcomes for Black cancer patients. While socio-demographic and clinical differences account for some of the noted disparities, further work is needed to unravel the influence of systemic effects of racism against Black people, which is argued to be the major contributor to disparate outcomes between Black and White patients with cancer. This review highlights evidence-based strategies that have the potential to help mitigate disparities, improve care for vulnerable populations, and build an equitable healthcare system. Lessons learned can also inform a more equitable response to other health conditions and crises.

Immune Inflammation Pathways as Therapeutic Targets to Reduce Lethal Prostate Cancer in African American Men

Despite substantial improvements in cancer survival, not all population groups have benefitted equally from this progress. For prostate cancer, men of African descent in the United States and England continue to have about double the rate of fatal disease compared to other men. Studies suggest that when there is equal access to care, survival disparities are greatly diminished. However, notable differences exist in prostate tumor biology across population groups. Ancestral factors and disparate exposures can lead to altered tumor biology, resulting in a distinct disease etiology by population group. While equal care remains the key target to improve survival, additional efforts should be made to gain comprehensive knowledge of the tumor biology in prostate cancer patients of African descent. Such an approach may identify novel intervention strategies in the era of precision medicine. A growing body of evidence shows that inflammation and the immune response may play a distinct role in prostate cancer disparities. Low-grade chronic inflammation and an inflammatory tumor microenvironment are more prevalent in African American patients and have been associated with adverse outcomes. Thus, differences in activation of immune-inflammatory pathways between African American and European American men with prostate cancer may exist. These differences may influence the response to immune therapy which is consistent with recent observations. This review will discuss mechanisms by which inflammation may contribute to the disparate outcomes experienced by African American men with prostate cancer and how these immunogenic and inflammatory vulnerabilities could be exploited to improve their survival.

Prevalence of prostate cancer at autopsy in Nigeria-A preliminary report

BACKGROUND AND OBJECTIVES

Prostate cancer is the most commonly diagnosed cancer in Nigerian men despite the lack of PSA based screening. Current prevalence estimates in Nigeria are based on cancer registry data obtained primarily from hospital admissions and therefore not truly reflective of prostate cancer incidence. Prior autopsy series did not adhere to modern pathologic quality practices. The aim of this study was to explore the prevalence of asymptomatic prostate cancer among Nigerian men at the time of autopsy.

METHODS

Prostates were collected at autopsy at the Universities of Lagos and Calabar Teaching Hospitals from men aged more than 40 who died from causes other than prostate cancer. Thirty-nine prostates from Nigerian men autopsied in 2017 to 2018 were formalin-fixed, weighed, and sliced at 4 mm intervals. Haematoxylin and eosin-stained paraffin sections were prepared from these slices. Presence and Gleason grade of prostatic adenocarcinomas and presence of high-grade prostatic intraepithelial neoplasia (HGPIN) were recorded.

RESULTS

Mean age of cases was 55 ± 11 years and mean prostatic weight was 23.0 ± 10.9 g. The crude prevalence of HGPIN was 20.6%. Overall crude prevalence of prostate cancer was 8.8% (n = 34), increasing from 8.3% for men aged 40-59 (n = 23) to 10.0% for men ≥60 years old (n = 10). Two tumors were small and had Gleason Grade 3 + 3 or 3 + 4, and one large stage T3 tumor with Gleason Grade 4 + 3 disease and neuroendocrine appearance was found in a 54-year-old man.

CONCLUSIONS

The 8.8% prevalence of subclinical prostate cancer at autopsy was similar to previously reported Nigerian studies with more limited tissue sampling (6.7%-10%), but considerably lower than estimates in other populations, including African Americans. Our findings suggest that latent, clinically asymptomatic prostate cancer is less frequent in Nigerians than in African Americans, despite shared genetic ancestry. Future studies with increased sample size are warranted to provide insight in the natural history and true prevalence of prostate cancer in West Africa.

Race as a Contributor to Stromal Modulation of Tumor Progression

Stromal cells play crucial roles in tumor development and are increasingly attractive targets for therapy. There are considerable racial disparities in the incidence and progression of many tumors, reflecting both environmental exposure and genetic differences existing between races. Tumorigenesis and tumor progression are linked to both the propensity to suffer an initiating event and the host response to such an event once it occurs, contributing to incidence and outcomes. In this review, we focused on racial disparities in the tumor microenvironment (TME) of different cancers as potential modulators of growth, metastasis, and response to treatment. Several studies suggest that the TME in AA has a distinct tumor biology and may facilitate both early onset and aggressive tumor growth while inhibiting anti-tumorigenic properties. The TME of AA patients often exhibits an immunosuppressive microenvironment with a substantial enrichment of immune inflammatory pathways and genes. As a result, AA patients can potentially benefit more from treatment strategies that modulate the immune system. Focusing on TME components for diagnostic and therapeutic purposes to address racial disparities is a promising area of investigation. Future basic and clinical research studies on personalized cancer diagnosis and treatment should acknowledge the significance of TME in racial disparities.

The Impact of Intensifying Prostate Cancer Screening in Black Men: A Model-Based Analysis

BACKGROUND

Black men in the United States have markedly higher rates of prostate cancer than the general population. National guidelines for prostate-specific antigen (PSA) screening do not provide clear guidance for this high-risk population. The purpose of this study is to estimate the benefit and harm of intensified PSA screening in Black men.

METHODS

Two microsimulation models of prostate cancer calibrated to incidence from the Surveillance, Epidemiology, and End Results program among Black men project the impact of different screening strategies (varying screening intervals, starting and stopping ages, and biopsy utilization following an abnormal PSA) on disease-specific mortality and overdiagnosis. Each strategy induces a mean lead time (MLT) for detected cases. A longer MLT reduces mortality according to estimates combining the US and European prostate cancer screening trials but increases overdiagnosis.

RESULTS

Under historical population screening, Black men had similar MLT to men of all races, and similar mortality reduction (range between models = 21-24% vs. 20-24%) but a higher frequency of overdiagnosis (75-86 vs. 58-60 per 1000 men). Screening Black men aged 40-84 years annually would increase both mortality reduction (29-31%) and overdiagnosis (112-129 per 1000). Restricting screening to age 45-69 years would still achieve substantial mortality reduction (26-29%) with lower overdiagnosis (51-61 per 1000). Increasing biopsy utilization to 100% of abnormal tests would further reduce mortality but substantially increase overdiagnosis.

CONCLUSIONS

Annual screening in Black men is expected to reduce mortality more than that estimated under historical screening. Limiting screening to men below 70 years is expected to help to reduce overdiagnosis.

Stigma, beliefs and perceptions regarding prostate cancer among Black and Latino men and women

BACKGROUND

Health disparities in prostate cancer (PC) are thought to reflect the complex interplay of socioeconomics, environment and biology. The potential impact of beliefs and perceptions about PC among Black and Latino populations on clinical disparities are not well understood. This qualitative study was conducted to assess current prevalent and pervasive stigma, beliefs and perceptions regarding PC among Blacks and Latinos living in a large metropolitan area, thereby identifying potentially modifiable barriers to care.

METHODS

Qualitative data were collected through four separate focus groups of self-identified Black and Latino adult men and women living in Philadelphia to better understand their perceptions of PC diagnosis, screening and treatment. Each focus group was single-sex and conducted by racial/ethnic group in order to assess possible differences in beliefs about PC based on gender and racial/ethnic affiliation. Audio recordings were transcribed verbatim by trained research assistants and qualitative data analysis was conducted using modified grounded theory.

RESULTS

There were a total of 34 participants: 19 Hispanics/Latinos and 15 Blacks, with equal numbers of men and women (n=17). Median age was 57 years (range: 18 to 85 years). Dominant themes that emerged with respect to PC diagnosis included the stigma surrounding this condition and the perceived role of an "unhealthy lifestyle" and certain sexual behaviors as risk factors for PC development. While the majority of participants acknowledged the importance of PC screening and early detection, discussion centered around the barriers to both the interest in seeking medical care and the likelihood of securing it. These barriers included misunderstanding of PC etiology, distrust of the medical profession, and financial/access limitations. Men expressed substantial confusion about PC screening guidelines. In the Black female group, the role of faith and religion in the course of disease was a major theme. Both Black and Latina females discussed the role of fear and avoidance around PC screening and treatment, as well as the prevalence of misinformation about PC in their familial and social communities.

CONCLUSION

Black and Latino focus groups revealed the existence of cultural beliefs, misunderstandings and fears pertaining to PC which could influence health-related behaviors. Some themes were common across groups; others suggested racial and gender predilections. Future targeted efforts focused on directly addressing prevalent misperceptions among underserved communities in urban settings could help to improve health literacy and equity in PC outcomes in these populations.

Presentation, follow-up, and outcomes among African/Afro-Caribbean men on active surveillance for prostate cancer: experiences of a high-volume UK centre

BACKGROUND

Experiences of African/Afro-Caribbean men on active surveillance (AS) for prostate cancer (PCa) in the United Kingdom (UK) are not well documented. We compared follow-up appointments, adherence, and clinical outcomes among African/Afro-Caribbean men on AS at a high-volume UK hospital with other ethnicities.

METHODS

Men with confirmed low-intermediate risk Pca who attended the AS clinic (2005-2016) and had undergone ≥1 follow-up biopsy (n = 458) were included. Non-adherence (defined as >20% missed appointments), suspicion of disease progression (any upgrading, >30% positive cores, cT-stage > 3, PIRADS > 3), any upgrading from diagnostic biopsy and conversion to active treatment (prostatectomy, radiotherapy or hormone therapy) according to ethnicity (African/Afro-Caribbean versus other ethnicities) were assessed using multivariable regression analysis.

RESULTS

Twenty-three percent of eligible men were recorded as African/Afro-Caribbean, while the remainder were predominantly Caucasian. African/Afro-Caribbean men had slightly lower PSA at diagnosis (median 5.0 vs. 6.0 ng/mL) and more positive cores at diagnosis (median 2 vs. 1). They had a substantially higher rate of non-attendance at scheduled follow-up visits (24% vs. 10%, p < 0.001). Adjusted analyses suggest African/Afro-Caribbean men may be at increased risk of disease progression (hazard ratio [HR]: 1.38; 95% confidence interval [CI] 0.99-1.91, P = 0.054) and upgrading (HR: 1.29; 95% CI 0.87-1.92, P = 0.305), though neither reached statistical significance. No difference in risk of conversion to treatment was observed between ethnic groups (HR: 1.03; 95% CI 0.64-1.47, P = 0.873).

CONCLUSIONS

African/Afro-Caribbean men on AS for PCa in the UK are less likely to adhere to scheduled appointments, suggesting a more tailored service addressing their specific needs may be required. While African/Afro-Caribbean men were no more likely to convert to treatment than Caucasian/other men, findings of a potentially higher risk of disease progression signal the need for careful selection and monitoring of African/Afro-Caribbean men on AS. Larger prospective, multicentre studies with longer follow-up are required to provide more definitive conclusions.

Global Trends of Latent Prostate Cancer in Autopsy Studies

Simple Summary

The incidence of prostate cancer (PC) is statistically biased due to the increase in prostate-specific antigen (PSA) screening and the accuracy of national cancer registration systems. However, studies on latent PC provide less biased information. This comprehensive review included studies evaluating latent PC in several countries. The prevalence of latent PC has been stable since 1950 in Western countries, but it has increased over time in Asian countries. Latent PC in Asian men has increased in prevalence and is higher in grade. This increase occurred not only due to the increase in PSA screening, but also due to increasing adoption of a Westernized lifestyle. Racial differences between Caucasian and Asian men may also explain the tumor location of latent PC. The autopsy findings in patients with latent PC included a significant proportion of high grade and stage cancers, suggesting a need to reconsider the definition of clinically insignificant PC.

Abstract

The incidence of prostate cancer (PC) has been increasing in Asian countries, where it was previously low. Although the adoption of a Westernized lifestyle is a possible explanation, the incidence is statistically biased due to the increase in prostate-specific antigen (PSA) screening and the accuracy of national cancer registration systems. Studies on latent PC provide less biased information. This review included studies evaluating latent PC in several countries after excluding studies using random or single-section evaluations and those that did not mention section thickness. The findings showed that latent PC prevalence has been stable since 1950 in Western countries, but has increased over time in Asian countries. Latent PC in Asian men has increased in both prevalence and number of high-grade cases. Racial differences between Caucasian and Asian men may explain the tumor location of latent PC. In conclusion, the recent increase in latent PC in Asian men is consistent with an increase in clinical PC. Evidence suggests that this increase is caused not only by the increase in PSA screening, but also by the adoption of a more Westernized lifestyle. Autopsy findings suggest the need to reconsider the definition of clinically insignificant PC.

Should Grade Group 1 (GG1) be called cancer?

INTRODUCTION

ISUP Grade Group 1 prostate cancer is the lowest histologic grade of prostate cancer with a clinically indolent course. Removal of the term 'cancer' has been proposed and has historical precedent both in urothelial and thyroid carcinoma.

METHODS

Evidence-based review identifying arguments for and against Grade Group 1 being referred to as cancer.

RESULTS

Grade Group 1 has histologic evidence of tissue microinvasion and 0.3-3% rate of extraprostatic extension. Genomic evaluation suggests overlap of a minority of Grade Group 1 cancers with those of Grade Group 2. Conversely, Grade Group 1 tumors appear to have distinct genetic and genomic profiles from Grade Group 3 or higher tumors. Grade Group 1 has no documented ability for regional or distant metastasis and long-term follow up after treatment or active surveillance is safe with excellent oncologic outcomes.

DISCUSSION

Grade Group 1 prostate cancer, while showing evidence of neoplasia on histology has a remarkably indolent natural history more akin to non-neoplastic precursor lesions. Consideration should be given to renaming Grade Group 1 prostate cancer, which has the potential to minimize overtreatment, treatment-related side effects, patient anxiety, and financial burden on the healthcare system.

Cancer in Africa: Is It a Genetic or Environmental Health Problem?

Patients of African ancestry have the poorest outcome and the shortest survival rates from cancer globally. This could be attributed to many variables including racial, biological, socioeconomic and sociocultural factors (either single, multiple or combined), which may be responsible for this major health problem. We sought to assess the most common types of cancer that endanger the health of the African people, and tried to investigate the real differences between African and other Non-African patients regarding incidence, prevalence and mortality rates of different cancers. Therefore, identifying the underlying aetiological causes responsible for the increased incidence and mortality rates of African patients will allow for changing the current plans, to make optimized modalities for proper screening, diagnosis and treatment for those African patients, in order to improve their survival and outcomes.

The Impact of African Ancestry on Prostate Cancer Disparities in the Era of Precision Medicine

Prostate cancer disproportionately affects men of African ancestry at nearly twice the rate of men of European ancestry despite the advancement of treatment strategies and prevention. In this review, we discuss the underlying causes of these disparities including genetics, environmental/behavioral, and social determinants of health while highlighting the implications and challenges that contribute to the stark underrepresentation of men of African ancestry in clinical trials and genetic research studies. Reducing prostate cancer disparities through the development of personalized medicine approaches based on genetics will require a holistic understanding of the complex interplay of non-genetic factors that disproportionately exacerbate the observed disparity between men of African and European ancestries.

Lower thiol, glutathione, and glutathione peroxidase levels in prostate cancer: a meta-analysis study

PURPOSE

Lowered thiol (-SH) groups and glutathione (GSH) metabolism may be associated with prostate cancer (PCa) and benign prostatic hyperplasia (BPH). The objectives of this study were to systematically review and meta-analyze the associations among -SH groups, GSH, GSH peroxidase (GPx), GSH reductase (GR), and GSH transferase (GST) and PCa/BPH.

METHODS

Four electronic databases were searched for studies that reported -SH and GSH variables in PCa/BPH and healthy controls (HC) and the data were meta-analyzed by calculating Hedges's g with 95% confidence intervals.

RESULTS

Twenty studies were included in this meta-analysis. Total -SH (g = -1.750, -2.341/-1.159), GPx (g = -0.789, -1.234/-0.344), GSH (g = -2.219, -4.132/-0.305), and the combination of -SH, GPx, and GSH (g = -1.271, -1.271/-0.800) were significantly lower in PCa patients than in HC. -SH (g = -1.752, -3.123/-0.381) and the combination of -SH, GPx, and GSH (g = -0.813, -1.298/-0.327) were significantly lower in BPH patients than in HC. GPx was significantly lower in PCa than in BPH patients (g = -0.455, -0.896/-0.014). Heterogeneity levels were very high, but Egger's test showed that none of the biomarkers showed significant publication bias.

CONCLUSION

Thiol/GPx antioxidant defenses are significantly attenuated in patients with PCa while patients with BPH occupy an intermediate risk group position between PCa patients and HC.

Premature Years of Life Lost Due to Cancer in the United States in 2017

BACKGROUND

Burden of cancer mortality is often measured by death counts or mortality rates, but potential years of life lost (PYLL) and PYLL per death may be more useful to estimate the impact of cancer-related deaths occurring at younger ages.

METHODS

We used U.S. national death certificate data. A total of 45 categories of common cancers were grouped for cancer-specific calculations of PYLL and PYLL per death. PYLL was defined as the sum of the total years of life lost prior to age 75 years.

RESULTS

The largest number of PYLL in 2017 was due to deaths from cancers of the lung/bronchus (891,313; 20.8%), colon/rectum (409,538; 9.6%), and breast (400,643; 9.4%). Cancers with the highest PYLLs generally also caused the largest number of deaths and had the highest mortality rates, with the exception of prostate cancer (5.1% of deaths, 2.0% of PYLL). In contrast, PYLLs per death were greatest for deaths due to cancers of testis (mean = 34.0 years), bones/joints (26.4), and other endocrine sites including thymus (25.2).

CONCLUSIONS

Although PYLLs generally reflect mortality rates, they more heavily weigh cancers that occur at younger ages. In contrast, PYLL per death, which is an average quantification of life years lost for individual patients with cancer, shows a different pattern.

IMPACT

Mortality rates, PYLL, and PYLL per death are complementary measures of the burden of deaths due to cancer that should be considered in tandem to prioritize public health interventions focused on preventing premature mortality.

An Up-to-date Assessment of US Prostate Cancer Incidence Rates by Stage and Race: A Novel Approach Combining Multiple Imputation with Age and Delay Adjustment

BACKGROUND

In the USA, it is unknown whether metastatic prostate cancer incidence has continued to increase and whether racial differences have persisted.

OBJECTIVE

Combining multiple imputation with age and delay adjustment, we provide an up-to-date, comprehensive assessment of US prostate cancer incidence trends by stage and race.

DESIGN, SETTING, AND PARTICIPANTS

From Surveillance Epidemiology and End Results (SEER)-18, 774 240 prostate cancer cases were diagnosed during 2004-2017.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multiple imputation assigned prostate cancer stage to the 4.7% of cases with missing stage, which varied by year and race-ethnicity. SEER delay factors adjusted case counts to anticipated future data corrections. Twenty datasets were imputed, and Rubin's rules were used for summary estimation. Overall and stage-specific rates were estimated and stratified by race and age group. Joinpoint software identified significant temporal changes and estimated annual percentage changes. We compared these estimates without multiple imputation and delay adjustment.

RESULTS AND LIMITATIONS

Metastatic prostate cancer incidence increased during 2011-2017, with an annual percentage change of 5.5. This was followed by increases in localized and regional disease since 2014. Non-Hispanic black men continued to have the highest incidence, especially for metastatic disease. The increasing rate of metastatic prostate cancer in non-Hispanic white men aged 50-74 yr accelerated recently, and the incidence was 56% higher in 2017 than in 2004. Rates without multiple imputation and delay adjustment were quantitatively and qualitatively different. This observational study is unable to assign causes to observed changes in prostate cancer incidence.

CONCLUSIONS

Multiple imputation and delay adjustment are essential for portraying accurately stage- and race-specific prostate cancer incidence as clinical practice evolves.

PATIENT SUMMARY

In the USA, diagnosis of prostate cancer that has spread to distant sites (metastatic disease) continues to increase. Black men continue to have higher risks of being diagnosed with metastatic prostate cancer than other race-ethnicities.

Associations of Prostate-Specific Antigen (PSA) Testing in the US Population: Results from a National Cross-Sectional Survey

Prostate-specific antigen (PSA) testing is one of the standard screening methods for prostate cancer (PC); however, a high proportion of men with abnormal PSA findings lack evidence for PC and may undergo unnecessary treatment. Furthermore, little is known about the prevalence of PSA testing for US men, after the US Preventive Services Task Force (USPSTF) recommended against routine PSA screening in 2012. Our objectives were to: (1) examine the self-reported patterns of PSA testing following a change in the USPSTF prostate cancer screening recommendations and (2) to determine the associated socio-demographic factors. Data were from the 2010 and 2015 National Health Interview Surveys. Men were ages ≥ 40 years and responded to the question "Ever had a PSA test?". Multivariable logistic regression was used to examine PSA testing prevalence in 2010 and 2015, and their associated socio-demographic factors. The analytic sample contained 15,372 men. A majority (75.2%) identified as non-Hispanic (NHW) and 14.2% were foreign-born. Those surveyed in 2015 were less likely to report ever having had a PSA test when compared to those in 2010. Compared to US-born and older NHW men, PSA testing was statistically significantly lower among foreign-born men and men belonging to all other racial categories. Fewer men reported PSA testing following the USPSTF 2012 recommendations. Associated socio-demographic factors included nativity, age, race/ethnicity, educational attainment and type of health insurance. Further studies are required to elucidate our findings and their health implications for the US native and foreign-born population.

"More men die with prostate cancer than because of it" - an old adage that still holds true in the 21st century

BACKGROUND

Prostate cancer (PCa) incidence has risen due to PSA testing, making it the commonest male malignancy. Most PSA-detected cases are organ-confined. Whilst radical treatment has increased, there has been little change in PCa-specific mortality. Over-detection of clinically insignificant PCa and active surveillance are increasing. We compared studies from the 21st century versus earlier reports demonstrating how commonly PCa is incidentally detected at autopsy. We describe the ongoing increasing prevalence of PCa with age, along with features of autopsy-detected disease.

METHODS

A literature review of PubMed and Scopus was conducted using the search terms "prostate cancer or carcinoma", "latent" or "autopsy", to January 2019. Citations and references from all publications found in this search were manually reviewed to identify additional articles.

RESULTS

63 publications were identified between 1898 and 2017, reporting over 29,000 autopsies on subjects aged between 20 and ≥90 years. PCa prevalence was 21% across all ages, and we found no significant difference in 21st century studies versus earlier studies. Autopsy-detected incidental PCa cases were typically small (~0.5cubic cm), predominantly low grade, and only occasionally (10%) extra-prostatic. PCa prevalence increased with age, being detected in >50% in men aged ≥90 years. The frequency of high-grade PCa almost doubled with each increasing age category.

CONCLUSION

Most autopsy-detected PCa cases continue to be clinically insignificant. The prevalence of autopsy-detected PCa was 30-fold greater than PCa-specific mortality in each ten-year age category. This should be considered when counselling elderly men regarding PSA-testing, particularly in the context of competing co-morbidity.

Lack of Racial Survival Differences in Metastatic Prostate Cancer in National Cancer Data Base (NCDB): A Different Finding Compared to Non-metastatic Disease

Background: Inconsistent findings have been reported in the literature regarding racial differences in survival outcomes between African American and white patients with metastatic prostate cancer (mPCa). The current study utilized a national database to determine whether racial differences exist among the target population to address this inconsistency.

Methods: This study retrospectively reviewed prostate cancer (PCa) patient data (N = 1,319,225) from the National Cancer Database (NCDB). The data were divided into three groupings based on the metastatic status: (1) no metastasis (N = 318,291), (2) bone metastasis (N = 29,639), and (3) metastases to locations other than bone, such as brain, liver, or lung (N = 952). Survival probabilities of African American and white PCa patients with bone metastasis were examined through parametric proportional hazards Weibull models and Bayesian survival analysis. These results were compared to patients with no metastasis or other types of metastases.

Results: No statistically supported racial disparities were observed for African American and white men with bone metastasis (p = 0.885). Similarly, there were no racial disparities in survival for those men suffering from other metastases (liver, lung, or brain). However, racial disparities in survival were observed among the two racial groups with non-metastatic PCa (p < 0.001) or when metastasis status was not taken into account (p < 0.001). The Bayesian analysis corroborates the finding.

Conclusion: This research supports our previous findings and shows that there are no racial differences in survival outcomes between African American and white patients with mPCa. In contrast, racial disparities in the survival outcome continue to exist among non-metastatic PCa patients. Further research is warranted to explain this difference.

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.

Clonal evaluation of prostate cancer molecular heterogeneity in biopsy samples by dual immunohistochemistry and dual RNA in situ hybridization

Prostate cancer is frequently multifocal. Although there may be morphological variation, the genetic underpinnings of each tumor are not clearly understood. To assess the inter and intra tumor molecular heterogeneity in prostate biopsy samples, we developed a combined immunohistochemistry and RNA in situ hybridization method for the simultaneous evaluation of ERG, SPINK1, ETV1, and ETV4. Screening of 601 biopsy cores from 120 consecutive patients revealed multiple alterations in a mutually exclusive manner in 37% of patients, suggesting multifocal tumors with considerable genetic differences. Furthermore, the incidence of molecular heterogeneity was higher in African Americans patients compared with Caucasian American patients. About 47% of the biopsy cores with discontinuous tumor foci showed clonal differences with distinct molecular aberrations. ERG positivity occurred in low-grade cancer, whereas ETV4 expression was observed mostly in high-grade cancer. Further studies revealed correlation between the incidence of molecular markers and clinical and pathologic findings, suggesting potential implications for diagnostic pathology practice, such as defining dominant tumor nodules and discriminating juxtaposed but molecularly different tumors of different grade patterns.