Prostate Cancer in Southern Africa: Does Africa Hold Untapped Potential to Add Value to the Current Understanding of a Common Disease?

The Role of Trace Metals in the Development and Progression of Prostate Cancer

Over the years, prostate cancer (PCa) research has been of great interest, and trace metals have attracted a lot of attention due to their association with prostate cancer development and progression. PCa has a complex etiology, with genetic, environmental, and lifestyle factors being implicated. Trace metals such as zinc (Zn), mercury (Hg), selenium (Se), lead (Pb), cadmium (Cd), manganese (Mn), arsenic (As), and nickel (Ni) have garnered much attention in recent years, suspected of having direct links to the modulation of cancer risk and progression through their impacts on prostate cancer omics (genomics, epigenetics, proteomics, and transcriptomics). This has led to them being the subject of extensive research in this regard. In this review, we explored the influence of trace metals and offered a comprehensive analysis of the current knowledge on how trace metals affect the biology of prostate cancer at a molecular level by integrating findings from the recent literature to help suggest possible directions for future research.

Knowledge and Attitudes towards Prostate Cancer and Screening among Males in Limpopo Province, South Africa

Inadequate knowledge and poor attitudes about prostate cancer (PC) negatively affect early screening practices among males. The PC mortality rate is increasing due to late reporting, screening, and treatment. This study explored the awareness, attitudes, and PC screening behaviours among males in the Limpopo, Thulamela municipality. This descriptive cross-sectional study involved 245 males that were randomly selected. A structured questionnaire was used to collect data. Fisher's exact tests and logistic regression analysis were used to examine the association between sociodemographic variables, awareness, and attitudes towards PC. Our findings revealed that 64.1% demonstrated inadequate awareness about PC. The overall score (84.9%) showed a positive attitude towards PC. However, 87.4% had a negative attitude towards the effectiveness of treatment for PC. The majority (96.7%) of respondents had never undergone a PSA test, although 53.1% were willing to undergo a PSA test. There was a significant positive correlation between awareness of prostate cancer and attitudes toward prostate cancer (r = 0.280, p < 0.001). Health status predicted awareness about PC, while age and health status predicted attitudes towards PC among men. Rural community-based programmes and heightened awareness campaigns are needed to conscientize men about the risk factors, symptoms, diagnosis, and treatment of PC in rural areas of Limpopo.

Enhancing public awareness and practice of prostate cancer screening among African men: A scoping review

BACKGROUND

Prostate cancer (PCa)-related incidence is on the increase, with black South African men presenting disproportionately with aggressive disease. Recent studies show a greater net benefit of prostate-specific antigen (PSA) screening of black men compared with the general population. This scoping review provides an overview of available research on strategies that have enhanced PCa screening awareness and practice in the African setting.

METHODS

Relevant databases were searched to identify 2010-2021 studies. Following scoping review guidelines, data were extracted, summarised and quantitatively analysed.

RESULTS

Of the 21 articles included, 19 were from the United States. Nine were published within the last five years and 14 were pre-test/post-test. Most articles evaluated the effect of health-promoting strategies on awareness and practice of PCa screening among black men. Community-oriented strategies enhanced awareness and practice of PCa screening. Healthcare providers and community members, including PCa survivors, participated in the strategies' planning, development and implementation. Topics that improve PCa knowledge and clear cultural misconceptions were addressed, targeting public spaces unique to these men. Prostate cancer health education methods were diverse, comprehensive, user friendly and culturally sensitive.

CONCLUSION

More research on strategies to enhance PCa screening awareness and practice among African men is needed, as this is scarce. Strategies enhancing PCa screening awareness and practice among African men are community oriented and entail health education methods, topics, presenters and venues. These strategies can be adopted in the South African setting.Contribution: This study recommends strategies to enhance the awareness and practice of PCa screening among African men.

The profile of Black South African men diagnosed with prostate cancer in the Free State, South Africa

BACKGROUND

Prostate cancer (PCa) ranks high in terms of morbidity and mortality, especially in Africa. Prostate-specific antigen (PSA) screening remains a practical method of screening for and thereby detecting PCa early, especially among African men who are more negatively affected. Modifiable risk factors for PCa are mostly behavioural and lifestyle. Understanding community-specific determinants is important when developing health promotion interventions.

OBJECTIVE

This study aimed to determine the profile of African men with PCa in the Free State, South Africa.

METHOD

A cross-sectional descriptive study was conducted using case record information and self-administered questionnaires among 341 African men with PCa attending the oncology and urology clinics of a tertiary hospital.

RESULT

Participants' median age at diagnosis was 66 years. Only 76 (22.3%) participants had ever heard of PCa prior to being diagnosed with the disease, 36 (47.4%) of whom had ever had screening performed. The majority (n = 298, 87.4%) were symptomatic; 50% sought medical help within six months. At diagnosis, 133 (39.0%) men presented with stage T3 or T4 disease, 75 (22.0%) with metastatic disease and 84 (24.6%) with Gleason score ≥ 8. Factors associated with advanced and high-grade disease included smoking, decreased sunlight exposure and physical activity, relatively increased ingestion of dairy products and red meat. Factors associated with early stage and low-grade disease included relatively increased ingestion of fruits, vegetables and fish.

CONCLUSION

Advanced and high-grade PCa disease is not uncommon among men ≥ 60 years in this study setting. Certain modifiable risk factors associated with advanced disease were established in this study. The majority had lower urinary tract symptoms (LUTS) prior to PCa diagnosis, but they were of poor health-seeking behaviour. Although there seems not to be a systematic delay in the definitive diagnosis and initiation of treatment for PCa, there is a need to improve on health education and awareness in the study setting.

Prostate Cancer Disparities and Management in Southern Africa: Insights into Practices, Norms and Values

Prostate cancer (PCa) is a leading cause of mortality in men of African origin. While men of African descent in high-income countries (HICs) demonstrate poor prognosis compared to their European counterparts, African men on the African continent, particularly Southern Africa have shown even higher PCa mortality rates. Extrinsic factors such as the socioeconomic status, education level, income level, geographic location and race contribute to PCa patient outcome. These are further deepened by the African norms which are highly esteemed and may have detrimental effects on PCa patients' health. Insights into African cultures and social constructs have been identified as key elements towards improving men's health care seeking behaviour which will in turn improve PCa patients' outcome. Compared to Southern Africa, the Eastern, Western and Central African regions have lower PCa incidence rates but higher mortality rates. The availability of cancer medical equipment has also been reported to be disproportionate in Africa, with most cancer resources in Northern and Southern Africa. Even within Southern Africa, cancer management resources are unevenly available where one country must access PCa specialised care in the neighbouring countries. While PCa seems to be better managed in HICs, steps towards effective PCa management are urgently needed in Africa, as this continent represents a significant portion of low-middle-income countries (LMICs). Replacing African men in Africa with African American men may not optimally resolve PCa challenges in Africa. Adopting western PCa management practices can be optimised by integrating improved core-African norms. The aim of this review is to discuss PCa disparities in Africa, deliberate on the significance of integrating African norms around masculinity and discuss challenges and opportunities towards effective PCa care in Africa, particularly in Southern Africa.

Knowledge, beliefs and intentions of African men in the Free State about prostate cancer screening

Background

African men are less likely to participate in prostate cancer (PCa) screening, which may be beneficial to some of them. Gaps in knowledge, cultural factors and beliefs are associated with their screening intentions.

Aim

To determine the knowledge, cultural factors and screening intentions of African males regarding PCa screening.

Setting

The study was conducted among African men attending randomly selected primary healthcare clinics in the Free State province.

Methods

An analytical, cross-sectional survey using self-administered questionnaires developed in line with the Theory of Planned Behaviour constructs.

Results

Of the 389 respondents, 18.3% had ever been screened for PCa with prostate-specific antigen (PSA) testing and 6.2% by digital rectal examination (DRE). About a quarter (24.4%) of the respondents had knowledge scores ≥ 50%. Factors associated with greater intent to screen for PCa were lower degree of fear/apprehension of PCa screening (mean score = 2.03; p < 0.001), higher perceived benefits of PCa screening (mean score = 2.69; p = 0.002), lower perceived situational barriers to PCa screening (mean score = 2.03; p = 0.006) and higher perceived risk of getting PCa (mean score = 2.66; p = 0.024).

Conclusion

The observed low level of knowledge and practice of PCa screening among the respondents could be enhanced through PCa awareness strategies targeted at these men or those that could influence their decision making, especially healthcare providers. Factors that enhance screening intentions should be promoted.

Contribution

This study improves on the scarce literature on factors associated with African men's PCa screening intention.

Cancer Survivorship: Religion in Meaning Making and Coping Among a Group of Black Prostate Cancer Patients in South Africa

The purpose of the study was to explore the role of religion in meaning making and coping among a group of black patients receiving some form of prostate cancer treatment at a public hospital in Limpopo Province, South Africa. A sample of 20 prostate cancer survivors, with ages ranging from 67 to 85 years (mean_age = 76yrs; SD = 5.3) selected through purposive sampling. Data were collected through in-depth, semi-structured individual interviews and analysed using interpretative phenomenological analysis (IPA). The findings demonstrated that religion is an important factor in meaning making and coping by prostate cancer survivors. The findings suggest that healthcare practitioners need to pay close attention to the meanings that cancer patients assign to their illness to provide the appropriate care and support.

Role of Precision Oncology in Type II Endometrial and Prostate Cancers in the African Population: Global Cancer Genomics Disparities

Precision oncology can be defined as molecular profiling of tumors to identify targetable alterations. Emerging research reports the high mortality rates associated with type II endometrial cancer in black women and with prostate cancer in men of African ancestry. The lack of adequate genetic reference information from the African genome is one of the major obstacles in exploring the benefits of precision oncology in the African context. Whilst external factors such as the geography, environment, health-care access and socio-economic status may contribute greatly towards the disparities observed in type II endometrial and prostate cancers in black populations compared to Caucasians, the contribution of African ancestry to the contribution of genetics to the etiology of these cancers cannot be ignored. Non-coding RNAs (ncRNAs) continue to emerge as important regulators of gene expression and the key molecular pathways involved in tumorigenesis. Particular attention is focused on activated/repressed genes and associated pathways, while the redundant pathways (pathways that have the same outcome or activate the same downstream effectors) are often ignored. However, comprehensive evidence to understand the relationship between type II endometrial cancer, prostate cancer and African ancestry remains poorly understood. The sub-Saharan African (SSA) region has both the highest incidence and mortality of both type II endometrial and prostate cancers. Understanding how the entire transcriptomic landscape of these two reproductive cancers is regulated by ncRNAs in an African cohort may help elucidate the relationship between race and pathological disparities of these two diseases. This review focuses on global disparities in medicine, PCa and ECa. The role of precision oncology in PCa and ECa in the African population will also be discussed.

Prostate cancer racial, socioeconomic, geographic disparities: targeting the genomic landscape and splicing events in search for diagnostic, prognostic and therapeutic targets

Prostate cancer (PCa) is one of the leading causes of deaths in men globally. This is a heterogeneous and complex disease that urgently warrants further insight into its pathology. Developed countries have thus far the highest PCa incidence rates, with comparatively low mortality rates. Even though PCa in the Asian population seems to have high incidence and mortality rates, the African countries are emerging as the focal center for this disease. It has also been reported that the Sub-Saharan (SSA) countries have both the highest incidence and mortality rates. To date, few studies have reported the link between PCa and African populations. Adequate evidence is still missing to fully comprehend this relationship. While it has been brought to attention that racial, geographical and socioeconomic status are contributing factors, men of African descent across the globe, irrespective of their geographical position have higher PCa incidence and mortality rates compared to their white counterparts. To date, hormone therapy is the mainstay treatment of PCa, while the dysregulation of androgen receptor (AR) signaling is a hallmark of PCa. One of the emerging problems with this therapeutic approach is resistance to antiandrogens, and that AR splice isoforms implicated in the progression of PCa lack the therapeutic ligand-binding domain (LBD) target. AR splice variants targeted therapy is emerging and in clinical trials. Leveraging PCa transcriptomics is key towards PCa precision medicine. The aim of this review is to outline the PCa epidemiology globally and in Africa, PCa associated risk factors, discuss AR signaling and PCa mechanisms, the role of dysregulated splicing in PCa as novel prognostic indicators and therapeutic targets.

Information Needs of Black Prostate Cancer Patients Receiving Treatment Within the South African Public Healthcare System

Introduction

Prostate cancer is the leading cancer type in black South African men. The South African public healthcare sector serves more than 84% of the population, which includes many of these men. Previous evidence suggests that patients’ information needs are influenced by culture. No studies could be found that explored the information needs of black men diagnosed with prostate cancer in a developing country from the patients’ perspectives. Therefore, this study set out to investigate the information needs of black men diagnosed with prostate cancer in a South African public healthcare setting.

Methods

Nine participants who had completed a radical course of external beam radiation therapy for prostate cancer were interviewed. These participants had gained experience from their cancer journey in this setting and could therefore provide information-rich perspectives about their information needs from the time of diagnosis to end of treatment. Interviews were conducted in the participants’ preferred language, with three interviews conducted in Zulu with an English translator.

Results

Important themes that emerged included patients' desire to receive more information regarding what was happening in the diagnosis stage, the implications of having prostate cancer and the origin of their symptoms. The participants expressed a need to understand the potential side effects of radiation therapy, the reason for bladder filling and on-treatment set-up imaging verification. Participants also wanted to know how they should care for themselves and adjust their lifestyles, and required more information about follow-up tests and appointments.

Conclusion

In South Africa, black men with prostate cancer expressed the need for more information about the implications of a prostate cancer diagnosis, the reasons for these treatments and what they were expected to do. They also require information about where to go and what will happen in the different parts of the healthcare system with regard to the diagnosis and treatment of the prostate cancer. Communities should also be educated about cancer to avoid misconceptions. In South Africa, healthcare workers should consider the life-worlds of black men in the public healthcare system when attending to their information needs.

Population Differentiation at the PVT1 Gene Locus: Implications for Prostate Cancer

Genetic variation in susceptibility to complex diseases, such as cancer, is well-established. Enrichment of disease associated alleles in specific populations could have implications for disease incidence and prevalence. Prostate cancer (PCa) is a disease with well-established higher incidence, prevalence, and worse outcomes among men of African ancestry in comparison to other populations. PCa is a multi-factorial, complex disease, but the exact mechanisms for its development and progression are unclear. The gene desert located on chromosome 8q24 is associated with aggressiveness of PCa. Interestingly, the non-protein coding gene locus Plasmacytoma Variant Translocation (PVT1) is present at chromosome 8q24 and is overexpressed in PCa. PVT1 gives rise to multiple transcripts with potentially different molecular and cellular functions. In an analysis of the PVT1 locus using data from the 1000 Genomes Project, we found the chromosomal region spanning PVT1 exons 4A and 4B to be highly differentiated between African and non-African populations. We further investigated levels of gene expression of PVT1 exons 4A and 4B and observed significant overexpression of these exons in PCa tissues relative to benign prostatic hyperplasia and to normal prostate tissues obtained from men of African ancestry. These results indicate that PVT1 exons 4A and 4B may have clinical implications in PCa a conclusion supported by the observation that transient and stable overexpression of PVT1 exons 4A and 4B significantly induce greater prostate epithelial cell migration and proliferation. We anticipate that further exploration of the role of PVT1 exons 4A and 4B may lead to the development of diagnostic, therapeutic, and other clinical applications in PCa.

Heterogeneity in the distribution of 159 drug-response related SNPs in world populations and their genetic relatedness

Interethnic variability in drug response arises from genetic differences associated with drug metabolism, action and transport. These genetic variations can affect drug efficacy as well as cause adverse drug reactions (ADRs). We retrieved drug-response related single nucleotide polymorphism (SNP) associated data from databases and analyzed to elucidate population specific distribution of 159 drug-response related SNPs in twenty six populations belonging to five super-populations (African, Admixed Americans, East Asian, European and South Asian). Significant interpopulation differences exist in the minor (variant) allele frequencies (MAFs), linkage disequilibrium (LD) and haplotype distributions among these populations. 65 of the drug-response related alleles, which are considered as minor (variant) in global population, are present as the major alleles (frequency ≥0.5) in at least one or more populations. Populations that belong to the same super-population have similar distribution pattern for majority of the variant alleles. These drug response related variant allele frequencies and their pairwise LD measure (r²) can clearly distinguish the populations in a way that correspond to the known evolutionary history of human and current geographic distributions, while D' cannot. The data presented here may aid in identifying drugs that are more appropriate and/or require pharmacogenetic testing in these populations. Our findings emphasize on the importance of distinct, ethnicity-specific clinical guidelines, especially for the African populations, to avoid ADRs and ensure effective drug treatment.

African KhoeSan ancestry linked to high-risk prostate cancer

BACKGROUNDS

Genetic diversity is greatest within Africa, in particular the KhoeSan click-speaking peoples of southern Africa. South African populations represent admixture fractions including differing degrees of African, African-KhoeSan and non-African genetic ancestries. Within the United States, African ancestry has been linked to prostate cancer presentation and mortality. Together with environmental contributions, genetics is a significant risk factor for high-risk prostate cancer, defined by a pathological Gleason score ≥ 8.

METHODS

Using genotype array data merged with ancestry informative reference data, we investigate the contribution of African ancestral fractions to high-risk prostate cancer. Our study includes 152 South African men of African (Black) or African-admixed (Coloured) ancestries, in which 40% showed high-risk prostate cancer.

RESULTS

Genetic fractions were determined for averaging an equal African to non-African genetic ancestral contribution in the Coloured; we found African ancestry to be linked to high-risk prostate cancer (P-value = 0.0477). Adjusting for age, the associated African ancestral fraction was driven by a significant KhoeSan over Bantu contribution, defined by Gleason score ≥ 8 (P-value = 0.02329) or prostate specific antigen levels ≥20 ng/ml (P-value = 0.03713). Additionally, we observed the mean overall KhoeSan contribution to be increased in Black patients with high-risk (11.8%) over low-risk (10.9%) disease. Linking for the first time KhoeSan ancestry to a common modern disease, namely high-risk prostate cancer, we tested in this small study the validity of using KhoeSan ancestry as a surrogate for identifying potential high-risk prostate cancer risk loci. As such, we identified four loci within chromosomal regions 2p11.2, 3p14, 8q23 and 22q13.2 (P-value = all age-adjusted < 0.01), two of which have previously been associated with high-risk prostate cancer.

CONCLUSIONS

Our study suggests that ancient KhoeSan ancestry may be linked to common modern diseases, specifically those of late onset and therefore unlikely to have undergone exclusive selective pressure. As such we show within a uniquely admixed South African population a link between KhoeSan ancestry and high-risk prostate cancer, which may explain the 2-fold increase in presentation in Black South Africans compared with African Americans.

Whole-Genome Sequencing Reveals Elevated Tumor Mutational Burden and Initiating Driver Mutations in African Men with Treatment-Naïve, High-Risk Prostate Cancer

: African-American men are more likely than any other racial group to die from prostate cancer. The contribution of acquired genomic variation to this racial disparity is largely unknown, as genomic from Africa is lacking. Here, we performed the first tumor-normal paired deep whole-genome sequencing for Africa. A direct study-matched comparison between African- and European-derived, treatment-naïve, high-risk prostate tumors for 15 cases allowed for further comparative analyses of existing data. Excluding a single hypermutated tumor with 55 mutations per megabase, we observed a 1.8-fold increase in small somatic variants in African- versus European-derived tumors (P = 1.02e-04), rising to 4-fold when compared with published tumor-matched data. Furthermore, we observed an increase in oncogenic driver mutations in African tumors (P = 2.92e-03); roughly 30% of impacted genes were novel to prostate cancer, and 79% of recurrent driver mutations appeared early in tumorigenesis. Although complex genomic rearrangements were less frequent in African tumors, we describe a uniquely hyperduplicated tumor affecting 149 transposable elements. Comparable with African Americans, ERG fusions and PIK3CA mutations were absent and PTEN loss less frequent. CCND1 and MYC were frequently gained, with somatic copy-number changes more likely to occur late in tumorigenesis. In addition to traditional prostate cancer gene pathways, genes regulating calcium ion-ATPase signal transduction were disrupted in African tumors. Although preliminary, our results suggest that further validation and investigation into the potential implications for elevated tumor mutational burden and tumor-initiating mutations in clinically unfavorable prostate cancer can improve patient outcomes in Africa. SIGNIFICANCE: The first whole-genome sequencing study for high-risk prostate cancer in African men allows a simultaneous comparison of ethnic differences relative to European populations and of the influences of the environment relative to African-American men. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/78/24/6736/F1.large.jpg.See related commentary by Huang, p. 6726.