Do differences in age specific androgenic steroid hormone levels account for differing prostate cancer rates between Arabs and Caucasians?

Definition, Prevalence, and Risk Factors of Low Sex Hormone-Binding Globulin in US Adults

CONTEXT

Lower sex hormone-binding globulin (SHBG) is associated with many diseases including cardiovascular disease, cancer, polycystic ovarian syndrome, arthritis, and liver disease. However, the definition of low SHBG and its prevalence in US adults are unknown.

OBJECTIVE

To define low SHBG and to determine its prevalence and risk factors in US adults.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included adults ≥20 years from the US National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016 who had fasting serum SHBG.

EXPOSURES

NHANES coverage during 2013-2016.

MAIN OUTCOMES MEASURES

Definition, prevalence, and risk factors of low SHBG.

RESULTS

This study included 4093 adults (weighted sample size of 204 789 616) with a mean (SD) age of 47.5 (17.0) years. In a "healthy" reference sub-cohort of 1477 adults, low SHBG was defined as SHBG < 12.3 nmol/L in men < 50 years, <23.5 nmol/L in men ≥ 50 years, <14.5 nmol/L in women < 30 years, and <21.9 nmol/L in women ≥ 30 years. The estimated US national prevalence of low SHBG was 3.3% in men, 2.7% in women, and 3.0% overall. Risk factors for this condition in both men and women included higher body mass index, diabetes, ethnicity (being other than Hispanic, non-Hispanic black, or non-Hispanic white), chronic obstructive pulmonary disease, coronary heart disease, and smoking.

CONCLUSIONS

This study established the criteria for low SHBG among US adults. The estimated US national prevalence of low SHBG was 3.3% in men and 2.7% in women.

Long-term testosterone undecanoate replacement therapy: Impact of ethnicity

BACKGROUND

Testosterone replacement therapy (TRT) is indicated for symptomatic male hypogonadism. However, the safety and efficacy profiles across different ethnicities for long-term TRT remain unclear.

OBJECTIVE

To measure the impact of ethnicity on various biochemical parameters following testosterone undecanoate (TU) replacement.

METHOD

A retrospective analysis of 50 male patients treated with TU from 2006 to 2017 in a large secondary care centre was performed. Changes in total testosterone, PSA, haematocrit, haemoglobin, total cholesterol and low-density lipoprotein (LDL) over eight years of treatment were analysed. Wilcoxon rank sum test was used to assess differences in these parameters between Caucasians and South Asians.

RESULTS

Thirty-one Caucasians (age: median (IQR) 55.0 years (49.0-68.0); total duration of follow-up 6.1 years (2.9-9.3)) and 19 South Asians (age: median (IQR) 52.0 years (38.0-69.0); duration of follow-up 6.5 years (1.3-8.4)) were treated with TU during the study period. There was no significant difference in total testosterone levels between the two ethnicities. We noted a higher free and bioavailable testosterone in South Asians than Caucasians, albeit within their reference range. PSA was higher in Caucasians than South Asians at two and eight years of TU therapy. After one year of TRT, haematocrit was higher in South Asians than Caucasians at one year, whereas LDL and total cholesterol were significantly higher in Caucasians than South Asians.

CONCLUSIONS

Caucasians have a tendency towards increased PSA, total cholesterol and LDL compared with South Asians with TU replacement therapy. There is a higher increment of haematocrit in South Asians following one year of TU replacement therapy. All biochemical changes following TRT were within the respective reference ranges suggesting no apparent risk of prostate cancer and venous thromboembolism.

Prostate cancer in the Arab population. An overview

This review evaluated prostate cancer studies from around the world and investigated the causes of differences among them. Prostate cancer incidence and mortality rates showed significant discrepancies between countries and ethnicities. In North America as well as in other western countries, the most common cancer was found to be prostate cancer; however, it appears to be not as prevalent among men in the Middle East and North Africa. Statistics show that screening of prostate-specific antigen levels should be applied depending on ethnicity and age. Other environmental aspects such as dietary and androgenic factors are believed to have caused these differences.

Pathological outcomes and agressiveness of low-risk prostate cancer in Northern African men

BACKGROUND

Northern African (NAf) men show a high incidence of advanced prostate cancer (PCa) at diagnosis. Several studies suggested the existence of ethnic differences in the PCa aggressiveness and this has led to some concerns related to the inclusion of some ethnic groups into active surveillance protocols.

OBJECTIVE

To evaluate pathological outcomes and aggressiveness of low risk PCa treated by radical prostatectomy in a NAf ethnic group.

SUBJECTS AND METHODS

Data of 147 NAfs, who underwent radical prostatectomy for low risk PCa diagnosed via a 12-core biopsy in 2 academic centers between 2011 and 2015, were reviewed retrospectively to assess rates of worse pathological outcomes defined as: Gleason score upgrade to at least 3+4, upstage to pT3a or higher or pN1, and positive surgical margins.

RESULTS

Overall significant upstage and/or upgrade occurred in 20.2% and positive surgical margins occured in18.3%. In multivariate logistic regression analysis, independent variables that predicted for upstage and/or upgrade or positive surgical margins in the entire cohort were: NCCN risk group (low risk>very low risk), advanced age>60 years, PSA>6ng/ml, PSA density≥0.15, more than 2 positive cores in biopsy, more than 50% cancer involvement in positive cores, clinical stage (T2a>T1c) and UCSF-CAPRA-S score>3.

CONCLUSIONS

Our study found that, at least pathologically, NAf men do not have more aggressive disease than Caucasians and African Americans in both low and very low risk PCa. Thus, we think that active surveillance is a suitable approach for selected patients since there is no definitive data that show a more aggressive natural history of PCa in NAf men.

Prostate Cancer in the Arab World: A View From the Inside

The rates of prostate cancer vary by more than 50-fold across different international populations. The aim of this review was to explore the differences in epidemiology and risk factors between the Middle Eastern Arab countries and some of the developed countries in Europe and North America. The age-standardized incidence rate of prostate cancer in the Arab countries is still lower than that in the Western countries, but is steadily increasing with time. Several factors come into play to explain this difference. There are health care systems-related factors such as the lack of good population-based registries, and population-related factors. The latter include the relatively young age structure in the Arab countries, lower reported androgen and prostate-specific antigen levels in Arab men, the effect of genetic differences on prostate cancer risk, the metabolic syndrome paradox, and the protective effect of the Mediterranean diet on a subset of the Arab population. In conclusion, the study of prostate cancer in the Arab world represents a challenge with the currently available cancer care systems and the increase in the burden of the disease. A multinational prospective study to investigate the epidemiology of prostate cancer in the Middle East, with specific attention to country/geographic variability along with a comparative analysis to that of the Western hemisphere is needed.

Pattern of prostate cancer presentation among the Egyptian population: A study in a single tertiary care center

INTRODUCTION

Prostate cancer is a common health problem that in the majority of cases starts to develop at the age of 50 years, reaching its peak at 60-70 years of age. A variation in its incidence and prevalence exists between western, Asian and Arabic populations. The aim of our work was to report the pattern of prostate cancer presentation in Alexandria University that as a tertiary referral center provides care for uro-oncology cases.

MATERIAL AND METHODS

Data collection for all patients diagnosed with prostate cancer at Alexandria University in Egypt through the year 2012 was done.

RESULTS

The mean age of the patients was 67. Mean serum total PSA, prostate volume and PSAd were 149 ng/ml, 63 grams and 3.1 ng/ml/gm respectively. 25% of patients were asymptomatic diagnosed accidentally during screening for prostate cancer. The remaining group was presenting with LUTS, including 23 patients who presented initially with back pain.

CONCLUSIONS

Egyptian men with prostate cancer have a markedly high PSA density and Gleason grade at diagnosis.

Differences in prostate cancer detection between Canadian and Saudi populations

Few studies have addressed racial differences in prostate cancer (PCa) detection between Western and Arabian countries, although PCa has a significantly lower prevalence in Arabic populations compared to Western populations. Therefore, an explanation of this difference is lacking. Serum prostate-specific antigen (PSA) is a valuable marker used to select patients who should undergo prostate biopsies, although the manner in which it is used may require adjustments based on the ethnic population in question. We investigated racial differences in the PCa detection rate between Canadian and Saudi populations. A retrospective analysis was performed of data collected prospectively over 5 consecutive years in urology clinics at the McGill University Health Center (MUHC) and King Saud University Hospital (KSUH). Men who had high (>4'ng/mL) or rising PSA levels and a negative digital rectal examination were eligible. A total of 1403 Canadian and 414 Saudi patients were evaluated for the study; 717 and 158 men, median age 64 and 68 years, were included in the MUHC and KSUH cohorts, respectively, P<0.0001). Median serum PSA, prostate volume, and PSA density values were 6.1'ng/mL, 47.3 g, and 0.12'ng·mL⁻¹·g⁻¹, respectively, for MUHC patients and 5.2'ng/mL, 64.5'g, and 0.08'ng·mL⁻¹·g⁻¹, respectively, for KSUH patients (P<0.0001, t-test followed by one-way ANOVA). In addition, the KSUH group had a significantly lower PCa detection rate among patients younger than 60 years of age and with PSA values <10'ng/mL.

Genome scan study of prostate cancer in Arabs: identification of three genomic regions with multiple prostate cancer susceptibility loci in Tunisians

Background

Large databases focused on genetic susceptibility to prostate cancer have been accumulated from population studies of different ancestries, including Europeans and African-Americans. Arab populations, however, have been only rarely studied.

Methods

Using Affymetrix Genome-Wide Human SNP Array 6, we conducted a genome-wide association study (GWAS) in which 534,781 single nucleotide polymorphisms (SNPs) were genotyped in 221 Tunisians (90 prostate cancer patients and 131 age-matched healthy controls). TaqMan^® SNP Genotyping Assays on 11 prostate cancer associated SNPs were performed in a distinct cohort of 337 individuals from Arab ancestry living in Qatar and Saudi Arabia (155 prostate cancer patients and 182 age-matched controls). In-silico expression quantitative trait locus (eQTL) analysis along with mRNA quantification of nearby genes was performed to identify loci potentially cis-regulated by the identified SNPs.

Results

Three chromosomal regions, encompassing 14 SNPs, are significantly associated with prostate cancer risk in the Tunisian population (P = 1 × 10^-4 to P = 1 × 10^-5). In addition to SNPs located on chromosome 17q21, previously found associated with prostate cancer in Western populations, two novel chromosomal regions are revealed on chromosome 9p24 and 22q13. eQTL analysis and mRNA quantification indicate that the prostate cancer associated SNPs of chromosome 17 could enhance the expression of STAT5B gene.

Conclusion

Our findings, identifying novel GWAS prostate cancer susceptibility loci, indicate that prostate cancer genetic risk factors could be ethnic specific.