Diabetes mellitus and risk of prostate cancer in the health professionals follow-up study

Diabetes Mellitus and Prostate Cancer Risk-A Systematic Review and Meta-Analysis

INTRODUCTION

Prostate cancer is the second most commonly diagnosed malignant tumor worldwide and poses a significant challenge to public health. This systematic review and meta-analysis aims to investigate the association between diabetes mellitus and the risk of developing prostate cancer.

METHODS

We conducted a search of PubMed, Embase, and the Cochrane Library from 1998 to 2024. The risk of bias within the included studies was assessed using the Newcastle-Ottawa Scale. The DerSimonian-Laird random-effect model was employed for the meta-analysis. Heterogeneity was evaluated using a forest plot and statistically assessed via the Q test, I2 index, and p-values.

RESULTS

Forty-three studies involving a total of 3,746,769 patients were included. Both case-control (pOR = 0.68, 95% CI: 0.61-0.97; I2 = 92.24%) and cohort studies (pRR = 0.71, 95% CI: 0.59-0.99; I2 = 85.41%) suggest that diabetes mellitus is associated with a reduced risk of prostate cancer, though with significant heterogeneity (p < 0.05). Subgroup analysis revealed that the risk of developing prostate cancer was significantly higher in patients with a family history of prostate cancer (pRR = 1.25, 95% CI: 1.16-1.35; I2 = 69.51%).

CONCLUSIONS

Our meta-analysis of recent observational studies indicates that diabetes mellitus is associated with a reduced risk of developing prostate cancer.

Influence of diabetes on microbiome in prostate tissues of patients with prostate cancer

Background

Although microbiota in prostatic tissues of patients with prostate cancer have been studied, results of different studies have been inconsistent. Different ethnicity of study subjects, different study designs, and potential contaminations during sample collection and experiments might have influenced microbiome results of prostatic tissues. In this study, we analyzed microbiota and their potential functions in benign and malignant tissues of prostate cancer considering possible contaminants and host variables.

Materials and methods

A total of 118 tissue samples (59 benign tissues and 59 malignant tissues) obtained by robot-assisted laparoscopic radical prostatectomy were analyzed and 64 negative controls (from sampling to sequencing processes) were included to reduce potential contaminants.

Results

Alteration of the microbiome in prostate tissues was detected only in patients with diabetes. Furthermore, the influence of diabetes on microbiome was significant in malignant tissues. The microbiome in malignant tissues of patients with diabetes was influenced by pathologic stages. The relative abundance of Cutibacterium was reduced in the high pathologic group compared to that in the intermediate group. This reduction was related to microbial pathways increased in the high pathologic group.

Conclusion

Results of this study indicate that diabetes can influence the progression of prostate cancer with microbiome alteration in prostate tissues. Although further studies are necessary to confirm findings of this study, this study can help us understand tissue microbiome in prostate cancer and improve clinical therapy strategies.

Impact of Family History and Germline Genetic Risk Single Nucleotide Polymorphisms on Long-Term Outcomes of Favorable-Risk Prostate Cancer

PURPOSE

Family history and germline genetic risk single nucleotide polymorphisms (SNPs) have been separately shown to stratify lifetime risk of prostate cancer. Here, we evaluate the combined prognostic value of family history of prostate and other related cancers and germline risk SNPs among patients with favorable-risk prostate cancer.

MATERIALS AND METHODS

A total of 1367 participants from the prospective Health Professionals Follow-up Study diagnosed with low- or favorable intermediate-risk prostate cancer from 1986 to 2017 underwent genome-wide SNP genotyping. Multivariable Cox regression was used to estimate the association between family history, specific germline risk variants, and a 269 SNP polygenic risk score with prostate cancer‒specific death.

RESULTS

Family history of prostate, breast, and/or pancreatic cancer was observed in 489 (36%) participants. With median follow-up from diagnosis of 14.9 years, participants with favorable-risk prostate cancer with a positive family history had a significantly higher risk of prostate cancer‒specific death (HR 1.95, 95% CI 1.15-3.32, P = .014) compared to those without any family history. The rs2735839 (19q13) risk allele was associated with prostate cancer‒specific death (HR 1.81 per risk allele, 95% CI 1.04-3.17, P = .037), whereas the polygenic risk score was not. Combined family history and rs2735839 risk allele were each associated with an additive risk of prostate cancer‒specific death (HR 1.78 per risk factor, 95% CI 1.25-2.53, P = .001).

CONCLUSIONS

Family history of prostate, breast, or pancreatic cancer and/or a 19q13 germline risk allele are associated with an elevated risk of prostate cancer‒specific death among favorable-risk patients. These findings have implications for how family history and germline genetic risk SNPs should be factored into clinical decision-making around favorable-risk prostate cancer.

Association between body mass index, metabolic syndrome and common urologic conditions: a cross-sectional study using a large multi-institutional database from the United States

INTRODUCTION

The study aims to determine whether body mass index (BMI), metabolic syndrome (MS) or its individual components (primary hypertension, type 2 diabetes mellitus and dyslipidemias) are risk factors for common urological diseases.

MATERIALS AND METHODS

Cross-sectional study with data collected on February 28, 2022 from the TriNetX Research Network. Patients were divided in cohorts according to their BMI, presence of MS (BMI > 30 kg/m2, type 2 diabetes mellitus, primary hypertension and disorders of lipoprotein metabolism) and its individual components and its association with common urological conditions was determined. For each analysis, odds ratio (OR) with 95% confidence intervals were calculated. Statistical significance was assessed at p < .05.

RESULTS

BMI > 30 kg/m2 was associated with increased risk of lithiasis, kidney cancer, overactive bladder, male hypogonadism, benign prostatic hyperplasia, and erectile dysfunction (p < .05). On the contrary, BMI was inversely associated with ureteral, bladder and prostate cancer (p < .05). In all urological diseases, MS was the strongest risk factor, with prostate cancer (OR = 2.53) showing the weakest and male hypogonadism the strongest (OR = 13.00) associations.

CONCLUSIONS

MS and its individual components were significant risk factors for common urological conditions. Hence holistic approaches with lifestyle modification might prevent common urological disease.Key messagesOverall, metabolic syndrome is the strongest risk factor for all the analysed urological diseases.Abnormally high body mass index can be a risk or protective factor depending on the threshold and urological disease that are being evaluated.Metabolic syndrome and increased BMI should be considered important factors associated to the prevalence of common urological diseases.

Risk analysis of metformin use in prostate cancer: a national population-based study

INTRODUCTION

Various approaches are required to prevent and treat heterogeneity-based prostate cancer. Here, we analyzed the anticancer effects of metformin, which has a good toxicity profile and is inexpensive.

METHOD

From January 2010 to December 2019, analysis was conducted retrospectively in a cohort from the National Health Insurance Service database. The wash-out period was set for cancer diagnosis in 2010 and 2011, and subjects (105,279) diagnosed with prostate cancer (ICD C61) from 2012 to 2014 were excluded The final subjects (105,216) were defined as the metformin administration group when they took metformin for 180 days or more from January 2012 to December 2019. The non-metformin group was defined as those who took less than 180 days from January 2012 to December 2019. The prevalence of prostate cancer according to metformin administration and the risk according to the cumulative duration of metformin were analyzed.

RESULTS

A total of 105,216 people were included in this study, with 59,844 in the metformin group and 45,372 in the metformin non-administration group. When calculating HRs (Hazard Rate) according to the cumulative period of metformin administration, metformin administration period length was inversely associated with prostate cancer risk (Q2 HR = 0.791 95% CI: 0.773-0.81, Q3 HR = 0.634 95% CI: 0.62-0.649, Q4 HR = 0.571 95% CI: 0.558-0.585). HRs tended to decrease with the cumulative duration of metformin administration.

CONCLUSION

This study confirmed that prostate cancer risk decreased with increasing duration of metformin administration. Metformin should be considered as a new strategy in the treatment and prevention of prostate cancer characterized by heterogeneity.

Emerging Hallmarks of Metabolic Reprogramming in Prostate Cancer

Prostate cancer (PCa) is the most common male malignancy and the fifth leading cause of cancer death in men worldwide. Prostate cancer cells are characterized by a hybrid glycolytic/oxidative phosphorylation phenotype determined by androgen receptor signaling. An increased lipogenesis and cholesterogenesis have been described in PCa cells. Many studies have shown that enzymes involved in these pathways are overexpressed in PCa. Glutamine becomes an essential amino acid for PCa cells, and its metabolism is thought to become an attractive therapeutic target. A crosstalk between cancer and stromal cells occurs in the tumor microenvironment because of the release of different cytokines and growth factors and due to changes in the extracellular matrix. A deeper insight into the metabolic changes may be obtained by a multi-omic approach integrating genomics, transcriptomics, metabolomics, lipidomics, and radiomics data.

Identification of prediagnostic metabolites associated with prostate cancer risk by untargeted mass spectrometry-based metabolomics: A case-control study nested in the Northern Sweden Health and Disease Study

Prostate cancer (PCa) is the most common cancer form in males in many European and American countries, but there are still open questions regarding its etiology. Untargeted metabolomics can produce an unbiased global metabolic profile, with the opportunity for uncovering new plasma metabolites prospectively associated with risk of PCa, providing insights into disease etiology. We conducted a prospective untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics analysis using prediagnostic fasting plasma samples from 752 PCa case-control pairs nested within the Northern Sweden Health and Disease Study (NSHDS). The pairs were matched by age, BMI, and sample storage time. Discriminating features were identified by a combination of orthogonal projection to latent structures-effect projections (OPLS-EP) and Wilcoxon signed-rank tests. Their prospective associations with PCa risk were investigated by conditional logistic regression. Subgroup analyses based on stratification by disease aggressiveness and baseline age were also conducted. Various free fatty acids and phospholipids were positively associated with overall risk of PCa and in various stratification subgroups. Aromatic amino acids were positively associated with overall risk of PCa. Uric acid was positively, and glucose negatively, associated with risk of PCa in the older subgroup. This is the largest untargeted LC-MS based metabolomics study to date on plasma metabolites prospectively associated with risk of developing PCa. Different subgroups of disease aggressiveness and baseline age showed different associations with metabolites. The findings suggest that shifts in plasma concentrations of metabolites in lipid, aromatic amino acid, and glucose metabolism are associated with risk of developing PCa during the following two decades.

Diabetes and the Prostate: Elevated Fasting Glucose, Insulin Resistance and Higher Levels of Adrenal Steroids in Prostate Cancer

Although epidemiological studies suggest a lower prostate cancer incidence rate in patients with type 2 diabetes, cancer survival is markedly reduced. Underlying mechanisms that connect the two diseases are still unclear. Potential links between type 2 diabetes and prostate cancer are hallmarks of the metabolic syndrome, such as hyperglycemia and dyslipidemia. Therefore, we explored the systemic metabolism of 103 prostate cancer patients with newly diagnosed and yet untreated prostate cancer compared to 107 healthy controls, who were carefully matched for age and BMI. Here, we report that patients with prostate cancer display higher fasting blood glucose levels and insulin resistance, without changes in insulin secretion. With respect to lipid metabolism, serum triglyceride levels were lower in patients with prostate cancer. In addition, we report increased adrenal steroid biosynthesis in these patients. Our results indicate that higher fasting glucose levels in patients with prostate cancer may be explained at least in part by insulin resistance, due to the enhanced synthesis of adrenal steroids.

Health Burdens and SES in Alabama: Using Geographic Information System to Examine Prostate Cancer Health Disparity

Socioeconomic disparities influence the risk of many diseases, including cancer. The cancer rate in Alabama is high, and the state has one of the highest rates of prostate cancer in the USA. Alabama's counties are embedded with socioeconomic disparities, politics, race, ethnicity, and oppression, among which social equity and socioeconomic status (SES) been closely associated with prostate cancer. The Geographic Information System (GIS) has become a valuable technology in understanding public health in many applications, including cancer. This study integrates Alabama's county-level prostate cancer incidence and mortality and its association with socioeconomic and health disparities. We conducted robust data mining from several data sources such as the Alabama State Cancer Profile data, Alabama Department of Health, American Cancer Society, Center for Disease Control, and National Cancer Institute. The research method is the Geographic Information System (GIS), and we employed prostate cancer data within GIS to understand Alabama's prostate cancer prevalence regarding SES. The GIS analysis indicated an apparent socioeconomic disparity between the Black Belt and Non-Black Belt counties of Alabama. The Black Belt counties' poverty rate is also remarkably higher than non-Black Belt counties. In addition, we analyzed the median household income by race. Our analysis demonstrates that the Asian background population in the state earned the highest median income compared to non-Hispanic whites and the African American population. Furthermore, the data revealed that the preexisting condition of diabetes and obesity is closely associated with prostate cancer. The GIS analysis suggests that prostate cancer incidence and mortality disparities are strongly related to SES. In addition, the preexisting condition of obesity and diabetes adds to prostate cancer incidences. Poverty also reflects inequalities in education, income, and healthcare facilities, particularly among African Americans, contributing to Alabama's health burden of prostate cancer.

Role of single nucleotide polymorphisms of the HSD3B1 gene (rs6203 and rs33937873) in the prediction of prostate cancer risk

3-β-hydroxysteroid dehydrogenase 1 (HSD3B1) is shown to affect dihydrotestosterone level in prostatic tissue which is a risk factor for prostate cancer (PC). The present study aimed to determine whether rs33937873 (G313A) and rs6203 (C338T) single nucleotide polymorphisms (SNP) in HSD3B1 gene was a potential risk factor for PC susceptibility and can predict the recurrence of PC in Egyptian patients. A total of 186 Egyptian patients were selected with incident primary PC and compared with 180 age healthy controls. The frequencies and the main effect of rs33937873 and rs6203 in HSD3B1 were compared and investigated between the patients and control using genotyping technique and statistical analysis. The mutant GA genotype of G313A in rs33937873 SNP was considered as an independent risk for PC in the multivariate regression analysis [odds ratio (OR)=2.7, 95% confidence intervals (CI): 1.2-5.5, P=0.01] together with positive history of hypertension (HTN) (OR=6.2, 95% CI: 3.2-12.1, P=0.0001) and begin prostatic hyperplasia (BPH; OR=8.9, 95% CI: 4.5-17.5, P=0.0001). Conversely, in rs6203 (C338T), C allele is considered as major risk allele in the development of PC (OR=1.8, 95% CI: 1.3-2.4, P=0.0003). The univariate logistic regression analyses indicated that CC genotype of rs6203 was a PC risk factor (OR=1.9, 95% CI: 1.3-2.9, P=0.002). In addition, the frequency of the A-C haplotype established by rs33937873-rs6203 was also significantly higher for PC (P=0.013). The predication of PC recurrence was associated only with positive family history (OR=7.7, 95% CI: 2.3-25.9, P=0.001) and not for The G313A and C338T SNPs. These results suggested that the two HSD3B1 polymorphisms rs33937873 and rs6203 may modify the risk of PC, particularly among patients with HTN and history of BPH, suggesting them as prominent future markers for prediction of PC risk.

5-Alpha Reductase Inhibitors and Prostate Cancer Mortality among Men with Regular Access to Screening and Health Care

BACKGROUND

How 5-alpha reductase inhibitor (5-ARI) use influences prostate cancer mortality is unclear. The objective of this study was to determine whether men taking 5-ARIs with regular health care access have increased prostate cancer mortality.

METHODS

We undertook two analyses in the Health Professionals Follow-up Study examining 5-ARI use, determined by biennial questionnaires, and prostate cancer. A cohort analysis followed 38,037 cancer-free men for prostate cancer incidence from 1996 through January 2017 and mortality through January 2019. A case-only analysis followed 4,383 men with localized/locally advanced prostate cancer for mortality over a similar period. HRs and 95% confidence intervals (CI) were calculated for prostate cancer incidence and mortality.

RESULTS

Men using 5-ARIs underwent more PSA testing, prostate exams and biopsies. Over 20 years of follow-up, 509 men developed lethal disease (metastases or prostate cancer death). Among men initially free from prostate cancer, 5-ARI use was not associated with developing lethal disease [HR, 1.02; 95% confidence interval (CI), 0.71-1.46], but was associated with reduced rates of overall and localized disease (HR, 0.71; 0.60-0.83). Among men diagnosed with prostate cancer, there was no association between 5-ARI use and cancer-specific (HR, 0.78; 95% CI, 0.48-1.27) or overall survival (HR, 0.88; 95% CI, 0.72-1.07).

CONCLUSIONS

Men using 5-ARIs were less likely to be diagnosed with low-risk prostate cancer, without increasing long-term risk of lethal prostate cancer or cancer-specific death after diagnosis.

IMPACT

Our results provide evidence that 5-ARI use is safe with respect to prostate cancer mortality in the context of regular health care access. See related commentary by Hamilton, p. 1259.

Testosterone Deficiency is Not Protective Against the Development of Adenocarcinoma of the Prostate in a Type 1 Diabetic Patient

We present a case of prostate cancer (PC) developing in a hypogonadal patient with well-controlled type 1 diabetes. The purpose of reporting this case is to emphasize that regular prostate examinations and prostate-specific antigen (PSA) measurements should be preformed in the diabetic male, even though the incidence of PC is lower in this group of patients. In addition, these examinations and tests need to be preformed even in the hypogonadal patient with diabetes since the presence of a low serum testosterone (T) level does not preclude the development of PC. This is because the development of PC is not related to serum androgen levels but to the androgen levels within the prostate, and dihydrotestosterone (DHT) levels and not T levels within the prostate gland are responsible for the development of PC. In the hypogonadal male, intraprostatic DHT may be high since DHT can be formed from adrenal androgens, particularly androstenedione, through activation of 5α-reductase 2, which is the minority enzyme in the normal prostate but becomes the major enzyme in the formation and growth of PC.

Incretin-Based Drugs and the Incidence of Prostate Cancer Among Patients with Type 2 Diabetes

BACKGROUND

There is some evidence that glucagon-like peptide 1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors have chemopreventive effects on prostate cancer cells, but real-world evidence for this possible effect is lacking. Thus, the objective of this study was to estimate whether use of GLP-1 receptor agonists and DPP-4 inhibitors, separately, is associated with a decreased risk of prostate cancer among patients with type 2 diabetes.

METHODS

We assembled two new-user, active comparator cohorts using the United Kingdom Clinical Practice Research Datalink (2007 to 2019). The first cohort included 5063 initiators of GLP-1 receptor agonists and 112,955 of sulfonylureas. The second cohort included 53,529 initiators of DPP-4 inhibitors and 114,417 of sulfonylureas. We fit Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for prostate cancer. We weighted the models using propensity score fine stratification, which considered over 50 potential confounders.

RESULTS

GLP-1 receptor agonists were associated with a decreased risk of prostate cancer when compared with sulfonylureas (incidence rates: 156.4 vs. 232.0 per 100,000 person-years, respectively; HR: 0.65, 95% CI: 0.43, 0.99). DPP-4 inhibitors were also associated with a decreased risk of prostate cancer when compared with sulfonylureas (incidence rates: 316.2 vs. 350.5 events per 100,000 person-years, respectively; HR: 0.90, CI: 0.81, 1.00).

CONCLUSIONS

The results of this study are consistent with the hypothesis that the use of GLP-1 receptor agonists and DPP-4 inhibitors, separately, may decrease the risk of prostate cancer when compared with the use of sulfonylureas.

Hormonal patterns in men with prediabetes and diabetes in NHANES III: possible links with prostate cancer

PURPOSE

Pathways involving sex hormones and insulin-like growth factors (IGFs) have been proposed to explain, in part, the lower risk of prostate cancer among men with diabetes. To gain insights into potential biological mechanisms we explored differences in serum concentrations of sex hormones and IGFs across the trajectory from normoglycemia to prediabetes to poorly controlled diabetes.

METHODS

Using cross-sectional data from the National Health and Nutrition Examination Survey III we examined differences in levels of circulating sex hormones, sex hormone-binding globulin (SHBG), IGF-1, and IFG-binding protein 3 (IGFBP-3), according to diabetes status: no diabetes [n = 648], prediabetes [n = 578], undiagnosed diabetes [n = 106], well-controlled diabetes [n = 42], and poorly controlled diabetes [n = 56]. Adjusted geometric mean concentrations were derived using multivariable linear regression, adjusted for age, race, and other lifestyle factors.

RESULTS

Total testosterone concentrations were lower among prediabetics (4.89 ng/mL, 95% confidence interval (CI) 4.95-5.21) than men without prediabetes/diabetes (5.29 ng/mL, 95% CI 5.06-5.53) but did not reduce further across diabetes groups. Concentrations of estradiol, estimated free testosterone, SHGB, IGF-1, and IGFBP-3 did not differ. While the ratio of IGF-1 to IGFBP-3 was lower among men with prediabetics and undiagnosed diabetes than men without prediabetes/diabetes, there was no trend across groups. A positive trend for the ratio of estradiol-to-testosterone levels was observed across groups (p trend = 0.045).

CONCLUSION

Our findings do not provide clear support for either an androgen driven or IGF-driven pathway for the inverse association between diabetes and prostate cancer risk.

Androgen-Dependent Prostate Cancer Cells Reprogram Their Metabolic Signature upon GLUT1 Upregulation by Manganese Superoxide Dismutase

Prostate cancer is the second leading cause of cancer in men across the globe. The prostate gland accounts for some unique glycolytic metabolic characteristics, which causes the metabolic features of prostate tumor initiation and progression to remain poorly characterized. The mitochondrial superoxide dismutase (SOD2) is one of the major redox metabolism regulators. This study points out SOD2 as one major regulator for both redox and glycolytic metabolism in prostate cancer. SOD2 overexpression increases glucose transporter GLUT-1 and glucose uptake. This is not an insulin-mediated effect and seems to be sex-dependent, being present in male mice only. This event concurs with a series of substantial metabolic rearrangements at cytoplasmic and mitochondrial level. A concomitant decrease in glycolytic and pentose phosphate activity, and an increase in electron transfer in the mitochondrial electronic chain, were observed. The Krebs Cycle is altered to produce amino-acid intermediates by decreasing succinate dehydrogenase. This in turn generates a 13-fold increase in the oncometabolite succinate. The protein energy sensor AMPK is decreased at basal and phosphorylated levels in response to glucose deprivation. Finally, preliminary results in prostate cancer patients indicate that glandular areas presenting high levels of SOD2 show a very strong correlation with GLUT-1 protein levels (R² = 0.287 p-value < 0.0001), indicating that in patients there may exist an analogous phenomenon to those observed in cell culture and mice.

The broad pathogenetic role of TCF7L2 in human diseases beyond type 2 diabetes

The TCF7L2 protein is a key transcriptional effector of the Wnt/β‐catenin signaling pathway, regulating gene expression. It was initially identified in cancer research and embryologic developmental studies. Later, the TCF7L2 gene was linked to type 2 diabetes (T2D), implicating TCF7L2 and Wnt‐signaling in metabolic disorders and homeostasis. In fact, TCF7L2‐T2D variants confer the greatest relative risk for T2D, unquestionably predicting conversion to T2D in individuals with impaired glucose tolerance. We aim to describe the relevance of TCF7L2 in other human disorders. The TCF7L2‐single nucleotide polymorphisms (SNPs) and T2D‐risk association have been replicated in numerous follow‐up studies, and research has now been performed in several other diseases. In this article, we discuss common TCF7L2‐T2D variants within the framework of their association with human diseases. The TCF7L2 functional regions need to be further investigated because the molecular and cellular mechanisms through which TCF7L2 contributes to risk associations with different diseases are still not fully elucidated. In this review, we show the association of common TCF7L2‐T2D variants with many types of diseases. However, the role of rare genetic variations in the TCF7L2 gene in distinct diseases and ethnic groups has not been explored, and understanding their impact on specific phenotypes will be of clinical relevance. This offers an excellent opportunity to gain a clearer picture of the role that the TCF7L2 gene plays in the pathophysiology of human diseases. The potential pleiotropic role of TCF7L2 may underlie a possible pathway for comorbidity in human disorders.

Differences in the relationship between diabetes and prostate cancer among Black and White non-Hispanic men

PURPOSE

Studies finding lower incidence rates of prostate cancer among men with diabetes have been primarily conducted in White non-Hispanic (WNH) populations. The purpose of this analysis is to compare the relationship between diabetes and prostate cancer among Black (BNH) and White non-Hispanic men.

METHODS

We used Surveillance, Epidemiology, and End Results (SEER)-Medicare data from 2011 to 2015 to compare incidence rates and tumor characteristics between BNH and WNH men by diabetes status. Age-adjusted incidence rates and corresponding rate ratios (RR) by diabetes status were calculated overall and by tumor grade, stage, and PSA level separately for BNH and WNH men. We used multivariable logistic regression to compare tumor characteristics among men with prostate cancer in the numerator, both within and across race/ethnic groups.

RESULTS

Overall age-adjusted incidence rates were significantly lower in men with diabetes compared to those without among WNH men [RR = 0.88 95% Confidence Interval (CI) 0.86-0.90] but there was no difference in rates by diabetes status among BNH men (RR = 1.01 95% CI 0.96-1.07). Men with diabetes were less likely to be diagnosed with distant-staged tumors compared to those without diabetes in both race/ethnic groups but the magnitude of difference by diabetes status was greater in BNH [Odds Ratio (OR) = 0.52 95% CI 0.42-0.64] than WNH (OR = 0.88 95% CI 0.81-0.95) men (p-value for interaction < 0.001).

CONCLUSION

The relationship between diabetes and prostate cancer differed between BNH and WNH men. The differences could have implications in evaluating the effectiveness of prostate cancer screening in men with diabetes across racial/ethnic subgroups.

Incidence, predictive factors and oncological outcomes of incidental prostate cancer after endoscopic enucleation of the prostate: a systematic review and meta-analysis

INTRODUCTION

This systematic review aims at reporting the incidence, predictive factors, and the oncological outcomes of incidental prostate cancer (IPCa) in men who underwent endoscopic enucleation of prostate (EEP).

METHODS

A literature search was performed using the following Medical Subject Heading (MeSH) terms and keywords: "Prostatic Neoplasms", "Prostate Cancer", "Transurethral Resection of Prostate", "Prostate resection", "Prostate enucleation". Meta-analysis was performed if there were two or more studies reporting the same outcome under the same definition. In case of insufficient data, results were presented in a narrative manner.

RESULTS

Sixty-one studies were included in qualitative synthesis and 55 were included in meta-analysis. The pooled IPCa rate was 0.08 (95% CI 0.073-0.088). Increasing age, higher preoperative serum prostate-specific antigen (PSA) level, higher preoperative PSA density (PSAD), smaller prostate volume, higher postoperative PSA velocity and lower enucleated prostate weight, were reported to have significant correlation with IPCa. In BPH patients, the mean pre-operative and post-operative PSA levels were 5.58 ± 1.48 ng/dL and 1.06 ± 0.27 ng/dL, respectively. In patients with IPCa, the mean pre-operative and post-operative PSA levels were 7.72 ± 2.90 ng/dL and 2.77 ± 1.66 ng/dL, respectively. The mean percentage PSA reduction was 82.0% ± 1.8% for BPH patients and 68.2% ± 12.1% for IPCa patients. IPCa was most commonly managed by active surveillance (68.7%).

CONCLUSIONS

The pooled incidence of IPCa after EEP was 8%. An absolute post-operative PSA level of < 2.0 and a percentage PSA reduction of > 70% should be expected in BPH patients after EEP.

Impact of poor glycemic control upon clinical outcomes after radical prostatectomy in localized prostate cancer

To evaluate the clinical impact of preoperative glycemic status upon oncological and functional outcomes after radical prostatectomy in patients with localized prostate cancer, we analyzed the data of 2664 subjects who underwent radical prostatectomy with preoperative measurement of hemoglobin A1c within 6 months before surgery. The possible association between high hemoglobin A1c (≥ 6.5 ng/dL) and oncological/functional outcomes was evaluated. Among all subjects, 449 (16.9%) were categorized as the high hemoglobin A1c group and 2215 (83.1%) as the low hemoglobin A1c group. High hemoglobin A1c was associated with worse pathological outcomes including extra-capsular extension (HR 1.277, 95% CI 1.000–1.630, p = 0.050) and positive surgical margin (HR 1.302, 95% CI 1.012–1.674, p = 0.040) in multi-variate regression tests. Kaplan–Meier analysis showed statistically shorter biochemical recurrence-free survival in the high hemoglobin A1c group (p < 0.001), and subsequent multivariate Cox proportional analyses revealed that high hemoglobin A1c is an independent predictor for shorter BCR-free survival (HR 1.135, 95% CI 1.016–1.267, p = 0.024). Moreover, the high hemoglobin A1c group showed a significantly longer incontinence-free survival than the low hemoglobin A1c group (p = 0.001), and high preoperative hemoglobin A1c was also an independent predictor for longer incontinence-free survival in multivariate Cox analyses (HR 0.929, 95% CI 0.879–0.981, p = 0.008). The high preoperative hemoglobin A1c level was independently associated with worse oncological outcomes and also with inferior recovery of urinary continence after radical prostatectomy.

Antidiabetic Drugs and Prostate Cancer Prognosis in a Finnish Population-Based Cohort

BACKGROUND

Hyperinsulemia and glycemic control may play a role as prostate cancer prognostic factors, whereas use of certain antidiabetic drugs, that is metformin, could improve the prognosis. We examined the link between antidiabetic medication use and prostate cancer survival taking into account simultaneous use of multiple drugs.

METHODS

The study cohort composed of 6,537 men in The Finnish Randomized Study of Screening for Prostate Cancer with prostate cancer diagnosed 1996 to 2009. Use of medication was attained from the nationwide prescription database of the Social Insurance Institution of Finland. Median follow-up was 9.2 years postdiagnosis. A total of 1,603 (24,5%) men had used antidiabetic medication. A total of 771 men died of prostate cancer during the follow-up. We used multivariable-adjusted Cox regression to evaluate the risk of prostate cancer death and onset of androgen deprivation therapy (ADT) with adjustment for prostate cancer clinical characteristics, comorbidities and use of other drugs. Separate analyses were further adjusted for blood glucose.

RESULTS

Risk of prostate cancer death was higher among antidiabetic drug users overall (HR = 1.42; 95% CI, 1.18-1.70) compared with nonusers, separately among insulin and metformin users. Adjustment for blood glucose level abolished the risk increase. Risk of ADT initiation was increased among the medication users (HR = 1.26; 95% CI, 1.05-1.49).

CONCLUSIONS

Men with prostate cancer using antidiabetic medication are generally at increased risk of dying from prostate cancer compared with nonusers. The risk association is driven by underlying diabetes, as adjustment for blood glucose level ameliorates the risk increase.

IMPACT

Type 2 diabetes should be considered as a risk factor when considering prostate cancer prognosis.

Metabolic syndrome, levels of androgens, and changes of erectile dysfunction and quality of life impairment 1 year after radical prostatectomy

Robust data evaluating the association of preoperative parameters of the patients with quality of life after radical prostatectomy are lacking. We investigated whether clinical and biological preoperative characteristics of the patients were associated with impaired patient-reported quality of life (QoL) and sexual outcomes 1 year after radical prostatectomy. We evaluated patient-reported outcomes among the 1343 men participating in the AndroCan trial (NCT02235142). QoL and erectile dysfunction (ED) were assessed before and 1 year after radical prostatectomy using validated self-assessment questionnaires (Aging Male's Symptoms [AMS] and the 5-item abridged version of the International Index of Erectile Function [IIEF5]). At baseline, 1194 patients (88.9%) accepted to participate. A total of 750 (55.8%) patients answered the 1-year postoperative questionnaires. Out of them, only 378 (50.4% of responders) provided answers that could be used for calculations. One year after prostatectomy, ED had worsened by 8.0 (95% confidence interval [CI]: 7.3–8.7; P < 0.0001) out of a maximum of 20. The global AMS score has worsened by 2.8 (95% CI: 1.7–3.8; P < 0.0001). ED scores 1 year postsurgery were positively correlated with preoperative age and percentage of fat mass, and negatively correlated with total cholesterol, dehydroepiandrosterone (DHEA), and androstenediol (D5); AMS were poorly correlated with preoperative parameters. QoL and sexual symptoms significantly worsened after radical prostatectomy. Baseline bioavailable testosterone levels were significantly correlated with smaller changes on AMS somatic subscores postprostatectomy. These findings may be used to inform patients with newly diagnosed prostate cancer.

Reduced risk of prostate cancer in a cohort of Lithuanian diabetes mellitus patients

BACKGROUND

During the past decade, a huge interest was devoted to the type-2 diabetes mellitus and their associations with prostate cancer development.

OBJECTIVES

The aim of this study was to determine whether type 2 diabetes mellitus and treatment with metformin is associated with prostate cancer risk.

MATERIALS AND METHODS

The cohort was composed of diabetic male patients identified in the National Health Insurance Fund database during 2000-2016 and cancer cases in national Cancer Registry. We calculated standardized incidence ratios (SIR) for prostate cancers as a ratio of observed number of cancer case in people with diagnosis of diabetes to the expected number of cancer cases in the underlying general population.

RESULTS

2754 prostate cancers were observed versus 3111.26 expected within the period of observation entailing an SIR of 0.89 (95% CI: 0.85-0.92). Significantly lower risk of prostate cancer was found in diabetes patients in all age groups, also was in metformin-users and never-users' groups, with higher risk reduction in metformin-users (SIR 0.71, 95% CI: 0.68-0.75) than in diabetes patients never-users (SIR 0.88, 95% CI: 0.80-0.96).

CONCLUSION

In this large population-based study, we found a significantly decreased risk of prostate cancer among men with diabetes and metformin-users.

Increased Expressions of Matrix Metalloproteinases (MMPs) in Prostate Cancer Tissues of Men with Type 2 Diabetes

Type 2 diabetes (T2D) is associated with worse prognosis of prostate cancer (PCa). The molecular mechanisms behind this association are still not fully understood. The aim of this study was to identify key factors, which contribute to the more aggressive PCa phenotype in patients with concurrent T2D. Therefore, we investigated benign and PCa tissue of PCa patients with and without diabetes using real time qPCR. Compared to patients without diabetes, patients with T2D showed a decreased E-cadherin/N-cadherin (CDH1/CDH2) ratio in prostate tissue, indicating a switch of epithelial-mesenchymal transition (EMT), which is a pivotal process in carcinogenesis. In addition, the gene expression levels of matrix metalloproteinases (MMPs) and CC chemokine ligands (CCLs) were higher in prostate samples of T2D patients. Next, prostate adenocarcinoma PC3 cells were treated with increasing glucose concentrations to replicate hyperglycemia in vitro. In these cells, high glucose induced expressions of MMPs and CCLs, which showed significant positive associations with the proliferation marker proliferating cell nuclear antigen (PCNA). These results indicate that in prostate tissue of men with T2D, hyperglycemia may induce EMT, increase MMP and CCL gene expressions, which in turn activate invasion and inflammatory processes accelerating the progression of PCa.

Examining the relationship between diabetes and prostate cancer through changes in screening guidelines

PURPOSE

Previous studies have found that men with diabetes are at reduced risk of prostate cancer compared to men without diabetes. The lower risk could be due to biologic differences and/or a diagnosis bias from use of the prostate-specific antigen (PSA) test as a screening and diagnostic tool. We sought to further examine the relationship between diabetes and incidence of prostate cancer and examine the potential impact of changes in PSA screening guidelines in 2008 and 2012.

METHODS

We used 2004-2015 Surveillance, Epidemiology and End Results (SEER)-Medicare data and limited the study population to men aged 67-74 with at least 2 years of continuous enrollment. Using the 5% Medicare sample as the denominator and prostate cancer cases as the numerator, we calculated age-adjusted rate ratios (RR) in 2006-2011 and 2012-2015 by diabetes status, overall and by tumor grade. We used multivariable logistic regression to compare tumor characteristics by diabetes status.

RESULTS

Men with diabetes had lower incidence rates of prostate cancer compared to men without diabetes in 2006-2011 [RR = 0.89 95% confidence interval (CI) 0.87-0.91] and 2012-2015 (RR = 0.92 95% CI 0.89-0.95) but the slight attenuation toward the null in 2012-2015 was primarily due to the change in RRs for low-grade tumors.

CONCLUSION

We found differences in the risk and characteristics of prostate cancer by diabetes status and that some risks have changed over time as guidelines have changed. With lower PSA use in the more recent time-period, rates of low-grade tumors have become more similar by diabetes status.

Differences in the prevalence of modifiable risk and protective factors for prostate cancer by race and ethnicity in the National Health and Nutrition Examination Survey

PURPOSE

Prostate cancer burden is disproportionate by race. Black men have the highest incidence and mortality rates. Rates for Hispanic men are significantly lower than for non-Hispanic Whites. Whether differences in prevalences of modifiable risk and protective factors for prostate cancer may explain these racial/ethnic differences remains unclear.

METHODS

We used data from the National Health and Nutrition Examination Surveys (NHANES), which are cross-sectional and nationally representative. We selected factors known or suspected to be associated with prostate cancer and calculated risk scores combining key factors. Age-adjusted means and proportions were calculated for each factor and risk score by race/ethnicity. We estimated odds ratios (OR) using polytomous logistic regression.

RESULTS

Prevalences of most factors are statistically significantly differed by race/ethnicity. In NHANES III, the prevalence of high risk score (i.e., > 25th percentile for all participants) was lower for all groups (non-Hispanic Black = 59.4%, non-US-born Mexican American = 51.4%, US-born Mexican American = 61.4%) vs. non-Hispanic White men (76.4%). Similar findings were observed for the fatal weighted risk score and for continuous NHANES.

CONCLUSIONS

Our findings from this nationally representative study suggest that a combination of multiple risk and protective factors may help to explain the lower rates of prostate cancer in Mexican Americans. However, variation in these factors did not explain the higher risk of prostate cancer in non-Hispanic Black men. No one lifestyle change can reduce prostate cancer equally across all racial/ethnic groups, and modifiable factors may not explain the increased risk in black men at all. Secondary prevention strategies may provide the most benefit for black men.

The association of diabetes with risk of prostate cancer defined by clinical and molecular features

BACKGROUND

To prospectively examine the association between diabetes and risk of prostate cancer defined by clinical and molecular features.

METHODS

A total of 49,392 men from the Health Professionals Follow-up Study (HPFS) were followed from 1986 to 2014. Data on self-reported diabetes were collected at baseline and updated biennially. Clinical features of prostate cancer included localised, advanced, lethal, low-grade, intermediate-grade, and high-grade. Molecular features included TMPRSS2: ERG and PTEN subtypes. Cox proportional hazards regression models were used to evaluate the association between diabetes and incidence of subtype-specific prostate cancer.

RESULTS

During 28 years of follow-up, we documented 6733 incident prostate cancer cases. Relative to men free from diabetes, men with diabetes had lower risks of total (HR: 0.82, 95% CI: 0.75-0.90), localised (HR: 0.82, 95% CI: 0.74-0.92), low-and intermediate-grade prostate cancer (HR: 0.77, 95% CI: 0.66-0.90; HR: 0.77, 95% CI: 0.65-0.91, respectively). For molecular subtypes, the HRs for ERG-negative and ERG-positive cases were 0.63 (0.42-0.95) and 0.72 (0.46-1.12); and for PTEN-intact and PTEN-loss cases were 0.69 (0.48-0.98) and 0.52 (0.19-1.41), respectively.

CONCLUSION

Besides providing advanced evidence for the inverse association between diabetes and prostate cancer, this study is the first to report associations between diabetes and ERG/PTEN defined prostate cancers.

Association of the extent of therapy with prostate cancer in those receiving testosterone therapy in a US commercial insurance claims database

BACKGROUND

Conflicting evidence remains in the association of testosterone therapy (TTh) with prostate cancer (PCa). This inconsistency maybe due, in part, to the small sample sizes from previous studies and an incomplete assessment of comorbidities, particularly diabetes.

OBJECTIVE

We investigated the association of PCa with TTh (injection or gel) and different TTh doses and determined whether this association varies by the presence of diabetes at baseline in a large, nationally representative, commercially insured cohort.

DESIGN

We conducted a retrospective cohort study of 189 491 men aged 40-60 years old in the IBM MarketScan® Commercial Database, which included 1424 PCa cases diagnosed from 2011 to 2014. TTh was defined using CPT codes from inpatient and outpatient, and NDC codes from pharmacy claims. Multivariable adjusted Cox proportional hazards models were used to compute hazard ratios for patients with incident PCa.

RESULTS

We found a 33% reduced association of PCa after comparing the highest category (>12) of TTh injections with the lowest (1-2 injections) category (HR = 0.67, 95% CI: 0.54-0.82). Similar statistical significant inverse association for PCa was observed for men who received TTh topical gels (>330 vs 1- to 60-days supply). Among nondiabetics, we found significant inverse association between TTh (injection and gel) and PCa, but a weak interaction between TTh injections and diabetes (P = .05).

CONCLUSION

Overall, increased use of TTh is inversely associated with PCa and this remained significant only among nondiabetics. These findings warrant further investigation in large randomized placebo-controlled trials to infer any health benefit by TTh.

Association Between Antidiabetic Medications and Prostate-Specific Antigen Levels and Biopsy Results

IMPORTANCE

Diabetic men appear to have a lower risk of prostate cancer. Whether antidiabetic medications are protective or potentially mask prostate cancer by lowering prostate-specific antigen (PSA) levels is unclear.

OBJECTIVE

To examine the associations of antidiabetic medication use with (1) PSA levels, (2) frequency of PSA testing, (3) receipt of biopsy following elevated PSA results, and (4) prostate cancer detection at biopsy.

DESIGN, SETTING, AND PARTICIPANTS

Population-based cohort study using data from the Stockholm PSA and Biopsy Register. Participants were all prostate cancer-free men aged 40 to 79 years residing in Stockholm County, Sweden, between January 1, 2006, and December 31, 2015. Data were analyzed from November 2018 to March 2019.

EXPOSURES

One or more prescription for metformin, sulfonylurea, or insulin, as recorded in Sweden's National Prescribed Drug Register.

MAIN OUTCOMES AND MEASURES

Levels of PSA following first exposure to antidiabetic medications were assessed using multivariable linear regression. Frequency of PSA testing was assessed via multivariable Poisson regression. Biopsy following elevated PSA (≥3.0 ng/mL) and prostate cancer detection at biopsy were assessed via multivariable logistic regression.

RESULTS

The cohort of 564 666 men (median [range] age, 65 [40-79] years) consisted of 4583 men initially exposed to metformin, 1104 exposed to sulfonylurea, and 978 exposed to insulin who were age matched with unexposed men (1:5). Exposed men had lower median (interquartile range) PSA levels before starting antidiabetic medications compared with unexposed men (1.2 [0.7-2.5] vs 1.6 [0.8-3.2] ng/mL). After accounting for baseline differences, PSA levels did not vary from those of unexposed men following exposure to antidiabetic medications. Frequency of PSA testing was higher for those receiving metformin (rate ratio, 1.07; 95% CI, 1.06-1.09) and sulfonylurea (rate ratio, 1.06; 95% CI, 1.03-1.08) but was lower for those receiving insulin (rate ratio, 0.79; 95% CI, 0.77- 0.81). Likelihood of biopsy after elevated PSA was lower among men receiving metformin (odds ratio, 0.87; 95% CI, 0.80-0.96) and insulin (odds ratio, 0.83; 95% CI, 0.74-0.93). There were no differences in prostate cancer detection at biopsy, regardless of PSA levels that triggered the biopsy.

CONCLUSIONS AND RELEVANCE

This study's findings do not support the hypothesis that the inverse association between diabetes and prostate cancer is mediated through antidiabetic medications lowering PSA levels to mask prostate cancer. They do suggest potential detection bias due to fewer biopsies among men receiving antidiabetic medications, which may explain the lower prostate cancer risk in men with diabetes.

Impact of Metabolic Diseases, Drugs, and Dietary Factors on Prostate Cancer Risk, Recurrence, and Survival: A Systematic Review by the European Association of Urology Section of Oncological Urology

CONTEXT

To date, established risk factors for prostate cancer (PCa) are limited to age, race, family history, and certain genetic polymorphisms. Despite great research efforts, available evidence on potentially modifiable risk factors is conflicting. Moreover, most studies on PCa risk factors did not consider the impact of prostate-specific antigen (PSA) testing on PCa diagnosis.

OBJECTIVE

To provide a detailed overview of the latest evidence on the role of metabolic diseases, drugs, and dietary factors for risk of PCa incidence, recurrence, and survival in men exposed to PSA testing.

EVIDENCE ACQUISITION

A systematic review of the English-language literature was performed using the MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses recommendations. Randomized, case-control, or cohort studies published during the periods 2008-2017 (on drugs and metabolic diseases) and 2003-2017 (on dietary factors), with extensive follow-up (≥8-10yr for studies on PCa risk; ≥2-5yr for studies on PCa recurrence, progression, and survival, depending on the review subtopic) and adjusting of the analyses, beyond established risk factors, for either rate of PSA testing (for risk analyses) or PCa stage and primary treatment (for survival analyses), were eligible for inclusion.

EVIDENCE SYNTHESIS

Overall, 39 reports from 22 observational studies were included. Studies were heterogeneous regarding definitions of exposure or outcomes, length of follow-up, risk of bias, and confounding. For some risk factors, evidence was insufficient to assess potential effects, while for others there was no evidence of an effect. For selected risk factors, namely metformin, aspirin and statin use, diabetes, obesity, and specific dietary intakes, there was low-quality evidence of modest effects on PCa risk.

CONCLUSIONS

Current evidence from long-term observational studies evaluating the effect of drugs, metabolic diseases, and dietary factors for PCa risk considering the impact of PSA testing is still not conclusive. Future research is needed to confirm the associations suggested by our review, exploring their potential biological explanations and selecting those risk factors most likely to trigger effective public health interventions.

PATIENT SUMMARY

We reviewed the available studies published in the recent literature on the potential role of drugs, metabolic diseases, and food and dietary factors for the risk of prostate cancer, considering the impact of prostate-specific antigen testing on prostate cancer diagnosis. We found that for some factors data are currently insufficient to make definitive conclusions, while for others available studies seem to indicate an effect on the risk of prostate cancer.

Poorly controlled diabetes increases the risk of metastases and castration-resistant prostate cancer in men undergoing radical prostatectomy: Results from the SEARCH database

BACKGROUND

Although diabetes is inversely related to prostate cancer (PC) risk, to the authors' knowledge the impact of glycemic control on PC progression is unknown. In the current study, the authors tested the association between hemoglobin A1c (HbA1c) and long-term PC outcomes among diabetic men undergoing radical prostatectomy (RP).

METHODS

The authors retrospectively reviewed data regarding men undergoing RP from 2000 to 2017 at 8 Veterans Affairs hospitals. Diabetic patients were identified using International Classification of Diseases, Ninth Revision (ICD-9) codes (250.x) or by an HbA1c value >6.5% at any time before RP. Cox models tested the association between HbA1c and biochemical disease recurrence (BCR), castration-resistant PC (CRPC), metastases, PC-specific mortality, and all-cause mortality. The model for BCR was adjusted for multiple variables. Due to limited events, models for long-term outcomes were adjusted for biopsy grade and prostate-specific antigen only.

RESULTS

A total of 1409 men comprised the study population. Of these, 699 patients (50%) had an HbA1c value <6.5%, 631 (45%) had an HbA1c value of 6.5% to 7.9%, and 79 (6%) had an HbA1c value ≥8.0%. Men with an HbA1c value ≥8.0% were younger (P < .001) and more likely to be black (P = .013). The median follow-up after RP was 6.8 years (interquartile range, 3.7-10.6 years). On multivariable analysis, HbA1c was not found to be associated with BCR. However, a higher HbA1c value was associated with metastasis (hazard ratio [HR], 1.21; 95% CI, 1.02-1.44 [P = .031]) and CRPC (HR, 1.27; 95% CI, 1.03-1.56 [P = .023]). Although not statistically significant, there were trends between higher HbA1c and risk of PC-specific mortality (HR, 1.24; 95% CI, 0.99-1.56 [P = .067]) and all-cause mortality (HR, 1.09; 95% CI, 0.99-1.19 [P = .058]).

CONCLUSIONS

Among diabetic men undergoing RP, a higher HbA1c value was associated with metastases and CRPC. If validated in larger studies with longer follow-up, future research should test whether better glycemic control improves long-term PC outcomes.

Metabolomic profiling for the identification of novel diagnostic markers and therapeutic targets in prostate cancer: an update

INTRODUCTION

An altered metabolic regulation is involved in the development and progression of different cancer types. As well as this, many genes associated with tumors are shown to have an important role in control of the metabolism. The incidence of prostate cancer (PCa) is increased in men with metabolic disorders. In particular, obesity is an established risk factor for PCa. An increased body mass index correlates with aggressive disease, and a higher risk of biochemical recurrence and prostate cancer-specific mortality. Increased lipogenesis is also one of the most significant events in PCa metabolism reprogramming. Areas covered: In this article, we provide an updated review of the current understanding of the PCa metabolome and evaluate the possibility of unveiling novel therapeutic targets. Expert opinion: Obesity is an established risk factor for PCa, and an increased BMI correlates with aggressive disease, and a higher risk of biochemical recurrence and prostate cancer-specific mortality. PCa metabolome is characterized by the accumulation of metabolic intermediates and an increased expression of genes in the tricarboxylic acid cycle, the induction of de novo lipogenesis and cholesterogenesis. PCa cells can induce different alterations in their microenvironment by modulating the crosstalk between cancer and stromal cells.

The effect of metformin therapy on incidence and prognosis in prostate cancer: A systematic review and meta-analysis

The relationship between metformin and prostate cancer (PCa) remains controversial. To clarify this association, the PubMed, Embase and Cochrane library databases were systematically searched from their inception dates to May 23, 2018, using the keywords "metformin" and "prostate cancer" to identify the related studies. The results included incidence, overall survival (OS), PCa-specific survival (CSS) and recurrence-free survival (RFS), which were measured as hazard ratios (HR) with a 95% confidence interval (95% CI) using Review Manager 5.3 software. A total of 30 cohort studies, including 1,660,795 patients were included in this study. Our study revealed that metformin treatment improves OS, CSS and RFS in PCa (HR = 0.72, 95% CI: 0.59-0.88, P = 0.001; HR = 0.78, 95% CI: 0.64-0.94, P = 0.009; and HR = 0.60, 95% CI: 0.42-0.87 P = 0.006, respectively) compared with non-metformin treatment. However, metformin usage did not reduce the incidence of PCa (HR = 0.86, 95% CI: 0.55-1.34, P = 0.51). In conclusion, compared with non-metformin treatment, metformin therapy can significantly improve OS, CSS and RFS in PCa patients. No association was noted between metformin therapy and PCa incidence. This study indicates a useful direction for the clinical treatment of PCa.

Age-Specific Reference Ranges of Prostate-Specific Antigen among Saudi Men as a Representation of the Arab Population

OBJECTIVE

To describe the reference ranges of serum prostate-specific antigen (PSA) in Saudi men. Materials/Subjects and Methods: Saudi males, aged 30 and above, were invited to participate in the study. Blood samples were taken from each subject to determine serum levels of PSA. Blood sugar levels, lipid profile, and anthropometric measurements were also obtained.

RESULTS

Our cohort consisted of 7,814 men; their mean PSA level was 1.24 ng/mL. The majority (90.5%) had PSA values between 0 and 2.5 ng/mL. The median PSA and the 95th percentile increased steadily with age. There was a sharp increase in the 95th percentile, from 3.8 ng/mL in men between 60 and 70 years old to 6.9 ng/mL in men over 71 years old. The 95th percentiles of PSA serum levels were lower in Saudi men than in the general population.

CONCLUSIONS

PSA serum levels in Saudi men are lower than in other communities. Creating age-specific reference ranges could improve the sensitivity of the PSA tests by allowing the detection of treatable tumors in younger men if the threshold of 4.0 ng/mL is lowered. Furthermore, unnecessary biopsies among older men may be avoided if the threshold is increased.

The relationship between diabetes, prostate-specific antigen screening tests, and prostate cancer

PURPOSE

Men with diabetes have been found to have a reduced risk of prostate cancer (PCa), potentially due to detection bias from lower prostate-specific antigen (PSA) levels or inhibition of tumor growth. Understanding if lower PCa rates are due to a lower risk of the disease or a detection bias from PSA testing can help inform the benefits and harms from prostate cancer screening.

METHODS

We used data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Screening Trial to assess the impact of PSA screening on PCa in men with diabetes and the potential role of detection bias and/or slower tumor growth. Comparing men by diabetes status, we calculated age-adjusted incidence rates by tumor grade and compared screening results, PSA levels, and tumor characteristics.

RESULTS

Men with diabetes had lower rates of PCa but was limited to low- and intermediate-grade tumors. Men with diabetes were less likely to be biopsied after their first positive screening test and men diagnosed with low/intermediate-grade tumors had significantly more advanced tumors with higher PSA levels.

CONCLUSIONS

Our findings provide additional evidence that detection bias is likely contributing to the lower rates of low- and intermediate-grade prostate cancers.

Type 2 Diabetes in Relation to the Risk of Renal Cell Carcinoma Among Men and Women in Two Large Prospective Cohort Studies

OBJECTIVE

We assessed whether type 2 diabetes is associated with renal cell carcinoma (RCC), independent of key potential confounders, in two large prospective cohorts with biennially updated covariate data.

RESEARCH DESIGN AND METHODS

A total of 117,570 women from the Nurses' Health Study (NHS) and 48,866 men from the Health Professionals Follow-Up Study (HPFS) were followed from 1976 and 1986, respectively, through 2014. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs for associations between type 2 diabetes and pathology-confirmed RCC, overall and by stage, grade, and histologic subtype.

RESULTS

During 38 years of follow-up in the NHS, we confirmed 418 RCC case subjects, including 120 fatal cases. Over 28 years in the HPFS, we confirmed 302 RCC case subjects, including 87 fatal cases. Women with type 2 diabetes had a significantly increased risk of RCC compared with women without type 2 diabetes (multivariable HR 1.53; 95% CI 1.14-2.04), with some evidence that the association was stronger for ≤5 (HR 2.15; 95% CI 1.44-3.23) than >5 (HR 1.22; 95% CI 0.84-1.78) years' duration of type 2 diabetes (P_difference 0.03). Among men, type 2 diabetes was not associated with total RCC (HR 0.89; 95% CI 0.56-1.41) or with RCC defined by stage, grade, or subtype. Sample sizes for analyses by stage, grade, and subtype were limited.

CONCLUSIONS

We found that type 2 diabetes was independently associated with a greater risk of RCC in women but not in men.

Difference in prostate cancer incidence around sixty years: effects of age and metabolic diseases

We examined the risk of prostate cancer in the Korean population stratified on the basis of age group and risk based on metabolic diseases, using National Health Insurance System (NHIS) data. Of the 51,827,813 people from the NHIS data in 2015, 10,879,591 men without prostate cancer who underwent a health examination were analyzed. The risk of prostate cancer was analyzed with stratification by age. Multivariate-adjusted Cox regression analysis was conducted to examine the association between prostate cancer and metabolic diseases by age groups. The risk of prostate cancer increased continuously with age and 59 years may be a point of inflection. The hazard ratio (HR) of prostate cancer development rose sharply as that age point passed. The population with metabolic diseases was more likely to develop prostate cancer than the population without any of these components. In addition, the incidence rate ratio (IRR) decreased from the youngest age group to the age group comprising 55-59 year olds. Beyond this age group, there was a plateau. The relative risk for prostate cancer associated with metabolic diseases also showed divergent associations with age. The risk of prostate cancer increased continuously with age and the peak Youden index was at 59 years. The relative risk for prostate cancer according to metabolic diseases also showed divergent associations beyond 59 years of age. Therefore, setting the age threshold at 59 years would improve the present clinical risk stratification for prostate cancer in Korea.

Androgen receptor overexpression in prostate cancer in type 2 diabetes

OBJECTIVE

While prostate cancer does not occur more often in men with diabetes, survival is markedly reduced in this patient group. Androgen signaling is a known and major driver for prostate cancer progression. Therefore, we analyzed major components of the androgen signaling chain and cell proliferation in relation to type 2 diabetes.

METHODS

Tumor content of 70 prostate tissue samples of men with type 2 diabetes and 59 samples of patients without diabetes was quantified by an experienced pathologist, and a subset of 51 samples was immunohistochemically stained for androgen receptor (AR). mRNA expression of AR, insulin receptor isoform A (IR-A) and B (IR-B), IGF-1 receptor (IGF1R), Cyp27A1 and Cyp7B1, PSA gene KLK3, PSMA gene FOLH1, Ki-67 gene MKI67, and estrogen receptor beta (ESR2) were analyzed by RT-qPCR.

RESULTS

AR mRNA and protein expression were associated with the tumor content only in men with diabetes. AR expression also correlated with downstream targets PSA (KLK3) and PSMA (FOLH1) and increased cell proliferation. Only in diabetes, AR expression was correlated to higher IR-A/IR-B ratio and lower IR-B/IGF1R ratio, thus, in favor of the mitogenic isoforms. Reduced Cyp27A1 and increased Cyp7B1 expressions in tumor suggest lower levels of protective estrogen receptor ligands in diabetes.

CONCLUSIONS

We report elevated androgen receptor signaling and activity presumably due to altered insulin/IGF-1 receptors and decreased levels of protective estrogen receptor ligands in prostate cancer in men with diabetes. Our results reveal new insights why these patients have a worse prognosis. These findings provide the basis for future clinical trials to investigate treatment response in patients with prostate cancer and diabetes.

Investigating the link between benign prostatic hypertrophy, BMI and type 2 diabetes mellitus

AIMS

To investigate the link between benign prostatic hypertrophy, BMI and type 2 diabetes mellitus.

MATERIALS AND METHODS

This was the retrospective study conducted at the urology clinic of NCRHA and SWRHA, in Trinidad. Data was obtained from 85 patients with high PSA values (>4.0ng/mL). The data collected were age, ethnicity, weight, height, lifestyle and their most recent blood sugar levels were recorded. Ultrasound reports of patients diagnosed with BPH were also analyzed to gather data on whether their hyperplasia was benign or malignant.

RESULTS

The majority of the sample population was of Afro-Trinidadian descent (41) followed by East Indian descent (26) and then of mixed ethnicity (18). Individuals in the sample population with a normal BMI had a mean PSA value of 23.66ng/mL, while those with a BMI in the overweight range had a mean PSA value of 28.1ng/mL, and those with a BMI in the obese range had a mean PSA value of 18.5ng/mL. There were no statistically significant differences in the mean values of PSA levels between diabetics and non-diabetics, between the 3 major ethnic groups in our sample population and between the 3 different groupings based on BMI ranges. However it was found that the average mean age of patients of East Indian descent (62.96±2.23) was significantly lower than that of patients of African descent (70.15±2.02).

CONCLUSIONS

This study did not show any significant differences in the mean values of PSA levels between diabetics and non-diabetics, between the 3 different groupings based on BMI ranges.

Impact of metabolic disorders on prostate cancer growth: Androgen and insulin resistance perspectives

Background

A high prevalence of cancers in metabolic disorders, like metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), recently has been noted, including prostate cancer (PC), which is androgen-sensitive. However, the pathological relationship among testosterone and insulin and insulin-like growth factor (IGF)-1 signaling in relation to MetS and T2DM with PC remains unclear.

Methods

Papers were reviewed, including those by the authors.

Results

In MetS or the initial stage of T2DM accompanying insulin resistance, insulin and IGF-1 signaling could be essential for PC growth. In the advanced stage of T2DM, the decrease in insulin secretion might work against PC growth. A decrease in testosterone concentration with T2DM also might suppress PC proliferation. Androgen deprivation therapy in patients with PC might increase the risk of MetS and/or T2DM and consequently cardiovascular events. Certain drugs for T2DM treatment, such as metformin and glucagon-like peptide-1 analog, potentially might be useful for the treatment of PC.

Conclusion

The improvement of insulin resistance appears to be essential for the prevention of PC growth. Further studies are needed to clarify the complicated pathophysiology of metabolic disorders in PC growth.

The association between plasma C-peptide concentration and the risk of prostate cancer: a nested case-control study within a Japanese population-based prospective study

The association between plasma C-peptide concentration and prostate cancer is unclear. Inconsistency of results from previous studies motivates this study. Using the Japan Public Health Center-based Prospective study, 201 prostate cancer cases and 402 controls were matched by age, public health center area, residence, date and time of blood collection, and fasting duration before blood collection. Odds ratios (OR) and 95% confidence intervals (CIs) were estimated by conditional logistic regression models. Out of 201 cases, 144 were localized and 48 were advanced. The overall association between median plasma C-peptide concentration and prostate cancer was not significant (OR for the highest tertile=0.81, 95% CI: 0.43-1.56, P-trend=0.54). Although stratification of prostate cancer by stage indicated different effects of plasma C-peptide on localized and advanced cases, there was no association between plasma C-peptide concentration and advanced prostate cancer (OR=2.82, 95% CI: 0.30-26.36 for the highest category, P-trend=0.37) and localized cases (OR=0.49, 95% CI: 0.23-1.04 for the highest category, P-trend=0.06) for patients fasting at the time of blood collection. The association between plasma C-peptide concentration and prostate cancer risk differed by cancer stage. Differentiation of localized and advanced prostate cancer cases is crucial when investigating the association between plasma C-peptide concentration and the risk of prostate cancer.

Prospective study of Type 2 diabetes mellitus, anti-diabetic drugs and risk of prostate cancer

Type 2 diabetes mellitus (T2DM) has consistently been associated with decreased risk of prostate cancer; however, if this decrease is related to the use of anti-diabetic drugs is unknown. We prospectively studied men in the comparison cohort in the Prostate Cancer data Base Sweden 3.0, with data on T2DM, use of metformin, sulfonylurea and insulin retrieved from national health care registers and demographic databases. Cox proportional hazards regression models were used to compute hazard ratios (HR) and 95% confidence intervals (CI) of prostate cancer, adjusted for confounders. The study consisted of 612,846 men, mean age 72 years (standard deviation; SD = 9 years), out of whom 25,882 men were diagnosed with prostate cancer during follow up, mean time of 5 years (SD = 3 years). Men with more than 1 year's duration of T2DM had a decreased risk of prostate cancer compared to men without T2DM (HR = 0.85, 95% CI = 0.82-0.88) but among men with T2DM, those on metformin had no decrease (HR = 0.96, 95% CI = 0.77-1.19), whereas men on insulin (89%) or sulfonylurea (11%) had a decreased risk (HR = 0.73, 95% CI = 0.55-0.98), compared to men with T2DM not on anti-diabetic drugs. Men with less than 1 year's duration of T2DM had no decrease in prostate cancer risk (HR = 1.11, 95% CI = 0.95-1.31). Our results gave no support to the hypothesis that metformin protects against prostate cancer as recently proposed. However, our data gave some support to an inverse association between T2DM severity and prostate cancer risk.

The Impact of Diabetes on the Risk of Prostate Cancer Development according to Body Mass Index: A 10-year Nationwide Cohort Study

Purpose: We examined the association between obesity and prostate cancer both with and without diabetic patients included in the analysis using nationally representative data of the Korean population from the National Health Insurance System (NHIS).

Materials and Methods: Of the 424,712 participants who underwent health examinations in 2002-2008, 139,519 men ≥40 years old and without prostate cancer were followed from the beginning of 2002 to the end of 2012. Multivariate adjusted Cox regression analysis was conducted to examine the hazard ratio (HR) and 95% confidence interval (CI) for the association between prostate cancer and body mass index (BMI) both with and without diabetes.

Results: The HR for prostate cancer according to the existence of diabetes was stratified by BMI in both age- and multivariable-adjusted models. In the population without diabetes, the HR for prostate cancer significantly increased as BMI increased beyond the reference range in a model adjusted for age and multiple variables; however, the increase in the HR was small. In the population with diabetes, the HR for prostate cancer significantly increased as BMI increased from < 18.5 kg/m² to within the reference range (18.5 to 22.9) in the multivariable-adjusted model. In addition, a marked decrease in HR in the population with BMI of < 18.5 kg/m² was seen compared to the reference or higher BMI population.

Conclusion: This population-based study shows the evidence of association between obesity and development of prostate cancer, and the risk increases vary according to the change of BMI category and the existence of diabetes.

Diabetes and mortality in patients with prostate cancer: a meta-analysis

BACKGROUND

There are conflicting results as to the association between pre-existing diabetes and the risk of mortality in patients with prostate cancer. The purpose of this study is to estimate the influence of pre-existing diabetes on prostate cancer-specific mortality and all-cause mortality.

METHODS

We searched PubMed and Embase to identify studies that investigated the association between pre-existing diabetes and risk of death among men with prostate cancer. Pooled risk estimates and 95 % confidence intervals were calculated using fixed-effects models or random-effects models. Heterogeneity tests were conducted between studies. Publication bias was analyzed by using the Egger's test, Begg's test, and the trim and fill method.

RESULTS

Of the 733 articles identified, 17 cohort studies that had 274,677 male patients were included in this meta-analysis. Pre-existing diabetes was associated with a 29 % increase in prostate cancer-specific mortality [relative risk (RR) 1.29, 95 % CI 1.22-1.38, I(2) = 66.68 %], and with a 37 % increase in all-cause mortality (RR 1.37, 95 % CI 1.29-1.45, p < 0.01, I(2) = 90.26 %). Additionally, in a subgroup analysis that was a type specific analysis focusing on type 2 diabetes and was conducted only with three cohort studies, pre-existing type 2 diabetes was associated with all-cause mortality (RR 2.01, 95 % CI 1.37-2.96, I(2) = 95.55 %) and no significant association with prostate cancer-specific mortality was detected (RR 1.17, 95 % CI 0.96-1.42, I(2) = 75.59 %). There was significant heterogeneity between studies and no publication bias was found.

CONCLUSIONS

This meta-analysis suggests diabetes may result in a worse prognosis for men with prostate cancer. Considering heterogeneity between studies, additional studies should be conducted to confirm these findings, and to allow generalization regarding the influence that each type of diabetes has on prostate cancer mortality.