Diabetes, prostate cancer screening and risk of low- and high-grade prostate cancer: an 11 year historical population follow-up study of more than 1 million men

Hill R, Awe O, Bhola O, Orumwense O, Deosaran P, Seecharan P, Avula P, Mohammed R, Terapalli A, Jardine RM. A retrospective study of prostate-specific antigen and international prostate symptoms scores from participants at a men's health screening initiative in Trinidad

Background

This study describes the characteristics of men attending a primary health care screening initiative, determines the proportion of men who have elevated International Prostate Symptom Score (IPSS) scores and prostate-specific antigen (PSA) levels, and determines any correlation between these scores as indicators for benign prostatic hyperplasia (BPH) or prostate cancer.

Methods

Data were collected from all patient records during men's health screening initiatives that occurred in December 2018, January 2019, and March 2019 in Trinidad and Tobago. A total of 350 medical records were analyzed to record patient demographics, PSA levels, and IPSS scores. Analysis of the data was performed with the use of Statistical Package for the Social Sciences software (version 27).

Results

Most men who attended the screening initiative belonged to the 61-65 age group (20.57%), with more than half of the men being married (57.71%) and employed (52.57%) and of patients with comorbidities (17%), the most prevalent included hypertension (6%) and diabetes mellitus (3.7%). A mean PSA level of 2.94 ng/ml and a mean IPSS of 7.62 were recorded. Moreover, 11.5% of the males had elevated PSA levels (>4 ng/ml) and 32.9% had elevated IPSS levels (>8). There were correlations between PSA and IPSS values (r = 0.161 and P = 0.006). Age was a predictor of both IPSS and PSA values (r = 0.214, P = 0.000 and r = 0.192, P = 0.000, respectively). Among diabetic participants, a small but significant correlation between IPSS and diabetes was shown (r = 0.223, P = 0.028). As a predictor of elevated IPSS, diabetes had an odds ratio of 1.132 (95% confidence interval (CI): 1.021-1.255).

Conclusion

Our findings are similar to those described in previous studies; however, further investigations are required to fully describe the relationship between PSA and IPSS. This may assist in advancing screening measures and improving health outcomes for men with BPH and prostate cancer. Primary care physicians should recognize the possible association between BPH and diabetes mellitus and offer appropriate screening where indicated.

Association Between Diabetes and Risk of Prostate Cancer: A Systematic Review and Meta-Analysis of Observational Studies

PURPOSE

Metabolic diseases such as diabetes mellitus may play a role in the development and progression of prostate cancer (PC); however, this association remains to be explored in the context of specific PC stages. The objective of this study was to systematically review the evidence for an association between diabetes and overall, early, or advanced PC risk.

MATERIALS AND METHODS

A systematic review with meta-analysis was performed (MEDLINE, EMBASE, and CINAHL) from inception until September 2023. Cohort and case-control studies that assessed PC risk in adult males (≥18 years) associated with type 2 diabetes mellitus or diabetes (if there was no distinction between diabetes type) were included. The Newcastle-Ottawa Scale (NOS) was used to assess study bias; those with NOS<7 were excluded. Evidence certainty was assessed with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) method.

RESULTS

Thirty-four studies (n=26 cohorts and n=8 case-controls) were included. Of these, 32 assessed diabetes and all PC stages combined, 12 included early PC stages, and 15 included advanced PC stages. Our meta-analysis showed diabetes had a protective effect against early PC development (n=11, risk ratio [RR]=0.71; 95% confidence interval [CI]=0.61-0.83, I²=84%) but no association was found for combined (n=21, RR=0.95; 95% CI=0.79-1.13, I²=99%) or advanced PC stages (n=15, RR=0.96; 95% CI=0.77-1.18, I²=98%) at diagnosis. According to GRADE, the evidence certainty was very low.

CONCLUSIONS

Diabetes may be protective against early PC stages, yet evidence linking diabetes to risk across all stages, and advanced PC specifically, is less conclusive. High heterogeneity may partially explain discrepancy in findings and was mostly associated with study design, method used for PC diagnosis, and risk measures. Our results may aid risk stratification of males with diabetes and inform new approaches for PC screening in this group, especially considering the reduced sensitivity of prostate-specific antigen values for those with diabetes.

Severity of Complications and Duration of Type 2 Diabetes and the Risk of Cancer: A Population-Based Study

BACKGROUND

The literature on the association between diabetes severity and cancer risk is limited and inconclusive. The study aimed to evaluate the association between the adapted Diabetes Complications Severity Index (aDCSI) and the duration of type 2 diabetes and cancer risk.

METHODS

Patients ages 20 years or older with newly diagnosed type 2 diabetes between January 1, 2007, and December 31, 2011, were identified from Taiwan National Health Insurance claims data. Standardized incidence ratios (SIR) were calculated to compare cancer incidence in people with diabetes with that in the general population. Poisson regression was used to examine whether SIRs differed by age, sex, aDSCI, and duration of diabetes.

RESULTS

A total of 756,547 patients were included, with a median follow-up of 8.8 years. Excluding the first year after diagnosis, the SIR for overall cancer was 1.18 [95% confidence interval (CI) 1.17-1.19]. Higher aDCSI was associated with increased SIRs for overall [SIR ratio 1.03 (1.02-1.03) per point increase], head and neck (1.03; 1.01-1.04), liver (1.04; 1.03-1.05), pancreas (1.03; 1.00-1.05), kidney (1.13; 1.10-1.15), and leukemia (1.09; 1.06-1.13). There was no association between aDCSI and colorectal, extrahepatic biliary tract, uterus and thyroid cancer, and a negative association with breast cancer (0.97; 0.95-0.98). Type 2 diabetes duration was associated with increased SIRs for overall [1.01 (1.00-1.02) per year increase], head and neck (1.03; 1.01-1.05), and liver cancer (1.04; 1.02-1.05).

CONCLUSIONS

The heterogeneity in the association between diabetes severity and diabetes-related cancers suggests diverse underlying connections.

IMPACT

Adopting distinct approaches in further research and prevention strategies for different kinds of diabetes-related cancers is important.

Diabetes and Prostate Cancer Outcomes in Men with Nonmetastatic Castration-Resistant Prostate Cancer: Results from the SEARCH Cohort

BACKGROUND

The prognosis of diabetic men with advanced prostate cancer is poorly understood and understudied. Hence, we studied associations between diabetes and progression to metastases, prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM) in men with nonmetastatic castration-resistant prostate cancer (nmCRPC).

METHODS

Data from men diagnosed with nmCRPC between 2000 and 2017 at 8 Veterans Affairs Health Care Centers were analyzed using Cox regression to determine HRs and 95% confidence intervals (CI) for associations between diabetes and outcomes. Men with diabetes were classified according to: (i) ICD-9/10 codes only, (ii) two HbA1c values > 6.4% (missing ICD-9/10 codes), and (iii) all diabetic men [(i) and (ii) combined].

RESULTS

Of 976 men (median age: 76 years), 304 (31%) had diabetes at nmCRPC diagnosis, of whom 51% had ICD-9/10 codes. During a median follow-up of 6.5 years, 613 men were diagnosed with metastases, and 482 PCSM and 741 ACM events occurred. In multivariable-adjusted models, ICD-9/10 code-identified diabetes was inversely associated with PCSM (HR, 0.67; 95% CI, 0.48-0.92) while diabetes identified by high HbA1c values (no ICD-9/10 codes) was associated with an increase in ACM (HR, 1.41; 95% CI, 1.16-1.72). Duration of diabetes, prior to CRPC diagnosis was inversely associated with PCSM among men identified by ICD-9/10 codes and/or HbA1c values (HR, 0.93; 95% CI, 0.88-0.98).

CONCLUSIONS

In men with late-stage prostate cancer, ICD-9/10 'code-identified' diabetes is associated with better overall survival than 'undiagnosed' diabetes identified by high HbA1c values only.

IMPACT

Our data suggest that better diabetes detection and management may improve survival in late-stage prostate cancer.

Rosiglitazone has a null association with the risk of prostate cancer in type 2 diabetes patients

Background

This study investigated the risk of prostate cancer in ever users and never users of rosiglitazone in diabetes patients in Taiwan.

Methods

The nationwide database of the National Health Insurance was used to enroll male patients who had a new diagnosis of type 2 diabetes mellitus at an age ≥ 25 years from 1999 to 2005. A total of 11,495 ever users and 11,495 never users of rosiglitazone matched on propensity score were selected and they were followed up for the incidence of prostate cancer from January 1, 2006 until December 31, 2011. Cox proportional hazard model incorporated with the inverse probability of treatment weighting using the propensity score was used to estimate hazard ratios.

Results

At the end of follow-up, incident cases of prostate cancer were found in 84 never users and 90 ever users of rosiglitazone. The calculated incidence was 173.20 per 100,000 person-years in never users and was 187.59 per 100,000 person-years in ever users. The overall hazard ratio (95% confidence intervals) for ever versus never users was 1.089 (0.808-1.466). The hazard ratios were 0.999 (0.643-1.552) for the first tertile (< 672 mg), 1.147 (0.770-1.709) for the second tertile (672-3584 mg) and 1.116 (0.735-1.695) for the third tertile (> 3584 mg) of cumulative dose. Sensitivity analyses consistently showed a null association between rosiglitazone and prostate cancer risk.

Conclusion

Rosiglitazone has a null effect on the risk of prostate cancer.

Prostate cancer genetic propensity risk score may modify the association between this tumour and type 2 diabetes mellitus (MCC-Spain study)

BACKGROUND

Some studies have reported an inverse association between type 2 diabetes mellitus (T2DM) and prostate cancer (PCa), but results on this issue are still inconsistent. In this study, we evaluate whether this heterogeneity might be related to differences in this relationship by tumour or by individual genetic susceptibility to PCa.

METHODS

We studied 1047 incident PCa cases and 1379 randomly selected controls, recruited in 7 Spanish provinces for the population-based MCC-Spain case-control. Tumour were classified by aggressiveness according to the International Society of Urological Pathology (ISUP), and we constructed a PCa polygenic risk score (PRS) as proxy for genetic susceptibility. The epidemiological questionnaire collected detailed self-reported data on T2DM diagnosis and treatment. The association between T2DM status and PCa was studied by fitting mixed logistic regression models, and, for its association by aggressiveness of PCa, with multinomial logistic regression models. To evaluate the possible modulator role of PRS in this relationship, we included the corresponding interaction term in the model, and repeated the analysis stratified by PRS tertiles.

RESULTS

Globally, our results showed an inverse association between T2DM and overall PCa limited to grade 1 tumours (OR_ISUP = 1: 0.72; 95% CI: 0.53-0.98), which could be compatible with a detection bias. However, PCa risk also varied with duration of diabetes treatment -inversely to metformin and positively with insulin-, without differences by aggressiveness. When we considered genetic susceptibility, T2DM was more strongly associated with lower PCa risk in those with lower PRS (OR_{tertile 1}: 0.31; 95% CI: 0.11-0.87), independently of ISUP grade.

CONCLUSIONS

Our findings reinforce the need to include aggressiveness and susceptibility of PCa, and T2DM treatments in the study of the relationship between both diseases.

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.

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.

Prevalent diabetes and risk of total, colorectal, prostate and breast cancers in an ageing population: meta-analysis of individual participant data from cohorts of the CHANCES consortium

BACKGROUND

We investigated whether associations between prevalent diabetes and cancer risk are pertinent to older adults and whether associations differ across subgroups of age, body weight status or levels of physical activity.

METHODS

We harmonised data from seven prospective cohort studies of older individuals in Europe and the United States participating in the CHANCES consortium. Cox proportional hazard regression was used to estimate the associations of prevalent diabetes with cancer risk (all cancers combined, and for colorectum, prostate and breast). We calculated summary risk estimates across cohorts using pooled analysis and random-effects meta-analysis.

RESULTS

A total of 667,916 individuals were included with an overall median (P25-P75) age at recruitment of 62.3 (57-67) years. During a median follow-up time of 10.5 years, 114,404 total cancer cases were ascertained. Diabetes was not associated with the risk of all cancers combined (hazard ratio (HR) = 0.94; 95% confidence interval (CI): 0.86-1.04; I2 = 63.3%). Diabetes was positively associated with colorectal cancer risk in men (HR = 1.17; 95% CI: 1.08-1.26; I2 = 0%) and a similar HR in women (1.13; 95% CI: 0.82-1.56; I2 = 46%), but with a confidence interval including the null. Diabetes was inversely associated with prostate cancer risk (HR = 0.81; 95% CI: 0.77-0.85; I2 = 0%), but not with postmenopausal breast cancer (HR = 0.96; 95% CI: 0.89-1.03; I2 = 0%). In exploratory subgroup analyses, diabetes was inversely associated with prostate cancer risk only in men with overweight or obesity.

CONCLUSIONS

Prevalent diabetes was positively associated with colorectal cancer risk and inversely associated with prostate cancer risk in older Europeans and Americans.

Outcomes of prostate cancer screening among men using antidiabetic medication

Diabetic men have decreased risk for prostate cancer (PCa) overall and lower PSA compared to non-diabetics. This may affect the outcomes of PSA-based screening. We investigated the effect of PSA-based screening at 4-year intervals on PCa incidence and mortality separately among users and non-users of antidiabetic medication with the hypothesis that screening would detect less low-grade cancer and more high-grade cancer in diabetic men. A cohort of 80,458 men from the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC) were linked to national prescription database to obtain information on antidiabetic medication purchases. PCa risk and mortality were compared between the FinRSPC screening arm (SA) and the control arm (CA) separately among users and non-users of antidiabetic medication. Among antidiabetic medication users median PSA was lower than in non-users (0.93 and 1.09 ng/ml, respectively, P for difference = 0.001). Screening increased overall PCa incidence compared to CA after the first screen both among medication users and non-users (HR 1.31, 95% CI 1.08–1.60 and HR 1.55, 95% CI 1.44–1.66, respectively). On the second and third screen the difference between SA and CA attenuated only among medication users. Detection of Gleason 6 tumors was lower among medication users, whereas no difference was observed in detection of Gleason 8–10 cancers. Concordantly, screening affected PCa mortality similarly regardless of antidiabetic medication use (HR 0.38, 95% CI 0.14–1.07 and HR 0.19, 95% CI 0.11–0.33 among users and non-users after three screens, respectively. P for difference = 0.18). Median PSA is lower in men using antidiabetic drugs than among non-users. Systematic PSA screening detects less low-risk tumors among medication users, whereas detection of high-risk tumors and mortality effects are similar regardless of medication use. This suggests that antidiabetic medication users may form a suitable target group for PCa screening, with less screening-related overdiagnosis of indolent tumors.

Separating disease and health for indirect reference intervals

The indirect approach to defining reference intervals operates ‘a posteriori’, on stored laboratory data. It relies on being able to separate healthy and diseased populations using one or both of clinical techniques or statistical techniques. These techniques are also fundamental in a priori, direct reference interval approaches. The clinical techniques rely on using clinical data that is stored either in the electronic health record or within the laboratory database, to exclude patients with possible disease. It depends on the investigators understanding of the data and the pathological impacts on tests. The statistical technique relies on identifying a dominant, apparently healthy, typically Gaussian distribution, which is unaffected by the overlapping populations with higher (or lower) results. It depends on having large databases to give confidence in the extrapolation of the narrow portion of overall distribution representing unaffected individuals. The statistical issues involved can be complex, and can result in unintended bias, particularly when the impacts of disease and the physiological variations in the data are under appreciated.

Diabetes and Prostate Cancer Outcomes in Obese and Nonobese Men After Radical Prostatectomy

Background

The link between diabetes and prostate cancer progression is poorly understood and complicated by obesity. We investigated associations between diabetes and prostate cancer-specific mortality (PCSM), castrate-resistant prostate cancer (CRPC), and metastases in obese and nonobese men undergoing radical prostatectomy (RP).

Methods

We included 4688 men from the Shared Equal Access Regional Cancer Hospital cohort of men undergoing RP from 1988 to 2017. Diabetes prior to RP, anthropometric, and clinical data were abstracted from 6 Veterans Affairs Medical Centers electronic medical records. Primary and secondary outcomes were PCSM and metastases and CRPC, respectively. Multivariable-adjusted hazard ratios (adj-HRs) and 95% confidence intervals (CIs) were estimated for diabetes and PCSM, CRPC, and metastases. Adjusted hazard ratios were also estimated in analyses stratified by obesity (body mass index: nonobese <30 kg/m²; obese ≥30 kg/m²). All statistical tests were 2-sided.

Results

Diabetes was not associated with PCSM (adj-HR = 1.38, 95% CI = 0.86 to 2.24), CRPC (adj-HR = 1.05, 95% CI = 0.67 to 1.64), or metastases (adj-HR = 1.01, 95% CI = 0.70 to 1.46), among all men. Interaction terms for diabetes and obesity were statistically significant in multivariable models for PCSM, CRPC, and metastases (P ≤ .04). In stratified analyses, in obese men, diabetes was associated with PCSM (adj-HR = 3.06, 95% CI = 1.40 to 6.69), CRPC (adj-HR = 2.14, 95% CI = 1.11 to 4.15), and metastases (adj-HR = 1.57, 95% CI = 0.88 to 2.78), though not statistically significant for metastases. In nonobese men, inverse associations were suggested for diabetes and prostate cancer outcomes without reaching statistical significance.

Conclusions

Diabetes was associated with increased risks of prostate cancer progression and mortality among obese men but not among nonobese men, highlighting the importance of aggressively curtailing the increasing prevalence of obesity in prostate cancer survivors.

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.

Promoting cell proliferation, cell cycle progression, and glycolysis: Glycometabolism-related genes act as prognostic signatures for prostate cancer

BACKGROUND

The Warburg effect seen in most solid tumors occurs only in the late stages of prostate cancer (PCa). Currently, the management of patients with low-risk localized PCa and patients after radical therapy remains a challenge. Our objective here was to evaluate glycometabolism-related genes as prognostic signatures for PCa.

METHODS

The International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA) databases and glycometabolism-related gene sets were obtained online. Glycometabolic prognostic signatures were identified and validated in a TCGA cohort and tested in an ICGC cohort. We used the gene set enrichment analysis to reveal biological processes associated with the glycometabolism-related signatures. Novel glycometabolism-related genes were selected for verifying their oncogenic phenotypes in vitro.

RESULTS

Two glycometabolic prognostic signatures were applied respectively to construct risk score formulas for PCa. Survival and receiver operating characteristic curve analyses were performed to detect the value of these prognostic signatures. We performed univariate and multivariate Cox regression analyses in the TCGA cohort, demonstrating the independence of the prognostic signatures. Three glycometabolism-related genes were found to be novel PCa-associated genes. These were shown to affect proliferation, cell cycle progression, and glycolysis of DU145 and PC3 cells in different degrees.

CONCLUSION

The present research represents the first glycometabolic and high-throughput investigation on PCa, revealing potential biomarkers and treatment targets. We confirm the vital role of glycometabolism in PCa and provide essential resources for future exploration of metabolism in PCa.

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.

Depression and prostate cancer risk: A Mendelian randomization study

Background

The association between depression and prostate carcinogenesis has been reported in observational studies but the causality from depression on prostate cancer (PCa) remained unknown. We aimed to assess the causal effect of depression on PCa using the two‐sample Mendelian randomization (MR) method.

Methods

Two sets of genetics instruments were used for analysis, derived from publicly available genetic summary data. One was 44 single‐nucleotide polymorphisms (SNPs) robustly associated with major depressive disorder (MDD) and the other was two SNPs related with depressive status as ever depressed for a whole week. Inverse‐variance weighted method, weighted median method, MR‐Egger regression, MR Pleiotropy RESidual Sum, and Outlier test were used for MR analyses.

Results

No evidence for an effect of MDD on PCa risk was found in inverse‐variance weighted (OR: 1.12, 95% CI: 0.97‐1.30, p = 0.135), MR‐Egger (OR 0.89, 95% CI: 0.29‐2.68, p = 0.833), and weighted median (OR: 1.08, 95% CI: 0.92‐1.27, p = 0.350). Also, no strong evidence for an effect of depressive status on PCa incidence was found using the inverse‐variance weighted method (OR 0.72, 95% CI: 0.35‐1.47, p = 0.364).

Conclusions

The large MR analysis indicated that depression may not be causally associated with a risk 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.

Diabetes and cancer: Epidemiological and biological links

The incidence of diabetes and cancer has increased significantly in recent years. Furthermore, there are many common risk factors for both diabetes and cancer, such as obesity, sedentary lifestyle, smoking, and ageing. A large body of epidemiological evidence has indicated that diabetes is considered as an independent risk factor for increased rates of heterogeneous types of cancer occurrence and death. The incidence and mortality of various types of cancer, such as pancreas, liver, colorectal, breast, endometrial, and bladder cancers, have a modest growth in diabetics. However, diabetes may work as a protective factor for prostate cancer. Although the underlying biological mechanisms have not been totally understood, studies have validated that insulin/insulin-like growth factor (IGF) axis (including insulin resistance, hyperinsulinemia, and IGF), hyperglycemia, inflammatory cytokines, and sex hormones provide good circumstances for cancer cell proliferation and metastasis. Insulin/IGF axis activates several metabolic and mitogenic signaling pathways; hyperglycemia provides energy for cancer cell growth; inflammatory cytokines influence cancer cell apoptosis. Thus, these three factors affect all types of cancer, while sex hormones only play important roles in breast cancer, endometrial cancer, and prostate cancer. This minireview consolidates and discusses the epidemiological and biological links between diabetes and various types of cancer.

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 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.

The evolving role of diet in prostate cancer risk and progression

PURPOSE OF REVIEW

This overview examines the rationale for dietary interventions for prostate cancer by summarizing the current evidence base and biological mechanisms for the involvement of diet in disease incidence and progression.

RECENT FINDINGS

Recent data have further solidified the association between insulin resistance and prostate cancer with the homeostatic model assessment of insulin resistance. Data also show that periprostatic adipocytes promote extracapsular extension of prostate cancer through chemokines, thereby providing a mechanistic explanation for the association observed between obesity and high-grade cancer. Regarding therapeutics, hyperinsulinemia may be the cause of resistance to phosphatidylinositol-3 kinase inhibitors in the treatment of prostate cancer, leading to new investigations combining these drugs with ketogenic diets.

SUMMARY

Given the recently available data regarding insulin resistance and adipokine influence on prostate cancer, dietary strategies targeting metabolic syndrome, diabetes, and obesity should be further explored. In macronutrient-focused therapies, low carbohydrate/ketogenic diets should be favored in such interventions because of their superior impact on weight loss and metabolic parameters and encouraging clinical data. Micronutrients, including the carotenoid lycopene which is found in highest concentrations in tomatoes, may also play a role in prostate cancer prevention and prognosis through complementary metabolic mechanisms. The interplay between genetics, diet, and prostate cancer is an area of emerging focus that might help optimize therapeutic dietary response in the future through personalization.

A historical cohort study on glycemic-control and cancer-risk among patients with diabetes

AIMS

This population-based historical cohort study examined whether poor glycemic-control (i.e., high glucose and HbA1c blood levels) in patients with diabetes is associated with cancer-risk.

METHODS

From a large healthcare database, patients aged 21-89 years, diagnosed with diabetes before January 2002 (prevalent) or during 2002-2010 (incident), were followed for cancer during 2004-2012 (excluding cancers diagnosed within the first 2 years since diabetes diagnosis). Risks of selected cancers (all-sites, colon, breast, lung, prostate, pancreas and liver) were estimated according to glycemic-control in a Cox regression model with time-dependent covariates, adjusted for age, sex, ethnic origin, socioeconomic status, smoking and parity. Missing glucose or HbA1c values were imputed.

RESULTS

Among 440,000 patients included in our analysis, cancer was detected more than 2 years after diabetes diagnosis in 26,887 patients (6%) during the follow-up period. Associations of poor glycemic-control with all-sites cancer and most specific cancers were either null or only weak (hazard ratios (HRs) for a 1% HbA1c or a 30 mg/dl glucose increase between 0.94 and 1.09). Exceptions were pancreatic cancer, for which there was a strong positive association (HRs: 1.26-1.51), and prostate cancer, for which there was a moderate negative association (HRs: 0.85-0.96).

CONCLUSION

Overall, poor glycemic-control appears to be only weakly associated with cancer-risk, if at all. A substantial part of the positive association with pancreatic cancer is attributable to reverse causation, with the cancer causing poorer glycemic-control prior to its diagnosis. The negative association with prostate cancer may be related to lower PSA levels in those with poor control.

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.

Pre-existing diabetes mellitus and all-cause mortality in cancer patients: a register-based study in Latvia

BACKGROUND

Most studies from high income countries consistently report that preexisting diabetes reduces overall survival of cancer patients. We examined this association in a retrospective cohort study using two nation-wide population-based data sets in Latvia.

MATERIAL AND METHODS

The Cancer Register, linked with the Diabetes Register and Causes of Death Database, was the first data source used to select 22,936 men and 25,338 women with cancer diagnosed from 2009 to 2013. The follow-up period ended on 28 February 2015. The National Health Service data served as a second data source, which was used to select 10,130 men and 13,236 women with cancer as the main diagnosis, who were discharged from oncology hospitals from 2009 to 2012. Prescriptions of reimbursed antidiabetic medications indicated prior diabetes status. The follow-up period started at the date of discharge and ended on 31 December 2013. A Cox proportional hazards model was used to assess association between preexisting diabetes and all-cause mortality, adjusted for age.

RESULTS

Men with preexisting diabetes had better overall short-term survival: the age-adjusted hazard ratios (95% CI) were 0.86 (0.79-0.93) for the first year and 0.89 (0.80-0.98) for the first two years after cancer diagnosis according to the disease register and health service data, respectively. After three full follow-up years, their relative mortality increased, with an age-adjusted hazard ratio of 1.60 (1.28-1.99). Among women, preexisting diabetes was associated with slightly higher all-cause mortality during the entire follow-up period, with age-adjusted hazard ratios of 1.17 (1.10-1.24) for the disease register data and 1.11 (1.02-1.21) for the health service data.

CONCLUSION

Interestingly, we found better overall survival of diabetic men during the first years after cancer diagnosis. We hypothesize that access to health services may be advantageous to diabetic patients who are in close contact with the healthcare system.

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.

Fasting blood glucose, glycaemic control and prostate cancer risk in the Finnish Randomized Study of Screening for Prostate Cancer

Background

Diabetic men have lowered overall risk of prostate cancer (PCa), but the role of hyperglycaemia is unclear. In this cohort study, we estimated PCa risk among men with diabetic fasting blood glucose level.

Methods

Participants of the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC) were linked to laboratory database for information on glucose measurements since 1978. The data were available for 17,860 men. Based on the average yearly level, the men were categorised as normoglycaemic, prediabetic, or diabetic. Median follow-up was 14.7 years. Multivariable-adjusted Cox regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for prostate cancer overall and separately by Gleason grade and metastatic stage.

Results

In total 1,663 PCa cases were diagnosed. Compared to normoglycaemic men, those men with diabetic blood glucose level had increased risk of PCa (HR 1.52; 95% CI 1.31–1.75). The risk increase was observed for all tumour grades, and persisted for a decade afterwards. Antidiabetic drug use removed the risk association. Limitations include absence of information on lifestyle factors and limited information on BMI.

Conclusions

Untreated diabetic fasting blood glucose level may be a prostate cancer risk factor.

Factors associated with prostate specific antigen testing in Australians: Analysis of the New South Wales 45 and Up Study

Australia has one of the highest incidence rates of prostate cancer (PC) worldwide, due in part to widespread prostate specific antigen (PSA) testing. We aimed to identify factors associated with PSA testing in Australian men without a diagnosis of prostate cancer or prior prostate disease. Participants were men joining the 45 and Up Study in 2006–2009, aged ≥45 years at recruitment. Self-completed questionnaires were linked to cancer registrations, hospitalisations, health services data and deaths. Men with a history of PC, radical prostatectomy or a “monitoring” PSA test for prostate disease were excluded. We identified Medicare reimbursed PSA tests during 2012–2014. Multivariable logistic regression was used to estimate adjusted odds ratios (OR) for the association between having PSA tests and factors of interest. Of the 62,765 eligible men, 51.8% had at least one screening PSA test during 2012–2014. Factors strongly associated with having a PSA test included having 27+ general practitioner consultations (versus 3–9 consultations; OR = 2.00; 95%CI = 1.90–2.11), benign prostatic hyperplasia treatment (versus none; OR = 1.59(95%CI = 1.49–1.70), aged 60–69 years (versus 50–59 years; OR = 1.54; 95%CI = 1.48–1.60). These results emphasise the important role of primary care in decision making about PSA testing.

Sitagliptin may reduce prostate cancer risk in male patients with type 2 diabetes

This retrospective cohort study evaluated the risk of prostate cancer associated with sitagliptin use in Taiwanese male patients with type 2 diabetes mellitus by using the reimbursement databases of the National Health Insurance. Male patients with newly diagnosed type 2 diabetes mellitus at an age ≥25 years between 1999 and 2010 were recruited. A total of 37,924 ever users of sitagliptin and 426,276 never users were followed until December 31, 2011. The treatment effect of sitagliptin (for ever versus never users, and for tertiles of cumulative duration of therapy) was estimated by Cox regression incorporated with the inverse probability of treatment weighting using propensity score. Analyses were also conducted in a 1:1 matched pair cohort based on 8 digits of propensity score. Results showed that during follow-up, 84 ever users and 2,549 never users were diagnosed of prostate cancer, representing an incidence of 140.74 and 240.17 per 100,000 person-years, respectively. The hazard ratio (95% confidence intervals) for ever users versus never users was 0.613 (0.493-0.763). The respective hazard ratio for the first, second, and third tertile of cumulative duration of sitagliptin use <5.9, 5.9-12.7 and >12.7 months was 0.853 (0.601-1.210), 0.840 (0.598-1.179) and 0.304 (0.191-0.483), respectively; and was 0.856 (0.603-1.214), 0.695 (0.475-1.016) and 0.410 (0.277-0.608) for cumulative dose <15,000, 15,000-33,600 and >33,600 mg, respectively. Findings were supported by analyses in the matched cohort. In conclusion, sitagliptin significantly reduces the risk of prostate cancer, especially when the cumulative duration is >12.7 months or the cumulative dose >33,600 mg.