Type 2 diabetes and risk of prostate cancer: a meta-analysis of observational studies

Acarbose might be associated with reduced risk of gastric cancer in patients with diabetes mellitus: A nationwide population-based cohort study

BACKGROUND

Several epidemiologic studies have revealed a higher risk of cancer in patients with diabetes mellitus (DM) relative to the general population. To investigate whether the use of acarbose was associated with higher/lower risk of new-onset cancers.

METHOD

We conducted a retrospective cohort study, using a population-based National Health Insurance Research Database of Taiwan. Both inpatients and outpatients with newly onset DM diagnosed between 2000 and 2012 were collected. The Adapted Diabetes Complications Severity Index (aDCSI) was used to adjust the severity of DM. The Cox proportional hazards regression model was used to estimate the hazard ratio (HR) of disease.

RESULTS

A total of 22 502 patients with newly diagnosed DM were enrolled. The Cox proportional hazards regression model indicating acarbose was neutral for risk for gastroenterological malignancies, when compared to the acarbose non-acarbose users group. However, when gastric cancer was focused, acarbose-user group had significantly lowered HR than non-acarbose users group (p = 0.003). After adjusted for age, sex, cancer-related comorbidity, severity of DM, and co-administered drugs, the HR of gastric cancer risk was 0.43 (95% CI = 0.25-0.74) for acarbose-user patients.

CONCLUSION

This long-term population-based study demonstrated that acarbose might be associated with lowered risk of new-onset gastric cancer in diabetic patients after adjusting the severity of DM.

Comparisons of the risks of new-onset prostate cancer in type 2 diabetes mellitus between SGLT2I and DPP4I users: a population-based cohort study

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2I) have been suggested to reduce new-onset cancer amongst type-2 diabetes mellitus (T2DM) patients. This study aims to compare the risks of prostate cancer between SGLT2I and dipeptidyl peptidase-4 inhibitors (DPP4I) amongst T2DM patients.

DESIGN, SETTING AND PARTICIPANTS

This was a retrospective population-based cohort study of prospectively recorded data on male patients with T2DM who were prescribed either SGLT2I or DPP4I between 1st January 2015 and 31st December 2020 from Hong Kong.

METHODS

The primary outcome was new-onset prostate cancer. The secondary outcomes included cancer-related mortality and all-cause mortality. Propensity score matching (1:1 ratio) using the nearest neighbor search was performed and multivariable Cox regression was applied. A three-arm analysis including the glucagon-like peptide-1 receptor agonist (GLP1a) cohort was conducted.

RESULTS

This study included 42129 male T2DM patients (median age: 61.0 years old [SD: 12.2]; SGLT2I: n = 17,120; DPP4I: n = 25,009). In the propensity score matched cohort, the number of prostate cancers was significantly lower in SGLT2I users (n = 60) than in DPP4I (n = 102). Over a follow-up duration of 5.61 years, SGLT2I was associated with lower prostate cancer risks (HR: 0.45; 95% CI: 0.30-0.70) than DPP4I after adjustments. The subgroup analyses showed that the interactions between SGLT2I and age, hypertension, heart failure, and GLP-1a were not statistically significant. The result remained consistent in the sensitivity analysis.

CONCLUSION

The study demonstrated SGLT2I was associated with lower risks of new-onset prostate cancer after propensity score matching and adjustments compared to DPP4I amongst T2DM patients.

The effect of SGLT2 inhibition on prostate cancer: Mendelian randomization and observational analysis using electronic healthcare and cohort data

We evaluated the effect of sodium-glucose cotransporter 2 (SGLT2) inhibition on prostate cancer by evidence triangulation. Using Mendelian randomization, we found that genetically proxied SGLT2 inhibition reduced the risk of overall (odds ratio = 0.56, 95% confidence interval [CI] = 0.38 to 0.82; 79,148 prostate cancer cases and 61,106 controls), advanced, and early-onset prostate cancer. Using electronic healthcare data (nSGLT2i = 24,155; nDPP4i = 24,155), we found that the use of SGLT2 inhibitors was associated with a 23% reduced risk of prostate cancer (hazard ratio = 0.77, 95% CI = 0.61 to 0.99) in men with diabetes. Using data from two prospective cohorts (n4C = 57,779; nUK_Biobank = 165,430), we found little evidence to support the association of HbA1c with prostate cancer, implying a non-glycemic effect of SGLT2 inhibition on prostate cancer. In summary, this study provides multiple layers of evidence to support the beneficial effect of SGLT2 inhibition on reducing prostate cancer risk. Future trials are warranted to investigate whether SGLT2 inhibitors can be recommended for prostate cancer prevention.

Association between the metabolic score for insulin resistance and prostate cancer: a cross-sectional study in Xinjiang

Background

Insulin resistance is associated with the development and progression of various cancers. However, the epidemiological evidence for the association between insulin resistance and prostate cancer is still limited.

Objectives

To investigate the associations between insulin resistance and prostate cancer prevalence.

Methods

A total of 451 patients who were pathologically diagnosed with prostate cancer in the First Affiliated Hospital of Xinjiang Medical University were selected as the case population; 1,863 participants who conducted physical examinations during the same period were selected as the control population. The metabolic score for insulin resistance (METS-IR) was calculated as a substitute indicator for evaluating insulin resistance. The Chi-square test and Mann-Whitney U test were performed to compare the basic information of the case population and control population. Univariate and multivariate logistic regression analyses to define factors that may influence prostate cancer prevalence. The generalized additive model (GAM) was applied to fit the relationship between METS-IR and prostate cancer. Interaction tests based on generalized additive model (GAM) and contour plots were also carried out to analyze the interaction effect of each factor with METS-IR on prostate cancer.

Results

METS-IR as both a continuous and categorical variable suggested that METS-IR was negatively associated with prostate cancer prevalence. Smoothed curves fitted by generalized additive model (GAM) displayed a nonlinear correlation between METS-IR and prostate cancer prevalence (P < 0.001), and presented that METS-IR was negatively associated with the odds ratio (OR) of prostate cancer. The interaction based on the generalized additive model (GAM) revealed that METS-IR interacted with low-density lipoprotein cholesterol (LDL-c) to influence the prostate cancer prevalence (P = 0.004). Contour plots showed that the highest prevalence probability of prostate cancer was achieved when METS-IR was minimal and low-density lipoprotein cholesterol (LDL-c) or total cholesterol (TC) was maximal.

Conclusions

METS-IR is nonlinearly and negatively associated with the prevalence of prostate cancer. The interaction between METS-IR and low-density lipoprotein cholesterol (LDL-c) has an impact on the prevalence of prostate cancer. The study suggests that the causal relationship between insulin resistance and prostate cancer still needs more research to confirm.

Associations between Diabetes Mellitus and Selected Cancers

Cancer is one of the major causes of mortality and is the second leading cause of death. Diabetes mellitus is a serious and growing problem worldwide, and its prevalence continues to grow; it is the 12th leading cause of death. An association between diabetes mellitus and cancer has been suggested for more than 100 years. Diabetes is a common disease diagnosed among patients with cancer, and evidence indicates that approximately 8-18% of patients with cancer have diabetes, with investigations suggesting an association between diabetes and some particular cancers, increasing the risk for developing cancers such as pancreatic, liver, colon, breast, stomach, and a few others. Breast and colorectal cancers have increased from 20% to 30% and there is a 97% increased risk of intrahepatic cholangiocarcinoma or endometrial cancer. On the other hand, a number of cancers and cancer therapies increase the risk of diabetes mellitus. Complications due to diabetes in patients with cancer may influence the choice of cancer therapy. Unfortunately, the mechanisms of the associations between diabetes mellitus and cancer are still unknown. The aim of this review is to summarize the association of diabetes mellitus with selected cancers and update the evidence on the underlying mechanisms of this association.

Glycemic control and cancer outcomes in oncologic patients with diabetes: an Italian Association of Medical Oncology (AIOM), Italian Association of Medical Diabetologists (AMD), Italian Society of Diabetology (SID), Italian Society of Endocrinology (SIE), Italian Society of Pharmacology (SIF) multidisciplinary critical view

BACKGROUND

 Increasing evidence suggests that diabetes increases the risk of developing different types of cancer. Hyperinsulinemia, hyperglycemia and chronic inflammation, characteristic of diabetes, could represent possible mechanisms involved in cancer development in diabetic patients. At the same time, cancer increases the risk of developing new-onset diabetes, mainly caused by the use of specific anticancer therapies. Of note, diabetes has been associated with a ∼10% increase in mortality for all cancers in comparison with subjects who did not have diabetes. Diabetes is associated with a worse prognosis in patients with cancer, and more recent findings suggest a key role for poor glycemic control in this regard. Nevertheless, the association between glycemic control and cancer outcomes in oncologic patients with diabetes remains unsettled and poorly debated.

PURPOSE

 The current review seeks to summarize the available evidence on the effect of glycemic control on cancer outcomes, as well as on the possibility that timely treatment of hyperglycemia and improved glycemic control in patients with cancer and diabetes may favorably affect cancer outcomes.

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.

The association between diabetes mellitus and prostate cancer: a meta-analysis and Mendelian randomization

BACKGROUND

Prostate cancer is one of the most common types of cancer in the US, and it has a high mortality rate. Diabetes mellitus is also a dangerous health condition. While some studies have examined the relationship between diabetes mellitus and the risk of prostate cancer, there is still some debate on the matter. This study aims to carefully assess the relationship between prostate cancer and diabetes from both real-world and genetic-level data.

METHODS

This meta-analysis was conducted following the PRISMA 2020 reporting guidelines. The study searched three databases including Medline, Embase and Cochrane. The studies about the incidence risk of prostate cancer with diabetes mellitus were included and used to evaluate the association. The odds ratio (OR), risk ratio (RR) and 95% confidence intervals (95% CI) were estimated using Random Effects models and Fixed Effects models. Mendelian randomization study using genetic variants was also conducted.

RESULTS

A total of 72 articles were included in this study. The results showed that risk of prostate cancer decreased in diabetes patients. And the influence was different in different regions. This study also estimated the impact of body mass index (BMI) in the diabetes populations and found that the risk decreased in higher BMI populations. The MR analysis found that diabetes mellitus exposure reduced the risk of prostate cancer in the European population and Asia populations. Conclusions The diabetes mellitus has a protective effect on prostate cancer. And the influence of obesity in diabetes mellitus plays an important role in this effect.

Associations between diabetes and cancer: A 10-year national population-based retrospective cohort study

AIMS

To investigate the risk of cancer in people with diabetes compared to the population without diabetes and to gain insight into the timely association between diabetes and cancer at national level.

METHODS

A retrospective cohort study was conducted to analyse the role of diabetes in the development of cancer, based on service utilisation and antidiabetic dispensing data of the population between 2010 and 2021. Univariate and multivariate Cox regression were used to examine how diabetes status, in relationship with age and sex are related to the time to cancer diagnosis.

RESULTS

Examining a population of 3 681 774 individuals, people with diabetes have a consistently higher risk for cancer diagnosis for each cancer site studied. Diabetes adds the highest risk for pancreatic cancer (HR = 2.294, 99 % CI: 2.099; 2.507) and for liver cancer (HR = 1.830, 99 % CI: 1.631; 2.054); it adds the lowest - but still significant - risk for breast cancer (HR = 1.137, 99 % CI: 1.055; 1.227) and prostate cancer (HR = 1.171, 99 % CI: 1.071; 1.280).The difference in cancer rate is driven by the younger age group (40-54 years: for patients with diabetes 5.4 % vs. controls 4.4 %; 70-89 years: for patients with diabetes 12.7 % vs. controls 12.4 %). There are no consistent results whether the presence of diabetes increases the risk of cancer diagnosis differently in males and females. The cancer incidence starts to increase before the diagnosis of diabetes and peaks in the year after. By the year after the start of the inclusion date, the incidence is 114/10,000 population in the control group, vs 195/10,000 population in the group with diabetes. Following this, the incidence drops close to the control group.

CONCLUSIONS

Screening activities should be revised and the guidelines on diabetes should be complemented with recommendations on cancer prevention also considering that the cancer incidence is highest around the time of the diagnosis of diabetes. For prostate cancer, our results contradict many previous studies, and further research is recommended to clarify this.

Epithelial-mesenchymal transition dysregulation in prostate cancer: Insights from molecular unraveling and epidemiological analyses in Tunisia, North Africa

INTRODUCTION

The progression of prostate cancer (PCa) has been linked worldwide, including in African populations, to the dysregulation of the epithelial-mesenchymal transition (EMT).

METHODS

To clarify the connection among EMT markers, clinicopathological parameters, and epidemiological factors, we analyzed 35 PCa specimens from patients in Tunisia, a country in North Africa, arranged by stages. We also carried out extensive molecular and epidemiological analyses.

RESULTS

Significant dysregulation of EMT genes was found, with an overexpression of ZEB-1, Twist, Snail-1, and Vimentin (p < 0.05) and underexpression of E-cadherin and β-catenin (p < 0.05). Positive correlations were observed between transcription factors and the mesenchymal marker Vimentin (p < 0.001, r = 0.574; p = 0.029, r = 0.411; and p < 0.001; r = 0.506) according to Spearman correlation analyses, whereas negative correlations were found between epithelial markers (E-cadherin, β-catenin) and Vimentin (p < 0.05; r < 0). Higher PSA, Gleason scores, and metastasis were all correlated with the dysregulation of EMT (p < 0.05). Notably, there was a positive correlation between higher consumption of tobacco (≥20 Packets per year) and Vimentin expression (p < 0.001, r = 0.854), suggesting a relationship between smoking and EMT activation in the Tunisian population. Moreover, Twist showed a positive correlation with diabetes (p < 0.001, r = 0.385), whereas no significant correlations were found between EMT markers and comorbidities such as hypertension and coronary insufficiency. These results demonstrate the intricate connection between molecular changes, epidemiological factors, and disease progression, and they emphasize the crucial role that EMT plays in promoting PCa aggressiveness in African populations, particularly in Tunisia.

CONCLUSION

In summary, understanding these correlations could help develop focused treatment plans and enhance patient outcomes for PCa management in African settings.

Metformin Overcomes the Consequences of NKX3.1 Loss to Suppress Prostate Cancer Progression

BACKGROUND

The antidiabetic drug metformin has known anticancer effects related to its antioxidant activity; however, its clinical benefit for prostate cancer (PCa) has thus far been inconclusive. Here, we investigate whether the efficacy of metformin in PCa is related to the expression status of NKX3.1, a prostate-specific homeobox gene that functions in mitochondria to protect the prostate from aberrant oxidative stress.

OBJECTIVE

To investigate the relationship of NKX3.1 expression and metformin efficacy in PCa.

DESIGN, SETTING, AND PARTICIPANTS

Functional studies were performed in vivo and in vitro in genetically engineered mouse models and human LNCaP cells, and organotypic cultures having normal or reduced/absent levels of NKX3.1. Correlative studies were performed using two independent retrospective tissue microarray cohorts of radical prostatectomies and a retrospective cohort of prostate biopsies from patients on active surveillance.

INTERVENTION

Metformin was administered before or after the induction of oxidative stress by treatment with paraquat.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Functional endpoints included analyses of histopathology, tumorigenicity, and mitochondrial function. Correlative endpoints include Kaplan-Meier curves and Cox proportional hazard regression models.

RESULTS AND LIMITATIONS

Metformin reversed the adverse consequences of NKX3.1 deficiency following oxidative stress in vivo and in vitro, as evident by reduced tumorigenicity and restored mitochondrial function. Patients with low NKX3.1 expression showed a significant clinical benefit from taking metformin.

CONCLUSIONS

Metformin can overcome the adverse consequences of NKX3.1 loss for PCa progression by protecting against oxidative stress and promoting normal mitochondrial function. These functional activities and clinical correlates were observed only with low NKX3.1 expression. Thus, the clinical benefit of metformin in PCa may depend on the status of NKX3.1 expression.

PATIENT SUMMARY

Prostate cancer patients with low NKX3.1 are likely to benefit most from metformin treatment to delay disease progression in a precision interception paradigm.

Interactions of obesity, body shape, diabetes and sex steroids with respect to prostate cancer risk in the UK Biobank cohort

BACKGROUND

Obesity and diabetes are associated inversely with low-grade prostate cancer risk and affect steroid hormone synthesis but whether they modify each other's impact on prostate cancer risk remains unknown.

METHODS

We examined the independent associations of diabetes, body mass index (BMI), 'a body shape index' (ABSI), hip index (HI), circulating testosterone, sex hormone binding globulin (SHBG) (per one standard deviation increase) and oestradiol ≥175 pmol/L with total prostate cancer risk using multivariable Cox proportional hazards models for UK Biobank men. We evaluated multiplicative interactions (pMI ) and additive interactions (relative excess risk from interaction (pRERI ), attributable proportion (pAR ), synergy index (pSI )) with obese (BMI ≥30 kg/m2 ) and diabetes.

RESULTS

During a mean follow-up of 10.3 years, 9417 incident prostate cancers were diagnosed in 195,813 men. Diabetes and BMI were associated more strongly inversely with prostate cancer risk when occurring together (pMI  = 0.0003, pRERI  = 0.032, pAP  = 0.020, pSI  = 0.002). ABSI was associated positively in obese men (HR = 1.081; 95% CI = 1.030-1.135) and men with diabetes (HR = 1.114; 95% CI = 1.021-1.216). The inverse associations with obesity and diabetes were attenuated for high-ABSI ≥79.8 (pMI  = 0.022, pRERI  = 0.008, pAP  = 0.005, pSI  <0.0001 obesity; pMI  = 0.017, pRERI  = 0.047, pAP  = 0.025, pSI  = 0.0005 diabetes). HI was associated inversely in men overall (HR = 0.967; 95% CI = 0.947-0.988). Free testosterone (FT) was associated most strongly positively in normal weight men (HR = 1.098; 95% CI = 1.045-1.153) and men with diabetes (HR = 1.189; 95% CI = 1.081-1.308). Oestradiol was associated inversely in obese men (HR = 0.805; 95% CI = 0.682-0.951). The inverse association with obesity was stronger for high-FT ≥243 pmol/L (pRERI  = 0.040, pAP  = 0.031, pSI  = 0.002) and high-oestradiol (pRERI  = 0.030, pAP  = 0.012, pSI  <0.0001). The inverse association with diabetes was attenuated for high-FT (pMI  = 0.008, pRERI  = 0.015, pAP  = 0.009, pSI  = 0.0006). SHBG was associated inversely in men overall (HR = 0.918; 95% CI = 0.895-0.941), more strongly for high-HI ≥49.1 (pMI  = 0.024).

CONCLUSIONS

Obesity and diabetes showed synergistic inverse associations with prostate cancer risk, likely involving testosterone reduction for diabetes and oestrogen generation for obesity, which were attenuated for high-ABSI. HI and SHBG showed synergistic inverse associations with prostate cancer risk.

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.

Obesity, diabetes, and cancer: epidemiology, pathophysiology, and potential interventions

The proportion of deaths attributable to cancer is rising, and malignant neoplasms have become the leading cause of death in high-income countries. Obesity and diabetes are now recognized as risk factors for several types of malignancies, especially endometrial, colorectal, and postmenopausal breast cancers. Mechanisms implicated include disturbances in lipid-derived hormone secretion, sex steroids biosynthesis, hyperinsulinemia, and chronic inflammation. Intentional weight loss is associated with a mitigation of risk for obesity-related cancers, a phenomenon observed specially with bariatric surgery. The impact of pharmacological interventions for obesity and diabetes is not uniform: while metformin seems to protect against cancer, other agents such as lorcaserin may increase the risk of malignancies. However, these interpretations must be carefully considered, since most data stem from bias-prone observational studies, and high-quality randomized controlled trials with appropriate sample size and duration are needed to achieve definite conclusions. In this review, we outline epidemiological and pathophysiological aspects of the relationship between obesity, diabetes, and malignancies. We also highlight pieces of evidence regarding treatment effects on cancer incidence in these populations.

Diabetes, metabolic syndrome and prostate cancer risk: Results from the EPICAP case-control study

BACKGROUND

Diabetes may be associated with decreased prostate cancer (PCa) risk. However, previous studies have not always accounted for time since diabetes diagnosis or antidiabetic drug use. Futhermore, the role of metabolic syndrome (MetS) in PCa risk is still debated. We investigated the role of diabetes and MetS in PCa risk based on data from the Epidemiological study of PCa (EPICAP).

METHODS

EPICAP is a population-based case-control study that included 819 incident PCa cases in 2012-2013 and 879 controls frequency matched by age. MetS was characterized according to National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III). Logistic regression models adjusted for age, family history of PCa and ethnicity, were used to assess odds ratios (ORs) and their 95%conficence intervals (CIs) for the associations between diabetes, MetS and PCa risk.

RESULTS

Whereas we did not observed an association between diabetes and PCa, a decreased risk of PCa has been highlighted with an increasing treated diabetes duration (p-trend=0.008). No association has been observed between MetS, the number of MetS criteria and the risk of PCa. However, we suggested that NSAIDs use could modify the association between MetS and PCa risk.

CONCLUSION

Our results suggest an inverse association between the duration of diabetes and PCa risk. The role of metabolic factors, such as MetS and its components, in PCa risk remains unclear and requires further investigations.

Cancer and diabetes co-occurrence: A national study with 44 million person-years of follow-up

The number of new cases of cancer is increasing each year, and rates of diabetes mellitus are also increasing dramatically over time. It is not an unusual occurrence for an individual to have both cancer and diabetes at the same time, given they are both individually common, and that one condition can increase the risk of the other. In this manuscript, we use national-level diabetes (Virtual Diabetes Register) and cancer (New Zealand Cancer Registry) data on nearly five million individuals over 44 million person-years of follow-up to examine the occurrence of cancer amongst a national prevalent cohort of patients with diabetes. We completed this analysis separately by cancer for the 24 most commonly diagnosed cancers in Aotearoa New Zealand, and then compared the occurrence of cancer among those with diabetes to those without diabetes. We found that the rate of cancer was highest amongst those with diabetes for 21 of the 24 most common cancers diagnosed over our study period, with excess risk among those with diabetes ranging between 11% (non-Hodgkin's lymphoma) and 236% (liver cancer). The cancers with the greatest difference in incidence between those with diabetes and those without diabetes tended to be within the endocrine or gastrointestinal system, and/or had a strong relationship with obesity. However, in an absolute sense, due to the volume of breast, colorectal and lung cancers, prevention of the more modest excess cancer risk among those with diabetes (16%, 22% and 48%, respectively) would lead to a substantial overall reduction in the total burden of cancer in the population. Our findings reinforce the fact that diabetes prevention activities are also cancer prevention activities, and must therefore be prioritised and resourced in tandem.

Total Prostate Specific Antigen in Prostate Cancer Screening in Hyperglycemic Individuals

AIM

In this study, it was aimed to investigate the reliability of total prostate-specific antigen (t-PSA) in prostate cancer screening in hyperglycemic (≥126 mg/dL) individuals.

METHODS

This research was planned as a cross-sectional retrospective study. Three hundred eleven cases which underwent biopsy with the suspicion of prostate cancer in the hospital were included in the study. Prostate cancer risk groups were categorized as low, intermediate and high. Those with fasting blood glucose (FBG) levels lower than 126 mg/dL were considered as the normoglycemia group.

RESULTS

It was determined that the t-PSA measurement was higher in the patient group with cancer (P < .001). It was determined that the median t-PSA levels of the intermediate and high cancer groups were higher than the low cancer group (P < .001 and P = .001, respectively). t-PSA was found to be associated with increased cancer risk in cases with FBG <126. However, an increase in t-PSA values in cases with FBG ≥126 was not associated with increased prostate cancer. There is no relationship between FBG measurement and t-PSA measurement (rs=0.05, P = .446). In addition, it was determined that the t-PSA measurements of patients with FBG ≥126 and FBG<126 did not differ (P = .962).

CONCLUSIONS

As a contribution to literature, we found that the t-PSA test lost its sensitivity in cases with plasma glucose levels above normal. Loss of sensitivity may result in underdiagnosis in prostate cancer and this, in turn, results in diagnosis of the cancer at a later stage. In the future, it may be necessary to adopt a different approach in prostate cancer screening in hyperglycemic cases.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

Family history, obesity, urological factors and diabetic medications and their associations with risk of prostate cancer diagnosis in a large prospective study

Background

Prostate cancer (PC) aetiology is unclear. PC risk was examined in relation to several factors in a large population-based prospective study.

Methods

Male participants were from Sax Institute’s 45 and Up Study (Australia) recruited between 2006 and 2009. Questionnaire and linked administrative health data from the Centre for Health Record Linkage and Services Australia were used to identify incident PC, healthcare utilisations, Prostate Specific Antigen (PSA) testing reimbursements and dispensing of metformin and benign prostatic hyperplasia (BPH) prescriptions. Multivariable Cox and Joint Cox regression analyses were used to examine associations by cancer spread, adjusting for various confounders.

Results

Of 107,706 eligible men, 4257 developed incident PC up to end 2013. Risk of PC diagnosis increased with: PC family history (versus no family history of cancer; HR_adjusted = 1.36; 95% CI:1.21–1.52); father and brother(s) diagnosed with PC (versus cancer-free family history; HR_adjusted = 2.20; 95% CI:1.61–2.99); severe lower-urinary-tract symptoms (versus mild; HR_adjusted = 1.77; 95% CI:1.53–2.04) and vasectomy (versus none; HR_adjusted = 1.08; 95% CI:1.00–1.16). PC risk decreased with dispensed prescriptions (versus none) for BPH (HR_adjusted = 0.76; 95% CI:0.69–0.85) and metformin (HR_adjusted = 0.57; 95% CI:0.48–0.68). Advanced PC risk increased with vasectomy (HR_adjusted = 1.28; 95% CI:1.06–1.55) and being obese (versus normal weight; HR_adjusted = 1.31; 95% CI:1.01–1.69).

Conclusion

Vasectomy and obesity are associated with an increased risk of advanced PC. The reduced risk of localised and advanced PC associated with BPH, and diabetes prescriptions warrants investigation.

Are Diabetic Patients at Increased Risk for Biochemical Recurrence After Radical Prostatectomy?

Introduction Diabetic patients are at a lower risk for prostate cancer. However, the relationship between diabetes mellitus (DM) and biochemical recurrence (BCR) after radical prostatectomy (RP) is less clear. The goal of our study was to determine diabetes's value as a biochemical recurrence predictor. Materials and methods We conducted a retrospective analysis of 117 patients who had undergone open radical prostatectomy between 1999 and 2021 at our institution. Univariate and multivariate statistical analyses were used to identify factors associated with biochemical recurrence. Results On univariate analysis, factors associated with biochemical recurrence were diabetes (p=0.002), preoperative prostate-specific antigen (PSA) levels (p=0.022), positive digital rectal exam (p=0.035), number of positive biopsy cores (p<0.001), unfavorable intermediate risk group (p=0.014), peri-neural invasion (PNI) on RP specimen (p=0.043), tumor volume (p=0.011), and positive surgical margins (p<0.001). Multivariate analysis showed that factors independently associated with biochemical recurrence were diabetes (p=0.039; OR=2.788), number of positive cores (p=0.016; OR=4.124), and positive surgical margins (p=0.008; OR=3.876). Conclusion A history of diabetes mellitus should be taken into consideration when assessing patients' risk of biochemical recurrence after radical prostatectomy. More research on a larger scale is needed to determine diabetes' value as a biochemical predictor.

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.

The Impact of Metabolic Syndrome and Type 2 Diabetes Mellitus on Prostate Cancer

Prostate cancer (PCa) remains the second most common type of cancer in men worldwide in 2020. Despite its low death rate, the need for new therapies or prevention strategies is critical. The prostate carcinogenesis process is complex and multifactorial. PCa is caused by a variety of mutations and carcinogenic events that constitutes the disease's multifactorial focus, capable of not only remodeling cellular activity, but also modeling metabolic pathways to allow adaptation to the nutritional requirements of the tumor, creating a propitious microenvironment. Some risk factors have been linked to the development of PCa, including Metabolic Syndrome (MetS) and Type 2 Diabetes Mellitus (T2DM). MetS is intrinsically related to PCa carcinogenic development, increasing its aggressiveness. On the other hand, T2DM has the opposite impact, although in other carcinomas its effect is similar to the MetS. Although these two metabolic disorders may share some developmental processes, such as obesity, insulin resistance, and dyslipidemia, their influence on PCa prognosis appears to have an inverse effect, which makes this a paradox. Understanding the phenomena behind this paradoxical behavior may lead to new concepts into the comprehension of the diseases, as well as to evaluate new therapeutical targets. Thus, this review aimed to evaluate the impact of metabolic disorders in PCa's aggressiveness state and metabolism.

Nanoparticles of Costus&nbsp;speciosus Ameliorate Diabetes-Induced Structural Changes in Rat Prostate through Mediating the Pro-Inflammatory Cytokines IL 6, IL1β and TNF-α

Diabetes mellitus is a common global health problem. Among the complications that are frequently associated with DM are the alternation of sexual function and fertility, especially in young men. This study aimed to assess the efficacy of nanoparticles of Costus speciosus (C. speciosus) in preserving the prostatic structure of diabetic rats and to explore the mechanism behind this effect. A model of DM was induced in male albino rats by a single intraperitoneally injection of streptozotocin (STZ, 60 mg/kg body weight). Five groups (n = 10 each) of rats were included in this study: the control, C. speciosus gold nanoparticles-treated (150 mg/kg body weight through gastric intubation for 30 days), untreated diabetic, metformin-treated diabetic (500 mg/kg/day gastric intubation for 30 days) and the C. speciosus-treated diabetic group. The blood glucose, insulin and testosterone levels as well as oxidants/antioxidants status were assessed in the serum. Gene expression of proinflammatory cytokines TNF-α, IL1β and IL-6 were assessed in the prostate homogenate. At the end of the experiment, the rats were sacrificed and the prostate was dissected out and prepared for histopathological and immunohistochemistry study using Ki67 and Bcl-2. C. Speciosus nanoparticles significantly decreased (p = 0.03) the blood glucose level while significantly increasing insulin (p = 0.01) and testosterone (p = 0.04) levels compared to the untreated diabetic rats. Oxidants/antioxidants status was markedly improved after administration of C. speciosus. Prostatic expression of the mRNA of pro-inflammatory cytokines IL-6, IL1β and TNF-α was down-regulated in metformin- and C. speciosus-treated rats. The histological structure of the ventral prostate was preserved in metformin- and C. speciosus-treated diabetic rats with a significantly thicker epithelial cell layer and significant increase immunoexpression in Bcl-2 and Ki67. In conclusion, the protective effect induced by C. speciosus nanoparticles on the prostate of diabetic rats might be directly mediated through the down-regulation of inflammatory cytokines and the up-regulation of antioxidant activity and indirectly mediated through the anti-hyperglycemic effect through enhancing insulin secretion.

Antidiabetic Medications and the Risk of Prostate Cancer in Patients with Diabetes Mellitus: A Systematic Review and Meta-analysis

BACKGROUND

Antidiabetic medications (ADMs) may modify prostate cancer (PCa) risk in patients with diabetes mellitus (DM). Accordingly, the current study assessed the possible associations between ADMs and the risk of PCa in diabetics.

METHODS

A systematic literature search (PubMed, Embase and Cochrane Library) identified studies evaluating the associations between ADMs and incidence of PCa. A meta-analysis followed PRISMA was performed using odds ratio (OR) with 95% confidence interval (CI) as effect measures.

RESULTS

In total of 47 studies involving 3,094,152 patients with diabetes were included. Results of meta-analysis of the observational studies suggested no significant association between metformin, thiazolidinediones, sulfonylureas, insulin or dipeptidyl peptidase-4 inhibitors administration and the risk of PCa (All p-values > 0.05). Separate analysis of randomized controlled trials (RCTs) revealed a significant reduction in PCa risk with thiazolidinediones (OR = 0.55, p = 0.04) or glucagon-like peptide-1 receptor agonists (GLP-1RA) administration (OR = 0.53, p = 0.006), whereas no significant association was found in SGLT2 inhibitors (p = 0.3).

CONCLUSION

Thiazolidinediones or GLP-1RA administration may have benefits in PCa based on RCTs, however, further research is needed to confirm these findings.

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.

Insulin-like Growth Factor 2 mRNA-Binding Protein 2-a Potential Link Between Type 2 Diabetes Mellitus and Cancer

CONTEXT

Type 2 diabetes mellitus (T2DM) and cancer share a variety of risk factors and pathophysiological features. It is becoming increasingly accepted that the 2 diseases are related, and that T2DM increases the risk of certain malignancies.

OBJECTIVE

This review summarizes recent advancements in the elucidation of functions of insulin-like growth factor 2 (IGF-2) messenger RNA (mRNA)-binding protein 2 (IGF2BP2) in T2DM and cancer.

METHODS

A PubMed review of the literature was conducted, and search terms included IGF2BP2, IMP2, or p62 in combination with cancer or T2DM. Additional sources were identified through manual searches of reference lists. The increased risk of multiple malignancies and cancer-associated mortality in patients with T2DM is believed to be driven by insulin resistance, hyperinsulinemia, hyperglycemia, chronic inflammation, and dysregulation of adipokines and sex hormones. Furthermore, IGF-2 is oncogenic, and its loss-of-function splice variant is protective against T2DM, which highlights the pivotal role of this growth factor in the pathogenesis of these 2 diseases. IGF-2 mRNA-binding proteins, particularly IGF2BP2, are also involved in T2DM and cancer, and single-nucleotide variations (formerly single-nucleotide polymorphisms) of IGF2BP2 are associated with both diseases. Deletion of the IGF2BP2 gene in mice improves their glucose tolerance and insulin sensitivity, and mice with transgenic p62, a splice variant of IGF2BP2, are prone to diet-induced fatty liver disease and hepatocellular carcinoma, suggesting the biological significance of IGF2BP2 in T2DM and cancer.

CONCLUSION

Accumulating evidence has revealed that IGF2BP2 mediates the pathogenesis of T2DM and cancer by regulating glucose metabolism, insulin sensitivity, and tumorigenesis. This review provides insight into the potential involvement of this RNA binding protein in the link between T2DM and cancer.

Vitamin D Supplementation for Prevention of Cancer: The D2d Cancer Outcomes (D2dCA) Ancillary Study

CONTEXT

Observational studies suggest that low vitamin D status may be a risk factor for cancer.

OBJECTIVE

In a population with prediabetes and overweight/obesity that is at higher risk of cancer than the general population, we sought to determine if vitamin D supplementation lowers the risk of cancer and precancers.

METHODS

The Vitamin D and type 2 diabetes (D2d) cancer outcomes study (D2dCA) is an ancillary study to the D2d study, which was conducted at 22 academic medical centers in the United States. Participants had prediabetes and overweight/obesity and were free of cancer for the previous 5 years. Participants were randomized to receive vitamin D3 4000 IU daily or placebo. At scheduled study visits (4 times/year), cancer and precancer events were identified by questionnaires. Clinical data were collected and adjudicated for all reported events. Cox proportional hazard models compared the hazard ratio (HR) of incident cancers and precancers between groups.

RESULTS

Over a median follow-up period of 2.9 years, among 2385 participants (mean age 60 years and 25-hydroxyvitamin D 28 ng/mL), there were 89 cases of cancer. The HR of incident cancer for vitamin D vs placebo was 1.07 (95% CI 0.70, 1.62). Of 241 participants with incident precancers, 239 had colorectal adenomatous polyps. The HR for colorectal polyps for vitamin D vs placebo was 0.83 (95% CI 0.64, 1.07).

CONCLUSION

In the D2d population of participants with prediabetes and overweight/obesity, not selected for vitamin D insufficiency, vitamin D supplementation did not have a significant effect on risk of incident cancer or colorectal polyps.

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.

Type 2 Diabetes and Cancer: An Umbrella Review of Observational and Mendelian Randomization Studies

BACKGROUND

Type 2 diabetes mellitus (T2DM) has been associated with an increased risk of developing several common cancers, but it is unclear whether this association is causal. We aimed to summarize the evidence on T2DM and cancer and evaluate the validity of associations from both observational and Mendelian randomization (MR) studies.

METHODS

We performed an umbrella review of the evidence across meta-analyses of observational studies that examined associations of T2DM with risk of developing or dying from site-specific cancers, and MR studies that explored the potential causal association of T2DM and associated biomarkers with cancer risk.

RESULTS

We identified eligible observational meta-analyses that assessed associations between T2DM and cancer incidence for 18 cancer sites, cancer mortality for seven sites, and cancer incidence or mortality for four sites. Positive associations between T2DM and six cancers reached strong or highly suggestive evidence. We found eight MR studies assessing the association of genetically predicted T2DM and seven and eight studies assessing the association of genetically predicted fasting insulin or fasting glucose concentrations, respectively, upon site-specific cancers. Positive associations were found between genetically predicted T2DM and fasting insulin and risk of six cancers. There was no association between genetically predicted fasting plasma glucose and cancer except for squamous cell lung carcinoma.

CONCLUSIONS

We found robust observational evidence for the association between T2DM and colorectal, hepatocellular, gallbladder, breast, endometrial, and pancreatic cancers.

IMPACT

Potential causal associations were identified for genetically predicted T2DM and fasting insulin concentrations and risk of endometrial, pancreas, kidney, breast, lung, and cervical cancers.

High glucose: an emerging association between diabetes mellitus and cancer progression

The association of cancer and diabetes mellitus (DM) has been studied for decades. Hyperglycemia and the imbalance of hormones are factors that contribute to the molecular link between DM and carcinogenesis and cancer progression. Hyperglycemia alone or in combination with hyperinsulinemia are key factors that promote cancer aggressiveness. Many preclinical studies suggest that high glucose induces abnormal energy metabolism and aggressive cancer via several mechanisms. As evidenced by clinical studies, hyperglycemia is associated with poor clinical outcomes in patients who have comorbid DM. The prognoses of cancer patients with DM are improved when their plasma glucose levels are controlled. This suggests that high glucose level maybe be involved in the molecular mechanism that causes the link between DM and cancer and may also be useful for prognosis of cancer progression. This review comprehensively summarizes the evidence from recent pre-clinical and clinical studies of the impact of hyperglycemia on cancer advancement as well as the underlying molecular mechanism for this impact. Awareness among clinicians of the association between hyperglycemia or DM and cancer progression may improve cancer treatment outcome in patients who have DM.

Epidemiological link between obesity, type 2 diabetes mellitus and cancer

There exists a complex interaction between obesity, type 2 diabetes mellitus (T2DM) and cancer, and an increase in the incidence of cancer is expected with the growing obesity-diabetes pandemic. The association of cancer with diabetes mellitus and obesity appears to be site-specific, the highest risk being for post-menopausal breast cancer, endometrial cancer, and colorectal cancer. Moreover, there is worsening of hyperglycaemia with the onset of cancer, evidencing a bi-directional link between cancer and diabetes mellitus and the need for monitoring for diabetes in cancer survivors. In this review, we look at the epidemiological evidence from observational studies and Mendelian randomization studies linking obesity, diabetes, and cancer, as well as the complex pathophysiological mechanisms involved, including insulin resistance with associated hyperinsulinaemia, the effect of chronic low-grade inflammation, and the effect of various adipokines that are associated with obesity and T2DM. Additionally, we describe the novel therapeutic strategies, based on their role on the discrete pathophysiological mechanisms involved in the tumourigenesis.

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.

The Influence of Anti-Diabetic Drugs on Prostate Cancer

The incidences of prostate cancer (PC) and diabetes are increasing, with a sustained trend. The occurrence of PC and type 2 diabetes mellitus (T2DM) is growing with aging. The correlation between PC occurrence and diabetes is noteworthy, as T2DM is correlated with a reduced risk of incidence of prostate cancer. Despite this reduction, diabetes mellitus increases the mortality in many cancer types, including prostate cancer. The treatment of T2DM is based on lifestyle changes and pharmacological management. Current available drugs, except insulin, are aimed at increasing insulin secretion (sulfonylureas, incretin drugs), improving insulin sensitivity (biguanides, thiazolidinediones), or increasing urinary glucose excretion (gliflozin). Comorbidities should be taken into consideration during the treatment of T2DM. This review describes currently known information about the mechanism and impact of commonly used antidiabetic drugs on the incidence and progression of PC. Outcomes of pre-clinical studies are briefly presented and their correlations with available clinical trials have also been observed. Available reports and meta-analyses demonstrate that most anti-diabetic drugs do not increase the risk during the treatment of patients with PC. However, some reports show a potential advantage of treatment of T2DM with specific drugs. Based on clinical reports, use of metformin should be considered as a therapeutic option. Moreover, anticancer properties of metformin were augmented while combined with GLP-1 analogs.

Diabetes and Cancer: Metabolic Association, Therapeutic Challenges, and the Role of Natural Products

Cancer is considered the second leading cause of death worldwide and in 2018 it was responsible for approximately 9.6 million deaths. Globally, about one in six deaths are caused by cancer. A strong correlation was found between diabetes mellitus and carcinogenesis with the most evident correlation was with type 2 diabetes mellitus (T2DM). Research has proven that elevated blood glucose levels take part in cell proliferation and cancer cell progression. However, limited studies were conducted to evaluate the efficiency of conventional therapies in diabetic cancer patients. In this review, the correlation between cancer and diabetes will be discussed and the mechanisms by which the two diseases interact with each other, as well as the therapeutics challenges in treating patients with diabetes and cancer with possible solutions to overcome these challenges. Natural products targeting both diseases were discussed with detailed mechanisms of action. This review will provide a solid base for researchers and physicians to test natural products as adjuvant alternative therapies to treat cancer in diabetic patients.

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.

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.

Association of Type 2 Diabetes With Cancer: A Meta-analysis With Bias Analysis for Unmeasured Confounding in 151 Cohorts Comprising 32 Million People

BACKGROUND AND PURPOSE

Whether the association between type 2 diabetes (T2D) and cancer is causal remains controversial. The goal of this work is to assess the robustness of the observational associations between T2D and cancer to unmeasured confounding.

DATA SOURCES AND STUDY SELECTION

PubMed, Web of Science, and the Cochrane library were systematically searched on 10 January 2019 for observational studies investigating associations between T2D and cancer incidence or mortality.

DATA EXTRACTION AND DATA SYNTHESIS

Cohort-level relative risk (RR) was extracted. RRs were combined in random-effects meta-analyses and pooled estimates used in bias analyses. A total of 151 cohorts (over 32 million people, 1.1 million cancer cases, and 150,000 cancer deaths) were included. In meta-analyses, T2D was associated with incidence of several cancers, from prostate (RR 0.83; 95% CI 0.79, 0.88) to liver (2.23; 1.99, 2.49), and with mortality from pancreatic cancer (1.67; 1.30, 2.14). In bias analyses, assuming an unmeasured confounding associated with both T2D and cancer with a RR of 1.5, the proportion of studies with a true effect size larger than a RR of 1.1 (i.e., 10% increased risk in individuals with T2D) was nearly 100% for liver, pancreatic, and endometrial, 86% for gallbladder, 67% for kidney, 64% for colon, 62% for colorectal, and <50% for other cancer incidences, and 92% for pancreatic cancer mortality.

LIMITATIONS

Biases other than unmeasured confounding were not analytically assessed.

CONCLUSIONS

Our findings strongly suggest a causal association between T2D and liver, pancreatic, and endometrial cancer incidence, and pancreatic cancer mortality. Conversely, associations with other cancers were less robust to unmeasured confounding.

Racial and ethnic differences in risk of second primary cancers among prostate cancer survivors

PURPOSE

Previous studies have shown an overall decreased risk of second cancers among prostate cancer survivors, but this has not been comprehensively examined by race/ethnicity. We conducted a retrospective cohort study of 716,319 one-year survivors of prostate cancer diagnosed at ages 35-84 during 2000-2015 as reported to 17 US Surveillance, Epidemiology and End Results (SEER) registries.

METHODS

We estimated standardized incidence ratios (SIRs) for second primary non-prostate malignancies by race/ethnicity (non-Latino white, Black, Asian/Pacific Islander [API] and Latino), by Gleason, and by time since prostate cancer diagnosis. Poisson regression models were used to test heterogeneity between groups with the expected number as the offset.

RESULTS

60,707 second primary malignancies were observed. SIRs for all second cancers combined varied significantly by race/ethnicity: SIR_white: 0.88 (95% confidence interval: 0.87-0.89), SIR_Latino: 0.92 (0.89-0.95), SIR_Black: 0.97 (0.95-0.99), and SIR_API: 1.05 (1.01-1.09) (p-heterogeneity < 0.001). SIRs for all cancers combined were higher among survivors of higher vs. lower Gleason prostate cancers irrespective of race/ethnicity. We observed significant heterogeneity by race/ethnicity in SIRs for 9 of 14 second cancer types investigated including lung, bladder, kidney, and liver.

CONCLUSIONS

Our results confirm that most prostate cancer survivors have lower risks of second cancers than expected, but the magnitude varied by race/ethnicity. Exceptionally, API men had small but significantly increased risk. Further research to understand drivers of the observed race/ethnicity heterogeneity is warranted.

Preexisting diabetes, metformin use and long-term survival in patients with prostate cancer

OBJECTIVE

To assess prostate cancer-specific and overall survival in prostate cancer patients with or without preexisting type 2 diabetes mellitus (T2DM) with regards to metformin use.

METHODS

Patients diagnosed with prostate cancer in the Lithuanian population between 2001 and 2005 were identified through the Lithuanian Cancer Registry and followed until 2016, date of death, loss to follow-up or whichever came first. Information regarding the diagnosis of T2DM and antihyperglycemic medications were obtained from the National Health Insurance Fund database. Prostate cancer-specific and overall survival outcomes were analysed using univariate and multivariate Cox proportional hazard models.

RESULTS

Out of 6689 men included, 254 (3.8%) had preexisting T2DM. There were 4807 deaths during follow-up, including 2084 from prostate cancer. No differences were found in prostate cancer-specific survival between men with or without T2DM. The risk of overall mortality was higher (HR = 1.24, 95% CI = 1.07-1.43) in diabetic men. Univariate analysis showed cancer stage at diagnosis and age to be significant predictors of survival. After adjustment for age and stage at diagnosis, there was no difference in prostate-specific survival between non-diabetic patients compared to metformin users or metformin non-users. However, overall survival was lower in T2DM patients, with a higher mortality risk for metformin non-users (HR = 1.63, 95% CI = 1.27-2.10). Prostate cancer-specific mortality risk was insignificantly lower in diabetic men on metformin (HR = 0.74, 95% CI = 0.54-1.02).

CONCLUSION

There was no difference in long-term prostate cancer-specific survival in patients with or without T2DM. Overall survival was lower in T2DM patients not treated with metformin.

Hyperglycemia Enhances Cancer Immune Evasion by Inducing Alternative Macrophage Polarization through Increased O-GlcNAcylation

Diabetes mellitus (DM) significantly increases the risk for cancer and cancer progression. Hyperglycemia is the defining characteristic of DM and tightly correlates with a poor prognosis in patients with cancer. The hexosamine biosynthetic pathway (HBP) is emerging as a pivotal cascade linking high glucose, tumor progression, and impaired immune function. Here we show that enhanced glucose flow through the HBP drives cancer progression and immune evasion by increasing O-GlcNAcylation in tumor-associated macrophages (TAM). Increased O-GlcNAc skewed macrophage polarization to a M2-like phenotype supporting tumor progression. Finally, we found an upregulation of M2 markers on TAMs in DM2 patients with colorectal cancer compared with nondiabetic normoglycemic patients. Our results provide evidence for a new and targetable mechanism of cancer immune evasion in patients with hyperglycemia, advocating for strict control of hyperglycemia in patients with cancer.

Identification of metabolites associated with prostate cancer risk: a nested case-control study with long follow-up in the Northern Sweden Health and Disease Study

BACKGROUND

Prostate cancer is the second most frequently diagnosed cancer in men. Metabolomics can potentially provide new insights into the aetiology of prostate cancer by identifying new metabolic risk factors. This study investigated the prospective association between plasma metabolite concentrations and prostate cancer risk, both overall and by stratifying for disease aggressiveness and baseline age.

METHODS

In a case-control study nested in the Northern Sweden Health and Disease Study, pre-diagnostic concentrations of 148 plasma metabolites were determined using targeted mass spectrometry- and nuclear magnetic resonance-based metabolomics in 777 prostate cancer cases (follow-up ≥ 5 years) and 777 matched controls. Associations between prostate cancer risk and metabolite concentrations were investigated using conditional logistic regression conditioned on matching factors (body mass index, age and sample storage time). Corrections for multiple testing were performed using false discovery rate (20%) and Bonferroni. Metabolomics analyses generated new hypotheses, which were investigated by leveraging food frequency questionnaires (FFQs) and oral glucose tolerance tests performed at baseline.

RESULTS

After correcting for multiple testing, two lysophosphatidylcholines (LPCs) were positively associated with risk of overall prostate cancer (all ages and in older subjects). The strongest association was for LPC C17:0 in older subjects (OR = 2.08; 95% CI 1.45-2.98; p < 0.0001, significant also after the Bonferroni correction). Observed associations with risk of overall prostate cancer in younger subjects were positive for glycine and inverse for pyruvate. For aggressive prostate cancer, there were positive associations with six glycerophospholipids (LPC C17:0, LPC C20:3, LPC C20:4, PC ae C38:3, PC ae C38:4 and PC ae C40:2), while there was an inverse association with acylcarnitine C18:2. Moreover, plasma LPC C17:0 concentrations positively correlated with estimated dietary intake of fatty acid C17:0 from the FFQs. The associations between glycerophospholipids and prostate cancer were stronger in case-controls with normal glucose tolerance.

CONCLUSIONS

Several glycerophospholipids were positively associated with risk of overall and aggressive prostate cancer. The strongest association was observed for LPC C17:0. The associations between glycerophospholipids and prostate cancer risk were stronger in case-controls with normal glucose tolerance, suggesting a link between the glucose metabolism status and risk of prostate cancer.

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.

Is Type 2 Diabetes Causally Associated With Cancer Risk? Evidence From a Two-Sample Mendelian Randomization Study

We conducted a two-sample Mendelian randomization study to investigate the causal associations of type 2 diabetes mellitus (T2DM) with risk of overall cancer and 22 site-specific cancers. Summary-level data for cancer were extracted from the Breast Cancer Association Consortium and UK Biobank. Genetic predisposition to T2DM was associated with higher odds of pancreatic, kidney, uterine, and cervical cancer and lower odds of esophageal cancer and melanoma but not associated with 16 other site-specific cancers or overall cancer. The odds ratios (ORs) were 1.13 (95% CI 1.04, 1.22), 1.08 (1.00, 1.17), 1.08 (1.01, 1.15), 1.07 (1.01, 1.15), 0.89 (0.81, 0.98), and 0.93 (0.89, 0.97) for pancreatic, kidney, uterine, cervical, and esophageal cancer and melanoma, respectively. The association between T2DM and pancreatic cancer was also observed in a meta-analysis of this and a previous Mendelian randomization study (OR 1.08; 95% CI 1.02, 1.14; P = 0.009). There was limited evidence supporting causal associations between fasting glucose and cancer. Genetically predicted fasting insulin levels were positively associated with cancers of the uterus, kidney, pancreas, and lung. The current study found causal detrimental effects of T2DM on several cancers. We suggest reinforcing the cancer screening in T2DM patients to enable the early detection of cancer.

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.

Association of type 2 diabetes mellitus and antidiabetic medication with risk of prostate cancer: a population-based case-control study

BACKGROUND

Prostate cancer (PCa) and type 2 diabetes mellitus (T2DM) are prevalent conditions that often occur concomitantly. However, many aspects of the impact of T2DM, particularly the duration of T2DM and antidiabetic medications, on PCa risk are poorly understood.

METHODS

To assess the association of duration of T2DM and antidiabetic medication with PCa risk, we designed a matched case-control study, including 31,415 men with PCa and 154,812 PCa-free men in Prostate Cancer data Base Sweden (PCBaSe) 4.1.

RESULTS

Overall, a decreased risk of PCa was observed for men with T2DM (odds ratio (OR): 0.81, 95% confidence interval (CI): 0.78-0.84), as compared to men without T2DM. The decreased risk of PCa was consistently showed across duration of T2DM. With respect to use of antidiabetic drugs, this inverse association with duration was also found for all medications types, as compared to men without T2DM, including insulin, metformin and sulphonylurea (SU) (e.g. 3- < 5 yr insulin OR:0.69, 95%CI:0.60-0.80; 3- < 5 yr metformin OR: 0.82, 95%CI: 0.74-0.91; 3- < 5 yr SU OR: 0.72, 95%CI: 0.62-0.83). When stratifying by PCa risk categories, this decreased risk was most evident for diagnosis of low and intermediate-risk PCa (low-risk OR: 0.65, 95%CI: 0.66-0.70, intermediate-risk OR: 0.80, 95%CI: 0.75-0.85).

CONCLUSIONS

The study showed an inverse association between pre-existing T2DM and PCa across different durations of T2DM and all types of T2DM medication received. This inverse association was most evident for low- and intermediate-risk PCa, suggesting that whilst T2DM and its medication may protect some men from developing PCa, the relationship warrants further study.

Site-specific cancer risk in patients with type 2 diabetes: a nationwide population-based cohort study in Korea

BACKGROUND/AIMS

We aimed to evaluate site-specific cancer risk in diabetic patients and to investigate causal and temporal relationships by analyzing organ-specific cancer risk according to the duration of diabetes.

METHODS

Using a database provided by the Korean National Health Insurance Service, we conducted a retrospective, population-based cohort study of adults aged ≥ 30 years from January 2005 to December 2013. To verify the possibility of detection bias or reverse causation, we compared hazard ratios (HRs) for each cancer according to the following duration of diabetes: less than 6 months, 6 months to 3 years, and more than 3 years.

RESULTS

The incidence of overall cancer per 1,000 person-years was higher in patients with diabetes than in those without diabetes (20.36 vs. 10.83). The overall cancer risk according to the duration of diabetes was the highest within the first 6 months after diagnosis (HR, 2.03; 95% confidence interval [CI], 1.99 to 2.07), and the HR decreased with the duration of diabetes, ranging from 1.19 (95% CI, 1.18 to 1.21) between 6 months and 3 years to 1.12 (95% CI, 1.11 to 1.13) after 3 years. Both overall cancer risk and HR remained significantly higher in patients with diabetes than in those without diabetes. The risk for prostate cancer was higher in men with diabetes than in those without diabetes (HR, 1.12; 95% CI, 1.10 to 1.14). In women, the risk for endometrial cancer was significantly higher in patients with diabetes than in those without diabetes throughout the duration of diabetes.

CONCLUSION

The risk for stomach, colorectum, liver, pancreas, and kidney cancer appeared to be higher in patients with diabetes than in those without diabetes regardless of the sex or duration of diabetes.