Cancer risk for patients using thiazolidinediones for type 2 diabetes: a meta-analysis

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.

Non-Insulin Antidiabetic Agents and Lung Cancer Risk in Drug-Naive Patients with Type 2 Diabetes Mellitus: A Nationwide Retrospective Cohort Study

Lung cancer (LC) is the second most common cancer and the leading cause of cancer deaths in the U.S. Insulin therapy, a key treatment for managing Type 2 Diabetes Mellitus (T2DM), is associated with increased LC risk. The impact of non-insulin antidiabetic drugs, particularly GLP-1 receptor agonists (GLP-1RAs), on LC risk is not well understood. This study evaluated LC risk in T2DM patients, comparing seven non-insulin antidiabetic agents to insulin. Using the TriNetX Analytics platform, we analyzed the de-identified electronic health records of 1,040,341 T2DM patients treated between 2005 and 2019, excluding those with prior antidiabetic use or LC diagnoses. We calculated hazard ratios and confidence intervals for LC risk and used propensity score matching to control for confounding factors. All non-insulin antidiabetic drugs, except alpha-glucosidase inhibitors, were associated with significantly reduced LC risk compared to insulin, with GLP-1RAs showing the greatest reduction (HR: 0.49, 95% CI: 0.41, 0.59). GLP-1RAs were consistently associated with lowered LC risk across all histological types, races, genders, and smoking statuses. These findings suggest that non-insulin antidiabetic drugs, particularly GLP-1RAs, may be preferable for managing T2DM while reducing LC risk.

Cancer biology in diabetes update: Focusing on antidiabetic drugs

The association of type 2 diabetes with certain cancer risk has been of great interest for years. However, the effect of diabetic medications on cancer development is not fully understood. Prospective clinical trials have not elucidated the long-term influence of hypoglycemic drugs on cancer incidence and the safety for cancer-bearing patients with diabetes, whereas numerous preclinical studies have shown that antidiabetic drugs could have an impact on carcinogenesis processes beyond the glycemic control effect. Because there is no evidence of the safety profile of antidiabetic agents on cancer biology, careful consideration would be required when prescribing any medicines to patients with diabetes and existing tumor. In this review, we discuss the potential influence of each diabetes therapy in cancer 'initiation', 'promotion' and 'progression'.

Association of glucose-lowering drug target and risk of gastrointestinal cancer: a mendelian randomization study

BACKGROUND & AIMS

Glucose-lowering drug is associated with various cancers, but the causality with gastrointestinal cancer risk is rarely reported. We aimed to explore the causality between them in this Mendelian randomization (MR) study.

METHODS

Two-sample MR, summary-data-based (SMR), mediation MR, and colocalization analyses was employed. Ten glucose-lowering drug targets (PPARG, DPP4, GLP1R, INSR, SLC5A2, ABCC8, KCNJ11, ETFDH, GPD2, PRKAB1) and seven types of gastrointestinal cancer (anal carcinoma, cardia cancer, gastric cancer, hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC), pancreatic cancer, rectum cancer) were included. Patients with gastrointestinal cancers from six different large GWAS databases, including the UK Biobank and Finnish cohorts were incorporated, for discovery and external validation. Meta-analysis was employed to integrate the results from both discovery and validation cohorts, thereby ensuring the reliability of findings.

RESULTS

ABCC8/KCNJ11 were associated with pancreatic cancer risk in both two-sample MR (odds ratio (OR): 15.058, per standard deviation unit (SD) change of glucose-lowering durg target perturbation equivalent to 1 SD unit of HbA1c lowering; 95% confidence interval (95% CI): 3.824-59.295; P-value = 0.0001) and SMR (OR: 1.142; 95% CI: 1.013-1.287; P-value = 0.030) analyses. The mediation effect of body mass index (OR: 0.938; 95% CI: 0.884-0.995; proportion of mediation effect: 3.001%; P-value = 0.033) on ABCC8/KCNJ11 and pancreatic cancer was uncovered. Strong connections of DPP4 with anal carcinoma (OR: 0.123; 95% CI: 0.020-0.745; P-value = 0.023) and ICC (OR: 7.733; 95% CI: 1.743-34.310; P-value = 0.007) were detected. PPARG was associated with anal carcinoma (OR: 12.909; 95% CI: 3.217-51.795; P-value = 0.0003), HCC (OR: 36.507; 95% CI: 8.929-149.259; P-value < 0.0001), and pancreatic cancer (OR: 0.110; 95% CI: 0.071-0.172; P-value < 0.0001). SLC5A2 was connected with pancreatic cancer (OR: 8.096; 95% CI: 3.476-18.857; P-value < 0.0001). Weak evidence indicated the connections of GLP1R, GPD2, and PRKAB1 with anal carcinoma, cardia cancer, ICC, and rectum cancer. In addition, the corresponding results were consistently validated in both the validation cohorts and the integrated outcomes.

CONCLUSIONS

Some glucose-lowering drugs were associated with gastrointestinal cancer risk, which might provide new ideas for gastrointestinal cancer treatment.

Insulin Resistance: The Increased Risk of Cancers

Insulin resistance, also known as impaired insulin sensitivity, is the result of a decreased reaction of insulin signaling to blood glucose levels. This state is observed when muscle cells, adipose tissue, and liver cells, improperly respond to a particular concentration of insulin. Insulin resistance and related increased plasma insulin levels (hyperinsulinemia) may cause metabolic impairments, which are pathological states observed in obesity and type 2 diabetes mellitus. Observations of cancer patients confirm that hyperinsulinemia is a major factor influencing obesity, type 2 diabetes, and cancer. Obesity and diabetes have been reported as risks of the initiation, progression, and metastasis of several cancers. However, both of the aforementioned pathologies may independently and additionally increase the cancer risk. The state of metabolic disorders observed in cancer patients is associated with poor outcomes of cancer treatment. For example, patients suffering from metabolic disorders have higher cancer recurrence rates and their overall survival is reduced. In these associations between insulin resistance and cancer risk, an overview of the various pathogenic mechanisms that play a role in the development of cancer is discussed.

Obesity, obesities and gastrointestinal cancers

Obesity has been recognized to be increasing globally and is designated a disease with adverse consequences requiring early detection and appropriate care. In addition to being related to metabolic syndrome disorders such as type 2 diabetes, hypertension, stroke, and premature coronary artery disease. Obesity is also etiologically linked to several cancers. The non-gastrointestinal cancers are breast, uterus, kidneys, ovaries, thyroid, meningioma, and thyroid. Gastrointestinal (GI) cancers are adenocarcinoma of the esophagus, liver, pancreas, gallbladder, and colorectal. The brighter side of the problem is that being overweight and obese and cigarette smoking are mostly preventable causes of cancers. Epidemiology and clinical studies have revealed that obesity is heterogeneous in clinical manifestations. In clinical practice, BMI is calculated by dividing a person's weight in kilograms by the square of the person's height in square meters (kg/m2). A BMI above 30 kg/m2 (defining obesity in many guidelines) is considered obesity. However, obesity is heterogeneous. There are subdivisions for obesity, and not all obesities are equally pathogenic. Adipose tissue, in particular, visceral adipose tissue (VAT), is endocrine and abdominal obesity (a surrogate for VAT) is evaluated by waist-hip measurements or just waist measures. Visceral Obesity, through several hormonal mechanisms, induces a low-grade chronic inflammatory state, insulin resistance, components of metabolic syndrome, and cancers. Metabolically obese, normal-weight (MONW) individuals in several Asian countries may have BMI below normal levels to diagnose obesity but suffer from many obesity-related complications. Conversely, some people have high BMI but are generally healthy with no features of metabolic syndrome. Many clinicians advise weight loss by dieting and exercise to metabolically healthy obese with large body habitus than to individuals with metabolic obesity but normal BMI. The GI cancers (esophagus, pancreas, gallbladder, liver, and colorectal) are individually discussed, emphasizing the incidence, possible pathogenesis, and preventive measures. From 2005 to 2014, most cancers associated with overweight and Obesity increased in the United States, while cancers related to other factors decreased. The standard recommendation is to offer or refer adults with a body mass index (BMI) of 30 or more to intensive, multicomponent behavioral interventions. However, the clinicians have to go beyond. They should critically evaluate BMI with due consideration for ethnicity, body habitus, and other factors that influence the type of obesity and obesity-related risks. In 2001, the Surgeon General's ``Call to Action to Prevent and Decrease Overweight and Obesity'' identified obesity as a critical public health priority for the United States. At government levels reducing obesity requires policy changes that improve the food and physical activity for all. However, implementing some policies with the most significant potential benefit to public health is politically tricky. The primary care physician, as well as subspecialists, should identify overweight and Obesity based on all the variable factors in the diagnosis. The medical community should address the prevention of overweight and Obesity as an essential part of medical care as much as vaccination in preventing infectious diseases at all levels- from childhood, to adolescence, and adults.

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.

Diabetes medications and cancer risk associations: a systematic review and meta-analysis of evidence over the past 10 years

Diabetes medications may modify the risk of certain cancers. We systematically searched MEDLINE, Embase, Web of Science, and Cochrane CENTRAL from 2011 to March 2021 for studies evaluating associations between diabetes medications and the risk of breast, lung, colorectal, prostate, liver, and pancreatic cancers. A total of 92 studies (3 randomized controlled trials, 64 cohort studies, and 25 case-control studies) were identified in the systematic review, involving 171 million participants. Inverse relationships with colorectal (n = 18; RR = 0.85; 95% CI = 0.78-0.92) and liver cancers (n = 10; RR = 0.55; 95% CI = 0.46-0.66) were observed in biguanide users. Thiazolidinediones were associated with lower risks of breast (n = 6; RR = 0.87; 95% CI = 0.80-0.95), lung (n = 6; RR = 0.77; 95% CI = 0.61-0.96) and liver (n = 8; RR = 0.83; 95% CI = 0.72-0.95) cancers. Insulins were negatively associated with breast (n = 15; RR = 0.90; 95% CI = 0.82-0.98) and prostate cancer risks (n = 7; RR = 0.74; 95% CI = 0.56-0.98). Positive associations were found between insulin secretagogues and pancreatic cancer (n = 5; RR = 1.26; 95% CI = 1.01-1.57), and between insulins and liver (n = 7; RR = 1.74; 95% CI = 1.08-2.80) and pancreatic cancers (n = 8; RR = 2.41; 95% CI = 1.08-5.36). Overall, biguanide and thiazolidinedione use carried no risk, or potentially lower risk of some cancers, while insulin secretagogue and insulin use were associated with increased pancreatic cancer risk.

Pioglitazone and Prostate Cancer Risk in Taiwanese Male Patients with Type 2 Diabetes: A Retrospective Cohort Study

PURPOSE

This study investigated prostate cancer risk associated with pioglitazone use.

MATERIALS AND METHODS

The Taiwan's National Health Insurance database was used to create a propensity score-matched cohort of male patients with type 2 diabetes mellitus newly diagnosed in 1999-2005 and aged ≥25 years at baseline. The matched cohort included 20437 ever users and 20437 never users of pioglitazone. The patients were followed up for the incidence of prostate cancer until December 31, 2011. Hazard ratios (HRs) were created from Cox regression weighted on propensity score.

RESULTS

Prostate cancer was diagnosed in 121 ever users of pioglitazone (incidence: 175.84 per 100,000 person-years) and 143 never users of pioglitazone (incidence: 216.66 per 100,000 person-years). When ever users were compared to never users of pioglitazone, the HR was 0.815 (95% confidence interval [CI], 0.639-1.039; p=0.0987). When ever users were categorized into tertiles of cumulative duration of pioglitazone therapy (<6.83, 6.83-20.23, and >20.23 months), the HRs were 1.044 (95% CI, 0.741-1.471), 0.975 (95% CI, 0.690-1.377) and 0.539 (95% CI, 0.374-0.778), respectively. For the tertiles of cumulative dose of <5,040, 5,040-15,330, and >15,330 mg, the HRs were 1.008 (95% CI, 0.710-1.429), 1.090 (95% CI, 0.785-1.515) and 0.484 (95% CI, 0.330-0.711), respectively. A significantly lower risk associated with pioglitazone use could only be seen in patients aged <65 years (HR, 0.578; 95% CI, 0.360-0.927) but not in patients aged ≥65 years.

CONCLUSIONS

A significantly lower risk of prostate cancer is observed after a cumulative duration of pioglitazone therapy for >20.23 months or a cumulative dose of >15,330 mg. The risk reduction is mainly observed in patients aged <65 years.

Obesity, diabetes mellitus, and pancreatic carcinogenesis: Correlations, prevention, and diagnostic implications

The prevalence of obesity, diabetes mellitus (DM), and pancreatic cancer (PC) has been consistently increasing in the last two decades worldwide. Sharing various influential risk factors in genetics and environmental inducers in pathogenesis, the close correlations of these three diseases have been demonstrated in plenty of clinical studies using multiple parameters among different populations. On the contrary, most measures aimed to manage and treat obesity and DM effectively reduce the risk and prevent PC occurrence, yet certain drugs can inversely promote pancreatic carcinogenesis instead. Most importantly, an elevation of blood glucose with or without a reduction in body weight, along with other potential tools, may provide valuable clues for detecting PC at an early stage in patients with obesity and DM, favoring a timely intervention and prolonging survival. Herein, the epidemiological and etiological correlations among these three diseases and the supporting clinical evidence of their connections are first summarized to favor a better and more thorough understanding of obesity- and DM-related pancreatic carcinogenesis. After comparing the distinct impacts of different weight-lowering and anti-diabetic treatments on the risk of PC, the possible diagnostic implications of hyperglycemia and weight loss in PC screening are also addressed in detail.

Use of Antihyperglycemic Drugs and Risk of Cancer in Patients with Diabetes

PURPOSE OF REVIEW

Diabetes is associated with an increased risk for several types of cancer. Therefore, use of antihyperglycemic medications to lower blood glucose may modify cancer risk. Here we review available data on the link between the most common classes of antihyperglycemic agents and cancer risk among patients with diabetes.

RECENT FINDINGS

A database search was conducted between February 2022 and June 2022 on PubMed and Embase for systematic reviews and meta-analyses investigating the association between antihyperglycemic agents and risk of cancer. Use of biguanides such as metformin is associated with 20-30% lower risk for all cancer incidence, and somewhat greater benefit for cancer-related mortality. Alpha-glucosidase inhibitors, e.g., acarbose, have not been consistently associated with cancer. Similarly, no consistent effects have been reported for thiazolidinediones, but the relationship with cancer seems to depend on the type of drug, dose, and duration of treatment. Exposure to various types of incretin-based therapies (glucagon-like peptide-1 agonists and dipeptidyl peptidase-4 inhibitors) has not been found to significantly modify cancer risk. Inhibitors of sodium glucose cotransporter-2 may raise risk for bladder cancer and reduce risk for gastrointestinal cancer. Use of insulin and insulin analogs is associated with a significant increase in total cancer risk by almost 50% compared to other antihyperglycemic drugs. Likewise, insulin secretagogues like sulfonylureas have generally been linked to greater risk for cancer by ~ 20%, although these associations may be agent-specific and dose-dependent. Current evidence suggests that the risk of cancer associated with the use of antihyperglycemic medications among patients with diabetes depends on the class of drug and type of agent, dosage, and duration of treatment. More research is needed to delineate the mechanisms by which these agents affect the process of carcinogenesis.

Pioglitazone, Bladder Cancer and the Presumption of Innocence

BACKGROUND

Thiazolidinediones are potent exogenous agonists of PPAR-γ, which augment the effects of insulin to its cellular targets and mainly at the level of adipose tissue. Pioglitazone, the main thiazolidinedione in clinical practice, has shown cardiovascular and renal benefits in patients with type 2 diabetes, durable reduction of glycated hemoglobulin levels, important improvements of several components of the metabolic syndrome and beneficial effects of non-alcoholic fatty liver disease.

OBJECTIVE

Despite all of its established advantages, the controversy for an increased risk of developing bladder cancer, combined with the advent of newer drug classes that achieved major cardiorenal effects have significantly limited its use spreading a persistent shadow of doubt for its future role.

METHODS

Pubmed, Google and Scope databases have been thoroughly searched and relevant studies were selected.

RESULTS

This paper explores thoroughly both in vitro and in vivo (animal models and humans) studies that investigated the possible association of pioglitazone with bladder cancer.

CONCLUSION

Currently the association of pioglitazone with bladder cancer cannot be based on solid evidence. This evidence cannot justify its low clinical administration, especially in the present era of individualised treatment strategies. Definite clarification of this issue is imperative and urgently anticipated from future high quality and rigorous pharmacoepidemiologic research, keeping in mind its unique mechanism of action and its significant pleiotropic effects.

Obesity, metabolic syndrome, and cancer: pathophysiological and therapeutic associations

Overweight, obesity, and metabolic syndrome (MetS) have become epidemic conditions affecting 39%, 13%, and 20% of the population respectively. The aim of this article is to review the literature on the association of obesity and MetS with the risk of cancer. We also explore the effect of lifestyle modifications, such as diet, physical activity, and antidiabetic medications, on cancer incidence. Increased body mass index (BMI) has been associated with a multitude of site-specific cancers, reaching relative risk (RR) 1.54 [95% confidence interval (CI) 1.47-1.61] per 5 unit increase for endometrial cancer, as well as with overall cancer risk (RR 1.03, 95% CI 1.02-1.05). Central adiposity measured by waist circumference or waist-to-hip ratio has been suggested as a stronger predictor than BMI for several cancers, such as colorectal cancer. Metabolic Syndrome has been consistently and positively associated with the risk of very common cancers like colorectal (RR 1.34, 95% CI 1.24-1.44), endometrial (RR 1.62, 95% CI 1.26-2.07) and postmenopausal breast cancer (RR 2.01, 95% CI 1.55-2.60). Hyperglycemia and subsequently T2DM have been also shown to increase the risk of cancer. Nevertheless, these risk factors are modifiable and therefore implementing lifestyle modifications could prevent an important number of cancer cases. Adherence to cancer prevention guidelines, including maintaining a healthy weight, having regular physical exercise (RR 0.58-0.90 for different cite specific cancers) and following a healthy dietary pattern (RR 0.74-0.94 for different cite specific cancers) have a protective effect on the risk of cancer. The strength of this review is the presentation of the best evidence, as the data derive mainly from meta-analyses. Public health policies should focus on the modification of risk factors and future research is needed to reveal the pathophysiological links between these risk factors and cancer to develop more efficient prevention and treatment strategies.

Adapting Medication for Type 2 Diabetes to a Low Carbohydrate Diet

Healthcare professionals in the primary care setting need to be competent to safely adapt diabetes medications when patients with Type 2 Diabetes (T2D) alter their diet. Safe prescribing practice is supported through an understanding of the clinical evidence, basic science, and pharmacology of medications. This review article supports clinicians in the practical application of this knowledge to achieve safe practice. Traditional medical training and clinical practice for chronic disease has long revolved around the teaching of intensifying therapy and evidenced based prescribing, a crucial skill when chronic disease progresses. Now that we are witnessing remission of Type 2 Diabetes through nutritional interventions specifically low carbohydrate diets (LCD) we must apply the same effort and thought to de-prescribing as the underlying metabolic condition improves. There is minimal guidance in the literature on how to actively de-prescribe. The American Diabetes Association in their Standards of Medical Care in Diabetes–2021 acknowledges low carbohydrate nutritional therapy (LCD) as a viable option in the management of Type 2 Diabetes (T2D). Thus, the goal of our paper is to help close the gap between the clinical evidence, basic science, and pharmacology of T2D medications to the practical application and teamwork needed to facilitate safe medication reduction in the primary care setting when applied to a LCD. The LCD is an increasingly popular and effective option for managing T2D and can lead to an improvement in the condition, reduced medication burden, and contribute to significant weight loss. Safe initiation of a LCD in patients on medications requires significant monitoring and medication adjustments to decrease and eliminate the risk of hypoglycemia and hypotension. The health care team including clinicians in primary care, nursing, pharmacy and nutrition need to be competent in adjusting diabetes and antihypertensive medications to achieve safe and effective care. The most immediate and important adjustments are to insulin, sulfonylureas, SGLT2 inhibitors, blood pressure medications and diuretics. Interdisciplinary care teams can individualize therapy while following the guidance, which includes monitoring blood glucose and blood pressure closely, decreasing medications that can cause hypoglycaemia and hypotension, evaluating blood glucose and blood pressure data responses regularly, and open access communication with the team. The article is an international consensus document on de-prescribing that was put together by a multidisciplinary team of clinicians.

Diabetes and pancreatic cancer: Exploring the two-way traffic

Pancreatic cancer (PC) is often associated with a poor prognosis. Long-standing diabetes mellitus is considered as an important risk factor for its development. This risk can be modified by the use of certain antidiabetic medications. On the other hand, new-onset diabetes can signal towards an underlying PC in the elderly population. Recently, several attempts have been made to develop an effective clinical tool for PC screening using a combination of history of new-onset diabetes and several other clinical and biochemical markers. On the contrary, diabetes affects the survival after treatment for PC. We describe this intimate and complex two-way relationship of diabetes and PC in this review by exploring the underlying pathogenesis.

Thiazolidinediones, alpha-glucosidase inhibitors, meglitinides, sulfonylureas, and hepatocellular carcinoma risk: A meta-analysis

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related death worldwide. Effects of second-line oral antidiabetic medications on incident HCC risk in individuals with type 2 diabetes mellitus remain unclear. This study evaluated associations between sulfonylureas, thiazolidinediones, meglitinides and alpha-glucosidase inhibitors, and incident HCC risk.

METHODS

We systematically reviewed all studies on PubMed, Embase and Web of Science databases. Studies were included if they documented: (1) exposure to oral antidiabetic medication classes; (2) HCC incidence; (3) relative risks/odds ratios (OR) for HCC incidence. Eight eligible observational studies were identified. We performed random-effects meta-analyses to calculate pooled adjusted ORs (aORs) and 95% confidence intervals (CI).

RESULTS

Thiazolidinedione use (7 studies, 280,567 participants, 19,242 HCC cases) was associated with reduced HCC risk (aOR = 0.92, 95% CI = 0.86-0.97, I² = 43%), including among Asian subjects (aOR = 0.90, 95% CI = 0.83-0.97), but not Western subjects (aOR = 0.95, 95% CI = 0.87-1.04). Alpha-glucosidase inhibitor use (3 studies, 56,791 participants, 11,069 HCC cases) was associated with increased HCC incidence (aOR = 1.08; 95% CI = 1.02-1.14, I² = 21%). Sulfonylurea use (8 studies, 281,180 participants, 19,466 HCC cases) was associated with increased HCC risk in studies including patients with established liver disease (aOR = 1.06, 95% CI = 1.02-1.11, I² = 75%). Meglitinide use (4 studies, 58,237 participants, 11,310 HCC cases) was not associated with HCC incidence (aOR = 1.19; 95% CI = 0.89-1.60, I² = 72%).

CONCLUSIONS

Thiazolidinedione use was associated with reduced HCC incidence in Asian individuals with diabetes. Alpha-glucosidase inhibitor or sulfonylurea use was associated with modestly increased HCC risk; future research should determine whether those agents should be avoided in patients with chronic liver disease.

Targeting nutrient metabolism with FDA-approved drugs for cancer chemoprevention: Drugs and mechanisms

Proliferating cancer cells exhibit metabolic alterations and specific nutritional needs for adapting to their rapid growth. These changes include using aerobic glycolysis, lipid metabolic disorder, and irregular protein degradation. It may be useful to target metabolic abnormalities for cancer chemoprevention. Epidemiological and mechanism-related studies have indicated that many FDA-approved anti-metabolic drugs decrease tumor risk, inhibit tumor growth, or enhance the effect of chemotherapeutic drugs. Drugs targeting nutrient metabolism have fewer side effects with long-term use compared to chemotherapeutic drugs. The characteristics of these drugs make them promising candidates for cancer chemoprevention. Here, we summarize recent discoveries of the chemo-preventive effects of drugs targeting nutrient metabolic pathways and discuss future applications and challenges. Understanding the effects and mechanisms of anti-metabolic drugs in cancer has important implications for exploring strategies for cancer chemoprevention.

Glycemic control and the incidence of neoplasm in patients with type 2 diabetes: a meta-analysis of randomized controlled trials

PURPOSE

Previous epidemiologic studies indicate an increased risk of cancer and cancer mortality in patients with type 2 diabetes (T2D). Whether the resolution of hyperglycemia will lead to reduced risk of neoplasm in T2D remains uncertain. Therefore, we performed a meta-analysis to assess the association between glycemic control and incidence of neoplasm in T2D patients.

METHODS

Randomized controlled trials (RCTs) in T2D with significant HbA1c reduction difference between intensive/active and standard/control groups plus follow-up ≥48 weeks were included and analyzed by fixed-effect models, random-effect model, and meta-regression analysis accordingly.

RESULTS

Overall, 52 studies were included. Compared with standard/control treatment, intensive/active treatment led to significantly greater HbA1c reduction from baseline (WMD = -0.51%, 95% CI, -0.55 to -0.46%, P < 0.001), but was not associated with a decreased incidence of neoplasm (OR = 0.99, 95% CI, 0.94-1.03, I² = 2%) in T2D. Meta-regression analysis indicated that HbA1c reduction difference between intensive/active treatment and standard/control treatment was not associated with the incidence of neoplasm in T2D patients (β = -0.0011, 95% CI, -0.0058 to 0.0035, P = 0.625). In neoplasm-site subgroup analysis, a decreased incidence of breast neoplasm was observed in T2D patients using dipeptidyl-peptidase-4 inhibitor (OR = 0.56, 95% CI, 0.35-0.89, I² = 0%) and incidence of prostate neoplasm was reduced in T2D patients with glucagon-like peptide-1 receptor agonist treatment (OR = 0.66, 95% CI, 0.47-0.91, I² = 0%).

CONCLUSION

Improved glycemic control in short and medium periods achieved by existing glucose-lowering drugs or strategies may not confer reduced risk of neoplasm in patients with T2D. Studies with longer follow-up duration are needed to better elucidate the long-period effects.

Metformin Mitigates DPP-4 Inhibitor-Induced Breast Cancer Metastasis via Suppression of mTOR Signaling

The biological influence of antidiabetic drugs on cancer cells and diabetic cancer patients has not yet been completely elucidated. We reported that a dipeptidyl peptidase (DPP)-4 inhibitor accelerates mammary cancer metastasis by inducing epithelial-mesenchymal transition (EMT) through the CXCL12/CXCR4/mTOR axis. Metformin has been shown to inhibit the mTOR signaling pathway. In this study, we investigated whether metformin mitigates breast cancer metastasis induced by a DPP-4 inhibitor via suppression of mTOR signaling. In cultured mouse mammary and human breast cancer cells, metformin suppressed DPP-4 inhibitor KR62436 (KR)-induced EMT and cell migration via suppression of the mTOR pathway associated with AMPK activation. For the in vivo study, metformin intervention was performed in an allograft 4T1 breast cancer model mouse with or without KR. We also analyzed mice transplanted with shRNA-mediated DPP-4 knockdown 4T1 cells. Treatment with metformin inhibited the lung metastasis of DPP-4-deficient 4T1 mammary tumor cells generated by either KR administration or DPP-4 knockdown. Immunostaining of primary tumors indicated that DPP-4 suppression promoted the expression of EMT-inducing transcription factor Snail through activation of the CXCR4-mediated mTOR/p70S6K pathway in an allograft breast cancer model; metformin abolished this alteration. Metformin treatment did not alter DPP-4-deficiency-induced expression of CXCL12 in either plasma or primary tumors. Our findings suggest that metformin may serve as an antimetastatic agent by mitigating the undesirable effects of DPP-4 inhibitors in patients with certain cancers. IMPLICATIONS: Metformin could combat the detrimental effects of DPP-4 inhibitor on breast cancer metastasis via mTOR suppression, suggesting the potential clinical relevance. VISUAL OVERVIEW: http://mcr.aacrjournals.org/content/molcanres/19/1/61/F1.large.jpg.

Pleiotropic effects of anti-diabetic drugs: A comprehensive review

Diabetes mellitus characterized by hyperglycaemia presents an array of comorbidities such as cardiovascular and renal failure, dyslipidemia, and cognitive impairments. Populations above the age of 60 are in an urgent need of effective therapies to deal with the complications associated with diabetes mellitus. Widely used anti-diabetic drugs have good safety profiles and multiple reports indicate their pleiotropic effects in diabetic patients or models. This review has been written with the objective of identifying the widely-marketed anti-diabetic drugs which can be efficiently repurposed for the treatment of other diseases or disorders. It is an updated, comprehensive review, describing the protective role of various classes of anti-diabetic drugs in mitigating the macro and micro vascular complications of diabetes mellitus, and differentiating these drugs on the basis of their mode of action. Notably, metformin, the anti-diabetic drug most commonly explored for cancer therapy, has also exhibited some antimicrobial effects. Unlike class specific effects, few instances of drug specific effects in managing cardiovascular complications have also been reported. A major drawback is that the pleiotropic effects of anti-diabetic drugs have been mostly investigated only in diabetic patients. Thus, for effective repurposing, more clinical trials devoted to analyse the effects of anti-diabetic drugs in patients irrespective of their diabetic condition, are required.

Review of Associations Between Type 2 Diabetes and Cancer

Debate is ongoing regarding the relationship between type 2 diabetes and cancer, and the pathways linking the two are incompletely understood. Some posit that the relationship hinges on a common predisposing factor such as obesity, insulin resistance, or chronic inflammation that increases the risk of cancer independently. Others speculate that diabetes acts as an independent risk factor for cancer because of other molecular pathways and interactions. Additionally, antidiabetic medications have been associated with changes in cancer risk. This review presents a summary of the latest studies and data concerning the relationships among type 2 diabetes, antidiabetic medications, cancer risk, and cancer prognosis.

Implications of the Adiponectin System in Non-Small Cell Lung Cancer Patients: A Case-Control Study

Alterations of adipose tissue occurring in obesity have been recognized as a major risk factor for several cancers. The relationship between adipose tissue and lung cancer, which is the main cancer-related cause of death worldwide, still requires investigation. Perturbations in the adipokine system are likely to interfere with inter-organ crosstalk in lung cancer, which may influence the lung tumor microenvironment. Adiponectin (Acrp30) expression is deregulated in several cancer types. Acrp30 circulates as oligomers with a Low (LMW), Medium (MMW), and High Molecular Weight (HMW), with the latter mediating the main biological effects. Acrp30 acts through AdipoR1 and AdipoR2 receptors. T-cadherin has been described as a non-signaling receptor. This study's aim was to investigate the regulation of serum Acrp30 and its receptors in sample tissue from non-small cell lung cancer (NSCLC) patients. We recruited 72 NSCLC patients and 60 healthy controls, whom we evaluated in terms of their Acpr30 levels and oligomeric profile. In addition, the expression of AdipoRs in tissues from lung cancer specimens was also measured and compared to coupled healthy lung samples. Our findings show a significant reduction of total Acrp30 levels in NSCLC patients compared to normal subjects, with a specific down-regulation of HMW oligomers. Acrp30 expression was lower in lung adenocarcinoma than other subtypes, regardless of other factors. A significantly higher expression of AdipoR1 was observed, while no differences in R2 and a lower expression of T-cadherin were found in lung cancer specimens compared to normal healthy lung tissues. Involvement of the Acrp30 system in lung cancer may provide new insight into the interaction between adipose tissue and lung and sheds light on its potential ability to influence the lung tumor microenvironment.

Cancer Biology and Prevention in Diabetes

The available evidence suggests a complex relationship between diabetes and cancer. Epidemiological data suggest a positive correlation, however, in certain types of cancer, a more complex picture emerges, such as in some site-specific cancers being specific to type I diabetes but not to type II diabetes. Reports share common and differential mechanisms which affect the relationship between diabetes and cancer. We discuss the use of antidiabetic drugs in a wide range of cancer therapy and cancer therapeutics in the development of hyperglycemia, especially antineoplastic drugs which often induce hyperglycemia by targeting insulin/IGF-1 signaling. Similarly, dipeptidyl peptidase 4 (DPP-4), a well-known target in type II diabetes mellitus, has differential effects on cancer types. Past studies suggest a protective role of DPP-4 inhibitors, but recent studies show that DPP-4 inhibition induces cancer metastasis. Moreover, molecular pathological mechanisms of cancer in diabetes are currently largely unclear. The cancer-causing mechanisms in diabetes have been shown to be complex, including excessive ROS-formation, destruction of essential biomolecules, chronic inflammation, and impaired healing phenomena, collectively leading to carcinogenesis in diabetic conditions. Diabetes-associated epithelial-to-mesenchymal transition (EMT) and endothelial-to-mesenchymal transition (EndMT) contribute to cancer-associated fibroblast (CAF) formation in tumors, allowing the epithelium and endothelium to enable tumor cell extravasation. In this review, we discuss the risk of cancer associated with anti-diabetic therapies, including DPP-4 inhibitors and SGLT2 inhibitors, and the role of catechol-o-methyltransferase (COMT), AMPK, and cell-specific glucocorticoid receptors in cancer biology. We explore possible mechanistic links between diabetes and cancer biology and discuss new therapeutic approaches.

Assessing the Current State of Lung Cancer Chemoprevention: A Comprehensive Overview

Chemoprevention of lung cancer is thought to significantly reduce the risk of acquiring these conditions in the subpopulation of patients with underlying health issues, such as chronic obstructive pulmonary disorder and smoking-associated lung problems. Many strategies have been tested in the previous decades, with very few translating to successful clinical trials in specific subpopulations of patients. In this review, we analyze these strategies, as well as new approaches that have emerged throughout the last few years, including synthetic lethality concept and microbiome-induced regulation of lung carcinogenesis. Overall, the continuous effort in the area of lung chemoprevention is required to develop practical therapeutical approaches. Given the inconsistency of results obtained in clinical trials targeting lung cancer chemoprevention in various subgroups of patients that differ in the underlying health condition, race, and gender, we believe that individualized approaches will have more promise than generalized treatments.

Repurposing of drugs: An attractive pharmacological strategy for cancer therapeutics

Human malignancies are one of the major health-related issues though out the world and anticipated to rise in the future. The development of novel drugs/agents requires a huge amount of cost and time that represents a major challenge for drug discovery. In the last three decades, the number of FDA approved drugs has dropped down and this led to increasing interest in drug reposition or repurposing. The present review focuses on recent concepts and therapeutic opportunities for the utilization of antidiabetics, antibiotics, antifungal, anti-inflammatory, antipsychotic, PDE inhibitors and estrogen receptor antagonist, Antabuse, antiparasitic and cardiovascular agents/drugs as an alternative approach against human malignancies. The repurposing of approved non-cancerous drugs is an effective strategy to develop new therapeutic options for the treatment of cancer patients at an affordable cost in clinics. In the current scenario, most of the countries throughout the globe are unable to meet the medical needs of cancer patients because of the high cost of the available cancerous drugs. Some of these drugs displayed potential anti-cancer activity in preclinic and clinical studies by regulating several key molecular mechanisms and oncogenic pathways in human malignancies. The emerging pieces of evidence indicate that repurposing of drugs is crucial to the faster and cheaper discovery of anti-cancerous drugs.

Association of hepatocellular carcinoma with thiazolidinediones use: A population-based case-control study

The study aimed to investigate the association between the risk of hepatocellular carcinoma and thiazolidinediones use among type 2 diabetic patients who had risk factors for hepatocellular carcinoma.A population-based case-control study was performed using the database of the Taiwan National Health Insurance Program. The cases consisted of 23580 type 2 diabetic subjects aged 20 to 84 years with newly diagnosed hepatocellular carcinoma between 2000 and 2011. The sex- and age-matched controls consisted of 23580 randomly selected type 2 diabetic subjects without hepatocellular carcinoma between 2000 and 2011. Ever use of thiazolidinediones was defined as subjects who had at least 1 prescription of thiazolidinediones before the index date. Never use of thiazolidinediones was defined as subjects who did not have a prescription of thiazolidinediones before the index date. The odds ratio and 95% confidence interval for the association between hepatocellular carcinoma and cumulative duration of thiazolidinediones use was measured by a multivariable logistic regression model.Among subjects with any 1 of the comorbidities including alcohol-related disease, cirrhosis, hepatitis B infection, hepatitis C infection, and other chronic hepatitis, a multivariable logistic regression model demonstrated that there was a negative association between hepatocellular carcinoma and every 1-year increase of cumulative duration of thiazolidinediones use (adjusted odds ratio 0.94, 95% confidence interval 0.92-0.97).There was a negative association in a duration-dependent manner between the risk of hepatocellular carcinoma and thiazolidinediones use among type 2 diabetic patients who had risk factors for hepatocellular carcinoma.

The Body Weight Alteration and Incidence of Neoplasm in Patients With Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Whether hypoglycemic treatments with weight-alternating effects influence the incidence of neoplasm in type 2 diasbetes (T2D) remains uncertain. Therefore, we performed a meta-analysis to assess the association between the weight alteration and incidence of neoplasm in patients with T2D.

RESEARCH DESIGN AND METHODS

Systematic searches were conducted for studies published between the inception of 1950s and September 2019. Randomized controlled trials conducted in T2D patients with at least 48-week follow-up, significant weight change difference between treatment arms and reports of neoplasm events were included. Fixed-effects model and meta-regression analysis were accordingly used.

RESULTS

In all, 46 studies were included. Analysis indicated weight reduction was not associated with a decreased incidence of neoplasm (OR = 1.01, 95% CI, 0.96 to 1.07, I² = 17%) and weight elevation was not associated with an increased incidence of neoplasm (OR = 0.91, 95% CI, 0.76 to 1.09, I² = 0%). Meta-regression analysis showed a slower weight reduction rate (β = -5.983, 95% CI, -11.412 to 0.553, P = 0.03) instead of weight change difference (β = -0.030, 95% CI, -0.068 to 0.007, P = 0.115) was significantly associated with reduced risk of neoplasm in patients with T2D. Moreover, a decreased incidence of prostate, bladder, and uterine neoplasm was observed in T2D patients with weight reduction difference while an increased incidence of thyroid neoplasm was found in glucagon-like peptide-1 receptor analog (GLP-1RA) users with weight reduction difference.

CONCLUSIONS

Additional weight change achieved by current hypoglycemic agents or strategies in short and medium periods was not associated with incidence of most neoplasm in patients with T2D. However, a decreased incidence of prostate, bladder, and uterine neoplasm was shown in T2D patients with weight reduction difference while an increased risk of thyroid neoplasm was observed in T2D patients on GLP-1RA treatments with weight reduction difference. A more sustained and persistent weight reduction process may confer reduced risk of neoplasm in patients with T2D.

Association between colorectal cancer and thiazolidinediones administration in a case-control study

OBJECTIVES

This study was designed to assess whether there was an association between colorectal cancer and thiazolidinediones use.

METHODS

A population-based case-control study was performed using the database of the Taiwan National Health Insurance Program. The case group consisted of 20218 type 2 diabetic subjects aged 20 to 84 years with newly diagnosed colorectal cancer between 2000 and 2011. The date of a subject being diagnosed with colorectal cancer was defined as the index date. The control group consisted of 20218 randomly selected type 2 diabetic subjects aged 20 to 84 years without colorectal cancer between 2000 and 2011. A subject who had at least a prescription of thiazolidinediones before the index date was defined as "ever used". A subject who did not have a prescription of thiazolidinediones before the index date was defined as "never used". The odds ratio (OR) and 95% confidence interval (CI) was used to estimate the association between colorectal cancer and thiazolidinediones use by the multivariable logistic regression model.

RESULTS

After adjustment for potential confounders, the odds of thiazolidinediones use in cases with colorectal cancer were lower than the odds of thiazolidinediones use in subjects without colorectal cancer (adjusted OR 0.94, 95% CI 0.89-0.99).

CONCLUSIONS

The odds of thiazolidinediones use in cases with colorectal cancer were lower than subjects without colorectal cancer. A prospective study is required to test whether thiazolidinediones use has a protective effect against colorectal cancer.

A systematic review of observational studies of the association between pioglitazone use and bladder cancer

AIM

To conduct a systematic review of all observational studies on the effect of pioglitazone on the risk of bladder cancer.

METHODS

The MEDLINE and EMBASE databases were queried for papers published between 1 January 2000 and 30 October 2017. We took into consideration observational studies (both retrospective and prospective) that included participants with Type 2 diabetes prescribed anti-hyperglycaemic drugs.

RESULTS

While some studies reported an association, others did not, and meta-analyses of these studies showed a significantly increased risk; however, while meta-analysis is a powerful and practical statistical tool, its results should be considered with caution when applied to widely heterogeneous studies. We describe how many of these studies are affected by different types of bias, most notably time-related biases, which should preclude a pooled analysis that would result in biased estimation of the risk.

CONCLUSIONS

Given existing data, it is not appropriate to pool the outcomes of highly heterogeneous studies and further rigorously conducted observational research is needed to clarify the role of pioglitazone use on the incidence of bladder cancer.

Pioglitazone use and risk of bladder cancer: a systematic literature review and meta-analysis of observational studies

BACKGROUND

Studies investigating bladder cancer risk in pioglitazone-treated type 2 diabetes mellitus patients report conflicting results. Previous meta-analyses on this topic utilized publications prior to 2013. More long-term observational studies have been published since then. We reviewed the accumulated evidence and updated findings from previous meta-analyses.

METHODS

This meta-analysis was based on a systematic review of peer-reviewed observational studies published prior to September 30, 2016. Eligible studies were identified using a specified MEDLINE search. References from included studies and from previous meta-analyses were screened for additional records. Meta-analysis hazards ratios were derived using a random-effects model. Several sensitivity analyses including hierarchical Bayesian meta-analysis with country-specific effects were conducted.

RESULTS

Of 363 identified records, 23 studies were included in this review and 18 in the actual meta-analyses. For bladder cancer outcome, the estimated effect size for ever vs. never use of pioglitazone was 1.16 [95% confidence interval (CI), 1.04-1.28]. In the cumulative dose and duration analyses, highest effect was observed in the highest/longest exposure group, but substantial heterogeneity was present. In the sensitivity analysis, only studies adjusted for lifestyle-related factors were included and the frequentist effect size was 1.18 (95% CI, 1.00-1.40, p = 0.054). However, the risk was not verified in the Bayesian framework with an effect size of 1.17 [95% credible interval (CrI), 0.94-1.54].

CONCLUSIONS

In line with previous meta-analyses, we observed a small but statistically significant association between ever (vs. never) use of pioglitazone and bladder cancer risk; however, causality is not established and alternative explanations cannot be ruled out.

Melatonin May Increase Anticancer Potential of Pleiotropic Drugs

Melatonin (N-acetyl-5-methoxytryptamine) is not only a pineal hormone, but also an ubiquitary molecule present in plants and part of our diet. Numerous preclinical and some clinical reports pointed to its multiple beneficial effects including oncostatic properties, and as such, it has become one of the most aspiring goals in cancer prevention/therapy. A link between cancer and inflammation and/or metabolic disorders has been well established and the therapy of these conditions with so-called pleiotropic drugs, which include non-steroidal anti-inflammatory drugs, statins and peroral antidiabetics, modulates a cancer risk too. Adjuvant therapy with melatonin may improve the oncostatic potential of these drugs. Results from preclinical studies are limited though support this hypothesis, which, however, remains to be verified by further research.

Pancreatic Cancer and Diabetes Mellitus

PURPOSE OF REVIEW

The relationship between pancreatic ductal adenocarcinoma (PDAC) and diabetes mellitus (DM) is complex. We reviewed the recent medical literature regarding the effect of anti-diabetic medication on PDAC risk and survival, risk of PDAC in DM, and role of DM in early detection of PDAC.

RECENT FINDINGS

Studies report that while some anti-diabetic medications (e.g., metformin) may decrease the risk of PDAC, others (insulin, sulfonylureas and incretin-based therapies) may increase the risk. However, these observations may be subject to protopathic biases. Metformin's anti-tumor activity may have influence overall survival of PDAC, but epidemiological reports have largely been inconsistent to defend these findings due to heterogeneous methodologies. There is congruent data to support the association between DM and PDAC, with an inverse relationship to DM duration. Older subjects with new-onset DM are the only known high-risk group for PDAC, and strategy using this group for early detection has led to development of clinical risk prediction models that define a very high-risk PDAC group. Role of anti-diabetic medication in PDAC risk modification or survival is controversial. With successful efforts to distinguish type 2-DM from PDAC-DM using risk-stratifying models, there is an opportunity to initiate screening protocols for early detection of PDAC in a sub-set of DM subjects.

Linking type 2 diabetes and gynecological cancer: an introductory overview

Type 2 diabetes (T2D) is a chronic disease with a growing prevalence and a leading cause of death in many countries. Several epidemiological studies observed an association between T2D and increased risk of many types of cancer, such as gynecologic neoplasms (endometrial, cervical, ovarian and vulvar cancer). Insulin resistance, chronic inflammation and high free ovarian steroid hormones are considered the possible mechanisms behind this complex relationship. A higher risk of endometrial cancer was observed in T2D, even though this association largely attenuated after adjusting for obesity. A clear relationship between the incidence of cervical cancer (CC) and T2D has still not be determined; however T2D might have an impact on prognosis in patients with CC. To date, studies on the association between T2D and ovarian cancer (OC) are limited. The effect of pre-existing diabetes on cancer-specific mortality has been evaluated in several studies, with less clear results. Other epidemiological and experimental studies focused on the potential role of diabetes medications, mainly metformin, in cancer development in women. The correct understanding of the link between T2D and gynecologic cancer risk and mortality is currently imperative to possibly modify screening and diagnostic-therapeutic protocols in the future.

An updated meta-analysis of pioglitazone exposure and bladder cancer and comparison to the drug's effect on cardiovascular disease and non-alcoholic steatohepatitis

AIM

We performed a meta-analysis of epidemiological studies evaluating exposure to pioglitazone and the risk for bladder cancer and compared these results to the drug's effects on cardiovascular disease (CVD) and non-alcoholic steatohepatitis (NASH).

METHODS

Pubmed and Embase were searched for cohort and case control studies for all years through 2016.

RESULTS

Data from 17 papers were analyzed. In cohort studies, 822 of 357,888 pioglitazone-exposed patients (0.23%) developed bladder cancer while 7691 of 2,898,682 unexposed (0.26%) did. In case control studies, 3219 of 1,146,916 patients (0.28%) developed bladder cancer. A random effects model showed no significant association between ever vs never use or with cumulative doses of pioglitazone. However, there was a significant association with 1-2 years (HR = 1.28 [1.08-1.55]) and >2 years (HR = 1.42 [1.14-1.77]) of exposure. The numbers needed to treat for one additional case of bladder cancer ranged from 899 to 6380 while to benefit CVD and NASH, 4-256 and 2-12, respectively.

CONCLUSIONS

Given the very small prevalence of bladder cancer in diabetic patients exposed (or not) to pioglitazone (<0.3%) and the much greater beneficial effects of the drug on CVD and NASH, the use of pioglitazone should be resurrected.

Diabetes Mellitus and Risk of Hepatocellular Carcinoma

The occurrence of hepatocellular carcinoma (HCC) is two to three times higher in patients with diabetes mellitus (DM), the prevalence of which is increasing sharply worldwide. The purpose of this review was to describe clinical links between DM and HCC and potential biological mechanisms that may account for this association. We evaluated the role of potential pathways that could account for the development of HCC with different etiologies in the presence of DM. In addition, we also briefly discuss the potential effect of other factors such as type and dosage of antidiabetic medicines and duration of DM on HCC risk.

Global and Regional Effects of Bladder Cancer Risk Associated with Pioglitazone Therapy in Patients with Diabetes

It has been debated for several years as to whether the antidiabetic drug pioglitazone increases the risk for bladder cancer. A series of recent large population studies yielded conflicting results. To investigate why the observational studies yielded conflicting results, we conducted stratified analyses to analyze the potential confounders behind these discordant outcomes. A total of 2,764,731 participants from observational (OB) studies and 9,999 from randomized control trials (RCTs) were identified for these analyses. The stratified analysis revealed that the study type, adjustment for age/sex, treatment duration, cumulative dose, agents used in a control group, mean period of follow-up and study population region might contribute to the discordant outcomes. In terms of population regions, pioglitazone increased the risk for bladder cancer could be found in European population, and patients who undergo treatment with pioglitazone for longer durations (>12 months) or are administrated a larger cumulative dose (>28,000 mg) might require more attention, and the long-term effects (≥3.6 years) of pioglitazone needs be monitored more carefully.

The expanding role of metformin in cancer: an update on antitumor mechanisms and clinical development

Metformin has been used for nearly a century to treat type 2 diabetes mellitus. Epidemiologic studies first identified the association between metformin and reduced risk of several cancers. The anticancer mechanisms of metformin involve both indirect or insulin-dependent pathways and direct or insulin-independent pathways. Preclinical studies have demonstrated metformin's broad anticancer activity across a spectrum of malignancies. Prospective clinical trials involving metformin in the chemoprevention and treatment of cancer now number in the hundreds. We provide an update on the anticancer mechanisms of metformin and review the results thus far available from prospective clinical trials investigating metformin's efficacy in cancer.

Cancer risks of anti-hyperglycemic drugs for type 2 diabetes treatment - a clinical appraisal

AIM

A clinical appraisal of existing scientific literature sought to assess the need for long-term prospective epidemiological studies to investigate an increased cancer risk of anti-hyperglycemic medication in type 2 diabetes.

METHOD

A focus statement was formulated as: "With a higher risk of cancers in patients with type 2 diabetes, all anti-hyperglycemic drugs should undergo long-term, prospective epidemiological studies for cancer risks." Field surveys were sent to practicing physicians and endocrinologists to identify the currently prevalent level of acceptance of this statement. Subsequently, a meeting with a six-member panel of key opinion leaders was held to discuss published evidence in support and against the statement. This publication reviews the publications and discussion points brought forth in this meeting and their effect on statement acceptance by the panel.

RESULTS

Whereas the majority of field survey responders primarily agreed with the statement, panel members were divided in their statement support. This division remained intact after review of the literature.

CONCLUSIONS

While there was evidence that type 2 diabetes is associated with an increased risk of cancer, existing studies seemed insufficient to definitively demonstrate a link between cancer risk and use of specific anti-hyperglycemic therapies.

Thiazolidinedione drugs in the treatment of type 2 diabetes mellitus: past, present and future

Thiazolidinedione (TZD) drugs used in the treatment of type 2 diabetes mellitus (T2DM) have proven effective in improving insulin sensitivity, hyperglycemia, and lipid metabolism. Though well tolerated by some patients, their mechanism of action as ligands of peroxisome proliferator-activated receptors (PPARs) results in the activation of several pathways in addition to those responsible for glycemic control and lipid homeostasis. These pathways, which include those related to inflammation, bone formation, and cell proliferation, may lead to adverse health outcomes. As treatment with TZDs has been associated with adverse hepatic, cardiovascular, osteological, and carcinogenic events in some studies, the role of TZDs in the treatment of T2DM continues to be debated. At the same time, new therapeutic roles for TZDs are being investigated, with new forms and isoforms currently in the pre-clinical phase for use in the prevention and treatment of some cancers, inflammatory diseases, and other conditions. The aims of this review are to provide an overview of the mechanism(s) of action of TZDs, a review of their safety for use in the treatment of T2DM, and a perspective on their current and future therapeutic roles.

Diabetes drugs and the incidence of solid cancers: a survey of the current evidence

INTRODUCTION

The evaluation of the relationship between the use of antidiabetic drug and the occurrence of cancer is extremely challenging, both from the clinical and pharmacoepidemiological standpoint. This narrative review described the current evidence supporting a relationship between the use of antidiabetic drugs and the incidence of solid cancers. Areas covered: Data from pharmacoepidemiological studies on cancer incidence were presented for the main antidiabetic drugs and drug classes, including human insulin and insulin analogues, metformin, sulfonylureas, glinides, alpha-glucosidase inhibitors, thiazolidinediones, incretin mimetics, and sodium glucose co-transporter 2 inhibitors. The relationship between the use of antidiabetics and the incidence of solid cancer was described in strata by any cancer and by organ-specific cancer and by drug and by drug classes. Information supporting biological evidence and putative mechanisms were also provided. Expert opinion: The history of exploration of the relationship between antidiabetic drugs and the risk of solid cancers has showed several issues. Unrecognized biases and misinterpretations of study results have had important consequences that delayed the identification of actual risk and benefits of the use of antidiabetic drugs associated with cancer occurrence or progression. The lesson learned from the past should address the future research in this area, since in the majority of cases findings are controversial and confirmatory studies are warranted.

The role of thiazolidinediones in hepatocellular carcinoma risk reduction: a population-based cohort study in Taiwan

OBJECTIVES

The aim of this study was to investigate the effect of thiazolidinediones (TZDs) on the risk of hepatocellular carcinoma (HCC) development among diabetes mellitus (DM) patients.

METHODS

We conducted a population-based case-control study in Taiwan based on data from the Taiwan National Health Insurance Research Database. A total of 76,349 newly diagnosed DM patients were identified from claims between 2000 and 2010. Among diabetics, 3,026 and 12,104 patients respectively, received or did not receive TZDs. Comparison frequency was matched with age, sex, and index date, excluding those with cancer at baseline. The incidence of HCC at the end of 2010 and the risks associated with the presence of hepatitis B and C infections were analyzed. The effect of TZDs use on the reduction of HCC risk was also assessed.

RESULTS

The incidence of HCC was lower in the TZD cohort compared with the non-TZD cohort (418.3 vs. 484.6 per 100,000 person-years), with an adjusted hazard ratio (HR) of 0.53 (95% confidence interval = 0.38-0.77) using multivariable Cox proportional hazard regression. In the stratified analysis, HCC risk reduction was greater for diabetics without the comorbidities of cirrhosis, hepatitis B, hepatitis C, nonalcoholic fatty liver disease, end-stage renal disease, and hyperlipidemia, in the TZD cohort than in the non-TZD cohort. Male sex, cirrhosis, hepatitis B, and hepatitis C were significant independent factors predicting HCC (HRs of 1.43, 13.96, 2.31, and 2.15, respectively).

CONCLUSIONS

This study suggests that the use of TZDs may reduce the risk of developing HCC among DM patients. Comorbidity with cirrhosis and/or hepatitis B/C infection appears to be associated with an extremely increased risk of developing HCC in this patient subset. These high-risk patients should be closely monitored.

Energy sensing pathways: Bridging type 2 diabetes and colorectal cancer?

The recently rapid increase of obesity and type 2 diabetes mellitus has caused great burden to our society. A positive association between type 2 diabetes and risk of colorectal cancer has been reported by increasing epidemiological studies. The molecular mechanism of this connection remains elusive. However, type 2 diabetes may result in abnormal carbohydrate and lipid metabolism, high levels of circulating insulin, insulin growth factor-1, and adipocytokines, as well as chronic inflammation. All these factors could lead to the alteration of energy sensing pathways such as the AMP activated kinase (PRKA), mechanistic (mammalian) target of rapamycin (mTOR), SIRT1, and autophagy signaling pathways. The resulted impaired SIRT1 and autophagy signaling pathway could increase the risk of gene mutation and cancer genesis by decreasing genetic stability and DNA mismatch repair. The dysregulated mTOR and PRKA pathway could remodel cell metabolism during the growth and metastasis of cancer in order for the cancer cell to survive the unfavorable microenvironment such as hypoxia and low blood supply. Moreover, these pathways may be coupling metabolic and epigenetic alterations that are central to oncogenic transformation. Further researches including molecular pathologic epidemiologic studies are warranted to better address the precise links between these two important diseases.

Cancer-Incidence, prevalence and mortality in the oldest-old. A comprehensive review

Chronic health conditions are commonplace in older populations. The process of aging impacts many of the world's top health concerns. With the average life expectancy continuing to climb, understanding patterns of morbidity in aging populations has become progressively more important. Cancer is an age-related disease, whose risk has been proven to increase with age. Limited information is published about the epidemiology of cancer and the cancer contribution to mortality in the 85+ age group, often referred to as the oldest-old. In this review, we perform a comprehensive assessment of the most recent (2011-2016) literature on cancer prevalence, incidence and mortality in the oldest-old. The data shows cancer prevalence and cancer incidence increases until ages 85-89, after which the rates decrease into 100+ ages. However the number of overall cases has steadily increased over time due to the rise in population. Cancer mortality continues to increase after age 85+. This review presents an overview of plausible associations between comorbidity, genetics and age-related physiological effects in relation to cancer risk and protection. Many of these age-related processes contribute to the lowered risk of cancer in the oldest-old, likewise other certain health conditions may "protect" from cancer in this age group.

Diabetes, Pancreatogenic Diabetes, and Pancreatic Cancer

The relationships between diabetes and pancreatic ductal adenocarcinoma (PDAC) are complex. Longstanding type 2 diabetes (T2DM) is a risk factor for pancreatic cancer, but increasing epidemiological data point to PDAC as also a cause of diabetes due to unknown mechanisms. New-onset diabetes is of particular interest to the oncology community as the differentiation of new-onset diabetes caused by PDAC as distinct from T2DM may allow for earlier diagnosis of PDAC. To address these relationships and raise awareness of the relationships between PDAC and diabetes, a symposium entitled Diabetes, Pancreatogenic Diabetes, and Pancreatic Cancer was held at the American Diabetes Association's 76th Scientific Sessions in June 2016. This article summarizes the data presented at that symposium, describing the current understanding of the interrelationships between diabetes, diabetes management, and pancreatic cancer, and identifies areas where additional research is needed.

Deciphering the Roles of Thiazolidinediones and PPAR in Bladder Cancer

The use of thiazolidinedione (TZD) therapy in type II diabetic patients has proven useful in the lowering of blood glucose levels. However, recent investigations have shown that there may be potential health concerns associated, including the risk of developing bladder cancer as well as complications in the cardiovasculature. TZDs are ligands for the nuclear receptor PPARγ, and activation causes lipid uptake and insulin sensitization, both of which are critical processes for diabetic patients whose bodies are unable to utilize insulin effectively. Several studies have shown that PPARγ/TZDs decrease IGF-1 levels and, thus, reduce cancer growth in carcinomas such as the pancreas, colon, liver, and prostate. However, other studies have shed light on the potential of the receptor as a biomarker for uroepithelial carcinomas, particularly due to its stimulatory effect on migration of bladder cancer cells. Furthermore, PPARγ may provide the tumor-promoting microenvironment by de novo synthesis of nutrients that are needed for bladder cancer development. In this review, we closely examine the TZD class of drugs and their effects on PPARγ in patient studies along with additional molecular factors that are positive modulators, such as protein phosphatase 5 (PP5), which may have considerable implications for bladder cancer therapy.