The influence of glucose-lowering therapies on cancer risk in type 2 diabetes

Metformin and Colorectal Cancer

Colorectal Cancer (CRC) is one of the most frequently encountered neoplasms in humans. The incidence of CRC has been increasing and new strategies for prevention, including chemoprevention, are required to lower its incidence and associated mortality. Metformin is a biguanide compound commonly used for the treatment of diabetes mellitus. Many recent basic research, epidemiological and clinical trial studies have indicated that metformin has benefits not only in diabetes treatment, but also in lowering the risk of developing cancer (including CRC). These studies indicate that metformin may be a candidate chemoprevention agent for CRC. This review article shall discuss the present evidence of metformin treatment and CRC, as well as outline our challenge in the investigation of metformin use in chemoprevention therapy for colorectal tumors.

Obesity, Diabetes and Gastrointestinal Malignancy: The role of Metformin and other Anti-diabetic Therapy

The association between Diabetes and cancer has been known for decades with obesity and insulin resistance being postulated as the main underlying risk factors for both disorders. With rise of the epidemic of obesity in the USA and around the globe, there has been a rise in diabetes that is currently reaching epidemic proportions. Diabetes is known to be associated with increased risk of several types of malignancy including breast, cervical, pancreatic and colon cancer. In this review, we discuss the epidemic of obesity and its consequential epidemic of diabetes highlighting the pathophysiologic mechanisms of increased cancer in the diabetic population. We will then discuss the role of insulin therapy as well as, other antidiabetic medications, particularly metformin that has been to be associated with lower risk as well as better survival with GI malignancies based on several studies including a study that was recently published by our group.

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.

[Is cancer incidence different between type 2 diabetes patients compared to non-diabetics in hemodialysis? A study from the REIN registry]

BACKGROUND AND OBJECTIVES

In France, diabetes mellitus is now the second cause of end stage renal disease. In a large previous French national study, we observed that dialyzed diabetics have a significant lower risk of death by cancer. This first study was focused on cancer death but did not investigate cancer incidence. In this context, the aim of this second study was to compare the incidence of cancer in diabetic dialyzed patients compared to non-diabetic dialyzed patients in a French region.

METHODS

This epidemiologic multicentric study included 588 diabetic and non-diabetic patients starting hemodialysis between 2002 and 2007 in Bretagne. Data were issued from REIN registry and cancer incidence were individually collected from medical records. Diabetics and non-diabetics were matched one by one on age, sex and year of dialysis initiation.

RESULTS

During the follow-up, we observed 28 cancers (9.4%) in diabetic patients and 26 cancers (8.9%) in non-diabetics patients. The cumulative incidence to develop a cancer 2 years after the dialysis start was approximately 6% in both diabetics and non-diabetics patients. In univariate Fine and Gray analysis, BMI, hemoglobin, statin use had P-value<0.2. However, in the adjusted model, these variables were not significantly associated with cancer incidence.

CONCLUSION

This study lead on a little number of dialyzed patients did not show any significant difference on cancer incidence between diabetic and non-diabetic patients after hemodialysis start.

Regulatory Forum Opinion Piece: Review-Toxicological Pathology Profile and Regulatory Expectations for Nonclinical Development of Insulins and Insulin Analogues

The toxicological profile of insulins is exclusively due to exaggerated pharmacology resulting in hypoglycemic findings. Insulin analogues displaying modifications and aimed at improving pharmacokinetics do not induce different toxicity. The main target is the brain displaying neuronal necrosis. Wallerian degeneration of nerves occurs rarely after severe hypoglycemia. These findings are of potential human relevance; nevertheless, these changes are induced in normoglycemic animals whereas diabetic patients suffer from hyperglycemia. Therefore, it is usually not difficult to achieve a therapeutic window for subsequent use in patients. Based upon this and in the absence of classical toxicity, there has been no scientific need for diabetic animal models. A greater challenge is the mitogenicity already inherent with regular insulin. Thus, the focus for preclinical safety evaluation of analogues is to demonstrate that modifications in regular insulin do not result in enhanced mitogenicity. The approaches used to assess the mitogenic potential of insulin analogues have changed over time driven by scientific progression and changes within the regulatory environment. Therefore, in vitro and in vivo evaluation of cell proliferation has become common practice, and to date there has been no evidence that the mitogenic potential of insulin analogues may be increased compared to regular insulin.

Screening of colorectal cancer: present and future

Colorectal cancer (CRC) is the third most common cancer in males and second in females, and the fourth most common cause of cancer death worldwide. Currently, about 60-70% of diagnosed cases in symptomatic patients are detected at an advanced stage of disease. Earlier stage detection through the use of screening strategies would allow for better outcomes in terms of reducing the disease burden. Areas covered: The aim of this paper is to review the current published evidence from literature which assesses the performance and effectiveness of different screening tests for the early detection of CRC. Expert commentary: Adequate screening strategies can reduce CRC incidence and mortality. In the last few decades, several tests have been proposed for CRC screening. To date, there is still insufficient evidence to identify which approach is definitively superior, and no screening strategy for CRC can therefore be defined as universally ideal. The best strategy would be the one that can be economically viable and to which the patient can adhere best to over time. The latest guidelines suggest colonoscopy every 10 years or annual fecal immuno-chemical test (FIT) for people with normal risk, while for individuals with high risk or hereditary syndromes specific recommendations are provided.

Metformin depresses overactivated Notch1/Hes1 signaling in colorectal cancer patients with type 2 diabetes mellitus

The function of metformin in colorectal cancer (CRC) patients with diabetes mellitus (DM) remains a controversial topic because studies are increasingly focusing on epidemiologic features. We examined Notch1/Hes1 signaling in CRC with DM (DM-CRC) and investigated alterations in signaling caused by metformin treatment. For this purpose, information on pathological characteristics was collected from each patient. The proliferation of epithelium labeled with proliferating cell nuclear antigen and the differentiation of goblet cells were investigated using immunohistochemistry and periodic acid-Schiff staining, respectively. The factors involved in Notch1/Hes1 signaling were detected using qRT-PCR and western blot. In our study, we found that lymphatic metastasis, pTNM staging, and the carcinoembryonic antigen level were significantly different between groups. The depth of crypts and the rate of proliferating cell nuclear antigen-positive cells were distinctly higher in DM-CRC and patients who were managed with insulin. Moreover, the goblet cell differentiation rate was decreased in DM-CRC. The expression of Dll1, Notch1, Math1, and RBP-Jκ was increased in DM-CRC, whereas the expression of Dll4 and Hes1 was decreased in this group in normal tissue. In CRC tissue, the expression of Dll1 and Notch1 was clearly higher than that in DM-CRC. Furthermore, the trend in these changes was aggravated with insulin management and alleviated with metformin treatment. In conclusion, the abnormal cell proliferation and differentiation observed in DM-CRC are correlated with overactivated Notch1/Hes1 signaling, which is potentially relieved by metformin treatment.

Long-Term Use of Long-Acting Insulin Analogs and Breast Cancer Incidence in Women With Type 2 Diabetes

Purpose

The association between long-acting insulin analogs and increased breast cancer risk is uncertain, particularly with the short follow-up in previous studies. We assessed this risk long term in women with type 2 diabetes.

Methods

A population-based cohort of women 40 years or older, all of whom were treated with long-acting (glargine, detemir) or neutral protamine Hagedorn (NPH) insulin between 2002 and 2012, was formed using the United Kingdom’s Clinical Practice Research Datalink. Women were followed until February 2015 or breast cancer diagnosis. Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) and 95% CIs of incident breast cancer, comparing long-acting insulin analogs with NPH overall, as well as by duration and cumulative dose.

Results

The cohort included 22,395 women who received insulin treatment, with 321 incident breast cancer events occurring during up to 12 years of follow-up (incidence rate 3.3 per 1,000 person-years). Compared with NPH insulin, insulin glargine was associated with an increased risk of breast cancer (HR, 1.44; 95% CI, 1.11 to 1.85), mainly increasing 5 years after glargine initiation (HR, 2.23; 95% CI, 1.32 to 3.77) and after > 30 prescriptions (HR, 2.29; 95% CI, 1.26 to 4.16). The risk was particularly elevated among prior insulin users (HR, 1.53; 95% CI, 1.10 to 2.12) but not for new users, which included fewer patients and for which one cannot rule out an HR of 1.81. The risk associated with insulin detemir was not significantly elevated (HR, 1.17; 95% CI, 0.77 to 1.77).

Conclusion

Long-term use of insulin glargine is associated with an increased risk of breast cancer in women with type 2 diabetes. The risk associated with insulin detemir remains uncertain because there are fewer users of this insulin.

Diabetes and Overall Survival among Breast Cancer Patients in the U.S. Military Health System

Background: Although research suggests that type II diabetes mellitus (DM-2) is associated with overall and breast cancer-specific decreased survival, most prior studies of breast cancer survival investigated the effect of preexisting DM-2 without assessing the effect of DM-2 diagnosed at or after breast cancer diagnosis. This study examined the relationship between DM-2 diagnosed before and after breast cancer diagnosis and overall survival.Methods: This study uses linked Department of Defense cancer registry and medical claims data from 9,398 women diagnosed with breast cancer between 1998 and 2007. Cox proportional hazards models were used to assess the association between DM-2 and overall survival.Results: Our analyses showed that women with DM-2 diagnosed before breast cancer diagnosis tended to have a higher risk of mortality compared with women without diabetes [HR = 1.17; 95% confidence interval (CI), 0.95-1.44] after adjustment for potential confounders. Similarly, patients diagnosed with DM-2 at or after breast cancer diagnosis had increased mortality compared with women without DM-2 (HR = 1.39; 95% CI, 1.16-1.66). The similar tendency was also observed among most subgroups when results were stratified by race, menopausal status, obesity, tumor hormone receptor status, and stage.Conclusions: Using data from a health system that provides universal health care to its beneficiaries, this study showed an increased risk of death associated with DM-2, regardless of whether it was diagnosed before or at/after breast cancer diagnosis.Impact: These results suggest the potential effects of factors independent of the timing of DM-2 clinical diagnosis on the association of DM-2 with overall survival. Cancer Epidemiol Biomarkers Prev; 27(1); 50-57. ©2017 AACR.

Diabetes and risk of cancer incidence: results from a population-based cohort study in northern Italy

BACKGROUND

Aim of this study was to compare cancer incidence in populations with and without diabetes by cancer site. Furthermore, we aimed at comparing excess risk of cancer according to diabetes type, diabetes duration and treatment, the latter as regards Type 2 diabetes.

METHODS

By use of the Reggio Emilia diabetes registry we classified the resident population aged 20-84 at December 31^st 2009 into two groups: with and without diabetes. By linking with the cancer registry we calculated the 2010-2013 cancer incidence in both groups. The incidence rate ratios (IRR) by cancer site, type of diabetes, diabetes duration, and as concerns Type 2 diabetes, by treatment regimen were computed using Poisson regression model and non-diabetic group as reference.

RESULTS

The cohort included 383,799 subjects without diabetes and 23,358 with diabetes. During follow-up, we identified 1464 cancer cases in subjects with diabetes and 9858 in the remaining population. Overall cancer incidence was higher in subjects with diabetes than in those without diabetes (IRR = 1.22, 95%CI 1.15-1.29), with similar results focusing on subjects with at least 2-year diabetes duration. Cancer sites driving overall increased risk were liver, pancreas, Colon rectum, and bladder in both sexes, corpus uteri for females. There was also suggestion of an increased risk for kidney cancer in females and a decreased risk for prostate cancer. Excess risk was found in patients with Type 2 diabetes, more marked among insulin users, especially with combined therapy. We observed an increasing risk for diabetes duration up to 10 years from diagnosis (IRR = 1.44, 95%CI 1.29-1.61) and a subsequent decrease to moderate-higher risk (IRR = 1.15, 95%CI 1.04-1.30).

CONCLUSIONS

Our study indicates that the strength of association depends on specific cancer site. Insulin, monotherapy or combined therapy, per se or as an indication of poor blood glucose control, in addition to diabetes duration, may play a role in the association of diabetes and cancer.

Metformin: A Bridge between Diabetes and Prostate Cancer

Prostate cancer (PCa) has become the most frequent type of cancer in men. Recent data suggest that diabetic patients taking metformin have a lower incidence of certain cancer, including PCa. Metformin is the most common drug used in type II diabetes mellitus; its use has been shown to lower the incidence of several cancers, although there are ambiguous data about the anticancer activity of metformin. A large number of studies examined the potential antineoplastic mechanism of metformin although it is not still completely understood. This review summarizes the literature concerning the effects of metformin on PCa cells, highlighting its numerous mechanisms of action through which it can act. We analyze the possible causes of the discordances regarding the impact of metformin on risk of PCa; we discuss the latest findings in this field, suggesting that metformin may have a future role in the management of PCa both as monotherapy and in combination with other drugs.

Association between metformin use and progression of monoclonal gammopathy of undetermined significance to multiple myeloma in US veterans with diabetes mellitus: a population-based retrospective cohort study

BACKGROUND

Multiple myeloma is one of the most common haematological malignancies in the USA and is consistently preceded by monoclonal gammopathy of undetermined significance (MGUS). We aimed to assess the association between metformin use and progression of MGUS to multiple myeloma.

METHODS

We did a retrospective cohort study of patients registered in the US Veterans Health Administration database and diagnosed with MGUS between Oct 1, 1999, and Dec 31, 2009. We included patients (aged >18 years) with at least one International Classification of Diseases (9th revision) code for diabetes mellitus and one treatment for their diabetes before MGUS diagnosis. We reviewed patient-level clinical data to verify diagnoses and extract any available data for size of baseline M-protein and type of MGUS. We defined metformin users as patients with diabetes who were given metformin consistently for 4 years after their diabetes diagnosis and before multiple myeloma development, death, or censorship. Our primary outcome was time from MGUS diagnosis to multiple myeloma diagnosis. We used Kaplan-Meier curves and Cox models to analyse the association between metformin use and MGUS progression.

FINDINGS

We obtained data for 3287 patients, of whom 2003 (61%) were included in the final analytical cohort. Median follow-up was 69 months (IQR 49–96). 463 (23%) participants were metformin users and 1540 (77%) participants were non-users. 13 (3%) metformin users progressed to multiple myeloma compared with 74 (5%) non-users. After adjustment, metformin use was associated with a reduced risk of progression to multiple myeloma (hazard ratio 0·47, 95% CI 0·25–0·87).

INTERPRETATION

For patients with diabetes diagnosed with MGUS, metformin use for 4 years or longer was associated with a reduced risk of progression of MGUS to multiple myeloma. Prospective studies are needed to establish whether this association is causal and whether these results can be extrapolated to non-diabetic individuals.

FUNDING

Barnes-Jewish Hospital Foundation, National Institutes of Health, Agency for Healthcare Research and Quality, American Cancer Society.

Insulin Receptor Isoforms in Physiology and Disease: An Updated View

The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors (IGFs), particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues by involving not only different ligand-binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Of note, dysregulation of the IR-A/IR-B ratio is associated with insulin resistance, aging, and increased proliferative activity of normal and neoplastic tissues and appears to sustain detrimental effects. This review discusses novel information that has generated remarkable progress in our understanding of the physiology of IR isoforms and their role in disease. We also focus on novel IR ligands and modulators that should now be considered as an important strategy for better and safer treatment of diabetes and cancer and possibly other IR-related diseases.

Additional Benefits of Routine Drugs on Gastrointestinal Cancer: Statins, Metformin, and Proton Pump Inhibitors

BACKGROUND

Commonly used medications including statins, metformin, and proton pump inhibitors (PPIs) effectively reduce the risk of esophageal, gastric, and colorectal cancer (CRC).

SUMMARY

A number of observational studies and meta-analyses have shown that long-term statin use significantly reduces the incidence of gastrointestinal (GI) cancer. Moreover, statin use after GI cancer diagnosis has been significantly associated with better prognosis in large-scale cohort studies. Metformin was rigorously evaluated in a population-based study and meta-analysis, and was found to have an unexpected benefit in the prevention and prolonged survival of CRC patients with type 2 diabetes mellitus. In contrast, few studies have demonstrated the chemopreventive effect of metformin for esophageal and gastric cancer. Recent observational studies have demonstrated that PPIs effectively reduce the progression of nondysplastic Barrett's esophagus into esophageal adenocarcinoma in a dose-dependent manner. However, the association between chronic PPI use and CRC or gastric cancer risk is still controversial. It was expected that these 3 routinely used medicines would show a synergistic effect with conventional systemic chemotherapy in advanced GI cancers. However, recent phase III studies failed to show significantly better outcomes. Key Messages: Further studies are needed to identify "additional" anticancer effects of these commonly used medicines.

Metformin: historical overview

Metformin (dimethylbiguanide) has become the preferred first-line oral blood glucose-lowering agent to manage type 2 diabetes. Its history is linked to Galega officinalis (also known as goat's rue), a traditional herbal medicine in Europe, found to be rich in guanidine, which, in 1918, was shown to lower blood glucose. Guanidine derivatives, including metformin, were synthesised and some (not metformin) were used to treat diabetes in the 1920s and 1930s but were discontinued due to toxicity and the increased availability of insulin. Metformin was rediscovered in the search for antimalarial agents in the 1940s and, during clinical tests, proved useful to treat influenza when it sometimes lowered blood glucose. This property was pursued by the French physician Jean Sterne, who first reported the use of metformin to treat diabetes in 1957. However, metformin received limited attention as it was less potent than other glucose-lowering biguanides (phenformin and buformin), which were generally discontinued in the late 1970s due to high risk of lactic acidosis. Metformin's future was precarious, its reputation tarnished by association with other biguanides despite evident differences. The ability of metformin to counter insulin resistance and address adult-onset hyperglycaemia without weight gain or increased risk of hypoglycaemia gradually gathered credence in Europe, and after intensive scrutiny metformin was introduced into the USA in 1995. Long-term cardiovascular benefits of metformin were identified by the UK Prospective Diabetes Study (UKPDS) in 1998, providing a new rationale to adopt metformin as initial therapy to manage hyperglycaemia in type 2 diabetes. Sixty years after its introduction in diabetes treatment, metformin has become the most prescribed glucose-lowering medicine worldwide with the potential for further therapeutic applications.

Cancer risk among insulin users: comparing analogues with human insulin in the CARING five-country cohort study

AIMS/HYPOTHESIS

The aim of this work was to investigate the relationship between use of certain insulins and risk for cancer, when addressing the limitations and biases involved in previous studies.

METHODS

National Health Registries from Denmark (1996-2010), Finland (1996-2011), Norway (2005-2010) and Sweden (2007-2012) and the UK Clinical Practice Research Datalink database (1987-2013) were used to conduct a cohort study on new insulin users (N = 327,112). By using a common data model and semi-aggregate approach, we pooled individual-level records from five cohorts and applied Poisson regression models. For each of ten cancer sites studied, we estimated the rate ratios (RRs) by duration (≤0.5, 0.5-1, 1-2, 2-3, 3-4, 4-5, 5-6 and >6 years) of cumulative exposure to insulin glargine or insulin detemir relative to that of human insulin.

RESULTS

A total of 21,390 cancer cases occurred during a mean follow-up of 4.6 years. No trend with cumulative treatment time for insulin glargine relative to human insulin was observed in risk for any of the ten studied cancer types. Of the 136 associations tested in the main analysis, only a few increased and decreased risks were found: among women, a higher risk was observed for colorectal (RR 1.54, 95% CI 1.06, 2.25) and endometrial cancer (RR 1.78, 95% CI 1.07, 2.94) for ≤0.5 years of treatment and for malignant melanoma for 2-3 years (RR 1.92, 95% CI 1.02, 3.61) and 4-5 years (RR 3.55, 95% CI 1.68, 7.47]); among men, a lower risk was observed for pancreatic cancer for 2-3 years (RR 0.34, 95% CI 0.17, 0.66) and for liver cancer for 3-4 years (RR 0.36, 95% CI 0.14, 0.94) and >6 years (RR 0.22, 95% CI 0.05, 0.92). Comparisons of insulin detemir with human insulin also showed no consistent differences.

CONCLUSIONS/INTERPRETATION

The present multi-country study found no evidence of consistent differences in risk for ten cancers for insulin glargine or insulin detemir use compared with human insulin, at follow-up exceeding 5 years.

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.

β-Hydroxybutyrate improves β-cell mitochondrial function and survival

Pharmacological interventions aimed at improving outcomes in type 2 diabetes and achieving normoglycaemia, including insulin therapy, are increasingly common, despite the potential for substantial side effects. Carbohydrate-restricted diets that result in increased ketogenesis have effectively been used to improve insulin resistance, a fundamental feature of type 2 diabetes. In addition, limited evidence suggests that states of ketogenesis may also improve β-cell function in type 2 diabetics. Considering how little is known regarding the effects of ketones on β-cell function, we sought to determine the specific effects of β-Hydroxybutyrate (βHB) on pancreatic β-cell physiology and mitochondrial function. βHB treatment increased β-cell survival and proliferation, while also increasing mitochondrial mass, respiration and adenosine triphosphate (ATP) production. Despite these improvements, were unable to detect an increase in β-cell or islet insulin production and secretion. Collectively, these findings have two implications. Firstly, they indicate that β-cells have improved survival and proliferation in the midst of βHB, the circulating form of ketones. Secondly, insulin secretion does not appear to be directly related to apparent improvements in mitochondrial function and cellular proliferation.

Metformin and endometrial cancer survival: a quantitative synthesis of observational studies

Metformin has been reported to have anticancer effect and can affect patient survival in several malignancies. However, the results are inconclusive for endometrial cancer. Hence, we conducted a systematic review and meta-analysis to investigate the prognostic role of metformin in patients with endometrial cancer. Studies were identified from Pubmed and Embase database through March 2017. Observational studies reporting hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS) were selected. Data were abstracted and summarised using random-effects models. From 250 unique citations, we identified ten studies including 6242 patients with nine studies examining OS and five studies examining PFS. Meta-analysis demonstrated that metformin users had better OS (HR, 0.58; 95% CI, 0.45 to 0.76; P = 0.207, I² = 26.6%) and PFS (HR, 0.61; 95% CI, 0.49 to 0.76; P =0.768, I² = 0%) than non-users for endometrial cancer patients. Similar findings were observed using sensitivity analysis adjusted by trim and filled methods (HR, 0.47; 95% CI, 0.37 to 0.58) and subgroup analyses. Based on the current evidence, we find that metformin use is associated with better OS and PFS in patients with endometrial cancer. However, further large-scale prospective studies are needed to establish its validity.

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.

Diabetes Mellitus Following Renal Transplantation: Clinical and Pharmacological Considerations for the Elderly Patient

Post-transplant diabetes mellitus occurs in 30-50% of cases during the first year post-renal transplantation. It is associated with increased morbidity, mortality and healthcare costs. Risk factors include age and specific immunosuppression regimens. At the same time, renal transplantation is increasingly indicated in elderly (aged >65 years) patients as this proportion of older patients in the prevalent dialysis population has increased. The immune system and β cells undergo senescence and this impacts on the risk for developing post-transplant diabetes and our ability to prevent such development. It may, however, be possible to identify patients at risk of developing post-transplant diabetes, enabling treatment protocols that prevent or reduce the impact of post-transplant diabetes. Much work remains to be completed in this area and is facilitated by the growing base of knowledge regarding the pathophysiology of post-transplant diabetes. Should post-transplant diabetes develop, there are a range of treatment options available. There is increasing interest in using newer agents, although their safety and efficacy in transplant recipients remains to be conclusively established.

The effect of metformin on survival of patients with pancreatic cancer: a meta-analysis

We conducted a meta-analysis to analyse the effect of metformin on survival of pancreatic cancer patients at various stages. We performed a systematic search of PubMed, Embase, Cochrane, and Web of Science to identify all relevant studies. Summary hazard ratios (HR) of survival and 95% confidence intervals (95% CI) were calculated with a fixed or random effects model according to inter-study heterogeneity. Nine retrospective cohort studies and two randomized controlled trials (RCTs) were eligible. There was a significant improvement in survival (HR = 0.86, 95% CI 0.76–0.97; P < 0.05) in the metformin group compared with control. Subgroup analysis indicated that metformin improved survival in patients with resection (HR = 0.79, 95% CI 0.69–0.91; P < 0.05) and patients with locally advanced tumors (HR = 0.68, 95% CI 0.55–0.84; P < 0.05) but not in patients with metastatic tumors, even when RCT data were included (HR = 0.99, 95% CI 0.70–1.40; P > 0.05), or were excluded (HR = 0.89, 95% CI 0.61–1.31; P > 0.05). This meta-analysis indicated that the effect of metformin does correlate with tumor stage but should be prudently considered given the limited and variable studies performed to data.

Diabetes-induced mechanophysiological changes in the small intestine and colon

The disorders of gastrointestinal (GI) tract including intestine and colon are common in the patients with diabetes mellitus (DM). DM induced intestinal and colonic structural and biomechanical remodeling in animals and humans. The remodeling is closely related to motor-sensory abnormalities of the intestine and colon which are associated with the symptoms frequently encountered in patients with DM such as diarrhea and constipation. In this review, firstly we review DM-induced histomorphological and biomechanical remodeling of intestine and colon. Secondly we review motor-sensory dysfunction and how they relate to intestinal and colonic abnormalities. Finally the clinical consequences of DM-induced changes in the intestine and colon including diarrhea, constipation, gut microbiota change and colon cancer are discussed. The final goal is to increase the understanding of DM-induced changes in the gut and the subsequent clinical consequences in order to provide the clinicians with a better understanding of the GI disorders in diabetic patients and facilitates treatments tailored to these patients.

Alpha-glucosidase inhibitor use is associated with decreased colorectal neoplasia risk in patients with type 2 diabetes mellitus receiving colonoscopy: a retrospective study

Purpose

The purpose of this study was to clarify the factors that influence the incidence of colorectal neoplasia in patients with type 2 diabetes mellitus (DM).

Study Design and Setting

Among a total of 1176 patients who underwent total colonoscopy at our hospital, we retrospectively analyzed 168 patients with type 2 DM. Univariate and multivariate logistic regression analyses were then performed to identify the risk factors associated with colorectal neoplasia.

Results

A multivariate analysis of these patients demonstrated that male gender (odds ratio [OR] = 4.04, 95% confidence interval [CI] = 1.67-10.37, p = 0.002), taking statins (OR = 4.59, 95% CI = 1.69-13.43, p = 0.003), taking alpha glucosidase inhibitor (α-GI) (OR = 0.35, 95% CI = 0.13-0.87, p = 0.023) and taking low-dose aspirin (LDA) (OR = 0.32, 95% CI = 0.10-0.95, p = 0.040) were independent factors associated with an increased (male gender and statins) or decreased (α-GI and LDA) risk of colorectal neoplasia.

Conclusions

While male gender and taking statins are risk factors, taking α-GI as well as LDA may reduce the risk of colorectal neoplasia in patients with type2 DM.

Pancreatic Cancer Heralded by Worsening Glycemic Control: A Report of Two Cases

Pancreatic ductal adenocarcinoma is the third leading cause of cancer-related death in the United States. Since it is usually diagnosed at an advanced stage, its prognosis remains poor. The initial presentation varies according to the tumor location. The most common presenting signs are weight loss, jaundice, and pain. Several epidemiological, clinical, and experimental studies over the past 2 decades have shown that long-standing diabetes is a modest risk factor for pancreatic cancer. However, new-onset diabetes has also been observed to be an early manifestation of pancreatic cancer. We report 2 cases where worsening glycemic control led to the diagnosis of pancreatic cancer.

Prevention and treatment of cancer targeting chronic inflammation: research progress, potential agents, clinical studies and mechanisms

Numerous experimental and clinical studies indicate that chronic inflammation is closely related to the initiation, progression, and spread of cancer, in which proinflammatory cytokines, such as interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α), and transcription factors, such as nuclear factor-κB (NF-κB), and signal transducer and activator of transcription 3 (STAT3), play pivotal roles. Stimulated by proinflammatory cytokines, NF-κB and STAT3 can modulate the expression of target genes, most of which are oncogenic ones, and promote the survival, proliferation, invasion, and metastasis of cancer cells. Now it is generally accepted that inflammation-related molecules and pathways are useful targets for the prevention and treatment of cancer. In this review, we summarize the relationship between chronic inflammation and cancer and describe some potentially useful agents including aspirin, meformin, statins, and some natural products (green tea catechins, andrographolide, curcumin) for their cancer prevention and treatment activities targeting chronic inflammation. The results of typical clinical studies are included, and the influences of these agents on the proinflammatory cytokines and inflammation-related pathways are discussed. Data from the present review support that agents targeting chronic inflammation may have a broad application prospect for the prevention and treatment of cancer in the future.

Survival analysis using primary care electronic health record data: A systematic review of the literature

PURPOSE

An emerging body of research involves observational studies in which survival analysis is applied to data obtained from primary care electronic health records (EHRs). This systematic review of these studies examined the utility of using this approach.

METHOD

An electronic literature search of the Scopus, PubMed, Web of Science, CINAHL, and Cochrane databases was conducted. Search terms and exclusion criteria were chosen to select studies where survival analysis was applied to the data extracted wholly from EHRs used in primary care medical practice.

RESULTS

A total of 46 studies that met the inclusion criteria for the systematic review were examined. All were published within the past decade (2005-2014) with a majority ( n = 26, 57%) being published between 2012 and 2014. Even though citation rates varied from nil to 628, over half ( n = 27, 59%) of the studies were cited 10 times or more. The median number of subjects was 18,042 with five studies including over 1,000,000 patients. Of the included studies, 35 (76%) were published in specialty journals and 11 (24%) in general medical journals. The many conditions studied largely corresponded well with conditions important to general practice.

CONCLUSION

Survival analysis applied to primary care electronic medical data is a research approach that has been frequently used in recent times. The utility of this approach was demonstrated by the ability to produce research with large numbers of subjects, across a wide range of conditions and with the potential of a high impact. Importantly, primary care data were thus available to inform primary care practice.

Glycaemic control in people with type 2 diabetes mellitus during and after cancer treatment: A systematic review and meta-analysis

BACKGROUND

Cancer and Diabetes Mellitus (DM) are leading causes of death worldwide and the prevalence of both is escalating. People with co-morbid cancer and DM have increased morbidity and premature mortality compared with cancer patients with no DM. The reasons for this are likely to be multifaceted but will include the impact of hypo/hyperglycaemia and diabetes therapies on cancer treatment and disease progression. A useful step toward addressing this disparity in treatment outcomes is to establish the impact of cancer treatment on diabetes control.

AIM

The aim of this review is to identify and analyse current evidence reporting glycaemic control (HbA1c) during and after cancer treatment.

METHODS

Systematic searches of published quantitative research relating to comorbid cancer and type 2 diabetes mellitus were conducted using databases, including Medline, Embase, PsychINFO, CINAHL and Web of Science (February 2017). Full text publications were eligible for inclusion if they: were quantitative, published in English language, investigated the effects of cancer treatment on glycaemic control, reported HbA1c (%/mmols/mol) and included adult populations with diabetes. Means, standard deviations and sample sizes were extracted from each paper; missing standard deviations were imputed. The completed datasets were analysed using a random effects model. A mixed-effects analysis was undertaken to calculate mean HbA1c (%/mmols/mol) change over three time periods compared to baseline.

RESULTS

The available literature exploring glycaemic control post-diagnosis was mixed. There was increased risk of poor glycaemic control during this time if studies of surgical treatment for gastric cancer are excluded, with significant differences between baseline and 12 months (p < 0.001) and baseline and 24 months (p = 0.002).

CONCLUSION

We found some evidence to support the contention that glycaemic control during and/or after non-surgical cancer treatment is worsened, and the reasons are not well defined in individual studies. Future studies should consider the reasons why this is the case.

Metformin use and the risk of colorectal adenoma: A systematic review and meta-analysis

BACKGROUND AND AIM

Although it is known that metformin can reduce risk of colorectal cancer, it is unclear whether it protects against colorectal adenoma.

METHODS

This study conducted a systematic literature search on MEDLINE, EMBASE, and the Cochrane Library using the primary keywords "colorectal," "colon," "rectal," "rectum," "adenoma," "polyp," "neoplasia," "neoplasm," "metformin," and "diabetes." Studies were included if they evaluated the association between metformin use and colorectal adenoma and reported odds ratios (ORs) or provided data from which these could be estimated.

RESULTS

Ten studies and a total of 8726 patients were evaluated. Across all studies, a median of 32.1% (range: 15.2-53.0%) of patients taking metformin also had adenoma; a median of 43.5% (range: 20.5-59.6%) of those not taking metformin had adenoma. In our meta-analysis, metformin use reduced the risk of adenoma (pooled OR = 0.76, 95% confidence interval [CI] = 0.63-0.92, I²  = 60%). Upon subgroup analyses, metformin use tended to reduce risk of adenoma in a high-risk population consisting of patients with a history of colorectal neoplasia (CRN) (pooled OR = 0.61, 95% CI = 0.34-1.10, I²  = 79%). In addition, metformin reduced the risk of adenoma in a high-risk population consisting of patients with diabetes mellitus (pooled OR = 0.75, 95% CI = 0.62-0.91, I²  = 57%).

CONCLUSION

Metformin use seemed to be associated with a reduced risk of colorectal adenoma, especially in high-risk populations consisting of patients with diabetes mellitus or a history of CRN, although statistical power was not achieved in patients with a history of CRN.

Cancer risk of sulfonylureas in patients with type 2 diabetes mellitus: A systematic review

BACKGROUND

Increasing evidence suggests that oral hypoglycemic agents used in type 2 diabetes mellitus (T2DM) may affect cancer risk. Sulfonylureas (SUs) are the most frequently used antidiabetic medications for T2DM. Whether using SUs has any effect on cancer has received considerable attention. The aim of this study was to assess the effects of SUs on cancer risk in T2DM patients.

METHODS

Published studies were identified in PubMed, EMBASE, and the Cochrane Register of Clinical Studies, and ClinicalTrials.gov was searched for additional information to identify randomized controlled trials (RCTs), cohort studies, and case-control studies. The abstracts and full text were screened, data collected, and the risk of bias assessed for each individual study.

RESULTS

Seventy-seven studies (33 RCTs, 27 cohort studies, and 17 case-control studies) were analyzed. The RCTs did not report a difference in the risk of malignant tumor between SU-treated T2DM patients and controls (odds ratio [OR] 0.96; 95% confidence interval [CI] 0.78-1.18); cohort studies showed that cancer risk was higher in patients using SUs than metformin (relative risk 1.60 [95%CI 1.37-1.87]; adjusted hazard ratio 1.13 [95%CI 1.06-1.19]), and case-control studies suggested a trend for increased cancer risk in those using SUs compared with non-SU users (adjusted OR 1.13; 95%CI 0.93-1.37).

CONCLUSIONS

The available evidence clearly shows that SUs can significantly increase the risk of cancer compared with metformin. Although the evidence suggests the possibility that SU users may have a higher risk of cancer than those using alternative medications in addition to metformin, it remains inadequate to enable definitive conclusions to be drawn.

Targeting metabolism and AMP-activated kinase with metformin to sensitize non-small cell lung cancer (NSCLC) to cytotoxic therapy: translational biology and rationale for current clinical trials

Lung cancer is the most fatal malignancy worldwide, in part, due to high resistance to cytotoxic therapy. There is need for effective chemo-radio-sensitizers in lung cancer. In recent years, we began to understand the modulation of metabolism in cancer and its importance in tumor progression and survival after cytotoxic therapy. The activity of biosynthetic pathways, driven by the Growth Factor Receptor/Ras/PI3k/Akt/mTOR pathway, is balanced by the energy stress sensor pathway of LKB1/AMPK/p53. AMPK responds both to metabolic and genotoxic stress. Metformin, a well-tolerated anti-diabetic agent, which blocks mitochondria oxidative phosphorylation complex I, became the poster child agent to elicit AMPK activity and tumor suppression. Metformin sensitizes NSCLC models to chemotherapy and radiation. Here, we discuss the rationale for targeting metabolism, the evidence supporting metformin as an anti-tumor agent and adjunct to cytotoxic therapy in NSCLC and we review retrospective evidence and on-going clinical trials addressing this concept.

Higher risk of colorectal cancer in patients with newly diagnosed diabetes mellitus before the age of colorectal cancer screening initiation

Type 2 diabetes mellitus (T2DM) is associated with greater risk for colorectal cancer (CRC). The age of onset of T2DM is decreasing worldwide. An increased CRC risk in young T2DM patients could be relevant for the age at which to initiate CRC screening. We report on CRC risk in T2DM patients with attention to age of diagnosis. We used pharmacy data (from 1998 to 2010) from the PHARMO Database Network linked to the Eindhoven Cancer Registry. Multivariable time-dependent Cox regression analyses were conducted to calculate hazard ratios (HR) for developing CRC comparing T2DM with non-T2DM. During 2,599,925 years of follow-up, 394 CRC cases among 41,716 diabetes patients (mean age 64.0 yr, 48% men) and 1,939 CRC cases among 325,054 non-diabetic patients (mean age 51.2 yr, 46% men) were identified. Diabetes was associated with an increased CRC risk in both men and women (HR 1.3, 95% CI 1.2-1.5), particularly in the first 6 months after T2DM diagnosis and pronounced in the proximal colon. This risk was even higher in men younger than 55 years (HR 2.0, 95% CI 1.0-3.8). T2DM was associated with a time-varying and subsite-specific increased CRC risk, which was even higher in men aged <55 years.

Prognostic role of metformin intake in diabetic patients with colorectal cancer: An updated qualitative evidence of cohort studies

Several observational studies have shown that metformin can modify the risk and survival of colorectal cancer (CRC) in patients with diabetes mellitus, although the magnitude of this relationship has not been determined. We conducted an updated systematic review and meta-analysis to analyze the association between metformin and CRC mortality and searched relevant databases up to July 2016. The primary outcome was overall survival (OS). Secondary outcomes were cancer-specific survival (CS) and disease-free survival (DFS). Summary hazard ratios (HRs) were calculated using a random-effects model. Seventeen studies enrolling 269,417 participants were eligible for inclusion. Comparing with non-metformin users in diabetic CRC patients, the summary HRs for OS in metformin users were 0.69 (95% CI, 0.61-0.77). Subgroup analyses stratified by the study characteristics and sensitivity analysis by the trim-and-fill method (adjusted HR 0.77, 95% CI, 0.67-0.87) confirmed the robustness of the results. However, significant OS benefit was noted in patients with stage II and III disease. Five studies reported the CRC prognosis for CS and three for DFS; metformin intake was significantly associated with patient CS (HR 0.75, 95% CI, 0.59-0.94), but not DFS (HR 0.38, 95% CI, 0.13-1.17). Our findings suggest that metformin intake is associated with improved survival outcomes in terms of OS and CS in CRC patients with diabetes, particular for OS in stage II and stage III patients. Further studies should be conducted to determine CRC survival between metformin use and patient specific clinical and molecular profiles.

Evaluating the role of race and medication in protection of uterine fibroids by type 2 diabetes exposure

BACKGROUND

Uterine fibroids (UF) affect 77% of women by menopause, and account for $9.4 billion in annual healthcare costs. Type-2-diabetes (T2D) has inconsistently associated with protection from UFs in prior studies. To further evaluate the relationship between T2D and UFs we tested for association between T2D and UF risk in a large clinical population as well as the potential differences due to T2D medications and interaction with race.

METHODS

This nested case-control study is derived from a clinical cohort. Our outcome was UF case-control status and our exposure was T2D. UF outcomes and T2D exposure were classified using validated electronic medical record (EMR) algorithms. Logistic regression, adjusted for covariates, was used to model the association between T2D diagnosis and UF risk. Secondary analyses were performed evaluating the interaction between T2D exposure and race and stratifying T2D exposed subjects by T2D medication being taken.

RESULTS

We identified 3,789 subjects with UF outcomes (608 UF cases and 3,181 controls), 714 were diabetic and 3,075 were non-diabetic. We observed a nominally significant interaction between T2D exposure and race in adjusted models (interaction p = 0.083). Race stratified analyses demonstrated more protection by T2D exposure on UF risk among European Americans (adjusted odds ratio [aOR] = 0.50, 95% CI 0.35 to 0.72) than African Americans (aOR = 0.76, 95% CI 0.50 to 1.17). We also observed a protective effect by T2D regardless of type of T2D medication being taken, with slightly more protection among subjects on insulin treatments (European Americans aOR = 0.42, 95% CI 0.26 to 0.68; African Americans aOR = 0.60, 95% CI 0.36 to 1.01).

CONCLUSIONS

These data, conducted in a large population of UF cases and controls, support prior studies that have found a protective association between diabetes presence and UF risk and is further modified by race. Protection from UFs by T2D exposure was observed regardless of medication type with slightly more protection among insulin users. Further mechanistic research in larger cohorts is necessary to reconcile the potential role of T2D in UF risk.

Effects of prolonged exposure to low dose metformin in thyroid cancer cell lines

Background: Thyroid cancer is generally associated with an excellent prognosis, but there is significant long-term morbidity with standard treatment. Some sub-types however have a poor prognosis. Metformin, an oral anti-diabetic drug is shown to have anti-cancer effects in several types of cancer (breast, lung and ovarian cancer). The proposed mechanisms include activation of the Adenosine Mono-phosphate-activated Protein Kinase (AMPK) pathway and inhibition of the mTOR pathway (which promotes growth and proliferation). By inhibiting hepatic gluconeogenesis and increasing glucose uptake by muscles, metformin decreases blood glucose and circulating Insulin levels. Aims: Explore the effect of metformin on the growth and proliferation of thyroid cancer cell lines. Methods: The effects of metformin on thyroid cancer cell lines (FTC-133, K1E7, RO82-W-1, 8305C and TT) and normal thyroid follicular cells (Nthy-ori 3-1) were investigated using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay for cell proliferation; clonogenic assays; FACS analysis for apoptosis and cell cycle, H2A.X phosphorylation (γH2AX) assay for DNA repair and scratch assay for cell migration. Results: Metformin inhibited cell proliferation and colony formation at 0.03 mM and above and inhibited cell migration at 0.3 mM. At concentrations of 0.1 mM and above metformin increased the percentage of apoptotic cells and induced cell cycle arrest in G0/G1 phase at minimum concentration of 0.3 mM. Unlike previous reports, no effect on DNA repair response was demonstrated. Conclusion: Metformin suppressed growth of all thyroid cancer cell lines, at concentrations considered to be within in the therapeutic range for diabetic patients on metformin (<0.3 mM).

Sulfonylureas (not metformin) improve survival of patients with diabetes and resectable pancreatic adenocarcinoma

Patients with pancreatic adenocarcinoma have an increased propensity for diabetes. Recent studies suggest patients with diabetes and pancreatic adenocarcinoma treated with metformin have increased survival. This study was undertaken to determine whether metformin use is associated with increased survival in patients with pancreatic adenocarcinoma.

Differential Use of Screening Mammography in Older Women Initiating Metformin versus Sulfonylurea

PURPOSE

Differential use of screening mammography may lead to biased detection of breast cancer. This study aimed to compare receipt of screening mammography and the incidence of screen-detected breast cancer between metformin and sulfonylurea initiators.

METHODS

We used 2006-2014 US Medicare claims to identify initiators of metformin or sulfonylurea aged 65+ years continuously enrolled in Parts A/B for ≥2 years pre-initiation and ≥2 years post-initiation. We reported frequencies of screening mammograms and screen-detected breast cancer in 1 year pre-initiation among all cohort members and in 1 year post-initiation among cancer-free cohort members. Weighted screening risk differences (RDs) were estimated comparing metformin to sulfonylurea group.

RESULTS

We identified 41,436 and 13,367 initiators of metformin and sulfonylurea, 35% and 24% of which had ≥1 screening mammogram in 1 year pre-initiation (weighted RD: 6 percentage points; 95% CI: 5 to 7), respectively. The weighted RD for screen-detected breast cancer associated with metformin was 0.00 percentage points (95% CI: -0.09 to 0.09). Among cancer-free cohort members, metformin initiators had 5 percentage points (95% CI: 4 to 6) and 0.11 percentage points (95% CI: -0.02 to 0.23) absolute risk excess of screening mammography and screen-detected breast cancer in 1 year post-initiation, compared with sulfonylurea initiators, respectively.

CONCLUSIONS

Metformin initiators were more likely to receive screening mammograms than sulfonylurea initiators pre- and post-initiation, indicating possible detection bias due to differential screening mammography. Researchers should be aware of the potential for more screening mammograms pre- and post-initiation when interpreting the findings of metformin on breast cancer incidence. Copyright © 2017 John Wiley & Sons, Ltd.

Auxiliendo, Primum Non Nocere: A Preliminary View of the DEVOTE Trial Comparing Cardiovascular Safety of Insulin Degludec Versus Insulin Glargine in Type 2 Diabetes

A demonstration of cardiovascular safety is mandatory for all newly developed glucose-lowering agents, including insulin analogues. The vascular benefit of insulin is evident from the Diabetes Control and Complication Trial (DCCT) and United Kingdom Prospective Diabetes Study (UKPDS), and the cardiovascular safety of insulin glargine has been demonstrated in individuals with newly diagnosed diabetes or prediabetes in the ORIGIN trial (Outcome Reduction with an Initial Glargine Intervention). The top-line results of DEVOTE (Trial Comparing Cardiovascular Safety of Insulin Degludec vs. Insulin Glargine in Patients with Type 2 Diabetes at High Risk of Cardiovascular Events) have proven the cardiovascular safety of insulin degludec in persons with type 2 diabetes. In this commentary I discuss the interrelationship of insulin and cardiovascular health, while comparing the results of DEVOTE and ORIGIN.

Differential effects of metformin on age related comorbidities in older men with type 2 diabetes

AIMS

To identify distinct temporal likelihoods of age-related comorbidity (ARC) diagnoses: cardiovascular diseases (CVD), cancer, depression, dementia, and frailty-related diseases (FRD) in older men with type 2 diabetes (T2D) but ARC naïve initially, and assess the heterogeneous effects of metformin on ARCs and mortality.

METHODS

We identified a clinical cohort of male veterans in the United States who were ≥65years old with T2D and free from ARCs during 2002-2003. ARC diagnoses during 2004-2012 were analyzed using latent class modeling adjusted for confounders.

RESULTS

The cohort consisted of 41,204 T2D men with age 74.6±5.8years, HbA1c 6.5±0.97%, and 8393 (20.4%) metformin users. Four ARC classes were identified. 'Healthy Class' (53.6%): metformin reduced likelihoods of all ARCs (from 0.14% in dementia to 6.1% in CVD). 'High Cancer Risk Class' (11.6%): metformin reduced likelihoods of CVD (13.3%), cancer (45.5%), depression (5.0%), and FRD (13.7%). 'High CVD Risk Class' (17.4%): metformin reduced likelihoods of CVD (48.6%), cancer (3.2%), depression (2.8%), and FRD (6.3%). 'High Frailty Risk Class' (17.2%): metformin reduced likelihoods of CVD (18.8%), cancer (3.9%), dementia (3.8%), depression (15.6%), and FRD (23.8%).

CONCLUSIONS

Metformin slowed ARC development in old men with T2D, and these effects varied by ARC phenotype.

Effect of Insulin and Metformin Combination Treatment on Colon Adenoma and Advanced Adenoma Among DM II

BACKGROUND

The risk for colorectal adenoma and advanced adenoma among diabetes mellitus II (DM II) has been debated to differ with the type of anti-diabetic therapy. Insulin increases whereas metformin decreases the risk for colon adenoma (Ad) and advanced Ad (AAd). There have been no studies to evaluate the effect of combination treatment with insulin and metformin on colon Ad and AAd.

METHODS

The retrospective study included DM II patients undergoing screening colonoscopy. Subjects with incomplete colonoscopy, poor bowel preparation, personal history of colorectal cancer (CRC)/inflammatory bowel disease/hereditary nonpolyposis colorectal cancer/familial adenomatosis polyposis/colectomy or family history of CRC were excluded. Subjects were categorized into group 1 (insulin only), group 2 (metformin only), group 3 (combination of insulin and metformin) and group 4 (miscellaneous). Group 4 was excluded from data analysis. Ad detection rate (ADR) and advanced ADR (AADR) were calculated for each group.

RESULTS

Three hundred thirty-nine subjects composed the study group, with a mean age of 60.0 years and male to female ratio of 1:1.4. Composite ADR and AADR for study population was 35.1 and 15.3 %, respectively. Groups 1, 2 and 3 were composed of 88 (26.0 %), 211 (62.2 %) and 40 (11.8 %) subjects, respectively. ADR for groups 1, 2 and 3 was 40.9, 33.2 and 32.5 %, respectively (p value = 0.413). AADR for groups 1, 2 and 3 was 18.2, 15.2 and 10.0 %, respectively (p value = 0.489).

CONCLUSION

A decremental trend was observed in ADR and AADR across group 1, group 2 and group 3 (p value >0.05).

Impact of hyperglycemia on the efficacy of chemotherapy-A systematic review of preclinical studies

BACKGROUND

Antineoplastic agents can provoke hyperglycemia in cancer patients with and without diabetes mellitus. We systematically reviewed the impact of hyperglycemia on the efficacy of chemotherapy.

METHODS

MEDLINE was searched for preclinical intervention studies which compared chemotherapy response in hyperglycemic and euglycemic conditions.

RESULTS

Thirteen preclinical studies, including 23 cell lines and 2 animal experiments were identified. In 14 cell lines and 2 animal studies, chemotherapy response was lower in a hyperglycemic (>15mmol/L) compared to a euglycemic environment (5mmol/L). The response was similar in 4 cell lines. In the remaining 5 cell lines, the hyperglycemic environment potentiated chemotherapy efficacy.

CONCLUSION

Hyperglycemia attenuated the antiproliferative effect of chemotherapy in preclinical experiments, but the results are inconsistent. Whether hyperglycemia influences efficacy of chemotherapy in patients needs to be explored.

No Decreased Risk of Gastrointestinal Cancers in Users of Metformin in The Netherlands; A Time-Varying Analysis of Metformin Exposure

Previous studies on metformin use and gastrointestinal (GI) cancer risk have yielded inconclusive results on metformin's chemoprotective effects. We aimed to evaluate GI cancer risk in users of metformin in The Netherlands using a time-varying approach in a large population-based database. A cohort study was performed using the NCR-PHARMO database. Patients using ≥1 non-insulin antidiabetic drug (NIAD) during 1998 to 2011 were included (N = 57,621). Exposure to NIADs was modeled time-varyingly. Cox regression analysis estimated HRs of GI cancers in current metformin users versus current users of other NIADs. Covariables included age, sex, drugs known to impact cancer risk, history of hospitalization, and starting year of follow-up. A sensitivity analysis was performed, applying a new-user design. Current use of metformin was not associated with a decreased risk of GI cancer [HR, 0.97; 95% confidence interval (CI), 0.82-1.15] or specific GI cancer sites. The sensitivity analysis yielded comparable results. No decreasing trends were observed with increasing cumulative dose of metformin [HR 1.05, 95% CI, 0.85-1.28; HR 0.89, 95% CI, 0.73-1.10; HR 0.96, 95% CI, 0.77-1.19 for dose tertiles low (<405 g), medium (405-999 g), and high (≥999 g)]. In contrast, an increased risk of pancreatic cancer was found in current users of metformin plus insulin (HR, 4.90; 95% CI, 2.64-9.10). In conclusion, no decreased risk of GI cancer was found in current metformin users compared with current users of other NIADs. Variations in the exposure definition of metformin use may be one of the explanations of previously found reduced cancer risks in metformin users. Cancer Prev Res; 10(5); 290-7. ©2017 AACR.

A spatiotemporal hypothesis for the regulation, role, and targeting of AMPK in prostate cancer

The 5'-AMP-activated protein kinase (AMPK) is a master regulator of cellular homeostasis. Despite AMPK's known function in physiology, its role in pathological processes such as prostate cancer is enigmatic. However, emerging evidence is now beginning to decode the paradoxical role of AMPK in cancer and, therefore, inform clinicians if - and how - AMPK could be therapeutically targeted. Spatiotemporal regulation of AMPK complexes could be one of the mechanisms that governs this kinase's role in cancer. We hypothesize that different upstream stimuli will activate select subcellular AMPK complexes. This hypothesis is supported by the distinct subcellular locations of the various AMPK subunits. Each of these unique AMPK complexes regulates discrete downstream processes that can be tumour suppressive or oncogenic. AMPK's final biological output is then determined by the weighted net function of these downstream signalling events, influenced by additional prostate-specific signalling.

Metformin prevents hormonal and metabolic disturbances and 1,2-dimethylhydrazine-induced colon carcinogenesis in non-diabetic rats

Effects of two doses of the anti-diabetic drug, metformin (MF), on hormonal and metabolic levels of serum of non-diabetic male Wistar rats with 1,2-dimethylhydrazine (DMH)-induced colon tumor adenocarcinomas were studied. Carcinogenesis in the animals was also observed. Rats with DMH-induced colon adenocarcinomas had elevated levels of serum glucose, insulin, insulin-like growth factor-1, total cholesterol, triglycerides, catalase, malonic dialdehyde, glycated hemoglobin, aspartate aminotransferase, and alanine aminotransferase and decreased hemoglobin. Treatment with two doses of MF normalized majority of these changes in DMH-treated rats, whereas the drug was ineffective in rats without DMH treatment. The only exception was the decreased triglyceride levels in MF-treated rats. A 100 mg/kg dose of MF increased DMH-induced exophytic colon carcinomas and decreased endophytic tumors compared with untreated rats. Moreover, both MF doses increased DMH-induced and highly differentiated tumors and decreased the invasiveness of colon carcinomas compared with rats provided with DMH and water. Therefore, effects of MF on metabolic homeostasis are critical for preventing colon cancer.

Design and Characterization of Metformin-Loaded Solid Lipid Nanoparticles for Colon Cancer

Colorectal cancer is a global concern, and its treatment is fraught with non-selective effects including adverse side effects requiring hospital visits and palliative care. A relatively safe drug formulated in a bioavailability enhancing and targeting delivery platform will be of significance. Metformin-loaded solid lipid nanoparticles (SLN) were designed, optimized, and characterized for particle size, zeta potential, drug entrapment, structure, crystallinity, thermal behavior, morphology, and drug release. Optimized SLN were 195.01 ± 6.03 nm in size, -17.08 ± 0.95 mV with regard to surface charge, fibrous in shape, largely amorphous, and release of metformin was controlled. The optimized size, charge, and shape suggest the solid lipid nanoparticles will migrate and accumulate in the colon tumor preventing its proliferation and subsequently leading to tumor shrinkage and cell death.

Use of statins offsets insulin-related cancer risk

AIM

There is firm evidence of a relation between type 2 diabetes (T2DM) and increased risks of cancer at various sites, but it is still unclear how different antihyperglycaemic therapies modify site-specific cancer risks. The aim of this study was to provide a complete characterization of all possible associations between individual T2DM therapies, statin use and site-specific cancers in the Austrian population.

METHODS

Medical claims data of 1 847 051 patients with hospital stays during 2006-2007 were used to estimate age- and sex-dependent co-occurrences of site-specific cancer diagnoses and treatment with specific glucose-lowering drugs and statins.

RESULTS

Patients treated with insulin or insulin secretagogues showed up to ninefold increased risks for cancers of the colon [males only (m)], liver (m), pancreas, lung (m) and brain (m), as well as a strongly decreased risk for prostate cancer (m). In patients taking statins, the risks were generally decreased, with a greater risk reduction in patients not receiving antihyperglycaemic therapies. The strongest effects were observed for use of insulin and pancreatic cancer [m: OR 4.5, 95% CI: 3.1-6.6; females (f): OR 4.2, 95% CI: 2.5-7.1], sulfonylureas (m: OR 2.8, 95% CI: 1.7-4.6; f: OR 3.0, 95% CI: 2.1-4.2) or glitazones and skin cancer (f: OR 0.54, 95% CI: 0.36-0.80), as well as metformin and cancer of the prostate (m: OR 0.82, 95% CI: 0.75-0.91) and corpus uteri (f: OR 1.7, 95% CI: 1.4-2.0) and non-Hodgkin's lymphoma (f: OR 0.76, 95% CI: 0.64-0.91).

CONCLUSIONS

The use of statins offsets insulin-related cancer risks in patients with diabetes independently of sex and age. Overall, our data support the hyperglycaemia-cancer hypothesis. A reduction in endogenous or exogenous hyperinsulinaemia may be beneficial for cancer prevention. Therefore, insulin-sparing and insulin-sensitizing drugs should be the preferred treatment choices.

Diabetic Pharmacotherapy and Endometrial Cancer Risk Within a Publicly Funded Health Care System

OBJECTIVE

There is conflicting evidence regarding the association between metformin and endometrial cancer risk. The objective of this study was to evaluate the association between type of diabetic pharmacotherapy and endometrial cancer risk within a population-based study. The hypothesis was that metformin was associated with the lowest risk.

METHODS

This was a nested case-control study using data from the BC Cancer Registry (2000-2009) and from a province-wide prescription network (PharmaNet) since 1996. Patients were classified by drug exposure (metformin, thiazolidinediones, secretagogues, with or without insulin). The primary analysis was a conditional logistic regression to estimate the odds ratios for endometrial cancer in the drug exposure groups. Sensitivity analysis was carried out to account for uncertainty regarding various parameters. The secondary analysis evaluated the effect of dosage using a principal components analysis.

RESULTS

The study cohort comprised 492 cases and 4404 controls. The primary analysis revealed no difference in endometrial cancer risk between those using metformin and those prescribed other classes of medications (OR 1.5, 95% CI 0.9 to 2.4). Women receiving all classes of medications had almost a two-fold increase in risk (OR 1.9, 95% CI 1.1 to 3.3). The secondary analysis revealed an increased risk associated with a greater duration of treatment and number of prescriptions (OR 1.3, 95% CI 1.2 to 1.4).

CONCLUSION

In this population-based study, metformin was not associated with a decreased endometrial cancer risk. Women receiving multiple types of medications over a long time had the highest risk, implying that the extent of insulin resistance, rather than the effect of any specific medication, drives endometrial cancer risk.

Hyperglycaemia-induced resistance to Docetaxel is negated by metformin: a role for IGFBP-2

The incidence of many common cancers varies between different populations and appears to be affected by a Western lifestyle. Highly proliferative malignant cells require sufficient levels of nutrients for their anabolic activity. Therefore, targeting genes and pathways involved in metabolic pathways could yield future therapeutics. A common pathway implicated in energetic and nutritional requirements of a cell is the LKB1/AMPK pathway. Metformin is a widely studied anti-diabetic drug, which improves glycaemia in patients with type 2 diabetes by targeting this pathway. We investigated the effect of metformin on prostate cancer cell lines and evaluated its mechanism of action using DU145, LNCaP, PC3 and VCaP prostate cancer cell lines. Trypan blue dye-exclusion assay was used to assess levels of cell death. Western immunoblotting was used to determine the abundance of proteins. Insulin-like growth factor-binding protein-2 (IGFBP-2) and AMPK genes were silenced using siRNA. Effects on cell morphology were visualised using microscopy. IGFBP-2 gene expression was assessed using real-time RT-PCR. With DU145 and LNCaP cells metformin alone induced cell death, but this was reduced in hyperglycaemic conditions. Hyperglycaemia also reduced the sensitivity to Docetaxel, but this was countered by co-treatment with metformin. LKB1 was required for the activation of AMPK but was not essential to mediate the induction of cell death. An alternative pathway by which metformin exerted its action was through downregulation of IGFBP-2 in DU145 and LNCaP cells, independently of AMPK. This finding could have important implications in relation to therapeutic strategies in prostate cancer patients presenting with diabetes.