Risk factors for cancer development in type 2 diabetes: A retrospective case-control study

Association between glucose levels and all-cause mortality in cancer survivors: findings from NHANES 1999-2018

BACKGROUND

Hyperglycemia is a rapidly increasing risk factor for cancer mortality worldwide. However, the dose‒response relationship between glucose levels and all-cause mortality in cancer survivors is still uncertain.

METHODS

We enrolled 4,491 cancer survivors (weighted population 19,465,739) from the 1999-2019 National Health and Nutrition Examination Survey (NHANES). Cancer survivors were defined based on the question of whether they had ever been diagnosed with cancer by a doctor or a health professional. Hemoglobin A1c (HbA1c) was selected in this study as a stable marker of glucose level. Mortality was ascertained by linkage to National Death Index records until December 31, 2019. Cox proportional hazard, Kaplan‒Meier survival curves and Restricted cubic spline regression models were used to evaluate the associations between HbA1c and all-cause mortality risk in cancer survivors.

RESULTS

In NHANES, after adjusting for confounders, HbA1c had an independent nonlinear association with increased all-cause mortality in cancer survivors (nonlinear P value < 0.05). The threshold value for HbA1c was 5.4%, and the HRs (95% CI) below and above the threshold value were 0.917 (0.856,0.983) and 1.026 (1.010,1.043), respectively. Similar associations were found between fasting glucose and all-cause mortality in cancer survivors, and the threshold value was 5.7 mmol/L.

CONCLUSIONS

HbA1c was nonlinearly associated with all-cause mortality in cancer survivors, and the critical value of HbA1c in decreased mortality was 5.4%, suggesting optimal glucose management in cancer survivors may be a key to preventing premature death in cancer survivors.

A study on the relationship between malignancy and diabetes

BACKGROUND & AIMS

Today, malignancy and diabetes mellitus are important health problems with an increasing prevalence that have high morbidity and mortality. The purpose of this study was to examine the presence of overt diabetes mellitus (DM) in individuals with malignancy diagnosis, evaluate the effect of pre-diagnosis glucose control on the patients, DM duration and treatment options for malignancy development and type, and investigate the risk of DM development on non-diabetic patients with malignancy after cancer treatment.

METHODS

A total of 469 patients between the ages of 26 and 70 with different malignancies were divided into 3 groups. Group I: Patients with overt DM that were diagnosed before the malignancy diagnosis or diagnosed during the malignancy diagnosis (n = 97); Group II: Patients that developed DM during the malignancy (anticancer) treatment (n = 17), Group III: Non-diabetic patients with malignancy diagnosis (n = 355).

RESULTS

Group I participants were found to have the highest mean BMI value (33.2 ± 6.7 kg/m2) and lowest weekly physical activity duration (p < 0.05). While 28.8 % of the patients with overt DM before diagnosis were found not to be followed up for DM, 18.8 % were not using antidiabetic medication. A total of 29.4% of the patients who developed DM during the malignancy treatment were found to have pancreas surgery and 17.5 % had corticosteroid treatment.

CONCLUSIONS

Appropriate screening programs should be developed for diabetic patients, taking into account the common risk factors of cancer and DM. Also, oncological treatments in patients with malignancy may lead to the development of DM. Therefore, the effects of decided anticancer treatment on glucose metabolism should not be overlooked and glucose metabolism in the patient must be monitored regularly.

Global, regional, and national time trends in cancer mortality attributable to high fasting plasma glucose: an age-period cohort analysis

BACKGROUND

High fasting plasma glucose (HFPG) is the fastest-growing risk factor for cancer deaths worldwide. We reported the cancer mortality attributable to HFPG at global, regional, and national levels over the past three decades and associations with age, period, and birth cohort.

METHODS

Data for this study were retrieved from the Global Burden of Disease Study 2019, and we used age-period-cohort modelling to estimate age, cohort and period effects, as well as net drift (overall annual percentage change) and local drift (annual percentage change in each age group).

RESULTS

Over the past 30 years, the global age-standardized mortality rate (ASMR) attributable to HFPG has increased by 27.8%. The ASMR in 2019 was highest in the male population in high sociodemographic index (SDI) areas (8.70; 95% CI, 2.23-18.04). The net drift for mortality was highest in the female population in low SDI areas (2.33; 95% CI, 2.12-2.55). Unfavourable period and cohort effects were found across all SDI quintiles. Cancer subtypes such as "trachea, bronchus, and lung cancers", "colon and rectal cancers", "breast cancer" and "pancreatic cancer" exhibited similar trends.

CONCLUSIONS

The cancer mortality attributable to HFPG has surged during the past three decades. Unfavourable age-period-cohort effects on mortality were observed across all SDI quintiles, and the cancer mortality attributable to HFPG is expected to continue to increase rapidly in the future, particularly in lower SDI locations. This is a grim global public health issue that requires immediate attention.

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.

Alterations of Gut Mycobiota Profiles in Adenoma and Colorectal Cancer

Accumulating evidence indicates that gut microbiota dysbiosis contributes to colorectal cancer and adenoma. However, a few studies revealed the altered gut mycobiota architecture in colorectal cancer. The present study characterized the gut mycobiota profiles in adenoma and colorectal cancer patients by metagenomic sequencing. Malassezia restricta increased, while Leucoagaricus_sp_SymCcos and fungal_sp_ARF18 significantly decreased in adenoma. Phanerochaete_chrysosporium, Lachancea_waltii, and Aspergillus_rambellii were the top 3 fungi that were significantly enriched in colorectal cancer, while Candida_versatilis, Pseudocercospora_pini_densiflorae, and Candida_sp_JCM_15000 were dominant in the healthy controls. Thirteen fungi, ranked as critical biomarkers in diagnosing colorectal cancer, showed positive associations among all samples. Lachancea_waltii and Phanerochaete_chrysosporium showed the most significant association within CRC. The values of area under the receiver-operating characteristics curve (AUROC) of selected 13 mycobiota were 0.926 in the training model and 0.757 in the 10-fold validation model. Our study provided a reliable investigation of the alterations of gut mycobiota in the development of colorectal cancer and established a convincing diagnostic model for colorectal cancer, which might improve the treatment strategy for colorectal cancer in the future.

Hyperglycaemia-induced human hepatocellular carcinoma (HepG2) cell proliferation through ROS-mediated P38 activation is effectively inhibited by a xanthophyll carotenoid, lutein

AIMS

Diabetic population have a twofold to threefold increased risk of developing liver cancer, and hyperglycaemia is a prime causative factor that propends the tumour cells to undergo aggressive metabolic growth. In this study, we aimed to examine the molecular mechanism by which lutein inhibits hyperglycaemia-induced human hepatocarcinoma (HepG2) cell proliferation.

METHODS

The effect of lutein on high glucose-induced proliferation was measured using the WST-1 reagent. Its effect on intracellular reactive oxygen species (ROS) levels was measured by DCF assay. The effect on the expression of antioxidant enzymes, cell cycle regulatory proteins and intracellular protein kinases was analysed by western blotting. The modulatory effect of lutein on different phases of the cell cycle was analysed by flow cytometry.

RESULTS

The data showed that lutein at 5 µM concentration significantly blocked glucose-promoted HepG2 cell proliferation. Suppression of high glucose-induced cell proliferation by lutein was not associated with apoptosis induction, but it was linked with inhibition of hyperglycaemia-mediated elevated ROS and upregulated expression of high glucose-mediated repressed heme oxygenase 1 (HO1). Furthermore, G2/M phase cell cycle arrest and associated phosphorylation of Cdk1 and P53 were found to be linked with suppressed hyperglycaemia-mediated cell proliferation by lutein. In addition, lutein inhibited hyperglycaemia-induced activation of P38 which relates to high glucose-induced ROS-mediated growth suppression and modulated the phosphorylation of Erk, JNK and Akt in hyperglycaemic HepG2 cells.

CONCLUSION

Our findings portray that sufficient intake of lutein may offer a negative impact on diabetes-associated tumour growth.

Do diabetic complications influence cancer-related events in people with type 2 diabetes? A cohort approach

AIM

To investigate whether diabetic micro- and macrovascular complications (mMVC) influence cancer-related events in people with type 2 diabetes.

METHODS

People with type 2 diabetes from the SURDIAGENE cohort were characterized (duration of diabetes, HbA1c, mMVC, history of cancer) and prospectively followed-up for death and cancer-related events (occurrence, dissemination and cancer-related death).

RESULTS

Between 2002 and 2012, 1468 participants (58% men, mean age 64.8 ± 10.7 years, mean duration of diabetes 14.5 ± 9.9 years at baseline) were enrolled. At baseline, 119 (8%) had a personal history of cancer. Incident cancer occurred in 207 (14%) patients during a mean follow-up of 7.3 ± 3.7 years and was associated with older age, smoking status and personal history of cancer. mMVC were not associated with cancer-related events, considering cancer occurrence, node/metastasis dissemination and cancer-specific death. Risk of all-cause mortality was increased in diabetic patients cumulating cancer history and mMVC (HR 1.73, 95%CI 1.25-2.38) compared to those with neither cancer nor mMVC. In our cohort, cancer-related death was not associated with mMVC (HR 1.05, 95%CI 0.67-1.64), but conversely history of cancer was significantly associated with cardiovascular-related death (HR 2.41, 95%CI 1.36-4.26).

CONCLUSION

In our cohort, mMVC were not associated with cancer-related events, while history of cancer was significantly associated with cardiovascular death.

Effect of metformin use on the risk and prognosis of colorectal cancer in diabetes mellitus: a meta-analysis

BACKGROUND

Whether metformin is a protective factor of colorectal cancer (CRC) among CRC patients is still not entirely clear. Thus, we conducted this systemic review and meta-analysis to provide a comprehensive review of associations between metformin therapy and CRC risk or survival outcomes for clinical decisions.

METHODS

Articles published before July 2021 were searched in databases (PubMed and Web of Science). Odds ratio (OR)/risk ratio (RR) or hazard ratio (HR) and their confidence intervals (CIs) were computed using STATA 12.0 software. Q test and I2 were conducted to explore heterogeneities between studies.

RESULTS

The present meta-analysis showed that metformin use was associated with decreased risk and lower all-cause mortality of CRC in diabetes mellitus (DM) with random-effects models (risk: OR/RR = 0.71, 95% CI, 0.64-0.80, I2 = 89.3%, P < 0.001; all-cause mortality: HR = 0.72, 95% CI, 0.62-0.83, I2 = 60.1%, P = 0.014). In addition, the study showed that metformin use was associated with a lower CRC-specific mortality in DM in cohort studies with a fixed-effects model (HR = 0.80, 95% CI, 0.70-0.92, I2 = 34.7%, P = 0.190).

CONCLUSION

Overall, in this meta-analysis, we found that metformin may be a protective factor for CRC risk and prognosis in patients with DM. Further well-designed, large-scale clinical studies are needed to evaluate the accuracy of our findings and more preclinical experiments are needed to reveal the underlying mechanism of metformin.

Clinical Implication of Metformin in Relation to Diabetes Mellitus and Ovarian Cancer

Since multiple reports established an association between diabetes mellitus and various cancers, emerging studies have surfaced to understand the effects of metformin as an anti-cancer agent. Although there was previous, but conflicting evidence, of a relationship between diabetes and ovarian cancer (OvCa), recent studies have supported this association. The mechanism of cancer development in patients with diabetes is likely to involve hyperglycemia, hyperinsulinemia, chronic inflammation, reactive oxygen species, regulation of cellular homeostasis, and activation of various pathways that lead to tumor cell proliferation. Preclinical evidence indicating that metformin, a medication commonly used to treat type 2 diabetes mellitus, may protect against OvCa. Metformin exerts anti-cancer properties by activating the MAPK pathway, inhibiting the PI3K/AKT/mTOR pathway, increasing tumor suppressor genes, inducing G2/M cycle arrest, and various other processes. Several studies have shown the efficacy of metformin as an adjunct with standard chemotherapeutic agents due to its synergistic effects on OvCa cells. This review highlights the epidemiologic evidence supporting a link between diabetes and OvCa, the fundamental molecular mechanism underlying carcinogenesis in patients with diabetes, the anti-cancer effects of metformin, and the need for further clinical investigations on combination therapies with metformin and standard chemotherapeutic agents for OvCa.

Narrative review of the influence of diabetes mellitus and hyperglycemia on colorectal cancer risk and oncological outcomes

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Diabetes mellitus and hyperglycemia significantly affect the incidence and prognosis of colorectal cancer.

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Evidence of the effects of metformin remain controversial in cancer prognosis.

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Potential molecular mechanisms by which DM and hyperglycemia affects cancer risk.

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Potential roles of glucose modulation in CRC therapy.

Diabetes mellitus (DM) and hyperglycemia have been shown to have significant effects on the incidence, chemoresistance, and prognosis of colorectal cancer (CRC), as well as the outcomes of localized and metastatic CRC. Inflammation and endocrine effects may act as central mechanisms of DM and cancer and stimulate the insulin‐like growth factor 1–phosphoinositide 3-kinase–Akt–mammalian target of rapamycin (IGF-1–PI3K–AKT–mTOR) pathway. Dysregulation of the AMP-activated protein kinase (AMPK) pathway leads to metabolic imbalance and indicates cancer risk. The use of metformin for chemoprevention has been shown to reduce CRC and adenoma incidence through the upregulation of AMPK, which causes cell cycle arrest in the Gap 1–S (G1–S) phase and inhibits the mTOR pathway, even potentially reversing the epithelial–mesenchymal transition. However, evidence of the effects of metformin remain controversial in cancer prognosis. Several genes, such as transcription factor 7-like 2(TCF7L2), tumor protein P53 inducible nuclear protein 1(TP53INP1), gremlin 1 (GREM1), and potassium voltage-gated channel subfamily Q member 1(KCNQ1), are pleiotropically related to DM as well as cancer risk and prognosis. Epigenetic modification of members of the Let-7 family such as miR-497, miR-486, and miR-223 is strongly associated with impaired glucose tolerance and CRC risk. Herein we review the pathophysiological and epidemiological evidence as well as potential underlying molecular mechanisms by which DM and hyperglycemia affect CRC risk. We also suggest potential roles of glucose modulation in CRC therapy and propose an agenda for future research and clinical practice.

Hyperglycemia and Chemoresistance in Breast Cancer: From Cellular Mechanisms to Treatment Response

Female breast cancer is a complex, multifactorial disease. Studies have shown that hyperglycemia is one of the most important contributing factors to increasing the risk of breast cancer that also has a major impact on the efficacy of chemotherapy. At the cellular level, hyperglycemia can promote the proliferation, invasion, and migration of breast cancer cells and can also induce anti-apoptotic responses to enhance the chemoresistance of tumors via abnormal glucose metabolism. In this article, we focus on the latest progress in defining the mechanisms of chemotherapy resistance in hyperglycemic patients including the abnormal behaviors of cancer cells in the hyperglycemic microenvironment and the impact of abnormal glucose metabolism on key signaling pathways. To better understand the advantages and challenges of breast cancer treatments, we explore the causes of drug resistance in hyperglycemic patients that may help to better inform the development of effective treatments.

Diabetes, Antidiabetic Medications and Cancer Risk in Type 2 Diabetes: Focus on SGLT-2 Inhibitors

In the last decade, cancer became the leading cause of death in the population under 65 in the European Union. Diabetes is also considered as a factor increasing risk of cancer incidence and mortality. Type 2 diabetes is frequently associated with being overweight and obese, which also plays a role in malignancy. Among biological mechanisms linking diabetes and obesity with cancer hyperglycemia, hyperinsulinemia, insulin resistance, increased levels of growth factors, steroid and peptide hormones, oxidative stress and increased activity of pro-inflammatory cytokines are listed. Antidiabetic medications can modulate cancer risk through directly impacting metabolism of cancer cells as well as indirectly through impact on risk factors of malignancy. Some of them are considered beneficial (metformin and thiazolidinedions—with the exception of bladder cancer); on the other hand, excess of exogenous insulin may be potentially harmful, while other medications seem to have neutral impact on cancer risk. Inhibitors of the sodium-glucose cotransporter-2 (SGLT-2) are increasingly used in the treatment of type 2 diabetes. However, their association with cancer risk is unclear. The aim of this review was to analyze the anticancer potential of this class of drugs, as well as risks of site-specific malignancies associated with their use.

Waist circumference, body mass index, and colorectal cancer risk according to diabetes status: A Korean nationwide population-based cohort study

BACKGROUND AND AIM

We investigated the relationship of BMI and waist circumference with the risk of colorectal cancer (CRC) using a population-based cohort database and to explore the relationship of CRC with diabetes status.

METHODS

Retrospective data (age >20 years) on anthropometric variables, blood parameters of fasting sugar, lipid levels, and blood pressure were collected from the National Health Insurance Corporation database between 2009 and 2012. Cox regression models were used to estimate hazard ratio (HR) and corresponding 95% confidence intervals (95% CI).

RESULTS

Of the 23 121 360 people studied, 120 579 were diagnosed with CRC after a median follow-up period of 5.4 years. Both waist circumference and body mass index were positively associated with increased risk of CRC, regardless of age or sex. After mutual adjustment, only waist circumference was significantly associated with increased risk of CRC (HR = 1.275, 95% CI: 1.205-1.349). When the risk of CRC was compared according to diabetes status among people with the same waist circumference range, risk of CRC was higher for those with worse diabetes status.

CONCLUSION

When waist circumference and body mass index were mutually adjusted, only waist circumference was associated with CRC risk. In addition, the risk of CRC is gradually higher in those with worsening diabetes, even if their waist circumferences are within the same range.

Metformin and risk of cancer among patients with type 2 diabetes mellitus: A systematic review and meta-analysis

AIM

We carried out this meta-analysis on all published studies to estimate the overall cancer risk of the use of metformin in T2DM patients.

METHODS

We searched the PubMed, Embase and CNKI databases for all articles within a range of published years from 2007 to 2019 on the association between the use of metformin and cancer risk in T2DM patients. The odds ratio (OR) corresponding to the 95% confidence interval (95% CI) was used to assess the association using a random-effect meta-analysis.

RESULTS

Finally, 67 studies met the inclusion criteria for this study, with 10,695,875 T2DM patients and 145,108 cancer cases. Overall, For T2DM patients of ever vs. never metformin users, there was statistical evidence of significantly decreased cancer risk was found to be associated with ever metformin users (OR=0.70, 95% CI=0.65-0.76). Considering T2DM may be a specific and independent risk factor for various forms of cancer, due to its particular metabolic characteristics of glucose intolerance and hyperinsulinemia, we performed a comparison to estimate the effects of metformin on cancer risk with other anti-diabetes medications (ADMs), our results found significantly decreased cancer risk to be associated with the use of metformin (OR=0.80, 95% CI=0.73-0.87).

CONCLUSION

Our meta-analysis indicated that metformin may be a independent protective factor for cancer risk in T2DM patients.

The impact of metformin on survival in patients with melanoma-national cohort study

PURPOSE

The primary study outcome was melanoma-specific mortality in patients with type 2 diabetes mellitus (T2DM) using metformin.

METHODS

Data regarding patients were provided by the Lithuanian Cancer Registry and were linked with National Health Insurance Fund in accordance with unique personal identification numbers during the period of thirteen years.

RESULTS

About 2817 patients met eligibility criteria and were included in the retrospective cohort study. About 163 patients had pre-existing T2DM and 103 of them were treated with metformin. In the multivariable analysis, there was significant risk difference in melanoma-specific survival between diabetic, metformin-using patients, and nondiabetic patients (P=0.02) in favor of metformin users.

CONCLUSION

Melanoma patients with T2DM treated with metformin had lower risk of melanoma-specific mortality; however, prospective controlled studies are mandatory to confirm this finding.

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.

Increasing risk of diabetes mellitus in postmenopausal women with newly diagnosed primary breast cancer

AIMS/INTRODUCTION

We sought to determine if postmenopausal women who develop breast cancer are at increased risk of developing diabetes mellitus.

MATERIALS AND METHODS

The Taiwan National Health Insurance Research Database was searched from 2001 to 2015 for women aged ≥55 years (postmenopausal) with a diagnosis of primary breast cancer. Participants were age-matched with women without breast cancer in a 1:5 ratio. Cox proportional hazards analyses were used to examine associations between breast cancer, risk factors and the development of diabetes mellitus.

RESULTS

A total of 4,607 women with primary breast cancer and 23,035 age-matched controls without breast cancer were included (mean age 58.6 ± 9.1 years). Adjusting for age, income, urbanization, Charlson Comorbidity Index and medical conditions, the risk of diabetes mellitus for participants with breast cancer at 1, 5, 10 and 15 years was 1.70-, 1.34-, 1.27- and 1.24-fold higher, respectively, than for participants without breast cancer (adjusted hazard ratio [aHR] 1.70, 95% confidence interval [CI] 1.40-2.05; aHR 1.34, 95% CI 1.17-1.54; aHR 1.27, 95% CI 1.13-1.44; aHR 1.24, 95% CI 1.11-1.40). The risk of diabetes mellitus at 1 year for breast cancer patients receiving hormone therapy was 1.22-fold higher than in those not receiving hormone therapy (aHR 1.22, 95% CI 0.86-1.74), but without statistical significance.

CONCLUSIONS

Postmenopausal women with breast cancer are at increased risk of developing diabetes mellitus, independent of receiving hormone therapy, and should be closely monitored to establish an early diagnosis and therapeutic intervention for improving related outcomes.

Impact of type 2 diabetes on hospitalization and mortality in people with malignancy

AIM

To compare the characteristics of and outcomes for people with malignancies with and without a co-diagnosis of diabetes.

METHODS

Emergency department and hospital discharge data from a single centre for the period between 1 January 2015 and 31 December 2017 were used to identify people with a diagnosis of a malignancy and diabetes. Multivariate Cox regression models were used to estimate the effect of diabetes on all-cause mortality. A truncated negative binomial regression model was used to assess the impact of diabetes on length of hospital inpatient stay. Prentice-Williams-Peterson total time models were used to assess the effect of diabetes on number of emergency department re-presentations and inpatient re-admissions.

RESULTS

Of 7004 people identified with malignancies, 1195 (17.1%) were also diagnosed with diabetes. A diagnosis of diabetes was associated with a greater number of inpatient re-admissions [adjusted hazard ratio 1.13 (95% CI 1.03, 1.24)], a greater number of emergency department re-presentations [adjusted hazard ratio 1.13 (95% CI 1.05, 1.22)] and longer length of stay [adjusted incidence rate ratio 1.14 (95% CI 1.04, 1.25)]. A co-diagnosis of diabetes was also associated with a 48% increased risk of all-cause mortality [adjusted hazard ratio 1.48 (95% CI 1.22-1.76)].

CONCLUSIONS

People with malignancies and diabetes had significantly more emergency department presentations, more inpatient admissions, longer length of hospital stay and higher rates of all-cause mortality compared to people with a malignancy without diabetes.

Hormone replacement therapy and the risk of melanoma in post-menopausal women

STUDY QUESTION

Is hormone replacement therapy (HRT) associated with an increased risk of melanoma skin cancer or prognostic outcomes amongst post-menopausal women?

SUMMARY ANSWER

Whilst we found evidence of an association with melanoma risk, the lack of dose-response and associations observed with recent use, localised disease and intravaginal oestrogens suggests this is a non-causal association.

WHAT IS KNOWN ALREADY

Evidence on HRT and melanoma risk remains inconclusive, with studies providing conflicting results. Furthermore, evidence on melanoma survival is sparse, with only one previous study reporting protective associations with HRT use, likely attributable to immortal time bias.

STUDY DESIGN, SIZE, DURATION

We conducted a nation-wide population-based case-control study and a retrospective cohort study utilising the Danish healthcare registries. Case-control analyses included 8279 women aged 45-85 with a first-ever diagnosis of malignant melanoma between 2000 and 2015, matched by age and calendar time to 165 580 population controls. A cohort of 6575 patients with a diagnosis of primary malignant melanoma between 2000 and 2013 and followed through 2015 was examined to determine if HRT use had an impact on melanoma survival outcomes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Based on prescriptions dispensed since 1995, ever-use of HRT was defined as having filled at least one prescription for HRT prior to the index date. In total, 2629 cases (31.8%) and 47 026 controls (28.4%) used HRT. Conditional logistic regression was used to calculate odds ratios (ORs) for melanoma risk according to HRT use, compared with non-use, adjusting for potential confounders. For cohort analyses, Cox proportional hazards models was used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for second melanoma incidence and all-cause mortality associated with HRT.

MAIN RESULTS AND THE ROLE OF CHANCE

High use of HRT was associated with an OR of 1.21 (95% CI 1.13-1.29) for melanoma risk, with no evidence of a dose-response pattern. Results were most pronounced amongst recent high users (OR, 1.28; 95% CI 1.17-1.41), for localised disease (OR, 1.25; 95% CI 1.15-1.36) and for intravaginal oestrogen therapy (OR, 1.38; 95% CI 1.13-1.68). Compared with non-use, there was no evidence of an association for secondary melanoma for post-diagnostic new-use (fully adjusted HR, 1.56; 95% CI 0.64-3.80) or continuous HRT use (fully adjusted HR, 1.26; 95% CI 0.89-1.78). Similar associations were observed for all-cause mortality.

LIMITATIONS, REASONS FOR CAUTION

Despite the large sample size and the use of robust population-based registries with almost complete coverage, we lacked information on some important confounders including sun exposure.

WIDER IMPLICATIONS OF THE FINDINGS

Whilst we cannot rule out an association between HRT use and melanoma risk, the associations observed are also compatible with increased healthcare utilisation and thus increased melanoma detection amongst HRT users. No association between HRT use and melanoma survival outcomes was observed. This should provide some reassurance to patients and clinicians, particularly concerning the use of HRT in patients with a history of melanoma.

STUDY FUNDING/COMPETING INTEREST(S)

B.M.H. is funded by a Cancer Research UK Population Research Postdoctoral Fellowship. The funding source had no influence on the design or conduct of this study. A.P. reports participation in research projects funded by Alcon, Almirall, Astellas, Astra-Zeneca, Boehringer-Ingelheim, Servier, Novo Nordisk and LEO Pharma, all with funds paid to the institution where he was employed (no personal fees) and with no relation to the work reported in this article. The other authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Association of metabolic NCD risk factors with oral, breast and cervical precancers and cancers in India

OBJECTIVE

To find an association between metabolic non-communicable disease (NCD) risk factors (high blood pressure (BP), high random blood sugar (RBS) and overweight /obesity) and oral, breast, cervical cancers/precancerous or potentially malignant conditions.

DESIGN

This is an observational study using convenience sampling. The participants were screened through opportunistic or population-based screening.

SETTING

The study was conducted at a health promotion clinic (HPC) located in Northern India under the Indian Council of Medical Research. HPC is a screening clinic where screening is done for hypertension (HT), diabetes mellitus (DM), obesity, and oral, breast and cervical cancers. The study was conducted between December 2016 and January 2019.

PARTICIPANT

The number of participants screened was 8352 (6712 women and 1640 men). All consenting men and women above 18 years were included. All participants were screened for oral cancer, DM, HT and obesity. All women were also screened for breast and cervical cancers. Cervical screening was done for non-pregnant women 21 years and above with history of sexual activity.

RESULT

Oral potentially malignant disease (OPMD) was the most prevalent, followed by breast cancer, oral cancer, cervical cancer and cervical precancer. High RBS had a strong association with oral cancer (OR=2.29, 95% CI 1.09 to 4.82, p=0.03) and breast cancer (OR=1.95, 95% CI 1.01 to 3.76, p=0.05). High BP had a strong association with breast cancer (OR=2.50, 95% CI 1.43 to 4.35, p<0.0001). An inverse association was noted between oral cancer and overweight/obesity (OR=0.20, 95% CI 0.08 to 0.48, p<0.0001). Current tobacco use was strongly associated with oral cancer (OR=6.51, 95% CI 3.63 to 11.67, p<0.0001) and OPMD (OR=9.82, 95% CI 8.13 to 11.86, p<0.0001). No association was elicited between the metabolic NCD risk factors and cervical cancer/precancer.

CONCLUSIONS

The study reaffirms that NCD metabolic risk factors determine oral and breast cancers. Besides NCD risk factors, current tobacco use was a strong determinant of OPMD and oral cancer. Hence, primary and primordial prevention measures to control NCD metabolic risk factors and tobacco use should move along with secondary prevention of breast and oral cancers.

Prospective study of cancer in Japanese patients with type 2 diabetes: the Fukuoka Diabetes Registry

Background

Although the association between type 2 diabetes and cancer has been reported, few epidemiological studies have been conducted in Japanese patients whose leading cause of death is cancer. We prospectively studied the incidence of site-specific cancer, risk factors for developing cancer, cancer death, and survival in Japanese patients with type 2 diabetes.

Methods

We followed 4923 participants (mean age, 65 years) with type 2 diabetes attending an outpatient diabetes clinic for a median of 5.3 years (follow-up rate, 99.0%).

Results

During the follow-up period, cancer occurred in 450 participants (incidence rate, 22.3/1000 person-years in men and 12.2/1000 person-years in women). In men, prostate cancer was the most common cancer (4.3/1000 person-years), colorectal cancer was the second (3.6/1000 person-years), and gastric cancer was the third (3.3/1000 person-years). In women, colorectal cancer was the most common cancer (2.6/1000 person-years), gastric cancer was the second (2.0/1000 person-years), and breast cancer was the third (1.4/1000 person-years). Smoking, male sex, low-density lipoprotein cholesterol, family history of cancer, and reduced intake of isoflavone daidzein were significant risk factors for developing cancer using multivariable Cox proportional hazards models. The leading cancer death was lung cancer in men and pancreatic cancer in women. The survival was the best for prostate cancer and the worst for pancreatic cancer (2-year cancer-specific survival 95.4%, 30.0%, respectively).

Conclusions

Since the leading cause of death in patients with type 2 diabetes is cancer in Japan, clinicians should be aware of epidemiological data regarding cancer besides diabetic complications.

Effects of hyperglycemia on the progression of tumor diseases

Malignant tumors are often multifactorial. Epidemiological studies have shown that hyperglycemia raises the prevalence and mortality of certain malignancies, like breast, liver, bladder, pancreatic, colorectal, endometrial cancers. Hyperglycemia can promote the proliferation, invasion and migration, induce the apoptotic resistance and enhance the chemoresistance of tumor cells. This review focuses on the new findings in the relationship between hyperglycemia and tumor development.

Differences in risk factors of malignancy between men and women with type 2 diabetes: A retrospective case-control study

BACKGROUND

The aim of this multicenter, retrospective, case-control study was to identify differences in risk factors of malignancy between men and women with type 2 diabetes.

RESULTS

Among women the most prevalent malignancies were: breast and uterine cancers (35.6% and 14.4% respectively), while among men there were: colorectal and prostate cancers (24.5% and 13.3% respectively). In both gender metformin use was associated with lower cancer risk. Obesity and insulin treatment in dose-dependent and time-varying manner were associated with significantly increased risk of malignancy in females. In men, unexpectedly, cardiovascular disease was more prevalent in control group. Other variables did not show significant association with malignancy risk.

MATERIALS AND METHODS

118 women and 98 men with type 2 diabetes mellitus who developed cancer after diagnosis of diabetes and the same number of strictly age matched controls with type 2 diabetes and without malignancy were included into the study. Diabetes duration, antidiabetic medications use, glycated hemoglobin level, body mass index, smoking habits, occupation, presence of comorbidities and aspirin use were included into analyses.

CONCLUSIONS

Metformin demonstrated protective effect against cancer in both sexes. Obesity and insulin treatment seem to have greater impact on cancer risk among women.

Alpha-glucosidase inhibitors and risk of cancer in patients with diabetes mellitus: a systematic review and meta-analysis

Several studies have shown that anti-diabetic medications may modify the risk of cancer. We performed a systematic review and meta-analysis to evaluate the effect of alpha-glucosidase inhibitors (AGIs) on the risk of cancer in patients with diabetes mellitus. We conducted a systematic search of Medline, EMBASE, and Web of Science databases, up to September 30, 2016. Random-effects model was used to estimate the summary odds ratios (ORs) with 95% CI. Twenty-five studies (14 cohort, 7 case-control, and 4 randomized controlled trials) involving 1,285,433 patients with diabetes were included. Meta-analysis of observational studies showed that the use of AGIs was associated with a lower risk of developing cancer (OR = 0.86, 95% CI 0.78-0.96), especially gastrointestinal cancer (OR = 0.83, 95% CI 0.71-0.97). There was considerable heterogeneity across the studies introduced partly by the quality of included studies and adjustment for potential confounders. Meta-analysis of randomized controlled trials did not reveal any significant association between AGIs and cancer risk. Meta-analysis of observational studies indicated that AGIs may decrease the risk of cancer in individuals with diabetes.