The impact of diabetes mellitus on prognosis of early breast cancer in Asia

The effect of metabolic syndrome on prognosis of diffuse large B-cell lymphoma

PURPOSE

Metabolic syndrome (MetS), characterized by insulin resistance, is closely associated with the prognosis of various cancer types, but has not been reported in diffuse large B-cell lymphoma (DLBCL). The aim of this study is to examine how other clinicopathological variables and the MetS influence the prognosis of DLBCL.

METHODS

Clinical and pathological data were collected from 319 patients with DLBCL who were admitted to our hospital between January 2012 and December 2020. The data accessible with SPSS 27.0 enables the utilization of various statistical methods for clinical data analysis, including independent sample t test and univariate and multivariate COX regression.

RESULTS

The presence of MetS was linked to both overall survival (OS) and progression-free survival (PFS), in addition to other clinicopathological characteristics as age, IPI score, rituximab usage, and Ki-67 expression level. This link with OS and PFS indicated a poor prognosis, as shown by survival analysis. Subsequent univariate analysis identified IPI score, Ki-67 expression level, tumor staging, rituximab usage, lactate dehydrogenase expression level, and the presence or absence of MetS as factors linked with OS and PFS. Furthermore, multivariate Cox regression analysis confirmed the independent risk factor status of IPI score, Ki-67 expression level, rituximab usage, and the presence of MetS in evaluating the prognosis of patients with DLBCL.

CONCLUSION

This study's findings indicate that patients with pre-treatment MetS had a poor prognosis, with relatively shorter OS and PFS compared to those without pre-treatment MetS. Furthermore, the presence of MetS, IPI score, Ki-67 expression level, and rituximab usage were identified as independent risk factors significantly affecting the prognosis of DLBCL.

Hyperinsulinemia in Obesity, Inflammation, and Cancer

The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.

Diabetes mellitus is independently associated with adverse clinical outcome in soft tissue sarcoma patients

Diabetes mellitus (DM) and hyperglycemia are known predictors of adverse outcome in different tumor entities. The present study investigated the effect of DM and pre-surgery blood glucose levels on cancer specific survival (CSS), overall survival (OS), and disease-free survival (DFS) in non-metastatic soft tissue sarcoma (STS) patients. A total of 475 STS patients who underwent curative resection were included in this retrospective study. CSS, DFS, and OS were assessed using Kaplan-Meier curves. The association between pre-existing DM as well as mean pre-surgery blood glucose levels and all 3 survival endpoints was analyzed using Cox-hazard proportional (for OS and DFS) and competing risk regression models (for CSS). In unadjusted analysis, DM was significantly associated with adverse CSS (sub-hazard ratio [SHR]: 2.14, 95% confidence interval [CI] 1.18-3.90, p = 0.013) and OS (hazard ratio [HR]: 2.05, 95% CI 1.28-3.28) and remained significant after adjusting for established prognostic factors (CSS: adjusted SHR 2.33, 95% CI 1.21-4.49, p = 0.012; OS: adjusted HR 1.96, 95% CI 1.17-3.28, p = 0.010), respectively. There was no significant association of DM with DFS (p = 0.149). The mean pre-surgery glucose levels were not significantly associated with inferior outcome (CSS: p = 0.510, OS: p = 0.382 and DFS: p = 0.786). This study shows, that DM represents a negative prognostic factor for clinical outcome in STS patients after curative resection.

Type 2 diabetes, breast cancer specific and overall mortality: Associations by metformin use and modification by race, body mass, and estrogen receptor status

INTRODUCTION

While type 2 diabetes (T2D) has been associated with increased all-cause mortality among women diagnosed with breast cancer (BC), the association between T2D and breast cancer-specific (BCS) mortality is unresolved. The goal of this study was to examine the association between T2D and BCS mortality and examine the influence of metformin treatment on mortality rates.

METHODS

A retrospective cohort study was conducted between 2002 and 2008 at Emory University Hospitals among non-Hispanic black and white women who had confirmed diagnosis of stage I-III BC and known diabetes status (T2D: n = 73; non-T2D: n = 514). Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Compared to non-T2D patients, T2D women had almost a 2-fold increase in BCS mortality after adjusting for covariates (HR = 2.01; 95%CI = 1.02-3.98). Though attenuated, the increased hazard of death was also observed for all-cause mortality (HR = 1.74; 95%CI = 1.06-2.87). T2D patients who were not on metformin had substantially higher hazard of BCS mortality compared to non-diabetic patients (HR = 4.54; 95%CI = 1.98-10.44), whereas the association among T2D patients treated with metformin was weak (HR = 1.20; 95%CI = 0.36-3.97) and included the null.

CONCLUSIONS

Among women with BC, T2D is associated with increased BCS mortality. Metformin treatment for T2D during the initial diagnosis of BC may improve outcomes.

Improving health engagement and lifestyle management for breast cancer survivors with diabetes

Breast cancer survivors with type 2 diabetes are at high risk for cancer recurrence, serious health complications, more severe symptoms, psychological distress, and premature death relative to breast cancer survivors without diabetes. Maintaining glycemic control is critical for decreasing symptoms and preventing serious health problems. Many breast cancer survivors with type 2 diabetes have difficulty maintaining diabetes self-management behaviors and achieving glycemic control. Both cancer and diabetes-related symptoms (e.g., physical symptoms and psychological distress) are often barriers to engaging in diabetes self-management strategies. This study evaluates a novel diabetes coping skills training (DCST) intervention for improving breast cancer survivors' abilities to manage symptoms and adhere to recommended diabetes self-management behaviors. The telephone-based DCST protocol integrates three key theory-based strategies: coping skills training for managing symptoms, adherence skills training, and healthy lifestyle skills training. A randomized clinical trial will test the DCST intervention plus diabetes education by comparing it to diabetes education alone. Symptoms, distress, diabetes self-management behaviors, and self-efficacy will be assessed at baseline and 3, 6, and 12 months. Glycosylated hemoglobin (HbA1c) will be assessed at baseline, 6, and 12 months. This study addresses a critical gap in the care of breast cancer survivors by evaluating a novel behavioral intervention to improve the management of symptoms, adherence, and glycemic control in breast cancer survivors with type 2 diabetes. Special considerations for this medically underserved population are also provided. The findings of this study could lead to significant improvements in clinical care and beneficial outcomes for breast cancer survivors. Trials registration: ClinicalTrials.gov, NCT02970344, registered 11/22/2016.

Metabolic comorbidities and medical institution utilization among breast cancer survivors: a national population-based study

BACKGROUND/AIMS

We investigated metabolic comorbidity status and patterns of medical institution utilization among breast cancer survivors using medical claims data from the Health Insurance Review and Assessment Service (HIRA).

METHODS

Using claims data obtained from the HIRA, we selected breast cancer survivors between 2010 and 2015. Descriptive statistics were calculated to determine the frequency of metabolic comorbidities, as well as to analyze patterns of medical institution utilization in accordance with disease status.

RESULTS

A total of 89,953 breast cancer survivors were identified. Among these, 12,364 (13.7%) had hypercholesterolemia, 20,754 (23.1%) had hypertension (HTN), and 11,102 (12.3%) had diabetes mellitus (DM). In particular, more than half of breast cancer survivors older than 60 years had HTN, and other diseases sharply increased beginning at age 50 years. For HTN, a total of 531,292 claims were submitted; more than 80% (n = 473,737) were from primary medical institutions, whereas only 2.4% (n = 12,551) were from tertiary medical institutions. The number of claims submitted for DM was 231,526; those from primary medical institutions accounted for 68.5% (n = 158,566), whereas claims from tertiary medical institutions accounted for 12.0% (n = 27,693). In subgroup analyses, the utilization of secondary and tertiary medical institutions was higher among patients with severe diseases and those diagnosed following their breast cancer diagnosis.

CONCLUSION

More than 10% of breast cancer survivors were diagnosed with a metabolic comorbidity. Through analysis of medical institution utilization patterns, we ascertained that a communication system linking secondary and tertiary medical institutions with primary medical institutions is needed.

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.

Comorbidity and stage at diagnosis among lung cancer patients in the US military health system

PURPOSE

We investigated the association between comorbidities and stage at diagnosis among NSCLC patients in the US Military Health System (MHS), which provides universal health care to its beneficiaries.

METHODS

The linked data from the Department of Defense's Central Cancer Registry (CCR) and the MHS Data Repository (MDR) were used. The study included 4768 patients with histologically confirmed primary NSCLC. Comorbid conditions were extracted from the MDR data. Comorbid conditions were those included in the Charlson Comorbidity Index (CCI) and were defined as a diagnosis during a 3-year time frame prior to the NSCLC diagnosis. Multivariable logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (95% CI) of late stage (stages III and IV) versus early stage (stages I and II) in relation to pre-existing comorbidities.

RESULTS

Compared to patients with no comorbidities, those with prior comorbidities tended to be less likely to have lung cancer diagnosed at late stage. When specific comorbidities were analyzed, decreased odds of being diagnosed at late stage were observed among those with chronic obstructive pulmonary disease (COPD) (adjusted OR 0.78, 95% CI 0.68 to 0.90). In contrast, patients with a congestive heart failure or a liver cirrhosis/chronic hepatitis had an increased likelihood of being diagnosed at late stage (adjusted OR 1.30, 95% CI 1.00 to 1.69 and adjusted OR 1.87, 95% CI 1.24 to 2.82, respectively).

CONCLUSIONS

Among NSCLC patients in an equal access health system, the likelihood of late stage at diagnosis differed by specific comorbid diseases.

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.

Metformin use and survival after non-small cell lung cancer: A cohort study in the US Military health system

Research suggests that metformin may be associated with improved survival in cancer patients with type II diabetes. This study assessed whether metformin use after non-small cell lung cancer (NSCLC) diagnosis is associated with overall survival among type II diabetic patients with NSCLC in the U.S. military health system (MHS). The study included 636 diabetic patients with histologically confirmed NSCLC diagnosed between 2002 and 2007, identified from the linked database from the Department of Defense's Central Cancer Registry (CCR) and the Military Health System Data Repository (MDR). Time-dependent multivariate Cox proportional hazards models were used to assess the association between metformin use and overall survival during follow-up. Among the 636 patients, 411 died during the follow-up. The median follow-up time was 14.6 months. Increased post-diagnosis cumulative use (per 1 year of use) conferred a significant reduction in mortality (adjusted hazard ratio (HR) = 0.76; 95% CI = 0.65-0.88). Further analysis by duration of use revealed that compared to non-users, the lowest risk reduction occurred among patients with the longest duration of use (i.e. use for more than 2 years) (HR = 0.19; 95% CI = 0.09-0.40). Finally, the reduced mortality was particularly observed only among patients who also used metformin before lung cancer diagnosis and among patients at early stage of diagnosis. Prolonged duration of metformin use in the study population was associated with improved survival, especially among early stage patients. Future research with a larger number of patients is warranted.

The Impact of Preexisting Mental Health Disorders on the Diagnosis, Treatment, and Survival among Lung Cancer Patients in the U.S. Military Health System

BACKGROUND

Higher cancer-related mortality has been observed among people with mental health disorders than in the general population. Both delay in diagnosis and inadequate treatment due to health care access have been found to explain the higher mortality. The U.S. Military Health System (MHS), in which all beneficiaries have equal access to health care, provides an ideal system to study this disparity where there are no or minimal barriers to health care access. This study assessed preexisting mental health disorders and stage at diagnosis, receipt of cancer treatment, and overall survival among patients with non-small cell lung cancer (NSCLC) in the U.S. MHS.

METHODS

The study used data from the linked database from the Department of Defense's Central Cancer Registry and the MHS Data Repository (MDR). The study subjects included 5,054 patients with histologically confirmed primary NSCLC diagnosed between 1998 and 2007.

RESULTS

Patients with a preexisting mental disorder did not present with more advanced disease at diagnosis than those without. There were no significant differences in receiving cancer treatments between the two groups. However, patients with a mental health disorder had a higher mortality than those without [adjusted HR, 1.11; 95% confidence interval (CI), 1.03-1.20].

CONCLUSIONS

Poor survival in NSCLC in patients with a preexisting mental health disorder is not necessarily associated with delay in diagnosis and/or inadequate cancer treatment.

IMPACT

This study contributes to the current understanding that health care access may not be sufficient to explain the poor survival among patients with NSCLC with preexisting mental health disorders. Cancer Epidemiol Biomarkers Prev; 25(12); 1564-71. ©2016 AACR.

Diabetes mellitus and prognosis in women with breast cancer: A systematic review and meta-analysis

BACKGROUND

Diabetes mellitus is associated with an increased risk of breast cancer, but studies of the effects of diabetes on the prognosis of women with breast cancer have yielded inconsistent findings. The present meta-analysis aimed to investigate the impact of preexisting diabetes on the prognosis in terms of overall survival (OS), disease-free survival (DFS), and relapse-free period (RFP) in women with breast cancer.

METHODS

We searched the Embase and PubMed databases until June 2016 for cohort or case-control studies assessing the impact of diabetes on the prognosis of women with breast cancer. The pooled multivariate adjusted hazard ratio (HR) and their 95% confidence intervals (CIs) for OS, DFS, and RFP were used to analyze the impact of diabetes on the prognosis of breast cancer patients.

RESULTS

Seventeen studies involving 48,315 women with breast cancer met our predefined inclusion criteria. Meta-analysis showed that the pooled adjusted HR was 1.51 (95% CI 1.34-1.70) for OS and 1.28 (95% CI 1.09-1.50) for DFS in breast cancer patients with diabetes compared to those without diabetes. However, RFP did not differ significantly between patients with and without diabetes (HR 1.42; 95% CI 0.90-2.23).

CONCLUSIONS

The present meta-analysis suggests that preexisting diabetes is independently associated with poor OS and DFS in female breast cancer patients. However, the impact of diabetes on RFP should be further verified. More prospective studies are warranted to investigate whether appropriate glycemic control with modification of antihyperglycemic agents can improve the prognosis of female breast cancer patients with diabetes.

Associations between Diabetes and Quality of Life among Breast Cancer Survivors

Objective

We aimed to investigate the associations between diabetes and quality of life (QOL) among breast cancer survivors.

Methods

A cross-sectional survey was conducted at 34 Cancer Recovery Clubs across China from May 2014 to January 2015. Quality of life was measured by the Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) and the Quality of Life Questionnaire-Breast Cancer Module 23 (QLQ-BR23, simplified Chinese version). Information on social-demography, diagnosis and treatment of tumors, and diabetes mellitus were collected by self-reported questionnaires. Univariate analyses of covariance (ANCOVA) was performed to assess the difference in QOL between patients with or without diabetes mellitus, and multiple linear regression models were used to examine the associations after controlling for confounders.

Results

Diabetes, both of type 1 diabetes (T1DM) and type 2 diabetes (T2DM) significantly reduced QOL. This effect of diabetes on QOL is independent of tumor size, regional lymph node metastasis, distant metastasis and tumor stage index (TNM). After adjusting for different social-demography, diagnosis and treatment of the tumor, the tumor’s stage and other chronic comorbidities, breast cancer survivors with diabetes got significantly lower scores in functional dimensions (including physical, role, emotional and social functionings measured by EORTC QLQ-C30; body image (BRBI) and future perspective (BRFU) measured by QLQ-BR23, as well as economic difficulties than those without diabetes (P_adjusted<0.05). Diabetic patients also obtained higher scores in symptom dimensions, including fatigue, nausea and vomiting, pain, dyspnoea, insomnia, constipation and diarrhoea measured by EORTC QLQ-C30; side effects, breast symptoms and upset by hair loss measured by QLQ-BR23 (P_adjusted<0.05). Compared to patients with T1DM, those with T2DM are likely to suffer more by loss of functioning.

Conclusions

Diabetes was associated with the decreased QOL for breast cancer survivors.

The molecular mechanisms between metabolic syndrome and breast cancer

Metabolic syndrome, which is extremely common in developed and some developing countries, is a clustering of at least three of five of the following medical conditions: abdominal obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides, and low high-density lipoprotein levels. It has been proved that there is a strong association between metabolic syndrome and breast cancer. Metabolic syndrome could increase the risk of breast cancer and influence the prognosis of the breast cancer patients. Some characteristic of metabolic syndrome such as obesity and lack of physical exercise are all risk factors for developing breast cancer. The metabolic syndrome mainly include obesity, type 2 diabetes, hypercholesterolemia and nonalcoholic fatty liver disease, and each of them impacts the risk of breast cancer and the prognosis of the breast cancer patients in different ways. In this Review, we focus on recently uncovered aspects of the immunological and molecular mechanisms that are responsible for the development of this highly prevalent and serious disease. These studies bring new insight into the complex associations between metabolic syndrome and breast cancer and have led to the development of novel therapeutic strategies that might enable a personalized approach in the management of this disease.

Medication use by early-stage breast cancer survivors: a 1-year longitudinal study

Purpose

The aim of this study is to characterize the patterns of medication use by early-stage breast cancer (ESBC) survivors from diagnosis to 1 year post-chemotherapy.

Methods

A single-center longitudinal study was conducted with ESBC patients diagnosed between December 2011 and June 2014. Data on the medication use of individual patients were retrieved from prescription databases, supplemented by records from the National Electronic Health Records. The data covered the period from ESBC diagnosis to 1 year post-chemotherapy. Medication types were classified according to the World Health Organization’s Anatomical Therapeutic Chemical classification system, and medication for chronic diseases was created by adapting a list of 20 chronic diseases provided by the U.S. Department of Human and Health Services.

Results

Of the 107 patients involved in the study (mean age 51.1 ± 8.4 years; 78.5 % Chinese), 46.7 % manifested non-cancer comorbidities, of which hypertension (24.3 %) was the most prevalent, followed by hyperlipidemia (13.1 %) and diabetes (5.6 %). Calcium channel blockers (12.1 %) and lipid-modifying agents (11.2 %) were the most common chronic medication types used before chemotherapy, and their use persisted during chemotherapy (10.3 and 11.2 %, respectively) and after chemotherapy (11.2 and 13.1 %, respectively). Hormonal therapy was the predominant post-chemotherapy medication (77.6 %). A statistically significant increase (p < 0.0001) was observed in the mean number of chronic disease medication classes prescribed to patients between the pre-chemotherapy (0.53 ± 1.04) and chemotherapy (0.62 ± 1.08) periods and between the chemotherapy and post-chemotherapy (1.63 ± 1.35) periods.

Conclusions

There is an increase in trend of chronic medication usage in breast cancer survivors after cancer treatment. This study provides important insights into the design of medication management programs tailored to this population. Future studies should incorporate a control population to improve the interpretation of study results.

The Prognostic Impact of Type 2 Diabetes Mellitus on Early Cervical Cancer in Asia

BACKGROUND

Many studies have shown that type 2 diabetes mellitus (DM) increases the risk for several types of cancer but not cervical cancer (CC). Although DM and insulin-like growth factor 1 have preclinical and clinical implications for CC, less is known about the prognostic impact of DM on patients with early stage CC.

PATIENTS AND METHODS

We used the nationwide Taiwan Cancer Registry database to collect the characteristics of stage I-IIA cervical cancer patients diagnosed between 2004 and 2008. DM and other comorbidities were retrieved from the National Health Insurance database. Cervical cancer-specific survival (CSS) and overall survival (OS) times of patients according to DM status were estimated using the Kaplan-Meier method. We used a Cox proportional hazards model to calculate adjusted hazard ratios (HRs) for the effects of DM and other risk factors on mortality.

RESULTS

A total of 2,946 patients had primary stage I-IIA CC and received curative treatments, and 284 (9.6%) had DM. The 5-year CSS and OS rates for patients with DM were significantly lower than those without DM (CSS: 85.4% vs. 91.5%; OS: 73.9% vs. 87.9%). After adjusting for clinicopathologic variables and comorbidities, DM remained an independent unfavorable prognostic factor for CSS (adjusted HR: 1.46) and OS (adjusted HR: 1.55).

CONCLUSION

In Asian patients with early cervical cancer, DM is an independent unfavorable prognostic factor influencing both OS and CSS, even after curative treatments.

IMPLICATIONS FOR PRACTICE

Type 2 diabetes mellitus (DM) increases the incidence of several types of cancer but not cervical cancer (CC); however, less is known about the impact of DM on patients who already have CC. This study suggests that DM may increase the risk of cancer recurrence and death for early stage CC patients, even after curative treatments. Incorporating DM control should be considered part of the continuum of care for early stage CC patients, and close surveillance during routine follow-up in this population is recommended.

Type 2 Diabetes and Breast Cancer: The Interplay between Impaired Glucose Metabolism and Oxidant Stress

Metabolic disorders, especially type 2 diabetes and its associated complications, represent a growing public health problem. Epidemiological findings indicate a close relationship between diabetes and many types of cancer (including breast cancer risk), which regards not only the dysmetabolic condition, but also its underlying risk factors and therapeutic interventions. This review discusses the advances in understanding of the mechanisms linking metabolic disorders and breast cancer. Among the proposed mechanisms to explain such an association, a major role is played by the dysregulated glucose metabolism, which concurs with a chronic proinflammatory condition and an associated oxidative stress to promote tumour initiation and progression. As regards the altered glucose metabolism, hyperinsulinaemia, both endogenous due to insulin-resistance and drug-induced, appears to promote tumour cell growth through the involvement of innate immune activation, platelet activation, increased reactive oxygen species, exposure to protumorigenic and proangiogenic cytokines, and increased substrate availability to neoplastic cells. In this context, understanding the relationship between metabolic disorders and cancer is becoming imperative, and an accurate analysis of these associations could be used to identify biomarkers able to predict disease risk and/or prognosis and to help in the choice of proper evidence-based diagnostic and therapeutic protocols.

Metformin increases survival in hormone receptor-positive, HER2-positive breast cancer patients with diabetes

Introduction

Metformin use has recently been observed to decrease both the rate and mortality of breast cancer. Our study was aim to determine whether metformin use is associated with survival in diabetic breast cancer patients by breast cancer subtype and systemic treatment.

Methods

Data from the Asan Medical Center Breast Cancer Database from 1997 to 2007 were analyzed. The study cohort comprised 6,967 nondiabetic patients, 202 diabetic patients treated with metformin, and 184 diabetic patients that did not receive metformin. Patients who were divided into three groups by diabetes status and metformin use were also divided into four subgroups by hormone receptor and HER2-neu status.

Results

In Kaplan-Meier analysis, the metformin group had a significantly better overall and cancer specific survival outcome compared with non metformin diabetic group (P <0.005 for both). There was no difference in survival between the nondiabetic and metformin groups. In multivariate analysis, Compared with metformin group, patients who did not receive metformin tended to have a higher risk of metastasis with HR 5.37 (95 % CI, 1.88 to 15.28) and breast cancer death with HR 6.51 (95 % CI, 1.88 to 15.28) on the hormone receptor-positive and HER2-negative breast cancer. The significant survival benefit of metformin observed in diabetic patients who received chemotherapy and endocrine therapy (HR for disease free survival 2.14; 95 % CI 1.14 to 4.04) was not seen in diabetic patients who did not receive these treatments.

Conclusion

Patients receiving metformin treatment when breast cancer diagnosis show a better prognosis only if they have hormone receptor-positive, HER2-positive tumors. Metformin treatment might provide a survival benefit when added to systemic therapy in diabetic patients.

Clinicopathological characteristics and prognosis of breast cancer patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) can increase the risk of several common cancers, including breast cancer (BC). The purpose of the present study was to investigate the clinicopathological features and prognosis of BC patients with or without T2DM. Seventy-eight patients were diagnosed with T2DM prior to the diagnosis of BC in the Cancer Hospital of Shantou University Medical College (Shantou, China) between 2002 and 2008. A total of 300 BC patients without T2DM were randomly selected as study controls during the same period. The clinicopathological characteristics, overall survival (OS) and disease-free survival (DFS) rates of these two groups were compared. Fifty-five BC patients and 133 control patients with T2DM were >50 years old (70.5 and 44.3%, respectively). There were more T2DM BC patients with body mass index (BMI) ≥25 kg/m² (46.2 vs. 23.3%) and these patients had a higher rate of lymph node involvement (67.9 vs. 55.0%). The DFS of the two groups was 32.1 vs. 22.3%. The OS of the two groups was 24.4 vs. 13.7%. Following adjustment for BMI, tumor-node metastasis stage and stratification of age, the relapse risk of T2DM BC patients was >2-fold higher than that of the control group in the estrogen receptor/progesterone receptor (ER/PR)-positive patients. In Her-2-negative BC patients, the relapse risk of T2DM patients was 2.237-fold higher than that of the non-T2DM patients. In conclusion, T2DM BC patients were significantly older and more likely to be overweight, and had more lymph nodes involvement. T2DM was associated with poor prognosis in ER/PR positive or Her-2-negative BC patients.

Association of type 2 diabetes genetic variants with breast cancer survival among Chinese women

Objective

To evaluate whether the genetic susceptibility of T2D was associated with overall survival (OS) and disease-free survival (DFS) outcomes for breast cancer (BC).

Methods

Included in the study were 6346 BC patients who participated in three population-based epidemiological studies of BC and were genotyped with either GWAS or Exome-chip. We constructed a genetic risk score (GRS) for diabetes using risk variants identified from the GWAS catalog (http://genome.gov/gwastudies) that were associated with T2D risk at a minimum significance level of P ≤ 5.0E-8 among Asian population and evaluated its associations with BC outcomes with Cox proportional hazards models.

Results

During a median follow-up of 8.08 years (range, 0.01–16.95 years), 1208 deaths were documented in 6346 BC patients. Overall, the diabetes GRS was not associated with OS and DFS. Analyses stratified by estrogen receptor status (ER) showed that the diabetes GRS was inversely associated with OS among women with ER- but not in women with ER+ breast cancer; the multivariable adjusted HR was 1.38 (95% CI: 1.05–1.82) when comparing the highest to the lowest GRS quartiles. The association of diabetes GRS with OS varied by diabetes status (P for interaction <0.01). In women with history of diabetes, higher diabetes GRS was significantly associated with worse OS, with HR of 2.22 (95% CI: 1.28–3.88) for the highest vs. lowest quartile, particularly among women with an ER- breast cancer, with corresponding HR being 4.59 (95% CI: 1.04–20.28). No significant association between the diabetes GRS and OS was observed across different BMI and PR groups.

Conclusions

Our study suggested that genetic susceptibility of T2D was positively associated with total mortality among women with ER- breast cancer, particularly among subjects with a history of diabetes. Additional studies are warranted to verify the associations and elucidate the underlying biological mechanism.

Comorbidity is independently associated with poor outcome in extremity soft tissue sarcoma

Background

Comorbidity has not been examined as an independent prognostic factor in soft tissue sarcoma (STS). We examined the prognostic impact of comorbidity on oncologic outcome in STS with an adjustment for possible confounding factors.

Methods

A retrospective review was performed on 349 patients who had undergone surgery for high-grade localized STS of extremity at our institute. Conditions known to alter the risk of mortality, as defined in the Charlson comorbidity index, were classified as comorbidities and 43 patients (12%) had at least one comorbidity at the time of surgery. The association of comorbidity and oncologic outcomes of local recurrence-free survival (LRFS) and disease-specific survival (DSS) were tested with adjustment for confounding factors.

Results

Comorbidity was associated with old age, high tumor grade, and large tumor size. The presence of comorbidity was independently associated with poor LRFS and DSS, even after adjusting for confounding factors including age and treatment variables.

Conclusions

Our data suggest that the presence of comorbidity is an independent prognostic factor for extremity STS.

Impact of type 2 diabetes mellitus on the prognosis of early stage triple-negative breast cancer in People's Republic of China

Background

Type 2 diabetes mellitus (T2DM) is one of the most common chronic metabolic diseases. Increased cause-specific mortality and decreased disease-free survival (DFS) have been reported among cancer patients with T2DM compared with patients without T2DM, even after adjustments of other comorbidities. However, less is known about the impact of T2DM and other comorbidities on DFS in Chinese patients with early stage triple-negative breast cancer (TNBC).

Patients and methods

We assessed patients who were newly diagnosed with early stage primary TNBC at the Department of Breast Surgery, Fudan University, from 2003 to 2011. Of the 1,100 TNBC patients, 865 female patients had invasive and early stage TNBC. The association of the variables in the T2DM and non-T2DM groups was compared using the Pearson’s chi-square and independent t-tests. DFS was estimated using the Kaplan–Meier method. The effects of T2DM and other possible risk factors on DFS were assessed by Cox proportional hazards regression using univariate or multivariate analysis.

Results

A total of 865 early stage primary TNBC cases were studied, including 104 (12.02%) subjects with T2DM. Metastatic or recurrent disease was detected in 24 (23.08%) patients in the T2DM group and 35 (4.60%) patients in the non-T2DM group. Patients with T2DM exhibited a significantly lower DFS than patients without T2DM (log-rank P<0.001). Similar results were observed when patients with positive lymph nodes were compared with patients with negative lymph nodes (log-rank P=0.003). T2DM was independently associated with a lower DFS after adjustments of other variables (adjusted hazard ratio, 7.719; 95% confidence interval, 4.304–13.843; P<0.001) and adjustments of lymph node positivity (adjusted hazard ratio, 2.407; 95% confidence interval, 1.391–4.166; P=0.002). The DFS rates at 2 years for the T2DM group and the non-T2DM group were 78% and 97%, respectively. The prognostic influence of T2DM was consistent across the subgroups, including subgroups by age (>50 or ≤50), menopausal status (post- or premenopausal), tumor size (>5 cm or ≤5 cm), lymph node involvement (positive or negative), and adjuvant chemotherapy (received or not) using the Kaplan–Meier method (log-rank P<0.05).

Conclusion

In the People’s Republic of China, T2DM is an independent prognostic risk factor that indicates an increased likelihood of recurrence and metastasis in patients with early stage TNBC. The presence of T2DM should be taken into account when evaluating the risk for an early stage TNBC patient. More effective therapeutic regimens are needed for early stage TNBC patients with T2DM.

Diabetes, diabetes treatment and breast cancer prognosis

The objectives of this study are to assess the impact of pre-existing diabetes and diabetes treatment on breast cancer prognosis. 8,108 women with centrally confirmed invasive breast cancer in the Women's Health Initiative diagnosed between 1998 and 2013 were followed through the date of death or September 20, 2013. Information on diabetes and diabetes therapy were obtained via self-report and face-to-face review of current medication containers, respectively. Cox proportional hazard regression was used to estimate adjusted relative hazard ratios for overall mortality. The proportional subdistribution hazard model was used to estimate hazard ratios for breast cancer-specific mortality. Compared with women without diabetes, women with diabetes had significantly increased risk of overall mortality (HR 1.26 95 % CI 1.06-1.48), especially among those who took insulin or had longer duration of diabetes. However, diabetes was not associated with increased risk of breast cancer-specific mortality, regardless of type of treatment and duration of diabetes, despite the significant association of diabetes with unfavorable tumor characteristics. Our large prospective cohort study provides additional evidence that pre-existing diabetes increases risk of total mortality among women with breast cancer. The increased total mortality associated with diabetes was mainly driven by increased risk of dying from diseases other than breast cancer. Thus, the continuum of care for breast cancer patients with diabetes should include careful attention to CVD risk factors and other non-cancer conditions.

Metformin may function as anti-cancer agent via targeting cancer stem cells: the potential biological significance of tumor-associated miRNAs in breast and pancreatic cancers

Metformin is one of the most used diabetic drugs for the management of type II diabetes mellitus (DM) in the world. Increased numbers of epidemiological and clinical studies have provided convincing evidence supporting the role of metformin in the development and progression of a variety of human tumors including breast and pancreatic cancer. Substantial pre-clinical evidence from in vitro and in vivo experimental studies strongly suggests that metformin has an anti-cancer activity mediated through the regulation of several cell signaling pathways including activation of AMP kinase (AMPK), and other direct and indirect mechanisms; however, the detailed mechanism(s) has not yet been fully understood. The concept of cancer stem cells (CSCs) has gained significant attention in recent years due its identification and defining its clinical implications in many different tumors including breast cancer and pancreatic cancer. In this review, we will discuss the protective role of metformin in the development of breast and pancreatic cancers. We will further discuss the role of metformin as an anti-cancer agent, which is in part mediated through targeting CSCs. Finally, we will discuss the potential role of metformin in the modulation of tumor-associated or CSC-associated microRNAs (miRNAs) as part of the novel mechanism of action of metformin in the development and progression of breast and pancreatic cancers.

No increased venous thromboembolism risk in Asian breast cancer patients receiving adjuvant tamoxifen

Tamoxifen is an effective endocrine treatment for early breast cancer (EBC) but increases the risk of venous thromboembolism. Whether Asian EBC patients (pts) bear the same risk when treated with adjuvant tamoxifen is uncertain. EBC pts diagnosed between 2004 and 2009 were selected from a population database in Taiwan. The pts were followed up from the index date to December 31, 2011 to collect events of deep vein thrombosis (DVT) and pulmonary embolism (PE). Cumulative incidence rates and hazard ratios (HRs) were used to compare the risk between pts treated with and without tamoxifen. In addition, comorbidities were included in an adjusted model of the risk of DVT and PE. A total of 28,029 EBC pts, including 17,843 (63.8 %) in the tamoxifen group and 10,155 (36.2 %) in the nontamoxifen group, were analyzed. The 7-year cumulative incidence rates for DVT and PE were 2.58 and 0.32 % in the tamoxifen group and 2.51 and 0.32 % in the nontamoxifen group (P = 0.92 for DVT, P = 0. 65 for PE), respectively. The HR for the nonadjusted and adjusted models showed no differences in DVT and PE risks between the tamoxifen and nontamoxifen groups. The uterine cancer risk was significantly increased in the pts receiving tamoxifen (adjusted HR = 2.79, P < 0.001), suggesting tamoxifen compliance. The risks of developing DVT and PE are not increased in Asian EBC pts receiving adjuvant tamoxifen. Ethnicity differences should be considered when discussing optimal endocrine treatments with EBC pts.

The effect of metformin on breast cancer outcomes in patients with type 2 diabetes

Observational data suggest that metformin use decreases breast cancer (BC) incidence in women with diabetes; the impact of metformin on BC outcomes in this population is less clear. The purpose of this analysis was to explore whether metformin use influences BC outcomes in women with type 2 diabetes. Prospective institutional databases were reviewed to identify patients with diabetes who received chemotherapy for stages I–III BC from 2000 to 2005. Patients diagnosed with diabetes before or within 6 months of BC diagnosis were included. Males and those with type I, gestational, or steroid-induced diabetes were excluded. Patients were stratified based on metformin use, at baseline, defined as use at time of BC diagnosis or at diabetes diagnosis if within 6 months of BC diagnosis. Kaplan–Meier methods were used to estimate rates of recurrence-free survival (RFS), overall survival (OS), and contralateral breast cancer (CBC). We identified 313 patients with diabetes who received chemotherapy for BC, 141 (45%) fulfilled inclusion criteria and 76 (54%) used metformin at baseline. There were no differences in clinical presentation or tumor characteristics between metformin users and nonusers. At a median follow-up of 87 months (range, 6.9–140.4 months), there was no difference in RFS (P = 0.61), OS (P = 0.462), or CBC (P = 0.156) based on metformin use. Five-year RFS was 90.4% (95% CI, 84–97) in metformin users and 85.4% (95% CI, 78–94) in nonusers. In this cohort of patients with type 2 diabetes receiving systemic chemotherapy for invasive BC, the use of metformin was not associated with improved outcomes.

The influence of diabetes severity on receipt of guideline-concordant treatment for breast cancer

Diabetes severity may influence breast cancer treatment choices. We examined whether receipt of guideline-concordant breast cancer treatment varied with diabetes severity. Cancer registry data from seven states regarding 6,912 stage I-III breast cancers were supplemented by medical record abstraction and physician verification. We used logistic regression models to examine associations of diabetes severity with guideline-concordant locoregional treatment, adjuvant chemotherapy, and hormonal therapy adjusted for sociodemographics, comorbidity, and tumor characteristics. We defined guideline concordance using National Comprehensive Cancer Network guidelines, and diabetes and comorbidities using the Adult Comorbidity Evaluation-27 index. After adjustment, there was significant interaction of diabetes severity with age for locoregional treatment (p = 0.001), with many diabetic women under age 70 less frequently receiving guideline-concordant treatment than non-diabetic women. Among similarly aged women, guideline concordance was lower for women with mild diabetes in their late fifties through mid-sixties, and with moderate/severe diabetes in their late forties to early sixties. Among women in their mid-seventies to early eighties, moderate/severe diabetes was associated with increased guideline concordance. For adjuvant chemotherapy, moderate/severe diabetes was less frequently associated with guideline concordance than no diabetes [OR 0.58 (95 % CI 0.36-0.94)]. Diabetes was not associated with guideline-concordant hormonal treatment (p = 0.929). Some diabetic women were less likely to receive guideline-concordant treatment for stage I-III breast cancer than non-diabetic women. Diabetes severity was associated with lower guideline concordance for locoregional treatment among middle-aged women, and lower guideline concordance for adjuvant chemotherapy. Differences were not explained by comorbidity and may contribute to potentially worse breast cancer outcomes.

Clinical pathological characteristics and prognostic analysis of diabetic women with luminal subtype breast cancer

This study selected luminal-type breast cancer patients as the study subjects. The patients were divided into groups according to the presence of diabetes and the types of medication used, and the patients' clinicopathological characteristics and prognostic indicators were explored. A total of 5,785 patients with luminal-type breast cancer admitted to Tianjin Medical University Cancer Institute and Hospital between January 2002 and December 2006 were selected as the study subjects. The subjects included 680 breast cancer patients with diabetes and 5,105 breast cancer patients without diabetes. The patients were divided into Luminal A, Luminal B (high ki67), and Luminal B (her-2/neu+) subtypes. Each subtype was further divided into a metformin group, a non-metformin group, and a nondiabetic group. The research indicators included breast cancer mortality, age, body mass index (BMI), amenorrhea, the presence of cardiovascular and cerebrovascular disease, pathological stage, pathological type, lymph node involvement, vessel carcinoma embolus, and the chemotherapy and endocrine regimen. A Kaplan-Meier analysis was conducted to analyze the differences in breast cancer mortality rates among the groups. The Cox proportional hazard model was adopted to detect independent factors related to prognosis. Kaplan-Meier univariate analysis showed that for the Luminal A, Luminal B (high ki67), and Luminal B (her-2/neu+) subtypes, the cancer-specific mortality rates differed significantly among the metformin, non-metformin, and nondiabetic groups. The 5-year survival rates were 94%, 82%, and 91% (P = 0.002); 93.5%, 81%, and 89% (P < 0.001); and 84%, 77%, and 83% (P = 0.035) for the subtypes within each group, respectively. Cox regression multivariate analysis showed that compared with the metformin group, all three subtypes of the, the non-metformin group showed poorer prognosis (hazard ratio [HR], 3.579; 95% confidence interval [CI], 1.506-8.506 [P = 0.004]; HR, 3.232; 95% CI, 1.839-5.678 [P < 0.001]; HR, 2.034; 95% CI,1.019-4.059 [P = 0.044] for Luminal A, Luminal B (high ki67), and Luminal B (her-2/neu+, respectively). Compared with the metformin group, the diabetic group showed poorer prognosis only for the Luminal B (high ki67) subtype (HR, 1.762; 95% CI, 1.033-3.005 [P = 0.038]). In addition, for the Luminal A, Luminal B (high ki67), and Luminal B (her-2/neu+) subgroups, there was a higher proportion of elderly patients (P < 0.001) and postmenopausal patients (P < 0.001) in the metformin and non-metformin groups than in the nondiabetic group. Moreover, the probability of having cardiovascular and cerebrovascular disease was also higher (P < 0.001) in the metformin and non-metformin groups. For the Luminal B (high ki67) and Luminal B (her-2/neu +) subgroups, there was a higher proportion of obese patients in the metformin and non-metformin groups (P < 0.001). In terms of clinical characteristics, for the Luminal B (high ki67) subtype, the proportion of patients with invasive ductal carcinoma was lower in the non-metformin group than in the other two groups (P = 0.001). In both the metformin and non-metformin groups, the proportion of T3/4 patients was higher (P < 0.001), the proportion of patients with lymph node metastasis was higher (P = 0.001), and the proportion of patients with vessel carcinoma embolus was higher (P = 0.001) compared with the nondiabetic group. In conclusion, compared with the metformin group, the non-metformin group had a poorer prognosis for all subtypes of luminal breast cancer. In the diabetic group, only patients with the Luminal B (high ki67) subtype exhibited a poorer prognosis. Therefore, different diabetes medication may have a different impact on the prognosis of different subtypes of luminal breast cancer.

Diabetes mellitus without metformin intake is associated with worse oncologic outcomes after radical nephroureterectomy for upper tract urothelial carcinoma

AIMS

Evidence suggests a detrimental effect of diabetes mellitus (DM) on cancer incidence and outcomes. To date, the effect of DM and its treatment on prognosis in upper tract urothelial carcinoma (UTUC) remains uninvestigated. We tested the hypothesis that DM and metformin use impact oncologic outcomes of patients treated with radical nephroureterectomy (RNU) for UTUC.

METHODS

Retrospective analysis of 2492 patients with UTUC treated at 23 institutions with RNU without neoadjuvant therapy. Cox regression models addressed the association of DM and metformin use with disease recurrence, cancer-specific mortality and any-cause mortality.

RESULTS

A total of 365 (14.3%) patients had DM and 194 (7.8%) patients used metformin. Within a median follow-up of 36 months, 663 (26.6%) patients experienced disease recurrence, 545 patients (21.9%) died of UTUC and 884 (35.5%) patients died from any cause. Diabetic patients who did not use metformin were at significantly higher risk of disease recurrence and cancer-specific death compared to non-diabetic patients and diabetic patients who used metformin. In multivariable Cox regression analyses, DM treated without metformin was associated with worse recurrence-free survival (HR: 1.44, 95% CI 1.10-1.90, p = 0.009) and cancer-specific mortality (HR: 1.49, 95% CI 1.11-2.00, p = 0.008).

CONCLUSIONS

Diabetic UTUC patients without metformin use have significantly worse oncologic outcomes than diabetics who used metformin and non-diabetics. The possible mechanism behind the impact of DM on UTUC biology and the potentially protective effect of metformin need further elucidation.

The impact of type 2 diabetes mellitus on mortality in hospitalized female cancer patients in Taiwan

INTRODUCTION

The goal of this study was to determine the relationships among type 2 diabetes mellitus (DM), specific cancer histological types and mortality in hospitalized women.

METHODS

Patients over 19 years of age were included if the indication for hospital admission was a diagnosis of type 2 DM or a malignancy. In total, 67,660 female patients with a mean age 62.76 ± 14.48 years were enrolled. These patients were categorized into the following three groups: patients with cancer but without type 2 DM (group A); patients with cancer and type 2 DM (group B) and patients with type 2 DM but without cancer (group C). Attributable fractions (AF) were calculated as ([hazard ratio - 1]/hazard ratio) × 100 to evaluate the impact of type 2 DM on mortality for specific cancers.

RESULTS

Of the study participants, 37,204 (55%) were diagnosed with type 2 DM. The patients were categorized as follows: group A, 30,456 patients; group B, 5992 patients and group C, 31,212 patients. Group B patients had high frequencies of pancreatic, liver and renal cancers and low frequencies of thyroid, breast and ovarian cancers. Of the 36,448 cancer patients, 2906 (8%) died. The mortality rate in group B (10 %) was significantly higher than that in groups A and C. Type 2 DM was associated with increased mortality and AF for thyroid, nasopharyngeal, urinary tract, ovarian, breast and cervical cancers (hazard ratio over 1.50).

CONCLUSION

The incidence of type 2 DM in patients with different histological types of cancer varied widely, ranging from 8-34%. Among the cancer patients, type 2 DM had a significantly greater impact on the mortality rates of patients with cancers associated with relatively low mortality.

Type 2 diabetes mellitus, oral diabetic medications, insulin therapy, and overall breast cancer risk

Breast cancer is among the most common cancers worldwide. Diabetes is an important chronic health problem associated with insulin resistance, increased insulin level, changes in growth hormones and factors, and activation of mitogen-activating protein kinase (MAPK) pathways, leading to an increased breast cancer risk. This paper looked at the epidemiologic studies of the association between type 2 diabetes and risk of breast cancer and its effect on overall cancer-specific survival. The combined evidence overall supported a modest association between type 2 diabetes and the risk of breast cancer, which was found to be more prevalent among postmenopausal women. Effect of oral diabetics and insulin therapy on breast cancer risk was also evaluated. It was found that metformin and thiazolidinones tended to have a protective role. Metformin therapy trials for its use as an adjuvant for breast cancer treatment are still ongoing. Sulfonylurea and insulin therapy were found to be mildly associated with increased overall cancers. No evidence or studies evaluated the association of DPPIV inhibitors and GLP 1 agonists with breast cancer risk because of their recent introduction into the management of diabetes.

The epidemiology and molecular mechanisms linking obesity, diabetes, and cancer

The worldwide epidemic of obesity is associated with increasing rates of the metabolic syndrome and type 2 diabetes. Epidemiological studies have reported that these conditions are linked to increased rates of cancer incidence and mortality. Obesity, particularly abdominal obesity, is associated with insulin resistance and the development of dyslipidemia, hyperglycemia, and ultimately type 2 diabetes. Although many metabolic abnormalities occur with obesity and type 2 diabetes, insulin resistance and hyperinsulinemia appear to be central to these conditions and may contribute to dyslipidemia and altered levels of circulating estrogens and androgens. In this review, we will discuss the epidemiological and molecular links between obesity, type 2 diabetes, and cancer, and how hyperinsulinemia and dyslipidemia may contribute to cancer development. We will discuss how these metabolic abnormalities may interact with estrogen signaling in breast cancer growth. Finally, we will discuss the effects of type 2 diabetes medications on cancer risk.