The Clinical Effect of Metformin on the Survival of Lung Cancer Patients with Diabetes: A Comprehensive Systematic Review and Meta-analysis of Retrospective Studies

A phase II study of metformin plus pemetrexed and carboplatin in patients with non-squamous non-small cell lung cancer (METALUNG)

Immune checkpoint inhibitors (ICIs) ± chemotherapy is the standard treatment for driver mutation-negative non-small cell lung cancer (NSCLC). However, accessibility to ICIs in LMICs is limited due to high cost, and platinum-based chemotherapy remains the mainstay of treatment. Metformin has anticancer properties, and studies suggest synergism between metformin and pemetrexed. Based on preclinical evidence, this combination may be more beneficial for STK11-mutated NSCLC, a subgroup, inherently resistant to ICIs. In this Simon two-stage, single-arm phase 2 trial, we investigated metformin with pemetrexed-carboplatin (PC) in patients with treatment-naive stage IV non-squamous NSCLC. The primary outcome was 6-month progression-free survival (PFS) rate. Secondary outcomes were safety, overall survival (OS), overall response rate (ORR), proportion of STK11 mutation, and effect of STK11 mutation on 6-month PFS rate. The study was terminated for futility after interim analysis. The median follow-up was 34.1 months. The 6-month PFS rate was 28% (95% CI 12.4-0.46). The median PFS and OS were 4.5 (95% CI 2.2-6.1) and 7.4 months (95% CI 5.3-15.3), respectively. The ORR was 72%. Gastrointestinal toxicities were the most common. No grade 4/5 toxicities were reported. Targeted sequencing was possible in nine cases. Two patients had STK11 mutation and a poor outcome (PFS < 12 weeks). We could not demonstrate the benefit of metformin with CP in terms of improvement in 6-month PFS rate; however, the combination was safe (CTRI/2019/02/017815).

Efficacy of metformin adjunctive therapy as the treatment for non-diabetic patients with advanced non-small cell lung cancer: A Systematic review and Meta-analysis

Background

Currently, the anticancer effects of metformin on different types of lung cancer have been frequently studied. However, the relationship between metformin and prognosis in nondiabetic patients with lung cancer remains controversial. To systematically evaluate the efficacy of metformin adjunctive therapy as the treatment for nondiabetic patients with advanced non-small cell lung cancer (NSCLC) to provide an evidence-based reference for clinical medication.

Materials and Methods

The literatures related to Phase II or III randomized controlled trials (RCTs) of metformin adjunctive therapy in nondiabetic patients with advanced NSCLC, including EMBASE, PubMed, the Cochrane Library, and Scopus database, were retrieved by computer, and the search time ranged from January 2017 to August 2022. The risk of bias assessment tool recommended by Cochrane Systematic Evaluator Manual 5.1.0 was used to evaluate the quality of the RCTs included. Rev Man 5.3 software and STATA15.0 were used for meta-analysis.

Results

A total of 8 studies were included (925 patients). Meta-analysis results showed that there were no significant differences in progression-free survival (PFS) (hazard ratio [HR] = 0.95, 95% confidence interval [CI]: 0.66-1.36, P = 0.77), overall survival (OS) (HR = 0.89, 95% CI: 0.61-1.30, P = 0.55, n =7), objective response rate (ORR) (odds ratio [OR] = 1.37, 95% CI: 0.76-2.46, P = 0.30), and 1-year PFS rate (OR = 0.87, 95% CI: 0.39-1.94, P = 0.73, n = 3). Sensitivity analysis showed that PFS and OS indexes were stable.

Conclusion

Metformin adjunctive therapy can improve the DCR of nondiabetic patients with advanced NSCLC. In addition, the patients cannot obtain a prolonged PFS, OS, 1-year PFS rate, and higher ORR rate.

Addition of metformin for non-small cell lung cancer patients receiving antineoplastic agents

Background and purpose: Previous studies have found that metformin can inhibit tumor growth and improve outcomes for cancer patients. However, the association between the addition of metformin to the treatment regimen and survival in non-small cell lung cancer (NSCLC) patients receiving antineoplastic agents such as chemotherapy drugs, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), and immune checkpoint inhibitors (ICIs) remains unclear. This study aimed to evaluate the effect of metformin in NSCLC patients who received the aforementioned antineoplastic therapies.

Methods: Several electronic databases were searched for relevant studies published by 10 September 2022. The primary and secondary outcomes were overall survival (OS) and progression-free survival (PFS); eligible studies were those comparing patients with and without the addition of metformin. Hazard ratios (HRs) and 95% confidence intervals (CIs) were combined, with all statistical analyses performed using STATA 15.0.

Results: A total of 19 studies involving 6,419 participants were included, of which six were randomized controlled trials. The overall pooled results indicate that the addition of metformin improved OS (HR = 0.84, 95% CI: 0.71–0.98, p = 0.029) and PFS (HR = 0.85, 95% CI: 0.74–0.99, p = 0.039). However, subgroup analysis based on treatment type and comorbidity of diabetes mellitus demonstrated that improvements in OS and PFS were observed only in diabetic and EGFR-TKI-treated patients (OS: HR = 0.64, 95% CI: 0.45–0.90, p = 0.011; PFS: HR = 0.59, 95% CI: 0.34–1.03, p = 0.061).

Conclusion: Overall, this meta-analysis found that metformin use could improve outcomes for diabetic patients receiving EGFR-TKIs. However, no significant association between the addition of metformin and the survival of non-diabetic NSCLC patients receiving chemotherapy or ICI therapy was identified based on the current evidence.

Metformin: A Promising Antidiabetic Medication for Cancer Treatment

Metformin is a widely used drug in patients with type 2 diabetes mellitus. Metformin inhibits hepatic gluconeogenesis and increases glucose utilization in peripheral tissues. In recent years, several studies have shown that metformin is a potential therapeutic agent against cancer, alone or combined with other anticancer treatments. Metformin mainly activates the AMPK complex and regulates intracellular energy status, inhibiting the mitochondrial respiratory chain complex I and reducing the production of reactive oxygen species. Other anticancer targets of metformin are specific transcription factors inhibiting cell proliferation, promoting apoptosis and reducing drug resistance. In addition, metformin modulates tumor cells' response to anticancer treatments, favoring the activity of T cells. In diabetic patients, metformin reduces the occurrence of cancer and improves the prognosis and efficacy of anticancer treatments. In this review, we provided a comprehensive perspective of metformin as an anticancer drug.

Examining the relationship between metformin dose and cancer survival: A SEER-Medicare analysis

Cancer is a major health problem in the U.S and type 2 diabetes mellitus (T2DM) is known to increase the risk for the development of many cancers. Metformin, a first-line therapy for treating T2DM, is increasingly being used for its anticancer effects; however, the literature is limited on the effect of metformin dose on overall survival in patients with stage IV cancer. Overall survival was defined as the time interval from the date of diagnosis to the last known follow-up or death from any cause. Subjects who were alive on December 31, 2016 were censored. In this cohort study we examined the relationship between metformin dose and overall survival in persons with both T2DM and stage IV lung, breast, colorectal, prostate, or pancreas cancers. We used a retrospective study design with Cox proportional hazards regression analysis of the 2007–2016 of the Surveillance Epidemiology and End Results-Medicare (SEER) dataset. Of the 7,725 patients, 2,981(38.5%) had been prescribed metformin. Patients who used metformin had significantly better overall survival in both unadjusted (Unadjusted HR, 0.73; 95% CI, 0.69–0.76; p < 0.001) and adjusted models (adjusted HR, 0.77; 95% CI, 0.73–0.81; p < 0.001). The overall survival between patients who took metformin with average daily dose ≥ 1000mg or < 1000mg were not statistically significant (aHR, 1.00; 95% CI, 0.93–1.08; p = 0.90). Metformin use regardless of dose is associated with increased overall survival in older adults with stage IV cancer.

Advances in metformin‑based metabolic therapy for non‑small cell lung cancer (Review)

Therapeutic approaches that target the metabolism of tumor cells have been a popular research topic in recent years. Previous studies have demonstrated that glycolysis inhibitors reduce the proliferation of non‑small cell lung cancer (NSCLC) cells by interfering with the aerobic glycolytic pathway. However, the mitochondrial oxidative phosphorylation (OXPHOS) pathway in tumor cells has also been implicated in lung cancer metabolism. Metformin, a known inhibitor of mitochondrial OXPHOS, has been indicated to reduce NSCLC morbidity and mortality in clinical studies. The present article reviewed the therapeutic effects of metformin against NSCLC, both as a single agent and combined with other anticancer treatments, in order to provide a theoretical basis for its clinical use in adjuvant therapy for NSCLC.

The effect of metformin on viability and mitochondrial status of tumor and non-tumor cell line

Introduction: Metformin is a drug of choice in the therapy of type II Diabetes mellitus. There is a growing evidence of metformin's antitumor activity, but the suggested mechanisms of such activity are still not fully elucidated. Aim: To investigate the effect of therapeutic doses of metformin on viability and mitochondrial status of human non-small cell lung carcinoma (NCI-H460) and human immortalized lung fibroblasts (MRC-5) cell lines. Material and methods: Acid phosphatase and Crystal Violet assays were used for the determination of NCI-H460 and MRC-5 cell viability after the treatment with metformin (10-60 µM) for 1-7 days. Mitochondrial membrane potential, production of reactive oxygen species and superoxide anion, as well as mitochondrial mass were measured using flow cytometry after the treatment of the cells for 3, 24 and 120 h, followed by staining with appropriate fluorochromes: JC-1, DHR, DHE and Mitotracker Red. Results: Metformin did not change the viability of both NCI-H460 and MRC-5 cells in all investigated time-points and all used concentrations. Depolarization of mitochondrial membrane was observed 3 h post-treatment in MRC-5 cells. Prolonged treatment (120 h) increased superoxide anion production and mitochondrial mass in NCI-H460 cells. No significant changes in production of reactive oxygen species were observed in both cells lines after short or extended exposure to metformin. Conclusion: : Therapeutic concentrations of metformin do not influence the viability of NCI-H460 and MRC-5 cells, but induce mitochondrial depolarization after short-term exposure in lung fibroblasts and increase production of superoxide anion and mitochondrial mass in lung carcinoma cells after prolonged treatment.

The role of metformin on lung cancer survival: the first systematic review and meta-analysis of observational studies and randomized clinical trials

PURPOSE

To assess the effects of metformin use on lung cancer (LC) survival according to summarized results from observational studies (OBs) and randomized clinical trials (RCTs).

METHODS

We systematically searched electronic databases and, to our knowledge, for the first time, RCTs were included in a systematic review and meta-analysis about the role of metformin on LC survival. We carried out meta-analyses separately for OBs and RCTs. Analyses for overall survival (OS) concerning OBs were stratified by studies with and without time-dependent approach. Subgroup analyses were adopted for OBs to identify the sources of heterogeneity. Included studies were assessed for quality.

RESULTS

We identified ten OBs and four RCTs. For OBs, metformin use was associated with improved OS for LC patients. Only two studies used time-dependent approach in which a higher ratio was found when compared to the non-use of the time-dependent analysis in eight studies. OBs were classified as high quality but the risk of bias was "unclear" in eight OBs due to absence of the time-dependent analysis. For RCTs, metformin use was not beneficial for OS and neither for progression-free survival. Heterogeneous quality was found among RCTs. Sources of bias that could alter significantly the results or raise doubts were identified in RCTs.

CONCLUSION

Time-dependent analysis should be considered an appropriate strategy for OBs focused on the metformin use for LC patients' survival, and further studies applying this approach are required. More well-designed RCTs are needed to provide consistent results for the association between metformin use and LC survival.

The Relationship of Diabetes Mellitus to Efficacy of Immune Checkpoint Inhibitors in Patients with Advanced Non-Small Cell Lung Cancer

INTRODUCTION

Immune checkpoint inhibitors (ICI) are the new standard therapy in patients with metastatic NSCLC (mNSCLC). Metformin, previously associated with improved chemotherapy efficacy in diabetic and nondiabetic cancer patients, was recently associated with increased ICI efficacy. In this study, we aimed to explore the correlations between diabetes mellitus (DM), metformin use, and benefit from ICI in mNSCLC patients.

METHODS

All mNSCLC patients treated with ICI in our center between February 2015 and April 2018 were identified. Demographic and clinical data were extracted retrospectively. Cox proportional hazards regression, t tests, and χ2 tests were employed to evaluate associations of progression-free survival (PFS), overall survival (OS), overall response rate (ORR), and disease control rate (DCR), with DM status, metformin use, and HbA1c levels, as appropriate.

RESULTS

Of 249 mNSCLC patients treated with ICI, 57 (22.8%) had DM. Thirty-seven (64.9% of all diabetic patients) patients were treated with metformin. A significant negative correlation of DM with PFS and OS was demonstrated (HR 1.5 [1.01-2.06], p = 0.011, and HR 1.5 [1.08-2.08], p = 0.017, respectively). Metformin exposure had no significant correlation with PFS or OS in diabetic mNSCLC patients (HR 1.08 [0.61-1.93], p = 0.79, and HR 1.29 [0.69-2.39], p = 0.42, respectively). There were no differences between groups with respect to ORR and DCR.

CONCLUSION

Our data show a potential negative relationship between DM and ICI efficacy in mNSCLC patients. In contrast to reports with chemotherapy, we found no positive relationship between metformin use and ICI therapy in diabetic patients with mNSCLC. Further studies are needed to evaluate the effect of metformin in nondiabetic mNSCLC patients.

Metformin Adjunct With Antineoplastic Agents for the Treatment of Lung Cancer: A Meta-Analysis of Randomized Controlled Trials and Observational Cohort Studies

Objective: Resistance to anticancer agents ensures a poor prognosis in patients with lung cancer. Metformin could enhance the anticancer effects of standard antineoplastic agents [traditional chemotherapy drugs, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), or immune checkpoint inhibitors (ICIs)]; however, it is unclear whether metformin can be combined with antineoplastic agents in the treatment of lung cancer. To explore the efficacy of combinational strategies, we performed a systematic review and meta-analysis for diabetic and non-diabetic patients with lung cancer.

Method: An electronic literature search was performed to obtain relevant randomized controlled trials (RCTs) and observational cohort studies. Hazard ratios (HR) with 95% confidence intervals (CI) of overall survival (OS) and progression-free survival (PFS) outcomes were extracted. Subgroup analysis by antineoplastic agents, study type, histology and clinical stage were investigated.

Results: 14 studies (three RCTs and eleven observational cohort studies) consisting 3,856 patients were included in the meta-analysis. Compared to standard antineoplastic agents alone (traditional chemotherapy drugs, EGFR-TKIs or ICIs), the antineoplastic agents combined with metformin significantly improved OS (HR 0.73, 95% CI 0.66–0.81, p < 0.00001) and PFS (HR 0.72, 95% CI 0.59–0.88, p = 0.001); a similar association was found in observational evidence. Limited data from RCTs showed no differences in OS or PFS.

Conclusion: Metformin plus antineoplastic agents may improve survival outcomes of patients with lung cancer. Further investigation is needed.

Metformin use and lung cancer survival: a population-based study in Norway

BACKGROUND

We assessed associations between metformin use and survival in a nationwide Norwegian cohort of lung cancer (LC) patients.

METHODS

The study linked 22,324 LC patients from the Cancer Registry of Norway diagnosed 2005-2014 with the Norwegian Prescription Database. We estimated associations of pre- and post-diagnostic metformin use with overall survival (OS) and LC-specific survival (LCSS) using multivariable time-fixed and time-dependent Cox regression.

RESULTS

Pre-diagnostic metformin use was not associated with improved survival in all patients. Nevertheless, pre-diagnostic metformin use was associated with better LCSS in squamous cell carcinoma (SCC) patients (hazard ratio (HR) = 0.79; 95% confidence interval (CI) 0.62-0.99) and in patients with regional stage SCC (HR = 0.67; 95%CI 0.47-0.95). Post-diagnostic metformin use was associated with improved LCSS in all patients (HR = 0.83; 95%CI 0.73-0.95), in patients with SCC (HR = 0.75; 95%CI 0.57-0.98), regional stage LC (HR = 0.74; 95%CI 0.59-0.94), and regional stage SCC (HR = 0.57; 95%CI 0.38-0.86). OS showed similar results. Analyses of cumulative use showed a dose-response relationship in all patients, patients with adenocarcinoma and SCC, and with regional and metastatic LC.

CONCLUSIONS

Metformin use was associated with improved survival, especially LCSS in patients with regional stage SCC. Further prospective studies are required to clarify the role of metformin in LC treatment.

Pleiotropic Effects of Metformin on the Antitumor Efficiency of Immune Checkpoint Inhibitors

Cancer is an important threat to public health because of its high morbidity and mortality. In recent decades, immune checkpoint inhibitors (ICIs) have ushered a new therapeutic era in clinical oncology. The rapid development of immune checkpoint therapy is due to its inspiring clinical efficacy in a group of cancer types. Metformin, an effective agent for the management of type 2 diabetes mellitus (T2DM), has shown beneficial effects on cancer prevention and cancer treatment. Emerging studies have suggested that metformin in combination with ICI treatment could improve the anticancer effects of ICIs. Hence, we conducted a review to summarize the effects of metformin on ICI therapy. We also review the pleiotropic mechanisms of metformin combined with ICIs in cancer therapy, including its direct and indirect effects on the host immune system.

Shining a light on metabolic vulnerabilities in non-small cell lung cancer

Metabolic reprogramming is a hallmark of cancer which contributes to essential processes required for cell survival, growth, and proliferation. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and its genomic classification has given rise to the design of therapies targeting tumors harboring specific gene alterations that cause aberrant signaling. Lung tumors are characterized with having high glucose and lactate use, and high heterogeneity in their metabolic pathways. Here we review how NSCLC cells with distinct mutations reprogram their metabolic pathways and highlight the potential metabolic vulnerabilities that might lead to the development of novel therapeutic strategies.

A risk stratification model based on four novel biomarkers predicts prognosis for patients with renal cell carcinoma

BACKGROUND

Accurate prediction of the prognosis of RCC using a single biomarker is challenging due to the genetic heterogeneity of the disease. However, it is essential to develop an accurate system to allow better patient selection for optimal treatment strategies. ARL4C, ECT2, SOD2, and STEAP3 are novel molecular biomarkers identified in earlier studies as survival-related genes by comprehensive analyses of 43 primary RCC tissues and RCC cell lines.

METHODS

To develop a prognostic model based on these multiple biomarkers, the expression of four biomarkers ARL4C, ECT2, SOD2, and STEAP3 in primary RCC tissue were semi-quantitatively investigated by immunohistochemical analysis in an independent cohort of 97 patients who underwent nephrectomy, and the clinical significance of these biomarkers were analyzed by survival analysis using Kaplan-Meier curves. The prognostic model was constructed by calculation of the contribution score to prognosis of each biomarker on Cox regression analysis, and its prognostic performance was validated.

RESULTS

Patients whose tumors had high expression of the individual biomarkers had shorter cancer-specific survival (CSS) from the time of primary nephrectomy. The prognostic model based on four biomarkers segregated the patients into a high- and low-risk scored group according to defined cut-off value. This approach was more robust in predicting CSS compared to each single biomarker alone in the total of 97 patients with RCC. Especially in the 36 metastatic RCC patients, our prognostic model could more accurately predict early events within 2 years of diagnosis of metastasis. In addition, high risk-scored patients with particular strong SOD2 expression had a much worse prognosis in 25 patients with metastatic RCC who were treated with molecular targeting agents.

CONCLUSIONS

Our findings indicate that a prognostic model based on four novel biomarkers provides valuable data for prediction of clinical prognosis and useful information for considering the follow-up conditions and therapeutic strategies for patients with primary and metastatic RCC.

Metformin suppresses Nrf2-mediated chemoresistance in hepatocellular carcinoma cells by increasing glycolysis

The diabetes drug metformin has recently been shown to possess anti-cancer properties when used with other chemotherapeutic drugs. However, detailed mechanisms by which metformin improves cancer treatment are poorly understood. Here we provide evidence in HepG2 hepatocellular carcinoma cells that metformin sensitizes cisplatin-resistant HepG2 cells (HepG2/DDP) through increasing cellular glycolysis and suppressing Nrf2-dependent transcription. We show that metformin increases glucose uptake and enhances glucose metabolism through glycolytic pathway, resulting in elevated concentrations of intracellular NADPH and lactate. Consistently, high glucose medium suppresses Nrf2-dependent transcription and sensitizes HepG2/DDP cells to cisplatin. Elevated glycolysis was required for metformin to regulate Nrf2-dependent transcription and cisplatin sensitivity, as inhibition of glycolysis with 2-Deoxy-D-glucose (2-DG) significantly mitigates the beneficial effect of metformin. Together, our study has revealed an important biological process and gene transcriptional program underlying the beneficial effect of metformin on reducing chemo-resistance in HepG2 cells and provided new information on improving chemotherapy of liver cancers.

Metformin Enhances the Antitumor Activity of CD8+ T Lymphocytes via the AMPK-miR-107-Eomes-PD-1 Pathway

Metformin has been studied for its anticancer effects by regulating T cell functions. However, the mechanisms through which metformin stimulates the differentiation of memory T cells remain unclear. We found that the frequencies of memory stem and central memory T cells increased for both in peripheral and tumor-infiltrating CD8⁺ T cells in metformin-treated lung cancer patients compared with those not taking the medication. An in vitro assay showed that metformin promoted the formation of memory CD8⁺ T cells and enhanced their antiapoptotic abilities. In addition, AMP-activated protein kinase (AMPK) activation decreased microRNA-107 expression, thus enhancing Eomesodermin expression, which suppressed the transcription of PDCD1 in metformin-treated CD8⁺ T cells. In the CAR-T cell therapy model, metformin also exhibited cytotoxicity-promoting effects that led to decreased tumor growth. Metformin could reprogram the differentiation of CD8⁺ T cells, which may benefit the clinical therapy of cancer patients by facilitating long-lasting cytotoxic functions.

Effect of Metformin Plus Tyrosine Kinase Inhibitors Compared With Tyrosine Kinase Inhibitors Alone in Patients With Epidermal Growth Factor Receptor-Mutated Lung Adenocarcinoma: A Phase 2 Randomized Clinical Trial

IMPORTANCE

Metformin hydrochloride is emerging as a repurposed anticancer drug. Preclinical and retrospective studies have shown that it improves outcomes across a wide variety of neoplasms, including lung cancer. Particularly, evidence is accumulating regarding the synergistic association between metformin and epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs).

OBJECTIVE

To assess the progression-free survival (PFS) in patients with advanced lung adenocarcinoma who received treatment with EGFR-TKIs plus metformin compared with those who received EGFR-TKIs alone.

DESIGN, SETTING, AND PARTICIPANTS

Open-label, randomized, phase 2 trial conducted at the Instituto Nacional de Cancerología (INCan), Mexico City, Mexico. Eligible patients were 18 years or older, had histologically confirmed stage IIIB-IV lung adenocarcinoma with an activating EGFR mutation.

INTERVENTIONS

Patients were randomly allocated to receive EGFR-TKIs (erlotinib hydrochloride, afatinib dimaleate, or gefitinib at standard dosage) plus metformin hydrochloride (500 mg twice a day) or EGFR-TKIs alone. Treatment was continued until occurrence of intolerable toxic effects or withdrawal of consent.

MAIN OUTCOMES AND MEASURES

The primary outcome was PFS in the intent-to-treat population. Secondary outcomes included objective response rate, disease control rate, overall survival (OS), and safety.

RESULTS

Between March 31, 2016, and December 31, 2017, a total of 139 patients (mean [SD] age, 59.4 [12.0] years; 65.5% female) were randomly assigned to receive EGFR-TKIs (n = 70) or EGFR-TKIs plus metformin (n = 69). The median PFS was significantly longer in the EGFR-TKIs plus metformin group (13.1; 95% CI, 9.8-16.3 months) compared with the EGFR-TKIs group (9.9; 95% CI, 7.5-12.2 months) (hazard ratio, 0.60; 95% CI, 0.40-0.94; P = .03). The median OS was also significantly longer for patients receiving the combination therapy (31.7; 95% CI, 20.5-42.8 vs 17.5; 95% CI, 11.4-23.7 months; P = .02).

CONCLUSIONS AND RELEVANCE

To our knowledge, this is the first study to prospectively show that the addition of metformin to standard EGFR-TKIs therapy in patients with advanced lung adenocarcinoma significantly improves PFS. These results justify the design of a phase 3, placebo-controlled study.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03071705.

Meta-Analysis of the Association between Variants in ABCA7 and Alzheimer's Disease

The ATP-binding cassette transporter A7 (ABCA7) was identified as a known risk factor for Alzheimer's disease (AD). However, the relation between ABCA7 and AD was still inconsistent across these studies. Here, our meta-analysis aimed at confirming the association of ABCA7 with AD. Finally, 16 case-control studies (63747 versus 85833) were retrieved from PubMed and other databases. Three common loci were confirmed to increase the risk of AD (rs3764650: OR = 1.20, 95% CI = 1.16-1.24; rs3752246: OR = 1.13,95% CI = 1.08-1.19; rs4147929: OR = 1.17, 95% CI = 1.10-1.24), but the associations varied among the different races. Furthermore, ABCA7 loss-of-function (LOF) mutations conferred a higher risk for AD than did the above variants (LOF: OR = 1.78, 95%  = 1.43-2.22). In conclusion, ABCA7 genetic variants, especially the LOF mutations, were significantly associated with the risk of AD.

Diabetes Medication Use in Association with Survival among Patients of Breast, Colorectal, Lung, or Gastric Cancer

PURPOSE

Studies suggest that regular use of metformin may decrease cancer mortality. We investigated the association between diabetes medication use and cancer survival.

MATERIALS AND METHODS

The current study includes 633 breast, 890 colorectal, 824 lung, and 543 gastric cancer cases identified from participants of two population-based cohort studies in Shanghai. Information on diabetes medication use was obtained by linking to electronic medical records. The associations between diabetes medication use (metformin, sulfonylureas, and insulin) and overall and cancer-specific survival were evaluated using time-dependent Cox proportional hazards models.

RESULTS

After adjustment for clinical characteristics and treatment factors, use of metformin was associated with better overall survival among colorectal cancer patients (hazards ratio [HR], 0.55; 95% confidence interval [CI], 0.34 to 0.88) and for all four types of cancer combined (HR, 0.75; 95% CI, 0.57 to 0.98). Ever use of insulin was associated with worse survival for all cancer types combined (HR, 1.89; 95% CI, 1.57 to 2.29) and for the four cancer types individually. Similar associations were seen for diabetic patients. Sulfonylureas use was associated with worse overall survival for breast or gastric cancer (HR, 2.87; 95% CI, 1.22 to 6.80 and HR, 2.05; 95% CI, 1.09 to 3.84, respectively) among diabetic patients. Similar association patterns were observed between diabetes medication use and cancer-specific survival.

CONCLUSION

Metformin was associated with improved survival among colorectal cancer cases, while insulin use was associated with worse survival among patients of four major cancers. Further investigation on the topic is needed given the potential translational impact of these findings.

Abundance of mitochondrial superoxide dismutase is a negative predictive biomarker for endometriosis-associated ovarian cancers

Background

Endometrioid ovarian carcinoma and clear cell ovarian carcinoma are both classified as endometriosis-associated ovarian cancers (EAOCs). Despite the high rates of recurrence and mortality of EAOC, only a few prognostic biomarkers have been reported. Mitochondrial superoxide dismutase (SOD2) plays an important role in maintaining mitochondrial function through oxidative stress tolerance and contributes to chemotherapeutic resistance.

Methods

To clarify the clinical significance of SOD2 in EAOC, SOD2 expression was semi-quantitatively investigated by immunohistochemical analysis in 61 primary EAOC cases, and the correlations between SOD2 expression and clinicopathological data and survival were analyzed.

Results

Forty-six (75%) cases expressed high levels of SOD2. High SOD2 expression was associated with a poor prognosis on both univariate and multivariate analyses after adjusting for variables such as age, International Federation of Gynecology and Obstetrics (FIGO) stage, blood markers, histological type, and completion of treatment. There were 14 fatalities from 15 recurrences among 46 cases with high SOD2 expression. In contrast, only one recurrence and no fatalities were seen among 15 cases with low SOD2 expression.

Conclusion

Increased SOD2 expression is a predictive biomarker for worse prognosis in EAOC. The therapeutic efficacy of the current standard therapeutic protocol for EAOC is limited; thus, mitochondrial SOD2 should be a therapeutic target for SOD2-abundant EAOC.

Impact of metformin use on survival outcomes in non-small cell lung cancer treated with platinum

Preclinical evidence suggests that metformin, a widely used antidiabetic drug, may have a sensitizing effect on platinum. The purpose of this study was to evaluate the survival outcomes for non-small cell lung cancer (NSCLC) patients with type 2 diabetes mellitus (T2DM) using metformin during platinum-based chemotherapy.The clinicopathological parameters and survival data of 75 NSCLC patients with T2DM from January 2008 to December 2011 were collected and analyzed retrospectively. Patients were divided into 2 groups: metformin exposure group (n = 27) and non-metformin group (patients using other hypoglycemic agents or no drug for controlling n = 48). Univariate and multivariate analyses were performed to assess the association of metformin usage with overall survival (OS).Mean follow-up time was 58.7 months. The mean survival time was 36.74 months in the metformin group and 40.21 months in the non-metformin group. There was no significant difference in survival time between the 2 groups (P = .661). After adjusting gender, age, smoking status, tumor stage, tumor histology, and differentiation, multivariate analysis showed that metformin was not associated with the OS in NSCLC patients treated with concurrent platinum-based chemotherapy (hazard ratio: 1.071, 95% confidence interval: 0.577-1.986, P = .828).Our results indicated that metformin exposure had no significant effect on OS in NSCLC patients treated with platinum-based chemotherapy. Further studies are warranted to evaluate whether metformin could affect the survival of NSCLC patients treated with platinum-based chemotherapy.

Correlation between lung cancer and the HHIP polymorphisms of chronic obstructive pulmonary disease (COPD) in the Chinese Han population

To further investigate the relationship between lung cancer and hedgehog interacting protein (HHIP) polymorphisms of chronic obstructive pulmonary disease (COPD) patients, we conducted a case-control study in a Chinese Han population. Six HHIP SNPs with minor allele frequencies >5% (rs1489758, rs1489759, rs10519717, rs13131837, rs1492820, and rs7689420) were analyzed in 1,017 COPD patients (767 males and 246 females) and 430 non-COPD patients. Using logistic regression analysis, we found that rs7689420 was significantly associated with lung cancer in COPD patients in the Chinese Han population (P < 0.001). The recessive allele of rs7689420 was associated with the occurrence of lung cancer in all COPD patients (odds ratios [OR] of 0.609 and 0.424 for the CT and TT genotypes, respectively) as well as in serious COPD patients (OR of 0.403 and 0.305 for CT and TT, respectively). Additionally, rs1489759 and rs3131837 were associated with lung cancer in various genetic models. rs1489758, rs1489759, and rs10519717 were also associated with lung cancer in serious COPD patients. However, none of the SNPs were significantly associated with lung cancer in mild COPD patients or healthy subjects. Therefore, the HHIP SNPs of COPD patients likely play a role in lung cancer pathology in the Chinese Han population.

The prognostic value of metformin for advanced non-small cell lung cancer: a systematic review and meta-analysis

Background

The prognostic value of Metformin for concurrent non-small cell lung cancer (NSCLC) has been controversial in previous individual studies and meta-analyses. In order to further investigate the value of this medication, we conducted a systematic review and meta-analysis for patients with advanced or inoperable NSCLC.

Methods

We searched articles from PubMed, Scopus and Web of Science databases; the time interval was from the inception date of the databases to 1 September 2017. Inclusion criteria for eligible studies were: advanced or inoperable NSCLC; Metformin as an experimental group, and non-Metformin usage as a control group; progression-free survival (PFS) or overall survival (OS) as the outcome, with available hazard ratio (HR). Data synthesis was conducted based on the random-effect model.

Results

From a total of 97 articles in databases, we included seven eligible studies. Among them, only one study compared Metformin usage and non-Metformin usage for NSCLC patients who didn't have diabetes mellitus (DM): no significant difference was found in either OS or PFS. The remaining six studies compared Metformin usage and non-Metformin usage for patients with concurrent NSCLC and DM: according to meta-analysis, significantly prolonged OS was found in Metformin usage rather than non-Metformin usage [pooled HR =0.87 (0.77-0.99), P=0.04]; no significant difference was indicated in PFS [pooled HR =0.85 (0.67-1.07), P=0.16]. In subgroup analysis, among patients with late-stage NSCLC and DM, significant difference was found, regardless of OS [pooled HR =0.81 (0.70-0.94), P<0.01] or PFS [pooled HR =0.71 (0.58-0.88), P<0.01]. However, among patients with local advanced NSCLC and DM, there was no significant difference [OS: pooled HR =1.05 (0.79-1.40), P=0.74; PFS: pooled HR =0.94 (0.68-1.32), P=0.74].

Conclusions

The prognostic value of Metformin for concurrent late-stage NSCLC and DM was demonstrated. It deserves further confirmation and explanation.

Cancer survival in patients from a hospital-based cancer registry, China

Purpose: There are few reports on survival rate analysis from hospital-based cancer registries (HBCR) in China, although the National Center of Cancer Registry of China has launched such an effort with the mission to expand the scope of registration and follow-up. Our study aimed to evaluate survival and outcomes of cancer patients from a HBCR in eastern China.

Methods: Active and passive follow-up methods were used to obtain information on survival status for all patients from Qidong City and Haimen City in the databases of our hospital-based registrations from 2002 to 2014. Censor time for survival was 31^st March, 2016. Survival probability was estimated using the life-table method with SPSS Statistics software, and comparison of significant differences in survival rates was tested by Wilcoxon (Gehan) statistic.

Results: The outcomes of 5010 patients were identified in the follow-up for 5244 cases from Qidong and Haimen, with a follow-up rate of 95.65%, and a rate of lost to follow-up of 4.35%. The 1-, 3-, 5-, and 10-year observed survival (OS) rate in all-combined cancer sites were 59.80%, 37.70%, 30.82%, and 22.60%, respectively. The top 10 cancer sites in rank were cancers of lung, esophagus, liver, cervix, stomach, breast, colon-rectum, non-Hodgkin's lymphoma, nasopharynx, and ovary, with 5-year OS rates of 12.63%, 19.62%, 11.69%, 66.61%, 21.35%, 59.43%, 36.36%, 37.03%, 48.95% and 36.17%, respectively. Females experienced better survival than males for lung, esophageal, liver, nasopharyngeal and pancreatic cancers (P<0.05), but not for other sites (P>0.05). A significant difference was also found between males and females when all-sites were combined (P<0.01). There are significant differences (P<0.05) between the 2015 patients (from Qidong) and the 3001 patients (from Haimen) with 5-year OS rates of 32.72% vs 29.57%; no significant differences were found for 5-year OS rates for individual cancer sites (P>0.05) except for liver (P=0.0005) and ovary (P=0.0460) between the two cities. Younger patients had better prognosis, but significance was only seen in cervical (P=0.0102) and nasopharyngeal (P=0.0305) cancers.

Conclusion: The survival rates of each site or of all sites-combined in this setting are consistent with those elsewhere in China and abroad. Discrepancies in overall survival could be affected by the proportion of sites with or without better prognosis. Hospital-based cancer survival is a better index to evaluate outcomes that reflect the levels of comprehensive treatment and improvement of medical and health services.