Effect of Metformin Use on Survival in Resectable Pancreatic Cancer: A Single-Institution Experience and Review of the Literature

Magic of a Common Sugar Pill in Cancer: Can Metformin Raise Survival in Pancreatic Cancer Patients?

Pancreatic cancer is one of the common cancers globally, with a poor survival outcome. Metformin, a popular anti-diabetic drug, has gained popularity for its use in the chemoprevention of cancer. However, results regarding the survival benefit of metformin in pancreatic cancer have been unpredictable. In this review, we aim to analyze the use of metformin in pancreatic cancer patients with pre-existing diabetes mellitus for survival benefit. We systematically conducted a literature search in PubMed, Science Direct, and Scopus databases to collect the relevant articles and reviewed them. Eventually, 11 quality appraised articles were included accessing overall survival as the primary outcome. Our results concluded that metformin can efficaciously improve survival in pancreatic cancer patients with coexisting diabetes mellitus, but the results are still incongruent. Hence, further prospective studies and clinical trials are essential to provide a strong evidence-based recommendation that will help prolong the lifespan of patients.

Repurposing metformin for the treatment of gastrointestinal cancer

Diabetes mellitus type 2 and cancer share many risk factors. The pleiotropic insulin-dependent and insulin-independent effects of metformin might inhibit pathways that are frequently amplified in neoplastic tissue. Particularly, modulation of inflammation, metabolism, and cell cycle arrest are potential therapeutic cancer targets utilized by metformin to boost the anti-cancer effects of chemotherapy. Studies in vitro and in vivo models have demonstrated the potential of metformin as a chemo- and radiosensitizer, besides its chemopreventive and direct therapeutic activity in digestive system (DS) tumors. Hence, these aspects have been considered in many cancer clinical trials. Case-control and cohort studies and associated meta-analyses have evaluated DS cancer risk and metformin usage, especially in colorectal cancer, pancreatic cancer, and hepatocellular carcinoma. Most clinical studies have demonstrated the protective role of metformin in the risk for DS cancers and survival rates. On the other hand, the ability of metformin to enhance the actions of chemotherapy for gastric and biliary cancers is yet to be investigated. This article reviews the current findings on the anti-cancer mechanisms of metformin and its apparatus from pre-clinical and ongoing studies in DS malignancies.

Chemopreventive Agents After Pancreatic Resection for Ductal Adenocarcinoma: Legend or Scientific Evidence?

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is currently the fourth leading cause of cancer-related death in the USA. A wealth of evidence has demonstrated the chemopreventive activity of aspirin, statins, and metformin against PDAC. The aim of this study is to investigate the effect of aspirin, statins, and metformin on disease-free survival (DFS) and disease-specific survival (DSS) in a large population of PDAC patients undergoing pancreatic resection.

PATIENTS AND METHODS

All patients who underwent pancreatic resections between January 2015 and September 2018 were retrospectively reviewed. The potentially "chemopreventive agents" considered for the analysis were aspirin, statins, and metformin. Drug use was defined in case of regular assumption at least 6 months before diagnosis and regularly after surgery along the follow-up period.

RESULTS

A total of 430 patients were enrolled in this study, with median DFS and DSS of 21 months (IQR 13-30) months and 34 (IQR 26-52) months, respectively. On multivariable analysis, use of aspirin was associated with better DFS (HR: 0.62; p = 0.038). Metformin was associated with better DFS, without reaching statistical significance (p = 0.083). Use of statins did not influence DFS in the studied population. Aspirin, metformin, and statins were not associated with better DSS on multivariable analysis. Factors influencing DSS were pT3/pT4, N1, N2, no adjuvant treatment, G3, and ASA score > 3.

CONCLUSIONS

The results suggest that chronic use of aspirin is associated with increased DFS but not with better DSS after surgical resection in patients with PDAC.

Relationships are between metformin use and survival in pancreatic cancer patients concurrent with diabetes: A systematic review and meta-analysis

BACKGROUND

Increased risk and cancer-related mortality is observed in pancreatic cancer (PC) patients with diabetes mellitus (DM). Whether using metformin as glucose-lowering therapy can result in survival benefit in this group of patients is still unclear.

METHODS

A meta-analysis of 21 studies that including 38,772 patients was performed to investigate the association between metformin and overall survival in patients with PC and concurrent DM.

RESULTS

A significant survival benefit was observed in metformin treatment group compared with non-metformin group (hazard ratio [HR] = 0.83, 95% confidence interval [CI]: 0.74-0.91). These associations were observed in both subgroups of Asian countries (HR = 0.69, 95% CI: 0.60-0.79) and Western countries (HR = 0.86, 95% CI: 0.76-0.95), the former was more obvious. Survival benefit was gained for patients at early stage (HR = 0.75, 95% CI: 0.64-0.85) and mixed stage (HR = 0.81, 95% CI: 0.70-0.91), but not for patients at advanced stage (HR = 0.99, 95% CI: 0.74-1.24). Similarly, survival benefit was also observed in patients receiving surgery (HR = 0.82, 95% CI: 0.69-0.94) and comprehensive treatment (HR = 0.85, 95% CI: 0.77-0.93), but not in chemotherapy group (HR = 0.99, 95% CI: 0.67-1.30). No obvious benefit was suggested when pooled by time-varying COX model (HR = 0.94, 95% CI: 0.86-1.03).

CONCLUSIONS

These results suggest that metformin is associated with survival benefit in patients with PC and concurrent DM. Further randomized controlled trials and prospective studies with larger sample sizes are required to confirm our findings.

Survival Benefit of Metformin Use for Pancreatic Cancer Patients Who Underwent Pancreatectomy: Results From a Meta-Analysis

Objective: To evaluate the survival benefit of metformin use for pancreatic cancer (PC) patients underwent pancreatectomy.

Methods: Databases including EMBASE, PubMed, the Cochrane Library were searched to identify studies relevant to the outcomes on the survival benefit of metformin use for the PC patients who underwent pancreatectomy until June 30, 2019. STATA 12.0 software was used to performed the meta-analysis.

Results: 12 studies involving 35,346 PC patients were included in this meta-analysis. With a random-model, there are significant differences in overall survival (HR = 0.85, 95% CI: 0.77–0.94, P = 0.002) between PC patients who were treated with metformin underwent pancreatectomy and those who underwent pancreatectomy without metformin use. Subgroup analyses showed Caucasians (HR = 0.903, 95% CI = 0.825–0.940, P = 0.008) and Asian (HR = 0.691, 95% CI = 0.588–0.813, P = 0.001) PC patients have a significantly reduced risk of death for metformin users. Subgroup analyses also showed a survival benefit for PC patients at stage I-II (HR = 0.762, 95% CI = 0.677–0.858, P = 0.0001).

Conclusions: Metformin use is related to a better survival benefit for PC patients who underwent pancreatectomy, which would be a potential drug for the treatment of PC.

Cohort Study of Antihyperglycemic Medication and Pancreatic Cancer Patients Survival

Background: We assessed the association between the use of metformin and other antihyperglycemic medications on overall survival in diabetic patients with pancreatic cancer. Methods: Patients with pancreatic cancer and diabetes between 2000 and 2015 were identified from the Lithuanian Cancer Registry and the National Health Insurance Fund database. Cohort members were classified into six groups according to type 2 diabetes mellitus treatment: sulfonylurea monotherapy; metformin monotherapy; insulin monotherapy; metformin and sulfonylurea combination; metformin and other antihyperglycemic medications; all other combinations of oral antihyperglycemic medications. Survival was calculated from the date of cancer diagnosis to the date of death or the end of follow-up (31 December 2018). Results: Study group included 454 diabetic patients with pancreatic cancer. We found no statistically significant differences in overall survival between patients by glucose-lowering therapy. However, highest mortality risk was observed in patients on insulin monotherapy, and better survival was observed in the groups of patients using antihyperglycemic medication combinations, metformin alone, and metformin in combination with sulfonylurea. Analysis by cumulative dose of metformin showed significantly lower mortality risk in the highest cumulative dose category (HR 0.76, 95% CI 0.58–0.99). Conclusions: Our study showed that metformin might have a survival benefit for pancreatic cancer patients, suggesting a potentially available option for the treatment.

Association between Metformin Use and Clinical Outcomes Following Pancreaticoduodenectomy in Patients with Type 2 Diabetes and Pancreatic Ductal Adenocarcinoma

Retrospective studies on the association between metformin and clinical outcomes have mainly been performed on patients with non-resectable pancreatic ductal adenocarcinoma and may have been affected by time-related bias. To avoid this bias, recent studies have used time-varying analysis; however, they have only considered the start date of metformin use and not the stop date. We studied 283 patients with type 2 diabetes and pancreatic ductal adenocarcinoma following pancreaticoduodenectomy, and performed analysis using a Cox model with time-varying covariates, while considering both start and stop dates of metformin use. When start and stop dates were not considered, the metformin group showed significantly better survival. Compared with previous studies, adjusted analysis based on Cox models with time-varying covariates only considering the start date of postoperative metformin use showed no significant differences in survival. However, although adjusted analysis considering both start and stop dates showed no significant difference in recurrence-free survival, the overall survival was significantly better in the metformin group (Hazard ratio (HR), 0.747; 95% confidence interval (CI), 0.562–0.993; p = 0.045). Time-varying analysis incorporating both start and stop dates thus revealed that metformin use is associated with a higher overall survival following pancreaticoduodenectomy in patients with type 2 diabetes and pancreatic ductal adenocarcinoma.

Oncological benefit of metformin in patients with pancreatic ductal adenocarcinoma and comorbid diabetes mellitus

PURPOSE

Some clinical studies have suggested that metformin improved prognoses in several cancers. This study aimed to identify prognostic factors for pancreatic ductal adenocarcinoma (PDAC) and determine the utility of metformin administration.

METHODS

Between January 2007 and December 2015, 373 consecutive patients underwent curative surgery for PDAC. Among the patients, 121 were diagnosed as having diabetes mellitus (DM) before surgery. The characteristics and overall survival (OS) between patients with and without DM were compared retrospectively. Based on their metformin intake, patients with DM were divided into two groups. OS rates between patients with and without metformin intake were compared. Univariate and multivariate analyses were performed to identify prognostic factors for OS among all patients and those with PDAC and DM.

RESULTS

No significant differences in the 5-year survival rates between patients with and without DM were observed. Among the 121 patients with DM, 18 received metformin and 103 did not (other medications group). The 5-year survival rate was significantly better in the metformin group than in the other medications group (66.7% and 24.4%, respectively; p = 0.034). Multivariate analysis identified pN1 (p = 0.002), metformin administration (p = 0.022), and microvascular invasion (p = 0.023) as independent prognostic factors for OS in the patients with DM. Matched-pair analysis showed that OS tended to be better in the metformin group than in the other medications group (p = 0.067).

CONCLUSIONS

History of metformin intake may contribute to favorable prognosis in patients with PDAC and pre-existing DM.

The effect of metformin use on hypopharyngeal squamous cell carcinoma in diabetes mellitus patients

Background

Metformin is proven to improve the prognosis of various cancers, but it is unknown if metformin could ameliorate hypopharyngeal cancer in diabetes mellitus patients. This was a retrospective cohort study, and the effect and survival outcome of metformin on hypopharyngeal cancer with diabetes mellitus was investigated.

Methods

There were 141 hypopharyngeal cancer patients collected in a tertiary referral center from December 1st, 2011 to December 31st, 2013. There were 49 patients without diabetes mellitus (DM) and 92 patients with DM. In the 92 DM patients, there were 43 patients with metformin used and 49 patients without metformin used. All received patients followed up until September 1st, 2015.

Results

There was no significant difference in patients’ characteristics between the non-DM and DM groups, and also no significant difference in clinical T stage, N stage, metastatic condition, and disease stage between the non-DM and DM groups. DM with metformin patients had lower metastasis rates and better overall survival (OS) (p = 0.011) and disease-free survival (DFS) (p = 0.004) compared to non-DM and DM without metformin. Multivariate analysis also showed a better OS and DFS in DM-Met (+) with advanced hypopharyngeal cancer but not in early stage.

Conclusion

There was less distant metastasis and better survival outcomes in hypopharyngeal cancer DM patients who use metformin.

Metformin and pancreatic cancer survival: Real effect or immortal time bias?

High heterogeneity has been reported among cohort studies investigating the association between metformin and pancreatic cancer survival. Immortal time bias may be one importance source of heterogeneity, as it is widely present in previous cohort studies and may severely impair the validity. Our study aimed to examine whether metformin therapy improves pancreatic cancer survival, and to assess the impact of immortal time bias on the effect estimation of metformin in cohort studies. PubMed, EMbase and SciVerse Scopus were searched. Pooled relative risks (RRs) were derived using a random-effects model. Pooled RR from the six studies without immortal time bias showed no association between metformin and mortality in pancreatic cancer patients (RR 0.93, 95% CI 0.82, 1.05; p = 0.22 and I² = 75%). In contrast, pooled RR from the nine studies with immortal time bias showed a reduction of 24% in mortality associated with metformin (RR 0.76, 95% CI 0.69, 0.84; p < 0.001 and I² = 1%). From a meta-regression model, existence of immortal time bias was associated with a reduction of 18% in the effect estimate of metformin on pancreatic cancer survival (ratio of RR 0.82, 95% CI 0.70, 0.96; p = 0.02). In conclusions, cumulative evidence from cohort studies does not support a beneficial effect of metformin on pancreatic cancer survival. The association between metformin and pancreatic cancer survival has been greatly exaggerated in previous cohort studies due to the wide existence of immortal time bias. More rigorous designs and statistical methods are needed to account for immortal time bias.

Metformin-induced anticancer activities: recent insights

Metformin is a widely used antidiabetic drug, and there is evidence among diabetic patients that metformin is a chemopreventive agent against multiple cancers. There is also evidence in human studies that metformin is a cancer chemotherapeutic agent, and several clinical trials that use metformin alone or in combination with other drugs are ongoing. In vivo and in vitro cancer cell culture studies demonstrate that metformin induces both AMPK-dependent and AMPK-independent genes/pathways that result in inhibition of cancer cell growth and migration and induction of apoptosis. The effects of metformin in cancer cells resemble the patterns observed after treatment with drugs that downregulate specificity protein 1 (Sp1), Sp3 and Sp4 or by knockdown of Sp1, Sp3 and Sp4 by RNA interference. Studies in pancreatic cancer cells clearly demonstrate that metformin decreases expression of Sp1, Sp3, Sp4 and pro-oncogenic Sp-regulated genes, demonstrating that one of the underlying mechanisms of action of metformin as an anticancer agent involves targeting of Sp transcription factors. These observations are consistent with metformin-mediated effects on genes/pathways in many other tumor types.

Inhibition of long non-coding RNA HOTAIR enhances radiosensitivity via regulating autophagy in pancreatic cancer

Background

Resistance to radiation therapy is still a challenge for treatment of pancreatic cancer(PC). Long non-coding RNAs (lncRNA) HOTAIR has been found to play a oncogenic role in several cancers. However, the correlation between HOTAIR and radiotherapy in PC is still unclear.

Methods

TCGA data was collected to analyze the expression of HOTAIR and its relationship with PC progression. A series of functional experiments were conducted to explore the role of HOTAIR in PC radiosensitivity and its underlying molecular mechanisms.

Results

By the analysis of the TCGA data, we found HOTAIR expression in PC tissues was significantly higher than normal tissues and associated with tumor progression. The function analysis showed HOTAIR was enriched in biological regulation and response to stimulus. And in vitro study, the expression of HOTAIR was increased in PANC-1 and AsPC-1 cells after radiation. We identified that HOTAIR knockdown could enhance radiosensitivity and influence autophagy by up-regulating ATG7 expression in PC cells. By futher rescue experiments using rapamycin, activation of autophagy could reversed the the inhibition of cell proliferation and colony formation, as well as promotion of apoptosis mediated by HOTAIR knockdown, indicating that HOTAIR knockdown promoted radiosensitivity of PC cells by regulating autophagy.

Conclusion

Our finding revealed the the regulatory role of HOTAIR in radiosensitivity and provided a a new sight to improve radiotherapy effciency in PC.

Metformin as an Adjunctive Therapy for Pancreatic Cancer: A Review of the Literature on Its Potential Therapeutic Use

Pancreatic ductal adenocarcinoma has the worst prognosis of any cancer. New adjuvant chemotherapies are urgently required, which are well tolerated by patients with unresectable cancers. This paper reviews the existing proof of concept data, namely laboratory, pharmacoepidemiological, experimental medicine and clinical trial evidence for investigating metformin in patients with pancreatic ductal adenocarcinoma. Laboratory evidence shows metformin inhibits mitochondrial ATP synthesis which directly and indirectly inhibits carcinogenesis. Drug-drug interactions of metformin with proton pump inhibitors and histamine H2-receptor antagonists may be of clinical relevance and pertinent to future research of metformin in pancreatic ductal adenocarcinoma. To date, most cohort studies have demonstrated a positive association with metformin on survival in pancreatic ductal adenocarcinoma, although there are many methodological limitations with such study designs. From experimental medicine studies, there are sparse data in humans. The current trials of metformin have methodological limitations. Two small randomized controlled trials (RCTs) reported null findings, but there were potential inequalities in cancer staging between groups and poor compliance with the intervention. Proof of concept data, predominantly from laboratory work, supports assessing metformin as an adjunct for pancreatic ductal adenocarcinoma in RCTs. Ideally, more experimental medicine studies are needed for proof of concept. However, many feasibility criteria need to be answered before such trials can progress.

Effect of Metformin and Statin Use on Survival in Pancreatic Cancer Patients: a Systematic Literature Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Current epidemiological studies report conflicting results for the effect of statin or metformin on pancreatic cancer overall survival. This literature review and meta-analysis summarize the studies reporting an association between statin or metformin use and overall survival of pancreatic cancer patients.

METHODS

We systematically searched for studies about the association between statin or metformin use and pancreatic cancer overall survival in electronic databases (PubMed, ISI Web of Science, MEDLINE, Cochrane, Scopus, Google Scholar). A meta-analysis based on hazard ratios (HRs) and 95% confidence intervals (CIs) was performed using random effect models. Heterogeneity between the studies was examined using I2 statistics, and sensitivity analyses were conducted to assess the robustness of the findings.

RESULTS

Of 116 statin-related articles identified, 6 retrospective cohort studies representing 12,057 patients were included. There was significant heterogeneity between studies. Statin use was associated with improved survival among pancreatic cancer patients (meta-HR = 0.75; 95% CI: 0.59, 0.90; P < 0.001). Of 311 metformin-related articles, 8 retrospective cohort studies and 2 randomized clinical trials, representing 3,042 patients were identified. Metformin use was associated with better overall survival among pancreatic cancer patients (meta-HR = 0.79; 95% CI: 0.70, 0.92, P < 0.001), and significant heterogeneity was observed between studies.

CONCLUSION

Our findings suggest that the improved survival time of pancreatic cancer patients are associated with statin or metformin use. Due to the multiple sources of heterogeneity of the original studies, these findings should be considered cautiously, and confirmed with larger prospective individual-level studies.

Evidence-based complementary treatment of pancreatic cancer: a review of adjunct therapies including paricalcitol, hydroxychloroquine, intravenous vitamin C, statins, metformin, curcumin, and aspirin

Despite new and exciting research and renewed optimism about future therapy, current statistics of survival from pancreatic cancer remains dismal. Patients seeking alternative or complementary treatments should be warned to avoid the hype and instead look to real science. A variety of relatively safe and inexpensive treatment options that have shown success in preclinical models and/or retrospective studies are currently available. Patients require their physicians to provide therapeutic guidance and assistance in obtaining and administrating these various therapies. Paricalcitol, an analog of vitamin D, has been shown by researchers at the Salk Institute for Biological Studies to break though the protective stroma surrounding tumor cells. Hydroxychloroquine has been shown to inhibit autophagy, a process by which dying cells recycle injured organelles and internal toxins to generate needed energy for survival and reproduction. Intravenous vitamin C creates a toxic accumulation of hydrogen peroxide within cancer cells, hastening their death. Metformin inhibits mitochondrial oxidative metabolism utilized by cancer stem cells. Statins inhibit not only cholesterol but also other factors in the same pathway that affect cancer cell growth, protein synthesis, and cell cycle progression. A novel formulation of curcumin may prevent resistance to chemotherapy and inhibit pancreatic cancer cell proliferation. Aspirin therapy has been shown to prevent pancreatic cancer and may be useful to prevent recurrence. These therapies are all currently available and are reviewed in this paper with emphasis on the most recent laboratory research and clinical studies.

Synergistic anti-tumor effects of liraglutide with metformin on pancreatic cancer cells

Either metformin or liraglutide has been reported to have anti-tumor effects on pancreatic cancer cells. However, it is not clear whether their combined treatment has additive or synergistic anti-tumor effects on pancreatic cancer cells. In this study, the human pancreatic cancer cell line MiaPaca-2 was incubated with liraglutide and/or metformin. The cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, and wound-healing and transwell migration assays were used to detect cell viability, clonogenic survival, cell cycle and cell migration, respectively. RT-PCR and western blot analyses were used to determine the mRNA and protein levels of related molecules. Results showed that combination treatment with liraglutide (100 nmol/L) and metformin (0.75 mmol/L) significantly decreased cell viability and colony formation, caused cell cycle arrest, upregulated the level of pro-apoptotic proteins Bax and cleaved caspase-3, and inhibited cell migration in the cells, although their single treatment did not exhibit such effects. Combination index value for cell viability indicated a synergistic interaction of liraglutide and metformin. Moreover, the combined treatment with liraglutide and metformin could activate the phosphorylation of AMP-activated protein kinase (AMPK) more potently than their single treatment in the cells. These results suggest that liraglutide in combination with metformin has a synergistic anti-tumor effect on the pancreatic cancer cells, which may be at least partly due to activation of AMPK signaling. Our study provides new insights into the treatment of patients with type 2 diabetes and pancreatic cancer.

Metformin is associated with survival benefit in pancreatic cancer patients with diabetes: a systematic review and meta-analysis

Background

Pancreatic cancer is a highly lethal disease with a poor prognosis while metformin has been associated with a decreased risk of pancreatic cancer. Although the benefit of metformin was observed for pancreatic cancer prevention, it is not clear whether it can also affect the survival of pancreatic cancer patients with type 2 diabetes mellitus. A systematic review and meta-analysis was conducted to assess the effect of metformin on the survival of pancreatic cancer patients with type 2 diabetes mellitus.

Methods

Two independent authors searched PubMed and Web of science up to 08/07/2016. We assessed studies for eligibility, extracted data, and examined their quality, with the primary outcome as overall survival. We used published hazard ratio (HR) available or estimated based on other survival data. We pooled the data and used a random-effect model to combine direct comparisons from included articles. We also investigated treatment effects by different countries, quality and the time of metformin initiation.

RESULTS

We found that there was a relative survival benefit associated with metformin treatment compared with non-metformin treatment in both overall survival (OS) ([HR] 0.84; 95% confidence interval [CI]: 0.73 – 0.96). These associations were also observed in subgroups of Asian countries and high quality articles.

Conclusions

Our results support the notion that metformin maybe the best anti-diabetic medicine of choice in patients with pancreatic cancer and concurrent type 2 diabetes mellitus. The perspectives of enhancing survival of pancreatic cancer patients with diabetes mellitus by the use of metformin deserve more attention in future research and clinical practice.

Effects of metformin on survival outcomes of pancreatic cancer patients with diabetes: A meta-analysis

Pancreatic cancer risk is reduced by metformin treatment in patients with diabetes. However, the effect of metformin on pancreatic cancer overall survival is unclear. The aim of the present study was to determine the association between metformin and clinical outcomes of pancreatic cancer patients with diabetes. An electronic and manual search was conducted using PubMed, Web of Science, Medline-Ovid and Cochrane Library databases between the beginning and March 31, 2017. A total of 8 studies consisting of 4,293 patients with pancreatic cancer with diabetes were included, comprising 2,033 patients who had received metformin and 2,260 patients who had not. The meta-analysis showed that metformin was associated with a relative survival benefit in pancreatic cancer patients [hazard ratio (HR), 0.81; 95% confidence interval (CI), 0.70-0.93]. These associations were also observed in subgroups of Asian countries 0.64 (95% CI, 0.52-0.80) and Western countries 0.88 (95% CI, 0.82-0.95), as well as diabetes (no indication of diabetes type). Excluding the studies considered as be prone to immortal time bias resulted in HRs (95% CIs) of 0.86 (0.69-1.07). The results of this study support the notion that the use of metformin may improve the overall survival of patients with pancreatic cancer with concurrent diabetes. However, the proposed beneficial effect of metformin on pancreatic cancer survival may be based on immortal time bias. Further carefully designed studies with high quality are warranted to confirm this efficacy.

Effects of metformin on survival outcomes of pancreatic cancer: a meta-analysis

BACKGROUND AND AIM

Recent epidemiological studies indicated that metformin might improve the survival of various cancers. However, its benefit on pancreatic cancer was controversial.

METHODS

We performed this meta-analysis to investigate the benefit of metformin on pancreatic cancer. A comprehensive literature search was performed through PubMed, Cochrane Library and Embase. Relative risk (RR) and hazard ratio (HR) with 95% confidence interval (CI) were pooled.

RESULTS

The meta-analysis of 2 randomized controlled trials including181 pancreatic patients, revealed that metformin use was not associated with an improved overall survival at 6 months (RR=0.90, 95% CI=0.67-1.21), overall survival (HR=1.19, 95% CI=0.86-1.63) and progression-free survival (HR=1.39, 95% CI=0.97-1.99). But the meta-analysis of 8 cohorts, involving 2805 pancreatic patients with diabetes, demonstrated a favorable result with improved overall survival (HR=0.78, 95% CI=0.66-0.92).

CONCLUSIONS

Observations in the cohort studies supported a favorable role of metformin while the data from randomized controlled trials did not support that. Therefore, more high-quality RCTs are warranted.

Clinical significance and prospective molecular mechanism of MALAT1 in pancreatic cancer exploration: a comprehensive study based on the GeneChip, GEO, Oncomine, and TCGA databases

Purpose

Long noncoding RNAs (lncRNAs) are known to function as regulators in the development and occurrence of various tumors. MALAT1 is a highly conserved lncRNA and has vital functions in diverse tumors, including pancreatic cancer (PC). However, the underlying molecular regulatory mechanism involved in the occurrence and development of PC remains largely unknown. Thus, it is important to explore MALAT1 in PC and elucidate its function, which might offer a new perspective for clinical diagnosis and therapy.

Methods

First, we used the Gene Expression Omnibus, Oncomine, and The Cancer Genome Atlas databases to determine the clinical diagnostic and prognostic values of MALAT1. We next used our own GeneChip and The Cancer Genome Atlas database to collect the possible target genes of MALAT1 and further utilized a bioinformatics analysis to explore the underlying significant pathways that might be crucial in PC. Finally, we identified several key target genes of MALAT1 and hope to offer references for future research.

Results

We found that the expression of MALAT1 was significantly elevated in patients with PC. A receiver operating characteristics curve analysis showed a moderate diagnostic value (area under the curve =0.75, sensitivity =0.66, specificity =0.72). A total of 224 important overlapping genes were collected, and six hub genes (CCND1, MAPK8, VEGFA, FOS, CDH1, and HSP90AA1) were identified, of which CCND1, MAPK8, and VEGFA, are important genes in PC. Several pathways, including the mTOR signaling pathway, pathways in cancer, and the MAPK signaling pathway, were suggested to be the vital MALAT1 pathways in PC.

Conclusion

MALAT1 is suggested to be a promising diagnostic biomarker in PC. Six hub genes (CCND1, MAPK8, VEGFA, FOS, CDH1, and HSP90AA1), and specifically CCND1, MAPK8, and VEGFA, might be key MALAT1 target genes in PC. Due to their possible clinical significance in PC, several pathways, such as the mTOR signaling pathway, pathways in cancer, and the MAPK signaling pathway, are worthy of further study.

Differential and Joint Effects of Metformin and Statins on Overall Survival of Elderly Patients with Pancreatic Adenocarcinoma: A Large Population-Based Study

Background: Published evidence indicates that individual use of metformin and statin is associated with reduced cancer mortality. However, their differential and joint effects on pancreatic cancer survival are inconclusive.Methods: We identified a large population-based cohort of 12,572 patients ages 65 years or older with primary pancreatic ductal adenocarcinoma (PDAC) diagnosed between 2008 and 2011 from the Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database. Exposure to metformin and statins was ascertained from Medicare Prescription Drug Event files. Cox proportional hazards models with time-varying covariates adjusted for propensity scores were used to assess the association while controlling for potential confounders.Results: Of 12,572 PDAC patients, 950 (7.56%) had used metformin alone, 4,506 (35.84%) had used statin alone, and 2,445 (19.45%) were dual users. Statin use was significantly associated with improved overall survival [HR, 0.94; 95% confidence interval (CI), 0.90-0.98], and survival was more pronounced in postdiagnosis statin users (HR, 0.69; 95% CI, 0.56-0.86). Metformin use was not significantly associated with overall survival (HR, 1.01; 95% CI, 0.94-1.09). No beneficial effect was observed for dual users (HR, 1.00; 95% CI, 0.95-1.05).Conclusions: Our findings suggest potential benefits of statins on improving survival among elderly PDAC patients; further prospective studies are warranted to corroborate the putative benefit of statin therapy in pancreatic cancer.Impact: Although more studies are needed to confirm our findings, our data add to the body of evidence on potential anticancer effects of statins. Cancer Epidemiol Biomarkers Prev; 26(8); 1225-32. ©2017 AACR.

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

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

Use of Angiotensin System Inhibitors Is Associated with Immune Activation and Longer Survival in Nonmetastatic Pancreatic Ductal Adenocarcinoma

Purpose: Angiotensin system inhibitors (ASI) can improve prognosis in multiple cancer types, including pancreatic ductal adenocarcinoma (PDAC). However, no study has examined the effect of ASIs alone or combined with adjuvant chemotherapy in resected PDAC patients.Experimental Design: We performed an analysis of the records of ASI users and nonuser patients with PDAC seen at Massachusetts General Hospital (Boston, MA) between January 2006 and December 2010. To identify mechanisms of ASIs in PDAC, we performed RNA sequencing (RNA-Seq) of resected primary lesions.Results: A total of 794 consecutive patients were included. In 299 resected patients, ASI users experienced longer overall survival (OS) in both univariate (median OS, 36.3 vs. 19.3 months, P = 0.011) and adjusted multivariate [HR, 0.505; 95% confidence interval (CI), 0.339-0.750; P = 0.001] analyses. Propensity score-adjusted analysis also showed a longer median OS for chronic ASI users. In unresected patients, the beneficial effect of ASIs was significant in patients with locally advanced disease, but not in metastatic patients. RNA-Seq analysis revealed in tumors of ASI users (lisinopril) a normalized extracellular matrix, a reduced expression of genes involved in PDAC progression (e.g., WNT and Notch signaling), and an increased expression of genes linked with the activity of T cells and antigen-presenting cells. Finally, chronic use of ASI was associated with a gene expression signature that is predictive of survival in independent validation cohorts.Conclusions: In patients with nonmetastatic PDAC, chronic ASI use is associated with longer OS independently of chemotherapy. Our RNA-Seq analysis suggests that ASIs reduce the malignant potential of cancer cells and stimulate the immune microenvironment in primary PDAC. Clin Cancer Res; 23(19); 5959-69. ©2017 AACR.

No association between metformin use and survival in patients with pancreatic cancer: An observational cohort study

Several studies have suggested an association between use of metformin and an increased overall survival in patients diagnosed with pancreatic cancer, however with several important methodological limitations. The aim of the study was to assess the association between overall survival, pancreatic cancer, and metformin use.A retrospective cohort study of 1111 patients with pancreatic cancer was conducted using data from The Netherlands Comprehensive Cancer Organization (1998-2011). Data were linked to the PHARMO Database Network containing drug-dispensing records from community pharmacies. Patients were classified as metformin user or sulfonylurea derivatives user from the moment of first dispensing until the end of follow up. The difference in overall survival between metformin users and nonusers was assessed, and additionally between metformin users and sulfonylurea derivatives users. Univariable and multivariable parametric survival models were used and use of metformin and sulfonylurea derivatives was included as time-varying covariates.Of the 1111 patients, 91 patients were excluded because of differences in morphology, 48 patients because of using merely metformin before diagnosis, and 57 metformin-users ever used contemporary sulfonylurea derivatives and were therefore excluded. Lastly, 8 patients with a survival of zero months were excluded. This resulted in 907 patients for the analysis. Overall, 77 users of metformin, 43 users of sulfonylurea derivatives, and 787 nonusers were identified. The adjusted rate ratio for overall survival for metformin users versus nonusers was 0.86 (95% CI: 0.66-1.11; P = 0.25). The difference in overall survival between metformin users and sulfonylurea derivatives users showed an adjusted rate ratio of 0.90 (95% CI: 0.59-1.40; P = 0.67).No association was found between overall survival, pancreatic cancer, and metformin use. This was in concordance with 2 recently published randomized controlled trials. Future research should focus on the use of adjuvant metformin in other cancer types and the development or repurposing of other drugs for pancreatic cancer.

Expression of metastasis related genes S100A4 and MMP-9 in pancreatic cancer cells treated with metformin

AIM

To investigate the expression of metastasis related genes S100A4 and matrix metalloproteinase (MMP)-9 in pancreatic cancer cell lines BxPC-3 and AsPC-1 treated with metformin.

METHODS

Cells were incubated with metformin at different concentrations for 24, 48, or 72 h. Then, cell viability was measured by MTT assay, and IC₅₀ values were calculated. The two cell lines were then treated with metformin at IC₅₀ concentrations for 48 h, and RT-PCR was used to detect the expression of S100A4 and MMP-9 mRNAs.

RESULTS

Cell viability was apparently inhibited by metformin in both cell lines, and the inhibitory effect showed a time- and dose-dependent manner. The IC₅₀ values for BxPC-3 cells at 24, 48, and 72 h were 12.13 mmol/L, 10.43 mmol/L, and 9.55 mmol/L, respectively, and the corresponding values for AsPC-1 cells were 23.45 mmol/L, 15.44 mmol/L, and 11.30 mmol/L. After treatment with metformin for 48 h, the expression of S100A4 and MMP-9 mRNAs in the two cell lines was significantly decreased compared with control cells (P < 0.01).

CONCLUSION

Metformin inhibits pancreatic cancer cell growth in a time- and dose-dependent manner. Metformin may exert anti-metastasis effects by decreasing the expression of S100A4 and MMP-9 in pancreatic cancer cell lines.