Protective effects of metformin, statins and anti-inflammatory drugs on head and neck cancer: A systematic review

Serum Albumin Levels: A Biomarker to Be Repurposed in Different Disease Settings in Clinical Practice

Serum albumin (ALB), one of the most important proteins in human physiology, has the main functions of maintaining plasma oncotic pressure and plasma volume, transporting hormones, vitamins, oligominerals and drugs, and exerting a powerful antioxidant-anti-inflammatory role. Its prognostic value in liver and malabsorption syndromes is well known. In this narrative review, an analysis of the most important studies evaluating the prognostic significance of low serum ALB levels in hospitalized patients was performed. Specifically, the risk in emergency medicine, cardiovascular diseases, Coronavirus Disease 19 (COVID-19) infection, nephrology, oncology, and autoimmune rheumatic diseases has been examined to fully explore its clinical value. ALB is a negative acute-phase reactant and the reduction in its serum levels represents a threatening parameter for long-term survival in several clinical settings, and a strong biomarker for a poor prognosis in most diseases. Therefore, clinicians should consider serum ALB as a valuable tool to assess the efficacy of specific therapies, both in hospitalized patients and in chronic follow-up.

Effects of the Prior Use of Statins on Head and Neck Cancer Risk: A Hospital-Based Case-Control Study

Mechanisms related to the potential beneficial effects of statins on cancer are mainly related to the inhibition of the mevalonate pathway. The purpose of this study was to assess the association between prior use of statins and the risk of head and neck cancer. A hospital-based case-control study was conducted at the Dentistry Hospital of the University of Barcelona, including 101 incident cases of head and neck cancer and 101 controls matched to cases by age and sex. Multivariate logistic regression models were used to assess the association between prior statin exposure and head and neck cancer risk. Of the 202 patients included in total, 28.2% had previously received prescriptions for statins. Prior use of statins was found in 25.7% of cases and 30.7% of controls. Exposure to statins was not associated with head and neck cancer risk (OR = 0.72; 95% CI 0.28-1.84; p = 0.49). There was also no time- or dose-dependent association. Similar trends were observed when analyzed by subsites of cancer and recurrence rate. Our findings do not support a beneficial effect of prior statin exposure on head and neck cancer risk. Future research relying on observational data should emulate randomized clinical trials before clinical implications for repurposing drugs can be drawn.

Chemopreventive Effects of Concomitant or Individual Use of Statins, Aspirin, Metformin, and Angiotensin Drugs: A Study Using Claims Data of 23 Million Individuals

Despite previous studies on statins, aspirin, metformin, and angiotensin-converting-enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs), little has been studied about all their possible combinations for chemoprevention against cancers. This study aimed to comprehensively analyze the composite chemopreventive effects of all the combinations. In this case-control study, health records were retrieved from claims databases of Taiwan’s Health and Welfare Data Science Center. Eligible cases were matched at a 1:4 ratio with controls for age and sex. Both cases and controls were categorized into 16 exposure groups based on medication use. A total of 601,733 cancer cases were identified. Cancer risks (denoted by adjusted odds ratio; 99% confidence interval) were found to be significantly decreased: overall risk of all cancers in statin-alone (0.864; 0.843, 0.886), aspirin-alone (0.949; 0.939, 0.958), and ACEIs/ARBs (0.982; 0.978, 0.985) users; prostate (0.924; 0.889, 0.962) and female breast (0.967; 0.936, 1.000) cancers in metformin-alone users; gastrointestinal, lung, and liver cancers in aspirin and/or ACEIs/ARBs users; and liver cancer (0.433; 0.398, 0.471) in statin users. In conclusion, the results found no synergistic effect of multiple use of these agents on cancer prevention. Use of two (statins and aspirin, statins and metformin, statins and ACEIs/ARBs, and aspirin and ACEIS/ARBs) showed chemopreventive effects in some combinations, while the use of four, in general, did not.

Metformin for Cardiovascular Protection, Inflammatory Bowel Disease, Osteoporosis, Periodontitis, Polycystic Ovarian Syndrome, Neurodegeneration, Cancer, Inflammation and Senescence: What Is Next?

Diabetes is accompanied by several complications. Higher prevalence of cancers, cardiovascular diseases, chronic kidney disease (CKD), obesity, osteoporosis, and neurodegenerative diseases has been reported among patients with diabetes. Metformin is the oldest oral antidiabetic drug and can improve coexisting complications of diabetes. Clinical trials and observational studies uncovered that metformin can remarkably prevent or alleviate cardiovascular diseases, obesity, polycystic ovarian syndrome (PCOS), osteoporosis, cancer, periodontitis, neuronal damage and neurodegenerative diseases, inflammation, inflammatory bowel disease (IBD), tuberculosis, and COVID-19. In addition, metformin has been proposed as an antiaging agent. Numerous mechanisms were shown to be involved in the protective effects of metformin. Metformin activates the LKB1/AMPK pathway to interact with several intracellular signaling pathways and molecular mechanisms. The drug modifies the biologic function of NF-κB, PI3K/AKT/mTOR, SIRT1/PGC-1α, NLRP3, ERK, P38 MAPK, Wnt/β-catenin, Nrf2, JNK, and other major molecules in the intracellular signaling network. It also regulates the expression of noncoding RNAs. Thereby, metformin can regulate metabolism, growth, proliferation, inflammation, tumorigenesis, and senescence. Additionally, metformin modulates immune response, autophagy, mitophagy, endoplasmic reticulum (ER) stress, and apoptosis and exerts epigenetic effects. Furthermore, metformin protects against oxidative stress and genomic instability, preserves telomere length, and prevents stem cell exhaustion. In this review, the protective effects of metformin on each disease will be discussed using the results of recent meta-analyses, clinical trials, and observational studies. Thereafter, it will be meticulously explained how metformin reprograms intracellular signaling pathways and alters molecular and cellular interactions to modify the clinical presentations of several diseases.

Type 2 Diabetes Mellitus and Cancer: Epidemiology, Physiopathology and Prevention

Individuals with type 2 diabetes mellitus are at greater risk of developing cancer and of dying from it. Both diseases are age-related, contributing to the impact of population aging on the long-term sustainability of health care systems in European Union countries. The purpose of this narrative review was to describe, from epidemiological, pathophysiological and preventive perspectives, the links between type 2 diabetes mellitus and the most prevalent cancers in these patients. Multiple metabolic abnormalities that may occur in type 2 diabetes mellitus, particularly obesity, could explain the increased cancer risk. In addition, the effectiveness of drugs commonly used to treat type 2 diabetes mellitus (e.g., metformin and thiazolidinediones) has been broadly evaluated in cancer prevention. Thus, a better understanding of the links between type 2 diabetes mellitus and cancer will help to identify the contributing factors and the pathophysiological pathways and to design personalized preventive strategies. The final goal is to facilitate healthy aging and the prevention of cancer and other diseases related with type 2 diabetes mellitus, which are among the main sources of disability and death in the European Union and worldwide.

Early-Phase Interventional Trials in Oral Cancer Prevention

Simple Summary

Oral cancer is a devastating disease with increasing incidence worldwide. Oral epithelial dysplasia (OED) is a potentially malignant disorder and patients with OED are at increased risk of developing oral cancer. Current strategies for management of OED include surgery or close observation and both fail to address the underlying pathogenesis of the disease. There is an urgent need for evidence-based medical treatments for OED to prevent oral cancer development in this cohort. Chemoprevention trials to date have not delivered therapeutic agents for routine clinical practice. Historically, there has been significant heterogeneity in the design of oral cancer chemoprevention trials, with most failing to selectively recruit patients with biopsy-proven OED, which limits the usefulness of the findings in the OED population. The present paper aims to review the current evidence and the methodology of early-phase trials in oral cancer chemoprevention. Novel strategies in oral cancer chemoprevention will also be discussed.

Abstract

The increasing breadth of molecular targets, promise of immune-targeted therapies and repurposed agents have heightened interest in cancer prevention. While, to date, testing of oral cancer chemoprevention strategies has failed to deliver therapeutic agents for routine clinical practice, there remains an urgent need for further clinical research to overcome this hurdle. Patients at the greatest risk of disease stand to benefit the most from inclusion in clinical trials; therefore, there is a need to carefully define this population using validated clinical and molecular markers. Safety, tolerability and the efficacy of interventions is assessed through carefully selected endpoints. These endpoints may include pharmacodynamic, clinical, histological and on-target molecular modifications as an individual or as a composite endpoint. Early-phase trials provide an area of opportunity to explore novel and repurposed agents in the setting of oral cancer chemoprevention, eventually leading to phase III trials with clinical endpoints such as transformation and clinical outcome; these studies are large, lengthy and expensive and should be reserved for the most promising of agents. This paper will explore current evidence in oral cancer chemoprevention, drug repurposing, selection of appropriate endpoints for early-phase trials and novel therapeutic angles in oral cancer chemoprevention.

Metformin Inhibits the Development of Hypopharyngeal Squamous Cell Carcinoma through Circ_0003214-Mediated MiR-489-3p-ADAM10 Pathway

Purpose

This study aims to explore the function of metformin in hypopharyngeal squamous cell carcinoma (HSCC) and the underlying mechanism.

Methods

Cell viability, colony formation, cell apoptosis, and cell cycle were investigated using cell counting kit-8 assay, colony formation, and flow cytometry assay. Gene expression was detected by quantitative real-time polymerase chain reaction and western blot. The target relationship was validated by dual-luciferase reporter assay or RNA immunoprecipitation assay. An animal study was implemented to clarify the effect of metformin in vivo.

Results

Metformin suppressed HSCC cell viability and colony formation ability and induced cell cycle arrest and apoptosis, and circ_0003214 overexpression weakened these effects. Circ_0003214 regulated A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) expression via targeting miR-489-3p. Besides, miR-489-3p restoration reversed the role of circ_0003214, and ADAM10 knockdown reversed miR-489-3p inhibition-mediated effect. Moreover, metformin blocked tumor growth via the circ_0003214-miR-489-3p-ADAM10 axis in vivo.

Conclusion

Metformin inhibits HSCC progression through the circ_0003214/miR-489-3p/ADAM10 pathway.

Metformin generates profound alterations in systemic and tumor immunity with associated antitumor effects

BACKGROUND

Metformin is a commonly used antidiabetic medication which has demonstrated promise as an anticancer agent alone and in combination with conventional treatment regimens. There is increasing evidence that metformin can also generate immunomodulatory effects in solid tumors and is currently being investigated as an adjunct to immune checkpoint inhibitors (ICIs). We hypothesized that metformin would generate a shift in immunity unfavorable to tumor growth and tested this hypothesis in a preclinical model of head and neck cancer.

METHODS

Using a syngeneic mouse model of human papillomavirus-associated head and neck cancer (mEER/MTEC), we tested the impact of metformin on systemic and local immunity and tumor growth velocity. We compared the effects of acute and chronic treatment regimens on immunocyte presence and activation using a combination of flow cytometry and targeted transcriptomic analysis.

RESULTS

Acute metformin exposure generated measurable shifts in systemic myeloid and T-cell populations in non-tumor-bearing mice and decreased myeloid derived suppressor cell (MDSC) levels in tumor draining lymph nodes of tumor-bearing mice. Although metformin decreased regulatory T-cell (T-reg) and MDSC levels and increased CD8+ levels in murine tumors when combined with ICIs, acute metformin exposure was insufficient to generate substantial antitumor activity. Conversely, long-term metformin treatment significantly reduced tumor growth velocity, increased the CD8+/T-reg ratio, increased tumor infiltrating lymphocyte levels and upregulated component genes of the previously validated T-cell inflamed expression profile.

CONCLUSIONS

Metformin generates complex systemic and local immune effects which vary as a function of treatment duration. Combinatorial strategies with ICIs must take into account both the complexity and variability of these effects in order to generate maximal antitumor activity in future clinical trials.

Type 2 diabetes mellitus and risk of head and neck cancer subtypes: a systematic review and meta-analysis of observational studies

AIMS

The association between type 2 diabetes mellitus (T2DM) and risk of head and neck cancer (HNC) remains unclear. This study aims to perform a system review and meta-analysis to explore this relationship.

METHODS

PubMed, Web of Science, and Embase databases were searched for studies published up to July 31, 2020, regarding the association between T2DM and HNC risk. A random-effects model was utilized to calculate summary relative risks (RRs) with corresponding 95% confidence intervals (CIs).

RESULTS

Fourteen case-control studies and thirteen cohort studies were included in our analysis. We observed a weak association between T2DM and risk of HNC overall, but there was no statistical significance (RR, 1.04; 95% CI, 0.88-1.23; I² = 83.2%). Interestingly, there was a strong association in East Asia (RR, 1.46; 95% CI, 1.21-1.77; I² = 36.6%). For HNC subtypes, T2DM conferred a significantly elevated risk in oral cancer (RR, 1.22; 95% CI, 1.01-1.47; I² = 89.0%). However, in subgroup analyses of smoking, alcohol use, and body mass index (BMI)/obesity adjustments, the association between T2DM and oral cancer risk became insignificant. In addition, T2DM was not associated with a statistically elevated risk of pharyngeal cancer (RR, 1.18; 95% CI, 0.94-1.49; I² = 72.9%) and laryngeal cancer (RR, 1.03; 95% CI, 0.88-1.22; I² = 71.2%).

CONCLUSIONS

This meta-analysis indicates that T2DM is associated with an increased risk of HNC in East Asia. As for site-specific cancer types, the risk of oral cancer was significantly increased in T2DM patients, which appear to be mediated or confounded by smoking, alcohol use, or BMI/obesity.

Using genetic variants to evaluate the causal effect of cholesterol lowering on head and neck cancer risk: A Mendelian randomization study

Head and neck squamous cell carcinoma (HNSCC), which includes cancers of the oral cavity and oropharynx, is a cause of substantial global morbidity and mortality. Strategies to reduce disease burden include discovery of novel therapies and repurposing of existing drugs. Statins are commonly prescribed for lowering circulating cholesterol by inhibiting HMG-CoA reductase (HMGCR). Results from some observational studies suggest that statin use may reduce HNSCC risk. We appraised the relationship of genetically-proxied cholesterol-lowering drug targets and other circulating lipid traits with oral (OC) and oropharyngeal (OPC) cancer risk using two-sample Mendelian randomization (MR). For the primary analysis, germline genetic variants in HMGCR, NPC1L1, CETP, PCSK9 and LDLR were used to proxy the effect of low-density lipoprotein cholesterol (LDL-C) lowering therapies. In secondary analyses, variants were used to proxy circulating levels of other lipid traits in a genome-wide association study (GWAS) meta-analysis of 188,578 individuals. Both primary and secondary analyses aimed to estimate the downstream causal effect of cholesterol lowering therapies on OC and OPC risk. The second sample for MR was taken from a GWAS of 6,034 OC and OPC cases and 6,585 controls (GAME-ON). Analyses were replicated in UK Biobank, using 839 OC and OPC cases and 372,016 controls and the results of the GAME-ON and UK Biobank analyses combined in a fixed-effects meta-analysis. We found limited evidence of a causal effect of genetically-proxied LDL-C lowering using HMGCR, NPC1L1, CETP or other circulating lipid traits on either OC or OPC risk. Genetically-proxied PCSK9 inhibition equivalent to a 1 mmol/L (38.7 mg/dL) reduction in LDL-C was associated with an increased risk of OC and OPC combined (OR 1.8 95%CI 1.2, 2.8, p = 9.31 x10-05), with good concordance between GAME-ON and UK Biobank (I2 = 22%). Effects for PCSK9 appeared stronger in relation to OPC (OR 2.6 95%CI 1.4, 4.9) than OC (OR 1.4 95%CI 0.8, 2.4). LDLR variants, resulting in genetically-proxied reduction in LDL-C equivalent to a 1 mmol/L (38.7 mg/dL), reduced the risk of OC and OPC combined (OR 0.7, 95%CI 0.5, 1.0, p = 0.006). A series of pleiotropy-robust and outlier detection methods showed that pleiotropy did not bias our findings. We found limited evidence for a role of cholesterol-lowering in OC and OPC risk, suggesting previous observational results may have been confounded. There was some evidence that genetically-proxied inhibition of PCSK9 increased risk, while lipid-lowering variants in LDLR, reduced risk of combined OC and OPC. This result suggests that the mechanisms of action of PCSK9 on OC and OPC risk may be independent of its cholesterol lowering effects; however, this was not supported uniformly across all sensitivity analyses and further replication of this finding is required.

Association of metformin and development of dry age-related macular degeneration in a U.S. insurance claims database

PURPOSE

To assess whether metformin is associated with dry age-related macular degeneration (dAMD) development.

METHODS

In this retrospective cohort study, patients enrolled in a nationwide U.S. medical insurance claims database from 2002 to 2016 were included if they had diabetes mellitus, were ⩾55 years old, and were enrolled for ⩾2 years without a prior AMD diagnosis. The primary exposure was metformin use analyzed as either active or prior use or cumulative metformin dosage over the study period. A time updating Cox proportional hazard regression was used to estimate the hazard ratio of dAMD incidence with metformin exposure.

RESULTS

Among 1,007,226 diabetic enrollees, 53.3% were female and 66.4% were white with a mean hemoglobin A1c of 6.8%. Of eligible enrollees, 166,115 (16.5%) were taking metformin at the index date. Over the study period, 29,818 (3.0%) participants developed dAMD. In the active versus prior use of metformin model, active use conferred an increased hazard of developing dAMD (HR, 1.08; 95% CI, 1.04-1.12) while prior use had a decreased hazard (HR, 0.95; 95% CI 0.92-0.98). The cumulative metformin dosage model showed a significant trend toward increased hazard of dAMD incidence with increasing cumulative dosage (p < 0.001), with the lowest dosage quartile having decreased hazard of dAMD incidence (HR, 0.95; 95% CI, 0.91-0.99) and the highest having increased hazard (HR, 1.07; 95% CI, 1.01-1.13).

CONCLUSIONS

Small, conflicting associations between metformin exposure and development of dAMD were observed depending on cumulative dosage and whether drug use was active, suggesting metformin did not substantially affect the development of dAMD.

Metformin: A Novel Weapon Against Inflammation

It has become widely accepted that inflammation is a driving force behind a variety of chronic diseases, such as cardiovascular disease, diabetes, kidney disease, cancer, neurodegenerative disorders, etc. However, the existing nonsteroidal anti-inflammatory drugs show a limited utility in clinical patients. Therefore, the novel agents with different inflammation-inhibitory mechanisms are worth pursuing. Metformin, a synthetic derivative of guanidine, has a history of more than 50 years of clinical experience in treating patients with type 2 diabetes. Intense research efforts have been dedicated to proving metformin’s inflammation-inhibitory effects in cells, animal models, patient records, and randomized clinical trials. The emerging evidence also indicates its therapeutic potential in clinical domains other than type 2 diabetes. Herein, this article appraises current pre-clinical and clinical findings, emphasizing metformin’s anti-inflammatory properties under individual pathophysiological scenarios. In summary, the anti-inflammatory effects of metformin are evident in pre-clinical models. By comparison, there are still clinical perplexities to be addressed in repurposing metformin to inflammation-driven chronic diseases. Future randomized controlled trials, incorporating better stratification/targeting, would establish metformin’s utility in this clinical setting.

Effects of inflammatory and anti-inflammatory environments on the macrophage mitochondrial function

Mitochondrial response to inflammation is crucial in the metabolic adaptation to infection. This study aimed to explore the mitochondrial response under inflammatory and anti-inflammatory environments, with a focus on the tricarboxylic acid (TCA) cycle. Expression levels of key TCA cycle enzymes and the autophagy-related protein light chain 3b (LC3b) were determined in raw 264.7 cells treated with lipopolysaccharide (LPS) and metformin (Met). Additionally, reactive oxygen species (ROS) levels and mitochondrial membrane potential were assessed using flow cytometry. Moreover, 8-week-old C57BL/6J mice were intraperitoneally injected with LPS and Met to assess the mitochondrial response in vivo. Upon LPS stimulation, the expression of key TCA enzymes, including citrate synthase, α-ketoglutarate dehydrogenase, and isocitrate dehydrogenase 2, and the mitochondrial membrane potential decreased, whereas the levels of LC3b and ROS increased. However, treatment with Met inhibited the reduction of LPS-induced enzyme levels as well as the elevation of LC3b and ROS levels. In conclusion, the mitochondrial TCA cycle is affected by the inflammatory environment, and the LPS-induced effects can be reversed by Met treatment.

Ibuprofen induces ferroptosis of glioblastoma cells via downregulation of nuclear factor erythroid 2-related factor 2 signaling pathway

Ferroptosis is a newly discovered type of cell death decided by iron-dependent lipid peroxidation, but its role in glioblastoma cell death remains unclear. Ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), has been associated with antitumorigenic effects in many cancers. In this study, we first found that ibuprofen inhibited the viabilities of glioblastoma cells in vitro and in vivo, accompanied by abnormal increase in intracellular lipid peroxidation. Further study showed that the cell growth inhibition caused by ibuprofen could be rescued by the ferroptosis inhibitors deferoxamine (DFO), ferrostatin-1 and Liproxstatin-1. Nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) are key regulators of ferroptosis. Our data showed that Nrf2, GPX4 and SLC7A11 were downregulated in glioblastoma cells under ibuprofen treatment. Interestingly, we found that decreased mRNA expression of GPX4 and SLC7A11 was accompanied with reduced Nrf2, which is a redox sensitive transcription factor that controls the expression of intracellular redox-balancing proteins such as GPX4 and SLC7A11. All the data suggested that Nrf2 could regulate the expression of GPX4 and SLC7A11 in glioma cells. Taken together, our findings reveal that ibuprofen could induce ferroptosis of glioblastoma cells via downregulation of Nrf2 signaling pathway and is a potential drug for glioma treatment.

The Association between Metformin and Survival of Head and Neck Cancer: A Systematic Review and Meta-Analysis of 7 Retrospective Cohort Studies

Background:

Metformin has been associated with improved survival outcomes in various malignancies. However, observational studies in head and neck cancer are inconsistent.

Objective:

The study aimed to summarize and quantify the relationship between metformin use and the survival of head and neck cancer.

Methods:

A meta-analysis based on cohort studies was systematically conducted (published up to Jan 18, 2020), identified from PubMed, Embase, Web of Science, Cochrane Library, Google Scholar, and Scopus databases. Summary hazard ratios (HR) and 95% confidence intervals (CI) were calculated using a random-effects model.

Results:

Seven retrospective cohort studies including 3,285 head and neck cancer patients were included. The association between the use of metformin and cancer survival was not statistically significant: summarized HR of 0.89 (95% CI 0.66-1.18, P=0.413, I2=64.0%) for overall survival, summarized HR of 0.65 (95% CI 0.31-1.35, P=0.246, I2=60.3%) for disease-free survival, and summarized HR of 0.69 (95% CI 0.40-1.20, P=0.191, I2=73.1%) for disease-specific survival.

Conclusion:

In this meta-analysis of 7 retrospective cohort studies, there was not a statistically significant association between the use of metformin and better survival for head and neck cancer. However, the analysis may have been underpowered. More studies of prospective designs with larger sample sizes are needed to investigate the effect of metformin on the survival of head and neck cancer.

The impact of preoperative glycated hemoglobin levels on outcomes in oral squamous cell carcinoma

OBJECTIVES

This study aimed to investigate the association between preoperative glycated hemoglobin (HbA1c) levels and the treatment outcomes of oral cavity squamous cell carcinoma (OSCC).

METHODS

Three hundred and fifty-eight OSCC patients were consecutively enrolled between July 2004 and July 2016. Clinicopathological parameters and survival outcomes were analyzed following HbA1c stratification of 6.5% (HbA1c ≥ 6.5%: n = 74, 20.6%) and 7.0% (HbA1c ≥ 7.0%: n = 53, 14.8%).

RESULTS

Higher HbA1c levels were associated with elevated body mass index, lower albumin levels, wider surgical margins, and prolonged hospital stays (HbA1c 6.5%: p = .001, .048, .030, .009, respectively; HbA1c 7.0%: p = .092, .032, .009, .015, respectively). Survival rates stratified by HbA1c 6.5% were as follows: locoregional recurrence-free survival, p = .014; distant metastasis-free survival, p = .013; second primary cancer-free survival, p = .015; overall survival, p = .014; disease-specific survival, p = .002 and HbA1c 7.0%: locoregional recurrence-free survival, p = .013; distant metastasis-free survival, p = .013; second primary cancer-free survival, p = .014; overall survival, p = .015; disease-specific survival, p = .004. Multivariate analyses identified HbA1c as an independent prognostic factor for overall and disease-specific survival (HbA1c 6.5%: p = .014 and .002, respectively; HbA1c 7.0%: p = .036 and .013, respectively).

CONCLUSIONS

Oral squamous cell carcinoma patients with higher preoperative HbA1c levels had longer hospitalization and worse survival outcomes.