Association of diabetes duration and diabetes treatment with the risk of hepatocellular carcinoma

Antihyperglycaemic therapies and cancer risk

AIMS

This review is aimed at highlighting the potential mitogenic/tumour growth-promoting or antimitogenic/tumour growth-inhibiting effects of the main antihyperglycaemic drug classes.

METHODS

We review and discuss the most current studies evaluating the association between antidiabetic medications used in clinical practice and malignancies as described so far.

RESULTS

Metformin seems to be the only antidiabetic drug to exert protective effects both on monotherapy and also when combined with other oral antidiabetic drugs or insulins in several site-specific cancers. In contrast, several other drug classes may increase cancer risk. Some reason for concern remains regarding sulphonylureas and also the incretin-based therapies regarding pancreas and thyroid cancers and the sodium glucose cotransporter-2 inhibitors as well as pioglitazone regarding bladder cancer. The majority of meta-analyses suggest that there is no evidence for a causal relationship between insulin glargine and elevated cancer risk, although the studies have been controversially discussed. For α-glucosidase inhibitors and glinides, neutral or only few data upon cancer risk exist.

CONCLUSION

Although the molecular mechanisms are not fully understood, a potential risk of mitogenicity and tumour growth promotion cannot be excluded in case of several antidiabetic drug classes. However, more large-scale, randomized, well-designed clinical studies with especially long follow-up time periods are needed to get reliable answers to these safety issues.

Using Dynamic 99mT c-GSA SPECT/CT fusion images for hepatectomy planning and postoperative liver failure prediction

BACKGROUND

Available tools in liver surgery planning rely on the future remnant liver (FRL) volume. Inappropriate decision might be made since the same FRL volume might represent different liver functions depending on the severity of underlying liver damage. This study developed an alternative system to estimate FRL function and to predict the risk of postoperative liver failure.

METHODS

Current study recruited 71 prehepatectomy patients and 71 healthy volunteers. A technetium-99-labelled asialoglycoproteins was given to participants and SPECT was used to capture the intensity of the signal, represented by uptake index (UI). The agreement between preoperative UI values, liver function tests, and Child scores were evaluated. Linear regression was used to evaluate the agreement between predicted UI for FRL and postoperative UI values. Area under the receiver operating characteristic (AUC) curve was used to evaluate the discriminative performance of UI in differentiating patient with high risk of liver failure.

RESULTS

Preoperative UIs are highly correlated with Child score (P < 0.0001), especially to identify patients with ascites and elevated bilirubin. The predicted UIs were in close agreement with the actual postoperative UI values (r = 0.95 P < 0.001). The AUC analysis indicated that UI values had a high accuracy in predicting the risk of liver failure (AUC = 0.95, P < 0.0001). The best cut-off point was 0.9 and the corresponding sensitivity was 100 % and specificity was 92 %.

CONCLUSIONS

The new methodology reliably estimates FRL function and predicts the risk of liver failure. It provides a visual aid for liver surgeon in surgery planning and risk assessment.

Effect of pioglitazone on outcome following curative treatment for hepatocellular carcinoma in patients with hepatitis C virus infection: A prospective study

Pioglitazone is an insulin sensitizer used for the treatment of diabetes mellitus (DM). DM with insulin resistance is a risk factor for hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV) infection. We aimed to investigate the effects of pioglitazone on HCC recurrence following treatment in HCV-infected patients. Between 2009 and 2011, 85 HCV-infected HCC patients who underwent curative treatment were enrolled in this prospective study. Among 45 patients with type 2 DM, 27 were administered pioglitazone (pioglitazone group) following treatment. The remaining 58 patients were assigned to the control group. The primary outcome was recurrence-free survival. Changes in insulin resistance and serum adiponectin levels resulting from pioglitazone treatment were also assessed. In the whole analysis (n=85), no significant difference in recurrence-free survival was observed between the pioglitazone and control groups. However, in a spline model analysis of DM patients, a decreased risk of HCC recurrence was associated with increased body weight in patients with a body mass index (BMI) ≥23; this association became significant at BMI ≥24 (hazard ratio=0.17; 95% confidence interval: 0.03-0.95). In addition, significantly decreased homeostasis model assessment for insulin resistance values (P=0.002) and significantly increased serum high-molecular-weight adiponectin levels (P<0.001) were observed following pioglitazone treatment. Although pioglitazone did not suppress HCC recurrence in the whole analysis, it inhibited HCC recurrence in overweight HCV-infected diabetic patients. Moreover, pioglitazone improved insulin resistance and adipocytokine levels. Thus, pioglitazone may suppress HCC recurrence, which is associated with glucose and fat metabolism disorders.

Epidemiology of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common histologic type of primary liver cancer, accounting for between 85% and 90% of these malignancies. The overall prognosis of patients with liver cancer is poor, and an understanding of this disease and its risk factors is crucial for screening at-risk individuals, early recognition, and timely diagnosis. Most HCCs arise in the background of chronic liver disease caused by hepatitis B virus, hepatitis C virus, and chronic excessive alcohol intake. These underlying causes are characterized by marked variations in geography, gender, and other well-documented risk factors, some of which are potentially preventable.

Non-alcoholic fatty liver disease: a practical approach to treatment

Non-alcoholic fatty liver disease (NAFLD) affects up to a third of the population in many developed countries. Between 10% and 30% of patients with NAFLD have non-alcoholic steatohepatitis (NASH) that can progress to cirrhosis. There are metabolic risk factors common to both NAFLD and cardiovascular disease, so patients with NASH have an increased risk of liver-related and cardiovascular death. Management of patients with NAFLD depends largely on the stage of disease, emphasising the importance of careful risk stratification. There are four main areas to focus on when thinking about management strategies in NAFLD: lifestyle modification, targeting the components of the metabolic syndrome, liver-directed pharmacotherapy for high risk patients and managing the complications of cirrhosis.

Hepatocellular carcinoma in nonalcoholic fatty liver: Role of environmental and genetic factors

Hepatocellular carcinoma (HCC) is the fourth cause of cancer related mortality, and its incidence is rapidly increasing. Viral hepatitis, alcohol abuse, and exposure to hepatotoxins are major risk factors, but nonalcoholic fatty liver disease (NAFLD) associated with obesity, insulin resistance, and type 2 diabetes, is an increasingly recognized trigger, especially in developed countries. Older age, severity of insulin resistance and diabetes, and iron overload have been reported to predispose to HCC in this context. Remarkably, HCCs have been reported in non-cirrhotic livers in a higher proportion of cases in NAFLD patients than in other etiologies. Inherited factors have also been implicated to explain the different individual susceptibility to develop HCC, and their role seems magnified in fatty liver, where only a minority of affected subjects progresses to cancer. In particular, the common I148M variant of the PNPLA3 gene influencing hepatic lipid metabolism influences HCC risk independently of its effect on the progression of liver fibrosis. Recently, rare loss-of-function mutations in Apolipoprotein B resulting in very low density lipoproteins hepatic retention and in Telomerase reverse transcriptase influencing cellular senescence have also been linked to HCC in NAFLD. Indeed, hepatic stellate cells senescence has been suggested to bridge tissue aging with alterations of the intestinal microbiota in the pathogenesis of obesity-related HCC. A deeper understanding of the mechanisms mediating hepatic carcinogenesis during insulin resistance, and the identification of its genetic determinants will hopefully provide new diagnostic and therapeutic tools.

Glycogen synthase kinase-3β is associated with the prognosis of hepatocellular carcinoma and may mediate the influence of type 2 diabetes mellitus on hepatocellular carcinoma

BACKGROUND

Although many studies have shown glycogen synthase kinase-3β (GSK-3β) was associated with type 2 diabetes mellitus (T2DM) and implicated with a wide range of cancers, the role of GSK-3β in hepatocellular carcinoma(HCC) and the correlation among GSK-3β, T2DM and HCC remains unclear. Our objectives were to identify the effect of p-Ser9-GSK-3β on the prognosis of patients with HCC and to learn more about the interaction among T2DM, GSK-3β and the prognosis of HCC.

METHODS

Firstly we used reverse transcriptase-PCR(RT-PCR) and western blotting to determine the expression levels of GSK-3β and p-Ser9-GSK-3β in human HCC samples. We then used immunohistochemical staining to evaluate the expression pattern of p-Ser9-GSK-3β in 178 patients with HCC after curative partial hepatectomy. Finally we statistically analyzed the association of p-Ser9-GSK-3β and T2DM with the prognosis of patients with HCC.

RESULTS

P-Ser9-GSK-3β was over-expressed in tumor tissues compared with their normal counterparts. Correlation and regression analysis indicated that the over-expression of p-Ser9-GSK-3β was significantly associated with T2DM, and the correlation coefficient was 0.259 (P = 0.001). Multivariate analysis showed that the over-expression of p-Ser9-GSK-3β(P<0.001) and T2DM(P = 0.008) were independently associated with poor prognosis of HCC, respectively. Further analysis demonstrated that these two variables are closely related with each other.

CONCLUSION

The over-expression of p-Ser9-GSK-3β and T2DM are strongly correlated with worse surgical outcome of HCC. P-Ser9-GSK-3β may play a significant role in mediating the influence of T2DM on the prognosis of HCC.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Anti-diabetic medications and risk of primary liver cancer in persons with type II diabetes

Background:

Type II diabetes increases liver cancer risk but the risk may be mitigated by anti-diabetic medications. However, choice of medications is correlated with diabetes duration and severity, leading to confounding by indication.

Methods:

To address this association, we conducted a nested case–control study among persons with type II diabetes in the Clinical Practice Research Datalink. Cases had primary liver cancer and controls were matched on age, sex, practice, calendar time, and number of years in the database. Exposure was classified by type and combination of anti-diabetic prescribed and compared to non-use. Odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated using conditional logistic regression.

Results:

In 305 cases of liver cancer and 1151 controls, there was no association between liver cancer and anti-diabetic medication use compared to non-use (OR=0.74 (95% CI=0.45–1.20) for metformin-only, 1.10 (95% CI=0.66–1.84) for other oral hypoglycaemic (OH)-only, 0.89 (95% CI=0.58–1.37) for metformin+other OH, 1.11 (95% CI=0.60–2.05) for metformin+insulin, 0.81 (95% CI=0.23–2.85) for other OH+insulin, and 0.72 (95% CI=0.18–2.84) for insulin-only). Stratification by duration of diabetes did not alter the results.

Conclusions:

Use of any anti-diabetic medications in patients with type II diabetes was not associated with liver cancer, though there was a suggestion of a small protective effect for metformin.

Non-alcoholic fatty liver disease and diabetes: from physiopathological interplay to diagnosis and treatment

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in patients with diabetes mellitus and increasing evidence suggests that patients with type 2 diabetes are at a particularly high risk for developing the progressive forms of NAFLD, non-alcoholic steatohepatitis and associated advanced liver fibrosis. Moreover, diabetes is an independent risk factor for NAFLD progression, and for hepatocellular carcinoma development and liver-related mortality in prospective studies. Notwithstanding, patients with NAFLD have an elevated prevalence of prediabetes. Recent studies have shown that NAFLD presence predicts the development of type 2 diabetes. Diabetes and NAFLD have mutual pathogenetic mechanisms and it is possible that genetic and environmental factors interact with metabolic derangements to accelerate NAFLD progression in diabetic patients. The diagnosis of the more advanced stages of NAFLD in diabetic patients shares the same challenges as in non-diabetic patients and it includes imaging and serological methods, although histopathological evaluation is still considered the gold standard diagnostic method. An effective established treatment is not yet available for patients with steatohepatitis and fibrosis and randomized clinical trials including only diabetic patients are lacking. We sought to outline the published data including epidemiology, pathogenesis, diagnosis and treatment of NAFLD in diabetic patients, in order to better understand the interplay between these two prevalent diseases and identify the gaps that still need to be fulfilled in the management of NAFLD in patients with diabetes mellitus.

Metformin and cancer risk and mortality: a systematic review and meta-analysis taking into account biases and confounders

Treatment of diabetics with metformin is associated with decreased breast cancer risk in observational studies, but it remains unclear if this drug has clinical antineoplastic activity. In a recent presurgical trial, we found a heterogeneous effect of metformin on breast cancer proliferation (ki-67) depending upon insulin resistance (HOMA index). Here, we determined the associations of additional serum biomarkers of insulin resistance, tumor subtype, and drug concentration with ki-67 response to metformin. Two-hundred non-diabetic women were randomly allocated to metformin (850 mg/bid) or placebo for 4 weeks prior to breast cancer surgery. The ki-67 response to metformin was assessed comparing data obtained from baseline biopsy (ki-67 and tumor subtype) and serum markers (HOMA index, C-peptide, IGF-I, IGFBP-1, IGFBP-3, free IGF-I, hs-CRP, adiponectin) with the same measurements at definitive surgery. For patients with a blood sample taken within 24 h from last drug intake, metformin level was measured. Compared with placebo, metformin significantly decreased ki-67 in women with HOMA > 2.8, those in the lowest IGFBP-1 quintile, those in the highest IGFBP-3 quartile, those with low free IGF-I, those in the top hs-CRP tertile, and those with HER2-positive tumors. In women with HOMA index > 2.8, drug levels were positively correlated with the ki-67 decrease, whereas no trend was noted in women with HOMA < 2.8 (p-interaction = 0.07). At conventional antidiabetic doses, the effect of metformin on tumor ki-67 of non-diabetic breast cancer patients varies with host and tumor characteristics. These findings are relevant to design breast cancer prevention and treatment trials with metformin.

Incidence of bladder cancer in patients with type 2 diabetes treated with metformin or sulfonylureas

OBJECTIVE

Previous studies evaluating the effect of metformin on cancer risk have been impacted by time-related biases. To avoid these biases, we examined the incidence of bladder cancer in new users of metformin and sulfonylureas (SUs).

RESEARCH DESIGN AND METHODS

This cohort study included 87,600 patients with type 2 diabetes in The Health Improvement Network database. Use of metformin or an SU was treated as a time-dependent variable. Cox regression-generated hazard ratios (HRs) compared metformin use with SU use, adjusted for age, sex, smoking, obesity, and HbA1c level.

RESULTS

We identified 196 incident bladder cancers in the metformin cohort and 66 cancers in the SU cohort. Use of metformin was not associated with decreased bladder cancer risk (HR 0.81 [95% CI 0.60-1.09]). This association did not differ by sex (P for interaction = 0.20). We observed no association with duration of metformin relative to SU use (3 to <4 years of use: 0.57 [0.25-1.34]; 4 to <5 years of use: 0.93 [0.30-2.85; ≥5 years of use: 1.18 [0.44-3.19]; P for trend = 0.26).

CONCLUSIONS

Use of metformin is not associated with a decreased incidence of bladder cancer. Similar methods should be used to study other cancers that have previously been identified as potentially preventable with metformin.

Metformin and cancer risk and mortality: a systematic review and meta-analysis taking into account biases and confounders

Previous meta-analyses have shown that the antidiabetic agent metformin is associated with reduced cancer incidence and mortality. However, this effect has not been consistently demonstrated in animal models and recent epidemiologic studies. We performed a meta-analysis with a focus on confounders and biases, including body mass index (BMI), study type, and time-related biases. We identified 71 articles published between January 1, 1966, and May 31, 2013, through Pubmed, ISI Web of Science (Science Citation Index Expanded), Embase, and the Cochrane library that were related to metformin and cancer incidence or mortality. Study characteristics and outcomes were abstracted for each study that met inclusion criteria. We included estimates from 47 independent studies and 65,540 cancer cases in patients with diabetes. Overall cancer incidence was reduced by 31% [summary relative risk (SRR), 0.69; 95% confidence interval (CI), 0.52-0.90], although between-study heterogeneity was considerable (I(2) = 88%). Cancer mortality was reduced by 34% (SRR, 0.66; 95% CI, 0.54-0.81; I(2) = 21%). BMI-adjusted studies and studies without time-related biases also showed significant reduction in cancer incidence (SRR, 0.82; 95% CI, 0.70-0.96 with I(2) = 76% and SRR, 0.90; 95% CI, 0.89-0.91 with I(2) = 56%, respectively), albeit with lesser magnitude (18% and 10% reduction, respectively). However, studies of cancer mortality and individual organ sites did not consistently show significant reductions across all types of analyses. Although these associations may not be causal, our results show that metformin may reduce cancer incidence and mortality in patients with diabetes However, the reduction seems to be of modest magnitude and not affecting all populations equally. Clinical trials are needed to determine if these observations apply to nondiabetic populations and to specific organ sites.

Positive and negative effects of glitazones in carcinogenesis: experimental models vs. clinical practice

Diabetes increases cancer risk, which may be modulated by careful choice of treatment. Experimental reports showed efficacy of glitazones in various in vitro and in vivo models of carcinogenesis, but procarcinogenic effects in some models were reported too, and, similarly, data on cancer incidence in glitazone users are inconsistent. This review summarizes oncostatic effects of glitazones in preclinical and clinical studies and brings a brief summary of their impact on cancer risk in diabetic patients, with a focus on the association between pioglitazone use and bladder cancer.

Metabolic syndrome and non-alcoholic fatty liver disease in liver surgery: The new scourges?

The aim of this topic highlight is to review relevant evidence regarding the influence of the metabolic syndrome (MS) and its associated liver manifestation, non-alcoholic fatty liver disease (NAFLD), on the development of liver cancer as well as their impact on the results of major liver surgery. MS and NAFLD, whose incidences are significantly increasing in Western countries, are leading to a changing profile of the patients undergoing liver surgery. A MEDLINE search was performed for relevant articles using the key words "metabolic syndrome", "liver resection", "liver transplantation", "non alcoholic fatty liver disease", "non-alcoholic steatohepatitis" and "liver cancer". On one hand, the MS favors the development of primary liver malignancies (hepatocellular carcinoma and cholangiocarcinoma) either through NAFLD liver parenchymal alterations (steatosis, steatohepatitis, fibrosis) or in the absence of significant underlying liver parenchyma changes. Also, the existence of NAFLD may have a specific impact on colorectal liver metastases recurrence. On the other hand, the postoperative period following partial liver resection and liver transplantation is at increased risk of both postoperative complications and mortality. These deleterious effects seem to be related to the existence of liver specific complications but also higher cardio-vascular sensitivity in a setting of MS/NAFLD. Finally, the long-term prognosis after curative surgery joins that of patients operated on with other types of underlying liver diseases. An increased rate of patients with MS/NAFLD referred to hepatobiliary units has to be expected. The higher operative risk observed in this subset of patients will require specific improvements in their perioperative management.

Insight into the impact of diabetes mellitus on the increased risk of hepatocellular carcinoma: mini-review

Hepatocellular carcinoma is a multifactorial disease which is associated with a background of many causal risk factors. Diabetes mellitus however is one of the most common co-morbid illnesses found in hepatocellular carcinoma patients that are significantly associated with worsening of hepatocellular carcinoma development, patient prognosis and survival. Therefore, efforts have been focused on understanding the mechanisms underlying progression of hepatocellular carcinoma onset and development especially in diabetic patients. To our knowledge, there are no reports which address the impact of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) along with epigenetic regulations associated with increased risk of hepatocellular carcinoma confounded by diabetes mellitus. Therefore, this mini-review focuses on the possible intermediary mechanisms involved in worsening the onset and progression of hepatocellular carcinoma development confounded by diabetes mellitus. The first approach is to look at the role of inflammatory mediators (TNF-α and IL-6) in apoptosis and inflammation during hepatocarcinogenesis through monitoring levels of apoptotic regulators, B-cell lymphoma 2 protein which is encoded by BCL2 gene and apoptosis regulator BAX known as bcl-2-like protein 4 which is encoded by the BAX gene. The second approach is to focus on the possible epigenomic reprogramming that drives hepatocellular transformation since epigenetic modification of DNA is a key feature in the pathogenesis of hepatocarcinogenesis. Both approaches may suggest role of using Bcl2 and Bax as apoptotic and inflammatory markers for hepatocellular carcinoma detection as well as the importance impact of DNA methylation, hypomethylation or histone modifications as attractive candidates for early-detection biomarkers of hepatocellular carcinoma.

Metformin and cancer

Metformin is well-known as an anti-diabetic drug, but it seems to possess anti-cancerous properties as well. Adenosine monophosphate-activated protein kinase (AMPK) is a highly conserved regulator of the cellular response to the presence of low energy in all eukaryotic cells. It is considered a key sensor of the balance of cellular ATP and AMP concentrations. LKB1 serine/threonine kinase is a divergent yet evolutionarily well-conserved kinase, biochemically sufficient to activate AMPK in vitro and genetically required for AMPK activation. Because of this potent connection to AMPK, LKB1 may act as a central regulator of metabolism in vivo. Once activated, AMP kinase phosphorylates the transcriptional activator TorC2, thereby blocking its nuclear translocation and inhibiting the expression of genes involved in gluconeogenesis. Data suggest that LKB1/AMPK signaling plays a role in protection from apoptosis, specifically in response to agents that increase the cellular AMP/ATP ratio. Active AMPK signaling offers a protective effect by providing the cell with time to reverse the aberrantly high ratio of AMP/ATP. If unable to reverse this ratio, the cell will eventually undergo cell death. These observations offer the provocative suggestion of a potential therapeutic window in which LKB1-deficient tumor cells may be acutely sensitive to AMP analogues or sensitized to cell death by other stimuli when treated in combination with agents that increase the AMP/ATP ratio. LKB1 therefore is a classical tumor suppressor. AMPK is a direct LKB1 substrate. A consequence of AMPK activation by LKB1 is the inhibition of the mammalian target of rapamycin (mTOR) C1 pathway. Metformin's anti-cancerous properties have been demonstrated in various cancer cells in vitro, such as lung, pancreatic, colon, ovarian, breast, prostate, renal cancer cells, melanoma, and even in acute lymphoblastic leukemia cells. To test metformin's action in vivo, mice were implanted with transformed mammary epithelial cells and treated with three cycles of metformin and with the anthracycline doxorubicin. When combined with doxorubicin, metformin wiped out tumors and prevented recurrence. Metformin alone had no effect, and doxorubicin as a single agent initially shrank tumors, but they regrew later. Virtually no cancer stem cells were recovered immediately after treatment and the complete response was sustained for nearly two months. Further studies are needed to assess the anti-cancerous potentials of metformin in vivo. This article reviews the current knowledge on the actions of LKB1/AMPK and the effectiveness of metformin in cancer, specifically in diabetes patients.

Thiazolidinediones and cancer: results of a meta-analysis of randomized clinical trials

Recent epidemiological data have contributed to the formulation of the hypothesis about the long-term safety of pioglitazone, a thiazolidinedione (TZD), with respect to malignancies, in particular bladder cancer. The primary aim of this meta-analysis of randomized clinical trials, not designed a priori to test this hypothesis, was to explore whether TZDs affect the risk of cancer. A meta-analysis was performed including published and unpublished randomized trials with a duration of at least 52 weeks, enrolling patients with or without diabetes, comparing TZDs with either placebo or other drug therapies on various different outcomes. We found 22 trials reporting at least one cancer and enrolling 13,197 patients to TZD (pioglitazone: n = 3,710 and rosiglitazone: n = 9,487) and 12,359 to placebo or active comparator groups. The mean follow-up was 26.1 months. Overall, those assigned at random to TZDs had a significant reduction (MH-OR 0.85 [0.73-0.98]; p = 0.027) in the incidence of malignancies, with no significant difference in effect between pioglitazone and rosiglitazone. Specifically, subgroup analyses showed a significant reduction for rosiglitazone (MH-OR 0.82 [0.69-0.98]; p = 0.029), but not for pioglitazone (MH-OR 0.66 [0.34-1.28]; p = 0.22). In further subgroup analyses of site-specific malignancies based on the data from four trials, the risk of bladder cancer with pioglitazone (MH-OR) was 2.05 [0.84-5.02]; p = 0.12. Further, rosiglitazone, but not pioglitazone, was associated with a significantly reduced risk of bowel cancer. In contrast, pioglitazone, but not rosiglitazone, was associated with a significant reduction in breast cancer. The present meta-analysis of trials, not designed a priori to test the hypothesis, provides reassuring evidence that TZDs are not associated with risk of overall malignancies. In fact, they are compatible with the possibility of a decreased risk of cancer. In site-specific subgroup analyses, for rosiglitazone, there was a significant decreased risk of bowel cancer. Subgroup analyses for pioglitazone did not allow to exclude an increased risk of bladder cancer, while the risk of breast cancer was significantly decreased. While these data are also useful to formulate not test hypotheses, they provide somewhat more cogent evidence than the previously published epidemiological data.

The association between metabolic syndrome and hepatocellular carcinoma: systemic review and meta-analysis

BACKGROUND

The metabolic syndrome (MetS) and/or its individual components have been linked to the development of cancer. Recent studies have suggested a similar link to hepatocellular carcinoma (HCC). The aim of this study was to evaluate the direction and magnitude of the association between the MetS and HCC.

METHODS

Two reviewers independently conducted a systemic search to identify the available evidence from databases from January 1980 to June 2012. Search terms included "Metabolic syndrome," "insulin resistance syndrome," "metabolic abnormalities" combined with "hepatocellular carcinoma," and "liver cancer." No language restriction was applied to the search. Only studies reporting an effect measure for the association between MetS and HCC were eligible for inclusion. Publication bias was assessed using the Begg and Egger tests, with a visual inspection of funnel plot. All analyses were performed using Comprehensive Meta-analysis version 2 software.

RESULTS

Four studies (3 cohort and 1 case control) with a total of 829,651 participants were included in the analysis. The age range of participants was between 30 and 84 years. The combined analysis showed an overall 81% increased risk of HCC in cases with MetS (relative risk, 1.81; 95% confidence interval, 1.37-2.41). After excluding the single case-control study from analysis, the overall risk ratio remained statistically significant (relative risk, 1.49; 95% confidence interval, 1.27-1.74). Funnel plot inspection, Begg and Egger tests showed no evidence of publication bias for combined analysis.

CONCLUSIONS

Though studies are scarce, currently available epidemiologic data are suggestive of significantly higher risk of HCC among patients with MetS.

Chemopreventive strategies in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third most common cause of death from cancer. The incidence and mortality of HCC are increasing in most Western countries as a result of an ageing cohort infected with chronic hepatitis C, and are expected to continue to rise as a consequence of the obesity epidemic. Chemopreventive strategies aimed at decreasing the risk or delaying the onset of HCC are needed. Universal immunization against HBV and antiviral therapy against HBV and HCV in patients with established disease has consistently been associated with reduced HCC risk, especially in patients who achieve sustained virologic response. However, the cost-effectiveness of antiviral therapy for primary HCC prevention is not known. Several commonly prescribed medications seem promising as chemopreventive agents against HCC, including statins, antidiabetic medications and aspirin. Dietary agents such as coffee, vitamin E and fish oil as well as phytochemicals might also be associated with reduced risk of HCC. Though randomized controlled trials are ideally needed to firmly establish efficacy, such chemoprevention trials are logistically and ethically challenging. Well-designed, prospective, population-based cohort studies might provide the best evidence for chemopreventive efficacy of these agents.

Diabetes mellitus is associated with hepatocellular carcinoma: a retrospective case-control study in hepatitis endemic area

Background

A number of case-control patient studies have been conducted to investigate the association between diabetes mellitus (DM) and hepatocellular carcinoma (HCC). Despite some controversial reports, it has been suggested that DM is associated with HCC. The previous studies on this subject vary in the selection of populations, sample sizes, methodology, and analysis results. Therefore, it is necessary to further delineate the involvement of DM, together with other related risk factors, in HCC with large sample size and strict analysis methodology.

Methods

We conducted a hospital-based retrospective case-control study at Perking Union Medical College Hospital, China. A total of 1,568 patients with liver diseases were enrolled in the statistical study to evaluate the association of DM and other risk factors with HCC. Among these patients, 716 of them were diagnosed with benign liver diseases, and 852 patients were diagnosed as HCC. We utilized binary logistic regression and stepwise logistic regression to investigate the associations among DM, hypertension, fatty liver, cirrhosis, gallstone, HBV infection, HCV infection, and HCC.

Results

Statistical analysis through the stepwise regression model indicated that the prevalence of DM, male gender, cirrhosis, HCV infection, or HBV infection is higher in the HCC patient group compared to the control group. However, the prevalence of gallstone is negatively associated with HCC cases. DM co-exists with HBV infection, male gender, and age in the HCC cases. Binary logistic regression analysis suggested that DM may synergize with HBV infection in HCC development.

Conclusion

DM is strongly associated with the increased risk of HCC regardless of the prevalence of HBV infection, HCV infection, cirrhosis, male gender, and age. However, the synergistic interaction between DM and HBV in HCC occurrence is significant. Therefore, DM patients with HBV infection represent a very high HCC risk population and should be considered for HCC close surveillance program.

Epidemiology and risk factors of biliary tract and primary liver tumors

Primary liver and biliary tract tumors encompass a range of benign and malignant neoplasms. They consist of histologically distinct types of tumors that arise from and are influenced by hepatocytes, biliary epithelial cells, and mesenchymal cells. Improvements in imaging have allowed the detection and diagnosis of these neoplasms to be refined. Investigation at the histologic, molecular, and genetic levels has allowed neoplasms to be categorized and treated. Epidemiology has improved understanding of geographic, ethnic, gender, and cultural differences that link exposures with cancer risk. This article focuses on the epidemiology of major primary adult liver and biliary tract tumors.

Hepatocellular Carcinoma in Non-alcoholic Fatty Liver Disease: Epidemiology, Pathogenesis, and Prevention

Hepatocellular cancer (HCC) is the fifth most prevalent cancer worldwide and the third leading cause of cancer-related deaths. Non-alcoholic fatty liver disease (NAFLD), a spectrum of hepatic disorders associated with obesity and the metabolic syndrome, is a recognized risk factor for HCC. NAFLD that is advanced to cirrhosis carries the highest risk for HCC, but there is increasing concern that NAFLD-associated HCC may also occur in non-cirrhotic liver. As NAFLD is rapidly becoming the most common liver condition, it has been implicated in the worrisome trend of rising HCC incidence in a number of countries, which may offset successful measures in reducing the effect of virus-related liver cancer. Independently or in synergy with cirrhosis, NAFLD may provide a special oncogenic microenvironment through its pathogenic association with chronic nutrient excess and adipose tissue remodeling, characterized by pro-inflammatory adipokine profiles, lipotoxicity, altered hepatocellular bioenergetics, and insulin resistance. Better understanding of this complex process, and development of reliable biomarkers for HCC will be critical for early recognition and risk prediction. Moreover, correcting deranged lipid metabolism and restoring insulin sensitivity by lifestyle measures and targeted pharmacotherapy holds major promise for effective prevention of NAFLD-associated HCC.

NAFLD, NASH and liver cancer

NAFLD affects a large proportion of the US population and its incidence and prevalence are increasing to epidemic proportions around the world. As with other liver diseases that cause cirrhosis, NAFLD increases the risk of liver cancer, a disease with poor outcomes and limited therapeutic options. The incidences of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma are also rising, and HCC is now the leading cause of obesity-related cancer deaths in middle-aged men in the USA. In this Review, we summarize the correlations between liver cancer and NAFLD-related cirrhosis, and the role of the metabolic syndrome in the development of liver cancer from diverse aetiologies, including HCV-mediated cirrhosis. Recent advances in understanding the progression of NAFLD to HCC from preclinical models will also be discussed. Targeted genetic manipulation of certain metabolic or stress-response pathways, including one-carbon metabolism, NF-κB, PTEN and microRNAs, has been valuable in elucidating the pathways that regulate carcinogenesis in NAFLD. Although tremendous advances have occurred in the identification of diagnostic and therapeutic opportunities to reduce the progression of NAFLD, considerable gaps in our knowledge remain with regard to the mechanisms by which NAFLD and its risk factors promote liver cancer.

Metformin suppresses hepatocellular carcinoma cell growth through induction of cell cycle G1/G0 phase arrest and p21CIP and p27KIP expression and downregulation of cyclin D1 in vitro and in vivo

Metformin is used as a first-line therapy for type 2 diabetes, with reports of its usefulness for the prevention and control of several types of cancers. This study investigated the effects of metformin on hepatocellular carcinoma (HCC). The human HCC cell lines HepG2 and PLC/PRF/5 were cultured and treated with metformin or 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an activator of adenosine monophosphate (AMP)-activated protein kinase. Changes in cell viability and cell cycle distribution were evaluated by MTT and flow cytometry, respectively. Apoptosis was assessed by fluorescent-dye staining. An HCC model was established in 6- to 8-week-old BALB/c-nu mice by subcutaneous injection of PLC/PRF/5 cells. After 1 week, mice were treated intragastrically with metformin or vehicle. Tumor xenograft tissues were examined using immunohistochemistry for evaluation of the the expression of cyclin D1, p21CIP and p27KIP. HCC cells and tissues from the in vitro and in vivo experiments, respectively, were subjected to protein extraction and western blotting. We found that metformin treatment reduced HCC cell viability in a dose-dependent manner similar to AICAR treatment. In addition, metformin treatment induced HCC cell cycle arrest at G1/G0 phase and apoptosis. Intragastric treatment of the mouse PLC/PRF/5 cell xenograft model with metformin showed that metformin not only blocked tumor progression, but also reduced tumor morbidity. Treatment with metformin upregulated the expression of p21CIP and p27KIP, but downregulated cyclin D1 levels, both in vitro and in vivo. Metformin treatment also upregulated the expression of phosphorylated AMPK protein in xenograft tissues. These findings indicate that metformin warrants further evaluation as a novel therapeutic and preventive strategy against HCC.

The Effects of Metformin on Ovarian Cancer: A Systematic Review

Objective

The potential therapeutic effects of metformin on several cancers were reported. However, the evidence of the effects of metformin on ovarian cancer is still limited and inconclusive. This systematic review and meta-analysis study aims to summarize the existing evidence of the therapeutic effects of metformin on ovarian cancer.

Methods

We performed systematic searches using electronic databases including PubMed and EMBASE until December 2012. Key words included “metformin” AND (“ovarian cancer” OR “ovary tumor”). All human studies assessing the effects of metformin on ovarian cancer were eligible for inclusion. All articles were reviewed independently by 2 authors with a standardized approach for the purpose of study, study design, patient characteristics, exposure, and outcomes. The data were pooled using a random-effects model.

Results

Of 190 studies retrieved, only 3 observational studies and 1 report of 2 randomized controlled trials were included. Among those studies, 2 reported the effects of metformin on survival outcomes of ovarian cancer, whereas the other 2 reported the effects of metformin on ovarian cancer prevention. The findings of studies reporting the effects on survival outcomes indicated that metformin may prolong overall, disease-specific, and progression-free survival in ovarian cancer patients. The results of studies reporting the effects of metformin on ovarian cancer prevention were meta-analyzed. It indicated that metformin tended to decrease occurrence of ovarian cancer among diabetic patients with the pooled odds ratio of 0.57 (95% confidence interval, 0.16–1.99).

Conclusions

Our findings showed the potential therapeutic effects of metformin on survival outcomes of ovarian cancer and ovarian cancer prevention. However, most of the evidence was observational studies. There is a call for further well-conducted controlled clinical trials to confirm the effects of metformin on ovarian cancer survival and ovarian cancer prevention.

Lessons from mouse models of high-fat diet-induced NAFLD

Nonalcoholic fatty liver disease (NAFLD) encompasses a clinicopathologic spectrum of diseases ranging from isolated hepatic steatosis to nonalcoholic steatohepatitis (NASH), the more aggressive form of fatty liver disease that may progress to cirrhosis and cirrhosis-related complications, including hepatocellular carcinoma. The prevalence of NAFLD, including NASH, is also increasing in parallel with the growing epidemics of obesity and diabetes. However, the causal relationships between obesity and/or diabetes and NASH or liver tumorigenesis have not yet been clearly elucidated. Animal models of NAFLD/NASH provide crucial information, not only for elucidating the pathogenesis of NAFLD/NASH, but also for examining therapeutic effects of various agents. A high-fat diet is widely used to produce hepatic steatosis and NASH in experimental animals. Several studies, including our own, have shown that long-term high-fat diet loading, which can induce obesity and insulin resistance, can also induce NASH and liver tumorigenesis in C57BL/6J mice. In this article, we discuss the pathophysiology of and treatment strategies for NAFLD and subsequent NAFLD-related complications such as NASH and liver tumorigenesis, mainly based on lessons learned from mouse models of high-fat diet-induced NAFLD/NASH.

Metformin prevents liver tumorigenesis induced by high-fat diet in C57Bl/6 mice

The prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is increasing with the growing epidemics of obesity and diabetes. NAFLD encompasses a clinicopathologic spectrum of disease ranging from isolated hepatic steatosis to NASH, which is a more aggressive form of fatty liver disease, to cirrhosis and, finally, hepatocellular carcinoma (HCC). The exact mechanism behind the development of HCC in NASH remains unclear; however, it has been established that hepatic steatosis is the important risk factor in the development of HCC. Metformin has recently drawn attention because of its potential antitumor effect. Here, we investigated the effects of metformin on high-fat diet (HFD)-induced liver tumorigenesis, using a mouse model of NASH and liver tumor. Metformin prevented long-term HFD-induced liver tumorigenesis in C57Bl/6 mice. Of note, metformin failed to protect against liver tumorigenesis in mice that had already begun to develop NAFLD. Metformin improved short-term HFD-induced fat accumulation in the liver, associated with the suppression of adipose tissue inflammation. Collectively, these results suggest that metformin may prevent liver tumorigenesis via suppression of liver fat accumulation in the early stage, before the onset of NAFLD, which seems to be associated with a delay in the development of inflammation of the adipose tissue.

Diabetes is not an independent risk factor for hepatocellular carcinoma

BACKGROUND

It is controversial whether diabetes is a risk factor for hepatocellular carcinoma (HCC) in countries with high prevalence of viral hepatitis such as Taiwan.

METHODS

From the Taiwanese National Health Insurance, 1 000 000 insurants were randomly selected for the study. Among them, 494 080 men and 502 841 women without HCC were followed from 2003 until 2005. Relative risks were estimated taking into account alcohol-related diagnoses, chronic liver disease, potential HCC detection examinations and other covariates.

RESULTS

The diabetes patients were more likely to receive examinations of abdominal sonography, HBsAg, anti-HCV and alpha-fetoprotein. Multivariable-adjusted relative risk (95% confidence interval) was not significant for diabetes as a risk factor for HCC in either men or women: 0.932 (0.788-1.101) for men and 1.158 (0.968-1.386) for women. While comparing diabetes duration <1, 1-3 and ≥ 3 years to non-diabetes individuals, the respective relative risks were 1.043 (0.751-1.448), 0.945 (0.738-1.209) and 0.901 (0.744-1.091) for men; and were 0.950 (0.610-1.480), 1.169 (0.884-1.546) and 1.189 (0.974-1.452) for women. For both sexes, age, alcohol-related diagnoses, chronic liver disease and potential detection bias were significantly associated with higher risk, but dyslipidemia and stroke a lower risk. In addition, chronic obstructive pulmonary disease was associated with a lower risk and sulfonylurea a higher risk in men. Models that did not consider alcohol-related diagnoses, chronic liver disease and potential detection bias would result in spurious association between diabetes and HCC.

CONCLUSIONS

Diabetes is not an independent risk factor for HCC after considering the effects of alcohol-related diagnoses, chronic liver disease and potential detection bias.

Metabolic roles of AMPK and metformin in cancer cells

Metformin is one of the most widely used anti-diabetic agents in the world, and a growing body of evidence suggests that it may also be effective as an anti-cancer drug. Observational studies have shown that metformin reduces cancer incidence and cancer-related mortality in multiple types of cancer. These results have drawn attention to the mechanisms underlying metformin's anti-cancer effects, which may include triggering of the AMP-activated protein kinase (AMPK) pathway, resulting in vulnerability to an energy crisis (leading to cell death under conditions of nutrient deprivation) and a reduction in circulating insulin/IGF-1 levels. Clinical trials are currently underway to determine the benefits, appropriate dosage, and tolerability of metformin in the context of cancer therapy. This review highlights fundamental aspects of the molecular mechanisms underlying metformin's anti-cancer effects, describes the epidemiological evidence and ongoing clinical challenges, and proposes directions for future translational research.

Beyond aspirin-cancer prevention with statins, metformin and bisphosphonates

Cancer risk reduction using pharmacological means is an attractive modern preventive approach that supplements the classical behavioural prevention recommendations. Medications that are commonly used by large populations to treat a variety of common, non-cancer-related, medical situations are an attractive candidate pool. This Review discusses three pharmacological agents with the most evidence for their potential as cancer chemopreventive agents: anti-hypercholesterolaemia medications (statins), an antidiabetic agent (metformin) and antiosteoporosis drugs (bisphosphonates). Data are accumulating to support a significant negative association of certain statins with cancer occurrence or survival in several major tumour sites (mostly gastrointestinal tumours and breast cancer), with an augmented combined effect with aspirin or other non-steroidal anti-inflammatory drugs. Metformin, but not other hypoglycaemic drugs, also seems to have some antitumour growth activity, but the amount of evidence in human studies, mainly in breast cancer, is still limited. Experimental and observational data have identified bisphosphonates as a pharmacological group that could have significant impact on incidence and mortality of more than one subsite of malignancy. At the current level of evidence these potential chemopreventive drugs should be considered in high-risk situations or using the personalized approach of maximizing individual benefits and minimizing the potential for adverse effects with the aid of pharmacogenetic indicators.

Primary hepatocellular carcinoma and metabolic syndrome: An update

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. The incidence of hepatocellular carcinoma has increased dramatically by 80% over the past two decades in the United States. Numerous basic science and clinical studies have documented a strong association between hepatocellular carcinoma and the metabolic syndrome. These studies have documented that, in most patients, non-alcoholic fatty liver disease is the hepatic manifestation of the metabolic syndrome, which may progress to hepatocellular carcinoma through the cirrhotic process. However, minority of patients with non-alcoholic fatty liver disease may progress to hepatocellular carcinoma without cirrhosis. This review summarizes the current literature of the link between hepatocellular carcinoma and metabolic syndrome with special emphasis on various components of the metabolic syndrome including risk of association with obesity, diabetes mellitus, hyperlipidemia, and hypertension. Current understanding of pathophysiology, clinical features, treatments, outcomes, and surveillance of hepatocellular carcinoma in the background of metabolic syndrome and non-alcoholic fatty liver disease is reviewed. With the current epidemic of metabolic syndrome, the number of patients with non-alcoholic fatty liver disease is increasing. Subsequently, it is expected that the incidence and prevalence of HCC will also increase. It is very important for the scientific community to shed more light on the pathogenesis of HCC with metabolic syndrome, both with and without cirrhosis. At the same time it is also important to quantify the risk of hepatocellular carcinoma associated with the metabolic syndrome in a prospective setting and develop surveillance recommendations for detection of hepatocellular carcinoma in patients with metabolic syndrome.

Metformin therapy and risk of cancer in patients with type 2 diabetes: systematic review

Aims/Hypothesis

Diabetes treatments were related with either an increased or reduced risk of cancer. There is ongoing debate about a potential protective action of metformin. To summarize evidence on the association between metformin and risk of cancer and cancer mortality in patients with diabetes.

Methods

Data source: MEDLINE and EMBASE (January 1966-April 2012). We selected randomized studies comparing metformin and other hypoglycaemic agents and observational studies exploring the association between exposure to metformin and cancer. Outcomes were cancer mortality, all malignancies and site-specific cancers.

Results

Of 25307 citations identified, 12 randomized controlled trials (21,595 patients) and 41 observational studies (1,029,389 patients) met the inclusion criteria. In observational studies there was a significant association of exposure to metformin with the risk of cancer death [6 studies, 24,410 patients, OR:0.65, 95%CI: 0.53-0.80], all malignancies [18 studies, 561,836 patients, OR:0.73, 95%CI: 0.61-0.88], liver [8 studies, 312,742 patients, OR:0.34; 95%CI: 0.19-0.60] colorectal [12 studies, 871,365 patients, OR:0.83, 95%CI: 0.74–0.92], pancreas [9 studies, 847,248 patients, OR:0.56, 95%CI: 0.36–0.86], stomach [2 studies, 100701 patients, OR:0.83, 95%CI: 0.76–0.91], and esophagus cancer [2 studies, 100694 patients, OR:0.90, 95%CI: 0.83–0.98]. No significant difference of risk was observed in randomized trials. Metformin was not associated with the risk of: breast cancer, lung cancer, ovarian cancer, uterus cancer, prostate cancer, bladder cancer, kidney cancer, and melanoma.

Conclusions/Interpretation

Results suggest that Metformin might be associated with a significant reduction in the risk of cancer and cancer-related mortality. Randomized trials specifically designed to evaluate the efficacy of metformin as an anticancer agent are warranted.

Nonalcoholic fatty liver disease: current issues and novel treatment approaches

Nonalcoholic fatty liver disease (NAFLD) is considered the most common liver disorder in the Western world. It is commonly associated with insulin resistance, obesity, dyslipidaemia, type 2 diabetes mellitus (T2DM) and cardiovascular disease. Nonalcoholic steatohepatitis (NASH) is characterized by steatosis with necroinflammation and eventual fibrosis, which can lead to end-stage liver disease and hepatocellular carcinoma. Its pathogenesis is complex, and involves a state of 'lipotoxicity' in which insulin resistance, with increased free fatty acid release from adipose tissue to the liver, play a key role in the onset of a 'lipotoxic liver disease' and its progression to NASH. The diagnosis of NASH is challenging, as most affected patients are symptom free and the role of routine screening is not clearly established. A complete medical history is important to rule out other causes of fatty liver disease (alcohol abuse, medications, other). Plasma aminotransferase levels and liver ultrasound are helpful in the diagnosis of NAFLD/NASH, but a liver biopsy is often required for a definitive diagnosis. However, there is an active search for plasma biomarkers and imaging techniques that may non-invasively aid in the diagnosis. The treatment of NASH requires a multifaceted approach. The goal is to reverse obesity-associated lipotoxicity and insulin resistance via lifestyle intervention. Although there is no pharmacological agent approved for the treatment of NAFLD, vitamin E (in patients without T2DM) and the thiazolidinedione pioglitazone (in patients with and without T2DM) have shown the most consistent results in randomized controlled trials. This review concentrates on our current understanding of the disease, with a focus on the existing therapeutic approaches and potential future pharmacological developments for NAFLD and NASH.

Diabetes and risk of subsequent gastric cancer: a population-based cohort study in Taiwan

BACKGROUND

Epidemiological data concerning the association between diabetes and the subsequent development of gastric cancer are controversial. This population-based retrospective cohort study investigated the subsequent risk of gastric cancer for diabetic patients.

METHODS

From claims data of the universal health insurance of Taiwan, we identified 19,625 persons aged ≥20 years newly diagnosed with diabetes during 2000-2005. A comparison group (n = 78,500), frequency matched by age, sex, and calendar year, was randomly selected from people without diabetes. Incidence and hazard ratios (HR) of gastric cancer were ascertained during the follow-up period until 2008. We also explored associations of antidiabetic medicines with the incidence of gastric cancer.

RESULTS

During the follow-up period, 47 subjects in the diabetic group and 216 subjects in the comparison group suffered gastric cancer, with the incidence rates of 4.34 and 4.86 per 10,000 person-years, respectively. During the first 4 years after diabetes diagnosis, the incidence of gastric cancer was relatively low in diabetic patients [adjusted HR = 0.63; 95% confidence interval (CI) = 0.42-0.97]. However, after that time, the diabetic group had a 76% (95% CI = 1.06-2.91) higher risk of developing gastric cancer than the comparison group. In diabetic patients, alpha-glucosidase inhibitors were associated with a significantly decreased risk of gastric cancer (adjusted HR = 0.38; 95% CI = 0.15-0.96).

CONCLUSIONS

Our findings suggested that the association between diabetes and subsequent risk of gastric cancer may vary over time. Increased risk of gastric cancer was observed in patients with longer duration of diabetes.

Metformin and sulfonylureas in relation to cancer risk in type II diabetes patients: a meta-analysis using primary data of published studies

INTRODUCTION

Accumulating evidence suggests that patients with type 2 diabetes mellitus (T2DM) and hyperinsulinemia are at increased risk for developing malignancies. It remains to be fully elucidated whether use of metformin, an insulin sensitizer, and/or sulfonylureas, insulin secretagogues, affect cancer incidence in subjects with T2DM.

MATERIAL & METHODS

We performed a meta-analysis using PubMed, of randomized control trials (RCTs), cohorts, and case-control studies published through July 2012 that assess effects of metformin and/or sulfonylurea sulfonylureas on cancer risk at any site, in subjects with T2DM. Fixed and random effects meta-analysis models were used, and the effect size was summarized as relative risk (RR) for RCTs/cohorts and as odds ratio (OR) for the case-control studies.

RESULTS

Analysis of 24 metformin studies in subjects with T2DM showed that metformin use is associated with reduced risk for the development of cancer, in both cohort (RR=0.70 [95% CI=0.67-0.73]) and case-control studies (OR=0.90 [95% CI=0.84-0.98]), but this finding was not supported by RCTs (RR=1.01[95% CI=0.81-1.26]). Data from 18 sulfonylurea studies in subjects with T2DM showed that sulfonylurea use is associated with an increase in all-cancer risk, in cohort studies (RR=1.55 [95% CI=1.48 -1.63]), though data from RCTs (RR=1.17 [95% CI=0.95-1.45]) and case-control studies (OR=1.02 [95% CI=0.93-1.13]) failed to demonstrate a statistically significant effect.

CONCLUSIONS

This analysis using pooled primary data demonstrates that metformin use reduces, while sulfonylurea use may be associated with an increased cancer risk in subjects with T2DM. These findings need to be confirmed in large-scale RCTs before they are translated into clinical practice.

Genetic variation in the PNPLA3 gene and hepatocellular carcinoma in USA: risk and prognosis prediction

Nonalcoholic fatty liver disease (NAFLD) is an emerging epidemic with high prevalence in Western countries. Genome-wide association studies had reported that a variation in the patatin-like phospholipase domain containing 3 (PNPLA3) gene is associated with high susceptibility to NAFLD. However, the relationship between this variation and hepatocellular carcinoma (HCC) has not been well established. We investigated the impact of PNPLA3 genetic variation (rs738409: C>G) on HCC risk and prognosis in the United States by conducting a case-control study that included 257 newly diagnosed and pathologically confirmed Caucasian patients with HCC (cases) and 494 healthy controls. Multivariate logistics and Cox regression models were used to control for the confounding effects of HCC risk and prognostic factors. We observed higher risk of HCC for subjects with a homozygous GG genotype than for those with CC or CG genotypes, the adjusted odds ratio (OR) was 3.21 (95% confidence interval [CI], 1.68-6.41). We observed risk modification among individuals with diabetes mellitus (OR = 19.11; 95% CI, 5.13-71.20). The PNPLA3 GG genotype was significantly associated with underlying cirrhosis in HCC patients (OR = 2.48; 95% CI, 1.05-5.87). Moreover, GG allele represents an independent risk factor for death. The adjusted hazard ratio of the GG genotype was 2.11 (95% CI, 1.26-3.52) compared with CC and CG genotypes. PNPLA3 genetic variation (rs738409: C>G) may determine individual susceptibility to HCC development and poor prognosis. Further experimental investigations are necessary for thorough assessment of the hepatocarcinogenic role of PNPLA3.

Anti-diabetic medications and the risk of hepatocellular cancer: a systematic review and meta-analysis

Several preclinical and observational studies have shown that anti-diabetic medications (ADMs) can modify the risk of hepatocellular cancer (HCC) in patients with diabetes mellitus (DM). We performed a systematic review and meta-analyses of studies evaluating the effect of metformin, thiazolidinediones (TZDs), sulfonylureas, and/or insulin on the risk of HCC. We conducted a systematic search of Medline, EMBASE, and Web of Science up to August 2012. Studies were included if they (1) evaluated and clearly defined exposure to metformin, TZDs, sulfonylureas, and/or insulin, (2) reported HCC outcomes in patients with DM, and (3) reported relative risks or odds ratio (OR) or provided data for their estimation. Summary OR estimates with 95% confidence intervals (CIs) were estimated using the random-effects model. Ten studies reporting 22,650 cases of HCC in 334,307 patients with type 2 DM were included in the analysis. Meta-analysis of observational studies showed a 50% reduction in HCC incidence with metformin use (n=8 studies; OR 0.50, 95% CI 0.34-0.73), 62% and 161% increase in HCC incidence with sulfonylurea (n=8 studies; OR 1.62, 95% CI 1.16-2.24) or insulin use (n=7; OR 2.61, 95% CI 1.46-4.65), respectively. TZDs did not modify the risk of HCC (n=4; OR 0.54, 95% CI 0.28-1.02). There was considerable heterogeneity across studies, which was partly explained by study setting, location, and whether the studies adjusted for the concomitant use of other ADMs. Post-hoc analysis of randomized controlled trials did not reveal any significant association between ADM use and risk of HCC. ADMs may modify the risk of HCC in patients with DM, especially in the Western population. However, the effect of each individual agent should be interpreted with caution owing to inherent cancer-modifying effect of the comparator group.

Diabetes mellitus, insulin treatment, diabetes duration, and risk of biliary tract cancer and hepatocellular carcinoma in a European cohort

BACKGROUND

Evidence on associations between self-reported diabetes mellitus, diabetes duration, age at diabetes diagnosis, insulin treatment, and risk of biliary tract cancer (BTC) and hepatocellular carcinoma (HCC), independent of general and abdominal obesity is scarce.

PATIENTS AND METHODS

We conducted a prospective analysis in the EPIC-cohort study among 363 426 participants with self-reported diabetes data. Multivariable adjusted relative risks and 95% confidence intervals were estimated from Cox regression models. In a nested case-control subset, analyses were carried out in HCV/HBV-negative individuals.

RESULTS

During 8.5 years of follow-up, 204 BTC cases [including 75 gallbladder cancer (GBC) cases], and 176 HCC cases were identified. Independent of body mass index and waist-to-height ratio diabetes status was associated with higher risk of BTC and HCC [1.77 (1.00-3.13) and 2.17 (1.36-3.47)]. For BTC, the risk seemed to be higher in participants with shorter diabetes duration and those not treated with insulin. Regarding cancer subsites, diabetes was only associated with GBC [2.72 (1.17-6.31)]. The risk for HCC was particularly higher in participants treated with insulin. The results were not appreciably different in HCV/HBV-negative individuals.

CONCLUSION(S)

This study supports the hypothesis that diabetes is a risk factor for BTC (particularly GBC) and HCC. Further research is required to establish whether diabetes treatment or duration is associated with these cancers.

Mitogenic insulin receptor-A is overexpressed in human hepatocellular carcinoma due to EGFR-mediated dysregulation of RNA splicing factors

Insulin receptor (IR) exists as two isoforms resulting from the alternative splicing of IR pre-mRNA. IR-B promotes the metabolic effects of insulin, whereas IR-A rather signals proliferative effects. IR-B is predominantly expressed in the adult liver. Here, we show that the alternative splicing of IR pre-mRNA is dysregulated in a panel of 85 human hepatocellular carcinoma (HCC) while being normal in adjacent nontumor liver tissue. An IR-B to IR-A switch is frequently observed in HCC tumors regardless of tumor etiology. Using pharmacologic and siRNA approaches, we show that the autocrine or paracrine activation of the EGF receptor (EGFR)/mitogen-activated protein/extracellular signal-regulated kinase pathway increases the IR-A:IR-B ratio in HCC cell lines, but not in normal hepatocytes, by upregulating the expression of the splicing factors CUGBP1, hnRNPH, hnRNPA1, hnRNPA2B1, and SF2/ASF. In HCC tumors, there is a significant correlation between the expression of IR-A and that of splicing factors. Dysregulation of IR pre-mRNA splicing was confirmed in a chemically induced model of HCC in rat but not in regenerating livers after partial hepatectomy. This study identifies a mechanism responsible for the generation of mitogenic IR-A and provides a novel interplay between IR and EGFR pathways in HCC. Increased expression of IR-A during neoplastic transformation of hepatocytes could mediate some of the adverse effects of hyperinsulinemia on HCC.

Metformin and cancer

Type 2 diabetes mellitus is a rising cause of cardiovascular morbidity and mortality. A number of studies have also identified diabetic patients as having increased risk for the development of cancer. Metformin is a widely prescribed antidiabetic drug with an established efficacy coupled with a favorable safety profile and low cost. An increasing number of studies have associated metformin treatment with a decrease of cancer risk. Moreover, metformin has also been associated with improved outcomes in cancer patients. These possible pleiotropic effects of metformin may establish metformin as a cancer prevention and treatment option. However, any favorable effects of metformin on cancer are not always corroborated by clinical trials. Larger studies are expected to better investigate the possible antineoplastic effects of metformin.

Risk factors for intrahepatic cholangiocarcinoma: association between metformin use and reduced cancer risk

The associations between diabetes, smoking, obesity, and intrahepatic cholangiocarcinoma (ICC) risk remain inconclusive. Metformin is purportedly associated with a reduced risk for various cancers. This case-control study evaluated risk factors for ICC and explored the effects of metformin on ICC risk in a clinic/hospital-based cohort. ICC patients observed at the Mayo Clinic (Rochester, MN) between January 2000 and May 2010 were identified. Age, sex, ethnicity, and residential area-matched controls were selected from among Mayo Clinic Biobank participants. The associations between potential factors and ICC risk were determined. Six hundred and twelve cases and 594 controls were identified. Factors associated with increased ICC risk included biliary tract diseases (adjusted odds ratio [AOR]: 81.8; 95% confidence interval [CI]: 11.2-598.8; P < 0.001), cirrhosis (AOR, 8.0; 95% CI: 1.8-36.5; P = 0.007), diabetes (AOR, 3.6; 95% CI: 2.3-5.5; P < 0.001), and smoking (AOR, 1.6; 95% CI: 1.3-2.1; P < 0.001). Compared to diabetic patients not treated with metformin, the odds ratio (OR) for ICC for diabetic patients treated with metformin was significantly decreased (OR, 0.4; 95% CI: 0.2-0.9; P = 0.04). Obesity and metabolic syndrome were not associated with ICC.

CONCLUSION

This study confirmed diabetes and smoking as independent risk factors for ICC. A novel finding was that treatment with metformin was significantly associated with a 60% reduction in ICC risk in diabetic patients.

Diabetes and nonalcoholic Fatty liver disease: a pathogenic duo

Recent data increasingly support a complex interplay between the metabolic condition diabetes mellitus and the pathologically defined nonalcoholic fatty liver disease (NAFLD). NAFLD predicts the development of type 2 diabetes and vice versa, and each condition may serve as a progression factor for the other. Although the association of diabetes and NAFLD is likely to be partly the result of a "common soil," it is also probable that diabetes interacts with NAFLD through specific pathogenic mechanisms. In particular, through interrelated metabolic pathways currently only partly understood, diabetes appears to accelerate the progression of NAFLD to nonalcoholic steatohepatitis, defined by the presence of necroinflammation, with varying degrees of liver fibrosis. In the research setting, obstacles that have made the identification of clinically significant NAFLD, and particularly nonalcoholic steatohepatitis, difficult are being addressed with the use of new imaging techniques combined with risk algorithms derived from peripheral blood profiling. These techniques are likely to be used in the diabetes population in the near future. This review examines the pathogenic links between NAFLD and diabetes by exploring the epidemiological evidence in humans and also through newer animal models. Emerging technology to help screen noninvasively for differing pathological forms of NAFLD and the potential role of preventive and therapeutic approaches for NAFLD in the setting of diabetes are also examined.

Statins are associated with a reduced risk of hepatocellular cancer: a systematic review and meta-analysis

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Several studies have shown that statins could have chemopreventive effects on HCC. We performed a systematic review and meta-analysis of studies that evaluated the effects of statins on the risk of HCC.

METHODS

We conducted a systematic search of MEDLINE, Embase, and Web of Science through May 2012 and manually reviewed the literature. Studies were included if they evaluated and clearly defined exposure to statins, reported the incidence of HCC, and reported relative risks or odds ratios (ORs) or provided data for their estimation. Ten studies reporting 4298 cases of HCC in 1,459,417 patients were analyzed. Summary OR estimates with 95% confidence intervals (CIs) were calculated using the random effects model. Statistical heterogeneity was assessed with the Cochran's Q statistic and I(2) statistic.

RESULTS

Statin users were less likely to develop HCC than statin nonusers (adjusted OR, 0.63; 95% CI, 0.52-0.76), although the results were heterogeneous (P = .01, I(2) = 59%). This heterogeneity could be accounted for by study location (Asian population [n = 4]: adjusted OR, 0.52; 95% CI, 0.42-0.64; Western population [n = 6]: adjusted OR, 0.67; 95% CI, 0.53-0.85) and design (observational studies [n = 7]: adjusted OR, 0.60; 95% CI, 0.49-0.73; clinical trials [n = 3]: adjusted OR, 0.95; 95% CI, 0.62-1.45).

CONCLUSIONS

Based on meta-analysis, statin use is associated with a reduced risk of HCC, most strongly in Asian but also in Western populations. Randomized clinical trials in populations at high risk for HCC (especially in Asian populations with hepatitis B) are warranted.

Association of metformin use with cancer incidence and mortality: a meta-analysis

PURPOSE

To assess the effect of metformin intake on cancer incidence and mortality.

METHODS

Original articles in English published until June 15, 2012 were searched for in electronic databases (MEDLINE, ISI Web of Science and EMBASE databases) and relevant reviews were examined. Meta-analysis was applied to calculate the summary relative risk (SRR) and their 95% confidence intervals (95% CI). Sensitivity analysis was conducted to assess the robustness of the pooled estimator. The risk of publication bias was assessed by the Egger regression asymmetry test.

RESULTS

According to the eligibility criteria, 37 studies comprising 1,535,636 participants, were selected in terms of intervention and data of cancer incidence or mortality. Among metformin users compared with non-users, the SRR for overall-cancer incidence was 0.73 (95% CI, 0.64-0.83) and that for mortality was 0.82 (95% CI, 0.76-0.89). The risk reductions for liver, pancreatic, colorectal and breast cancer incidence were 78%, 46%, 23% and 6%, respectively. Also, metformin can reduce the mortality of liver cancer (SRR, 0.23; 95% CI, 0.09-0.60) and breast cancer (SRR, 0.63; 95% CI, 0.40-0.99). No statistically significant association between metformin and prostate cancer incidence was found.

CONCLUSIONS

Metformin can reduce the incidence of overall cancer, liver cancer, pancreatic cancer, colorectal cancer and breast cancer as well as the mortality of overall cancer, liver cancer and breast cancer. No beneficial effect on prostate cancer incidence was found for meformin intake in the meta-analysis.

Cancer risk for patients using thiazolidinediones for type 2 diabetes: a meta-analysis

OBJECTIVE

To clarify and quantify the effect of thiazolidinediones (TZDs; e.g., pioglitazone, rosiglitazone) on the risk of bladder cancer, other selected cancers, and overall cancer in patients with type 2 diabetes, we performed a systematic review and meta-analysis of observational studies.

METHODS

A PubMed/MEDLINE search was conducted for studies published in English up to June 30, 2012. Random-effect models were fitted to estimate summary relative risks (RR).

RESULTS

Seventeen studies satisfying inclusion criteria (3 case-control studies and 14 cohort studies) were considered. Use of TZDs was not associated to the risk of cancer overall (summary RR: 0.96; 95% confidence interval [CI]: 0.91-1.01). A modest excess risk of bladder cancer was reported in pioglitazone (RR: 1.20; 95% CI: 1.07-1.34 from six studies) but not in rosiglitazone (RR: 1.08; 95% CI: 0.95-1.23 from three studies) users. The RRs of bladder cancer were higher for longer duration (RR: 1.42 for >2 years) and higher cumulative dose of pioglitazone (RR: 1.64 for >28,000 mg). Inverse relations were observed with colorectal cancer (RR: 0.93; 95% CI: 0.90-0.97 from six cohort studies) and liver cancer (RR: 0.65; 95% CI: 0.48-0.89 from four studies), whereas there was no association with pancreatic, lung, breast, and prostate cancers.

CONCLUSIONS

Adequate evidence excludes an overall excess cancer risk in TZD users within a few years after starting treatment. However, there is a modest excess risk of bladder cancer, particularly with reference to pioglitazone. Assuming that this association is real, the potential implications on the risk-benefit analysis of TZD use should be evaluated.

Alcohol, postprandial plasma glucose, and prognosis of hepatocellular carcinoma

AIM

To identify factors associated with prognosis of hepatocellular carcinoma (HCC) after initial therapy.

METHODS

A total of 377 HCC patients who were newly treated at Katsushika Medical Center, Japan from January 2000 to December 2009 and followed up for > 2 years, or died during follow-up, were enrolled. The factors related to survival were first analyzed in 377 patients with HCC tumor stage T1-T4 using multivariate Cox proportional hazards regression analysis. A similar analysis was performed in 282 patients with tumor stage T1-T3. Additionally, factors associated with the period between initial and subsequent therapy were examined in 144 patients who did not show local recurrence. Finally, 214 HCC stage T1-T3 patients who died during the observation period were classified into four groups according to their alcohol consumption and postprandial glucose levels, and differences in their causes of death were examined.

RESULTS

On multivariate Cox proportional hazards regression analysis, the following were significantly associated with survival: underlying liver disease stage [non-cirrhosis/Child-Pugh A vs B/C, hazard ratio (HR): 0.603, 95% CI: 0.417-0.874, P = 0.0079], HCC stage (T1/T2 vs T3/T4, HR: 0.447, 95% CI: 0.347-0.576, P < 0.0001), and mean postprandial plasma glucose after initial therapy (< 200 vs ≥ 200 mg/dL, HR: 0.181, 95% CI: 0.067-0.488, P = 0.0008). In T1-T3 patients, uninterrupted alcohol consumption after initial therapy (no vs yes, HR: 0.641, 95% CI: 0.469-0.877, P = 0.0055) was significant in addition to underlying liver disease stage (non-cirrhosis/Child-Pugh A vs B/C, HR: 0649, 95% CI: 0.476-0.885, P = 0.0068), HCC stage (T1 vs T2/T3, HR: 0.788, 95% CI: 0.653-0.945, P = 0.0108), and mean postprandial plasma glucose after initial therapy (< 200 mg/dL vs ≥ 200 mg/dL, HR: 0.502, 95% CI: 0.337-0.747, P = 0.0005). In patients without local recurrence, time from initial to subsequent therapy for newly emerging HCC was significantly longer in the "postprandial glucose within 200 mg/dL group" than the "postprandial glucose > 200 mg/dL group" (log-rank test, P < 0.05), whereas there was no difference in the period between the "non-alcohol group" (patients who did not drink regularly or those who could reduce their daily consumption to < 20 g) and the "continuation group" (drinkers who continued to drink > 20 g daily). Of 214 T1-T3 patients who died during the observation period, death caused by other than HCC progression was significantly more frequent in "group AL" (patients in the continuation and postprandial glucose within 200 mg/dL groups) than "group N" (patients in the non-alcohol and postprandial glucose within 200 mg/dL groups) (P = 0.0016).

CONCLUSION

This study found that abstinence from habitual alcohol consumption and intensive care for diabetes mellitus were related to improved prognosis in HCC patients.