The impact of immigration on the increasing incidence of hepatocellular carcinoma in the United States

Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma

Although hepatocellular carcinoma (HCC) is more common in the setting of cirrhosis, there is increasing evidence that it can develop in the setting of noncirrhotic nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) and that steatosis alone can promote carcinogenesis. In addition, obesity, diabetes, and metabolic syndrome are recognized risks for the development of HCC. A better understanding of the mechanisms involved in the development of NAFLD/NASH-related HCC will allow the discovery of new targets for therapeutic and preventive intervention. The surveillance for HCC in the setting of noncirrhotic NAFLD/NASH, obesity, diabetes, and metabolic syndrome remains an area of uncertainty.

The Geographic Distribution of Liver Cancer in Canada Does Not Associate with Cyanobacterial Toxin Exposure

BACKGROUND

The incidence of liver cancer has been increasing in Canada over the past decade, as has cyanobacterial contamination of Canadian freshwater lakes and drinking water sources. Cyanotoxins released by cyanobacteria have been implicated in the pathogenesis of liver cancer.

OBJECTIVE

To determine whether a geographic association exists between liver cancer and surrogate markers of cyanobacterial contamination of freshwater lakes in Canada.

METHODS

A negative binomial regression model was employed based on previously identified risk factors for liver cancer.

RESULTS

No association existed between the geographic distribution of liver cancer and surrogate markers of cyanobacterial contamination. As predicted, significant associations existed in areas with a high prevalence of hepatitis B virus infection, large immigrant populations and urban residences.

DISCUSSION AND CONCLUSIONS

The results of this study suggest that cyanobacterial contamination of freshwater lakes does not play an important role in the increasing incidence of liver cancer in Canada.

Viral hepatitis markers in liver tissue in relation to serostatus in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) incidence is increasing in the United States. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major causes of HCC. Hepatitis infection in patients with HCC is generally diagnosed by serology, which is not always consistent with the presence of HBV and HCV in the liver. The relationship of liver viral status to serostatus in hepatocarcinogenesis is not fully understood.

METHODS

HBV and HCV were evaluated in formalin-fixed, paraffin-embedded liver tissue specimens in a retrospective study of 61 U.S. HCC cases of known serologic status. HBV DNA and HCV RNA were detected by PCR, reverse transcription PCR (RT-PCR), and pyrosequencing, and HBsAg and HBcAg were evaluated by immunohistochemistry.

RESULTS

Viral markers were detected in the liver tissue of 25 of 61 (41%) HCC cases. Tissue viral and serologic status were discordant in 27 (44%) cases, including those with apparent "occult" infection. Specifically, HBV DNA was detected in tissue of 4 of 39 (10%) serum HBsAg (-) cases, including 1 anti-HCV(+) case; and HCV RNA was detected in tissue of 3 of 42 (7%) anti-HCV seronegative cases, including two with serologic evidence of HBV.

CONCLUSIONS

Viral hepatitis, including HBV-HCV coinfection, may be unrecognized in up to 17% of patients with HCC when based on serology alone. Further research is needed to understand the clinical significance of viral makers in liver tissue of patients with HCC in the absence of serologic indices.

IMPACT

The contribution of HBV and HCV to the increasing incidence of HCC in the United States may be underestimated.

Biological networks for predicting chemical hepatocarcinogenicity using gene expression data from treated mice and relevance across human and rat species

BACKGROUND

Several groups have employed genomic data from subchronic chemical toxicity studies in rodents (90 days) to derive gene-centric predictors of chronic toxicity and carcinogenicity. Genes are annotated to belong to biological processes or molecular pathways that are mechanistically well understood and are described in public databases.

OBJECTIVES

To develop a molecular pathway-based prediction model of long term hepatocarcinogenicity using 90-day gene expression data and to evaluate the performance of this model with respect to both intra-species, dose-dependent and cross-species predictions.

METHODS

Genome-wide hepatic mRNA expression was retrospectively measured in B6C3F1 mice following subchronic exposure to twenty-six (26) chemicals (10 were positive, 2 equivocal and 14 negative for liver tumors) previously studied by the US National Toxicology Program. Using these data, a pathway-based predictor model for long-term liver cancer risk was derived using random forests. The prediction model was independently validated on test sets associated with liver cancer risk obtained from mice, rats and humans.

RESULTS

Using 5-fold cross validation, the developed prediction model had reasonable predictive performance with the area under receiver-operator curve (AUC) equal to 0.66. The developed prediction model was then used to extrapolate the results to data associated with rat and human liver cancer. The extrapolated model worked well for both extrapolated species (AUC value of 0.74 for rats and 0.91 for humans). The prediction models implied a balanced interplay between all pathway responses leading to carcinogenicity predictions.

CONCLUSIONS

Pathway-based prediction models estimated from sub-chronic data hold promise for predicting long-term carcinogenicity and also for its ability to extrapolate results across multiple species.

Viral hepatitis among Somali immigrants in Minnesota: association of hepatitis C with hepatocellular carcinoma

OBJECTIVE

To study the frequencies of chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, and their associations with hepatocellular carcinoma (HCC) in immigrant Somalis seen at Mayo Clinic in Rochester, Minnesota.

PATIENTS AND METHODS

We determined the frequencies of HBV and HCV infection and HCC in immigrant Somalis seen at Mayo Clinic from July 1, 1996, through October 31, 2009. Non-Somali Olmsted County residents served as controls.

RESULTS

For Somali males and females, age-adjusted proportions (per 1000 population) were 209 and 123 for hepatitis B surface antigen (HBsAg), 644 and 541 for hepatitis B core antibody (HBcAb), and 99 and 66 for anti-HCV. The comparative proportions in non-Somalis were 20 and 9 for HBsAg, 126 and 97 for HBcAb, and 32 and 17 for anti-HCV. Hepatitis C virus RNA confirmed that 68 of 73 Somalis (93.2%) and 261 of 282 non-Somalis (92.6%) with positive anti-HCV test results had active HCV infection. Of 30 Somali patients with HCC, 22 (73.3%) tested anti-HCV positive (odds ratio [OR], 31.3; 95% confidence interval [CI], 13.0-75.5; P<.001; compared with anti-HCV-negative Somalis), 5 (16.7%) were HBsAg positive (OR, 1.4; 95% CI, 0.5-3.7; P=.53), and 18 (60.0%) were HBcAb positive (OR, 1.8; 95% CI, 0.8-4.2; P=.16). Viral hepatitis was diagnosed coincident with HCC in 9 of 20 patients (45.0%) with HCV-associated HCCs. Only 4 of 24 cases of HCC (16.7%) were detected during surveillance.

CONCLUSION

Both HBV and HCV occurred frequently in this sample of Somali immigrants. However, HCV was the major risk factor for HCC. Screening Somali immigrants for HCV infection may enhance the prevention, early detection, and optimal treatment of HCC.

Use of surveillance for hepatocellular carcinoma among patients with cirrhosis in the United States

Surveillance for hepatocellular carcinoma (HCC) in patients with cirrhosis is recommended but may not be performed. The extent and determinants of HCC surveillance are unknown. We conducted a population-based United States cohort study of patients over 65 years of age to examine use and determinants of prediagnosis surveillance in patients with HCC who were previously diagnosed with cirrhosis. Patients diagnosed with HCC during 1994-2002 were identified from the linked Surveillance, Epidemiology, and End-Results registry-Medicare databases. We identified alpha-fetoprotein (AFP) and ultrasound tests performed for HCC surveillance, and examined factors associated with surveillance. We identified 1,873 HCC patients with a prior diagnosis of cirrhosis. In the 3 years before HCC, 17% received regular surveillance and 38% received inconsistent surveillance. In a subset of 541 patients in whom cirrhosis was recorded for 3 or more years prior to HCC, only 29% received routine surveillance and 33% received inconsistent surveillance. Among all patients who received regular surveillance, approximately 52% received both AFP and ultrasound, 46% received AFP only, and 2% received ultrasound only. Patients receiving regular surveillance were more likely to have lived in urban areas and had higher incomes than those who did not receive surveillance. Before diagnosis, approximately 48% of patients were seen by a gastroenterologist/hepatologist or by a physician with an academic affiliation; they were approximately 4.5-fold and 2.8-fold, respectively, more likely to receive regular surveillance than those seen by a primary care physician only. Geographic variation in surveillance was observed and explained by patient and physician factors.

CONCLUSION

Less than 20% of patients with cirrhosis who developed HCC received regular surveillance. Gastroenterologists/hepatologists or physicians with an academic affiliation are more likely to perform surveillance.

NASH and HCC

Primary liver cancer is the fifth most common malignancy worldwide and the third leading cause of cancer mortality. Non-alcoholic fatty liver disease is the most common cause of chronic liver disease in the United States encompassing a spectrum of entities marked by hepatic steatosis in the absence of significant alcohol consumption. Although simple steatosis follows a generally benign course, the more aggressive form, non-alcoholic steatohepatitis, can progress to cirrhosis and result in complications including hepatocellular carcinoma. A significant number of cases of hepatocellular carcinoma remain cryptogenic without known underlying chronic liver disease. It is increasingly recognized that non-alcoholic steatohepatitis likely accounts for a substantial portion of cryptogenic hepatocellular carcinoma.

Hepatocellular carcinoma incidence trends in Canada: analysis by birth cohort and period of diagnosis

BACKGROUND AND AIMS

We examined birth cohort and calendar period trends in hepatocellular carcinoma (HCC) incidence in Canada (1976-2000). We also projected HCC incidence rates through 2015.

PATIENTS AND METHODS

Data were obtained from the Canadian Cancer Registry on all cases of HCC diagnosed among persons aged 20 years and older in Canada from 1976 to 2000 and was used to describe trends in HCC incidence rates.

RESULTS

We found that age-adjusted HCC incidence rates increased faster in males compared with females, 3.4% per year [95% confidence interval (CI): 3.0-3.8%] vs 2.2% per year (95% CI: 1.5-2.8%). An increasing birth cohort trend accelerated among males around the 1940 birth cohort and decelerated among females around the 1935 birth cohort. For calendar period trends, the increasing HCC risk was relatively constant over time among males whereas there was an acceleration in HCC risk around 1988 among females. Age-adjusted HCC incidence rates were projected to increase 73% in males and 28% in females from 1996 to 2015.

CONCLUSIONS

Our results suggest that HCC incidence rates will continue to increase in Canada during the next decade as persons born in more recent birth cohorts, who face a relatively greater risk for HCC, age.

Hepatitis C virus infection and hepatocellular carcinoma

Primary liver cancer is the sixth most common cancer in the world and the third most common cause of death attributable to cancer. Most primary liver cancers are hepatocellular carcinoma (HCC), accounting for 85% to 90% of cases. There is a trend of growing incidence of HCC in the United States. One of the most important risk factors for developing HCC is chronic hepatitis C virus (HCV) infection. Although several studies suggested the preventive effect of interferon from developing HCC in HCV-infected individuals, these findings need to be validated in large prospective and randomized trials.

Cluster of liver cancer and immigration: a geographic analysis of incidence data for Ontario 1998-2002

Background

Liver cancer is not common in Canada in general; however, clustering of the disease causes a concern. We conducted a spatial analysis to determine the geographic variation of liver cancer and its association with the proportion of immigration in Ontario. Liver cancer incidence data between 1998 and 2002 were obtained from the Ontario Cancer Registry. The Canadian Community Health Survey (CCHS) in 2001 provided information on potential risk factors.

Results

Age standardized incidence ratios (SIR) for liver cancer and prevalence of potential risk factors were calculated for each of 35 health regions. The SIRs for liver cancer varied across the 35 health regions (p < 0.01). Toronto and York health regions had a significantly higher SIR than other regions, indicated by the Scan method (p < 0.001). Poisson models with and without random effects were fitted to determine independent ecological contributors. After adjustment for sex, age and spatial location, the proportion of immigrants remained a significant determinant. Smoking, alcohol drinking, physical activity, education, income, obesity and diabetes did not substantially explain the geographic variation of liver cancer in Ontario.

Conclusion

Immigration is an important reason for the clustering of liver cancer in Ontario. More attention should be paid to areas with a high proportion of immigrants.

Epidemiology of hepatocellular carcinoma in USA

Hepatocellular carcinoma (HCC) is increasing in frequency the USA. Age-adjusted incidence, hospitalization, and mortality rates have doubled over the past two decades. There are striking differences in the incidence of HCC related to age, gender, race, and geographic region. Although it remains an affliction of the elderly (mean age 65), there has been a considerable shift toward younger cases. There is a birth cohort effect with those born after 1945. Men are affected three times more frequently than women, Asians two times more than African American and Hispanic people, who are affected two times more often than Caucasians. However, the recent increase has disproportionately affected Caucasian (and Hispanic) men between ages 45 and 65. Hepatitis C virus (HCV) infection acquired 2-4 decades ago explains at least half of the observed increase in HCC; HCV-related HCC is likely tocontinue to increase for the next decade. A variable but significant proportion of cases (15-50%) do not have evidence for the risk factors of either viral hepatitis or heavy alcohol consumption. Insulin resistance syndrome manifesting as obesity and diabetes is emerging as a risk factor for HCC in the USA and may operate through the formation of non-alcoholic fatty liver disease (NAFLD); however, its effect on the current trend in HCC remains unclear. While there has been a small recent improvement in survival, it remains generally dismal (median 8 months). Population-based data in the USA indicate low application rate of HCC potentially curative therapy and marked regional differences.

Viral Hepatitis and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common tumor worldwide, and one of the fastest rising tumors as a result of chronic hepatitis B and C infection. The patients at risk for developing HCC are those with underlying cirrhosis secondary to viral hepatitis. External factors such as alcohol, tobacco, obesity, and diabetes increase the risk of HCC among those with chronic viral hepatitis. Surveillance of patients with cirrhosis with alpha-fetoprotein and ultrasound has been shown to reduce survival. The diagnosis of HCC is established by the presence of an arterially enhancing mass in the presence of cirrhosis. Viral hepatitis represents an opportunity for prevention of HCC.

Hepatocellular carcinoma: epidemiology and molecular carcinogenesis

Primary liver cancer, which consists predominantly of hepatocellular carcinoma (HCC), is the fifth most common cancer worldwide and the third most common cause of cancer mortality. HCC has several interesting epidemiologic features including dynamic temporal trends; marked variations among geographic regions, racial and ethnic groups, and between men and women; and the presence of several well-documented environmental potentially preventable risk factors. Moreover, there is a growing understanding on the molecular mechanisms inducing hepatocarcinogenesis, which almost never occurs in healthy liver, but the cancer risk increases sharply in response to chronic liver injury at the cirrhosis stage. A detailed understanding of epidemiologic factors and molecular mechanisms associated with HCC ultimately could improve our current concepts for screening and treatment of this disease.

Rising costs and hospital admissions for hepatocellular carcinoma in Portugal (1993-2005)

AIM: To determine, for hepatocellular carcinoma (HCC), the patient demographic profile and costs of their admissions to the hospitals of the Portuguese National Health System from 1993 to 2005.

METHODS: The National Registry (ICD-9CM, Inter-national Classification of Diseases, 155.0) provided data from the 97 Hospitals in Portugal.

RESULTS: We studied 7932 admissions that progres-sively rose from 292 in 1993 to 834 in 2005, having a male predominance of 78% (6130/7932). The global rate of hospital admissions for HCC rose from 3.1/10⁵ in 1993 to 8.3/10⁵ in 2005. The average length of stay decreased from 17.5 ± 17.9 d in 1993 to 9.3 ± 10.4 d in 2005, P < 0.001. The average hospital mortality for HCC remained high over these years, 22.3% in 1993 and 26.7% in 2005. Nationally, hospital costs (in Euros - €) rose in all variables studied: overall costs from €533 000 in 1993, to €4 629 000 in 2005, cost per day of stay from €105 in 1993, to €597 in 2005, average cost of each admission from €1828 in 1993, to €5550 in 2005. In 2005, 1.8% (15/834) of hospital admissions for HCC were related to liver transplant, and responsible for a cost of about €1.5 million, corresponding to one third of the overall costs for HCC admissions in that same year.

CONCLUSION: From 1993 to 2005 hospital admissions in Portugal for HCC tripled. Overall costs for these admissions increased 9 times, with all variables related to cost analysis rising accordingly. Liver transplant, indicated in a small group of patients, showed a disproportionate increase in costs.

Hepatocellular carcinoma: recent trends in the United States

Hepatocellular carcinoma (HCC) is increasing in frequency in the United States. The age-adjusted incidence rates have doubled over the past 2 decades. Similar increases have affected the mortality and hospitalization rates. Although there has been a small recent improvement in survival, it remains generally dismal (median, 8 months). It is estimated that 8500 to 11,500 new cases of HCC occur annually in the United States. There are striking differences in the incidence of HCC related to age, gender, race, and geographic region. Although it remains an affliction of the elderly (mean age, 65 years) population, there has been a shift toward relatively younger age cases. Men are affected 3 times more frequently than women, Asians are affected 2 times more than blacks, and Hispanics are affected 2 times more often than whites. However, the recent increase has disproportionately affected white (and Hispanic) men between ages 45 and 65 years. The temporal changes of risk factors among HCC cases in the United States remain unclear. However, available studies indicate that hepatitis C virus (HCV) infection acquired 2-4 decades ago explains at least half of the observed increase in HCC; HCV-related HCC is likely to continue to increase for the next decade. A variable but significant proportion of cases (15% to 50%) do not have evidence of the risk factors of viral hepatitis or heavy alcohol consumption. The insulin resistance syndrome, manifesting as obesity and diabetes, is emerging as a risk factor for HCC in the United States; however, its impact on the current trend in HCC remains unclear.