Primary liver cancer mortality in the United States

Risk Factors for Hepatocellular Carcinoma: A Historical Perspective

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Screening for hepatocellular carcinoma

To determine the role of screening and to screen in a cost-effective manner, it is important to define the high-risk patient population that is most likely to benefit from screening and to identify a readily available diagnostic modality that is sensitive, specific, and inexpensive. Moreover, to have a major effect on the outcome of hepatocellular carcinoma, the test should be applicable in the majority of high-risk subjects. Herein, we identify the high-risk patient population, discuss various diagnostic modalities, and recommend a practical and cost-effective strategy for screening.

Epidemiology of hepatocellular carcinoma

The epidemiology of hepatocellular carcinoma (HCC) is characterized by marked differences between genders, ethnic groups, and geographic regions. These variations are explained by the nature, frequency, and time of acquisition of the major risk factors for cirrhosis--namely hepatitis B virus, hepatitis C virus (HCV), and alcoholic cirrhosis. The incidence and mortality of HCC has been rising in the US over the last two decades and is progressively affecting younger persons. The evidence indicates that HCV infection is responsible for the current trends.

Screening for hepatocellular carcinoma in chronic carriers of hepatitis B virus: incidence and prevalence of hepatocellular carcinoma in a North American urban population

OBJECTIVE

To prospectively determine the prevalence and annual incidence of hepatocellular carcinoma in hepatitis B carriers in a heterogeneous urban North American population and to assess the diagnostic accuracy of tests used for screening for this cancer.

DESIGN

Prospective cohort study of 1,069 chronic carriers of hepatitis B virus using screening with alpha-fetoprotein alone or in combination with ultrasonography every 6 months.

RESULTS

The mean age of the cohort was 39 +/- 12 years (+/- SD), 65% were men, 71% were Asians. At the first screening visit, serum alpha-fetoprotein was > or = 20 micrograms/L in 4%. In those subjects who were also screened by ultrasonography during the first visit, 9% were found to have focal lesions. Only 3 subjects were found to have hepatocellular carcinoma at the first screening, giving a prevalence of 281/100,000 chronic carriers of hepatitis B virus. The cohort was followed for 2,340 person-years (mean, 26 months follow-up, with a range from 6 to 60 months). During this period, 11 more subjects, 10 men and 1 woman, were diagnosed to have hepatocellular carcinoma (annual incidence, 470/100,000). In men only, the annual incidence was 657/100,000. During the study, 5 subjects died from hepatocellular carcinoma (annual mortality rate, 214/100,000). Sensitivity and specificity of serum alpha-fetoprotein > 20 micrograms/L were 64.3% and 91.4%, respectively. For ultrasonography, sensitivity was 78.8% and specificity 93.8%.

CONCLUSIONS

These data suggest that the incidence and prevalence of hepatocellular carcinoma in hepatitis B carriers in our area, an urban North American setting, are as high as in countries where hepatitis B is endemic. Current screening tests have significant false-positive and false-negative rates raising questions about the cost-benefit of screening for hepatocellular carcinoma in our study population.

Age-related, different clinicopathologic features of hepatocellular carcinoma patients

OBJECTIVE

The authors attempted to clarify the clinicopathologic differences of hepatocellular carcinoma (HCC) patients, according to age distribution, and to investigate whether these differences contribute a certain hepatocarcinogenesis.

SUMMARY BACKGROUND DATA

Hepatitis-associated viruses causing HCC have been investigated, and the infection of the viruses and etiologically, the peak age of the disease vary according to geographic barriers. However, a correlation between clinicopathologic differences and the age distribution of the patients is not well understood.

METHODS

The authors reviewed their institutional experience from 1978 to 1990 in treating 428 patients with HCC. The carrier rate for hepatitis B surface antigen (HBsAg), the frequency of occurrence of high serum alpha-fetoprotein (AFP) of 2000 ng/mL, the degree of liver damage represented by the retention rate of indocyanine green dye at 15 minutes (ICGR15), and the incidence of accompanying liver cirrhosis were investigated and compared in each decade of age.

RESULTS

The HBsAg carrier rate and the frequency of high serum AFP values were significantly prominent in the younger patients (20-49 yrs). The degree of liver damage and the incidence of liver cirrhosis were prominent in the elderly patients (older than 70 yrs) or the middle-aged patients (50-69 yrs); however, these four values in the middle-aged patients were intermediate with respect to those observed in the other two age groups. In addition, there was a positive correlation between the HBsAg carrier rate and the frequency of high serum AFP values or between the degree of liver damage represented by ICGR15 and the incidence of liver cirrhosis, showing that the former correlation was inversely related to the latter.

CONCLUSIONS

The authors' study indicates that there are age-related differences of clinicopathologic features in HCC patients, suggesting that there are different steps or mechanisms of hepatocarcinogenesis according to the patient's age-distribution.

Use of confirmatory assays for diagnosis of hepatitis C viral infection in patients with hepatocellular carcinoma

Serum samples from 87 patients with hepatocellular carcinoma (HCC) in the United States were tested for evidence of hepatitis C viral (HCV) infection using an immunoblot assay for antibodies to the hepatitis C virus and the polymerase chain reaction to detect HCV RNA. The findings with these assays were compared to those with a first generation enzyme-linked immunoassay (EIA). Antibody to HCV (anti-HCV) was detected in 14 patients (16%) by EIA; only eight of these were also positive by immunoblot and four had HCV RNA by reverse transcription polymerase chain reaction (RT-PCR). An additional four cases, negative by EIA, were found to be positive by immunoblot; two of these had HCV RNA in serum. Evidence of previous hepatitis B viral infection was noted in 15 patients (17%). Only two patients with antibody to hepatitis B core antigen also had anti-HCV by the immunoblot assay, suggesting that concomitant infection with the hepatitis B and C viruses was not common. Thus, HCV infection appears to play a less important role in the pathogenesis of HCC in the United States than in southern Europe and Japan and other etiologic factors should be sought in this population.

Hepatitis B virus, alpha-fetoprotein synthesis, and hepatocellular carcinoma in Zaire

We investigated the epidemiology of hepatocellular carcinoma (HCC) in Zaire, and evaluated the association between exposure to hepatitis B virus (HBV) and the development of HCC. Two hundred and twenty-three consecutive cases of HCC diagnosed over 19 years (1966-1985) were reviewed. HCC represented 8.32% of all carcinomas and 5.56% of all cancers. Frequency was higher in males (75.7%) than in females (24.3%); a sex ratio of 3/1. The majority (82.1%) of patients were aged 14 to 55 years with a peak occurrence in the fourth decade (28.6%). The mean age in males (41.27 +/- 17.5 years) and females (37.40 +/- 15.16 years) was significantly different (p < 0.02). Sera from 40 patients and 68 age and sex-matched controls were analyzed for markers of HBV infection: patients and controls had comparable rates of exposure (96% vs 72.1%, respectively). However, patients had significantly higher HBsAg carrier rates (56.7% vs 7.35%; p < 0.001), and lower anti-HBsAg seroconversion rates (25% vs 63.2%, p < 0.05). Using immunohistochemical analysis, the livers of patients were evaluated for HBsAg and HBcAg. These HBV antigens were more frequent in non-tumourous hepatocytes (53.3% vs 23.3%, respectively) than in HCC cells (13.3% vs 3.3%). Serum alpha-fetoprotein (AFP) was abnormal (> 20 ng/ml) in 90% of patients. The geometric mean (GM) AFP was 7273.8 ng/ml. AFP levels were significantly higher in HBsAg-positive HCC cases (GM: 19,322.6 ng/ml; 95% confidence interval (CI): [3639.2, 102,565.2]) than in antigen negative cases (GM: 1939.5 ng/ml; 95% CI: [182.8, 19,952.6]), but did not correlate with HBV replication. Immunohistochemical detection of AFP revealed a similar correlation between AFP and HBsAg. Neither AFP level nor HBsAg production correlated with cellular atypia or tumor grade.

Prospective study of early detection of hepatocellular carcinoma in patients with cirrhosis

We prospectively monitored 140 cirrhotic patients for the development of hepatocellular carcinoma for 6 yr, using periodical screening by high-resolution convex-array ultrasonography and alpha-fetoprotein. Twenty-eight patients were positive for HBs antigen, 26 patients had received blood transfusions and were negative for HBs antigen and 26 patients had a history of heavy drinking. We detected hepatocellular carcinoma in 40 patients during this period. The overall cumulative incidence of hepatocellular carcinoma in the 6 yr was 39%; the cumulative incidence was 59% in patients with HBsAg, 53% in patients who had had blood transfusions and were negative for HBsAg and 22% in patients who had a history of heavy drinking and who were without HBsAg. Detection of the carcinoma in 85% of these 40 patients was based on results of ultrasonography. Twenty-six of the patients (65%) had a small hepatocellular carcinoma of 2 cm or less. alpha-Fetoprotein levels were lower than 100 ng/ml in 56% of these 40 patients. Patients with cirrhosis are at high risk of developing hepatocellular carcinoma, especially patients with HBsAg or with a history of blood transfusion who are negative for HBsAg. Periodic monitoring by use of ultrasonography in particular is recommended for early detection of hepatocellular carcinoma.

Hepatocellular carcinoma: molecular biology of its growth and relationship to hepatitis B virus infection

Hepatocellular carcinoma is a very common tumor worldwide and is associated with high mortality rates. Evidence that the development of hepatocellular carcinoma is related to chronic HBV infection has accumulated from epidemiologic studies, information from animal and cell culture models, and molecular biologic evidence that HBV components can be found within hepatocellular carcinoma tissue. Integration of HBV DNA within host liver cell chromosomes may be a crucial step in the development of hepatocellular carcinoma. Integration is associated with disruption of both structure and function of DNA at the site of integration. The study of individual examples of HBV DNA integration in hepatocellular carcinoma tissue illustrates possible mechanisms of hepatocarcinogenesis by HBV. In many cases, activation of various growth factors has been found in association with HBV DNA integration including IGF II, oncogenes such as c-myc, and novel growth factors such as the retinoic acid receptor. A clearer understanding of the mechanisms involved may allow for possible therapeutic interventions in the future, or perhaps even the prevention of hepatocellular carcinoma.

Hepatocellular carcinoma imaging

Radionuclide scintigraphy can give a specific diagnosis when a hypervascular "cold" defect on colloid scans "fills in" with gallium scanning. The majority of hepatocellular carcinomas will also accumulate hepatobiliary agents especially in delayed images. Magnetic resonance imaging is superior to other modalities in providing anatomic detail, such as location and relation to vessels, needed by the surgeon in operative planning.