Effect of the dose and duration of interferon-alpha therapy on the incidence of hepatocellular carcinoma in noncirrhotic patients with a nonsustained response to interferon for chronic hepatitis C

Oncogenic viruses and hepatocellular carcinoma

About 80% of hepatocellular carcinoma (HCC) is caused by hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infections especially in the setting of established cirrhosis or advanced fibrosis, making HCC prevention a major goal of antiviral therapy. HCC tumors are highly complex and heterogeneous resulting from the aberrant function of multiple molecular pathways. The roles of HCV or HBV in promoting HCC development are still either directly or indirectly are still speculative, but the evidence for both effects is compelling. In patients with chronic hepatitis viral infection, cirrhosis is not a prerequisite for tumorigenesis.

Maintenance therapy with peginterferon alfa-2b does not prevent hepatocellular carcinoma in cirrhotic patients with chronic hepatitis C

BACKGROUND & AIMS

Several studies have reported that low doses of interferon can delay the development of hepatocellular carcinoma (HCC) and progression of chronic hepatitis C. We investigated the incidence of clinical events among participants of the Evaluation of PegIntron in Control of Hepatitis C Cirrhosis (EPIC)3 program.

METHODS

Data were analyzed from an open-label randomized study of patients with chronic hepatitis C who had failed to respond to interferon alfa plus ribavirin. All patients had compensated cirrhosis with no evidence of HCC. Patients received peginterferon alfa-2b (0.5 μg/kg/week; n=311) or no treatment (controls, n=315) for a maximum period of 5 years or until 98 patients had a clinical event (hepatic decompensation, HCC, death, or liver transplantation). The primary measure of efficacy was time until the first clinical event.

RESULTS

There was no significant difference in time to first clinical event among patients who received peginterferon alfa-2b compared with controls (hazard ratio [HR], 1.452; 95% confidence interval [CI]: 0.880-2.396). There was no decrease in the development of HCC with therapy. The time to disease progression (clinical events or new or enlarged varices) was significantly longer for patients who received peginterferon alfa-2b compared with controls (HR, 1.564; 95% CI: 1.130-2.166). In a prospectively defined subanalysis of patients with baseline portal hypertension, peginterferon alfa-2b significantly increased the time to first clinical event compared with controls (P=.016). There were no new safety observations.

CONCLUSIONS

Maintenance therapy with peginterferon alfa-2b is not warranted in all patients and does not prevent HCC. However, there is a potential clinical benefit of long-term suppressive therapy in patients with preexisting portal hypertension.

Surveillance for hepatocellular carcinoma and early diagnosis

Good management of patients at risk for the development of hepatocellular carcinoma includes regular ultrasound surveillance, and aggressive management of lesions detected at ultrasound. Good radiology and good pathology are essential to the appropriate management of these small lesions. With good quality testing it is possible to cure the majority of HCCs using minimally invasive techniques such as radiofrequency ablation. Such an approach has the potential to convert HCC from a disease in which incidence more or less equaled mortality to one in which cure is frequently possible.

Screening for hepatocellular carcinoma

This article reviews methodological issues around screening for hepatocellular carcinoma, and discusses selection of the at-risk group, which screening test to use, and how frequently it should be applied. Screening of patients at risk for hepatocellular carcinoma should be undertaken using ultrasonography applied at six-month intervals. Patients at risk include all those with cirrhosis, and certain non-cirrhotic patients withchronic hepatitis B. In this population, screening has been shown to reduce disease-specific mortality. Although data do not exist for other populations, screening is nonetheless advised because small cancers can be cured with appreciable frequency.

Hepatocellular carcinoma: therapy and prevention

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for the development of HCC are well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. Despite these scientific advances and the implementation of measures for the early detection of HCC in patients at risk, patient survival has not improved during the last three decades. This is due to the advanced stage of the disease at the time of clinical presentation and limited therapeutic options. The therapeutic options fall into five main categories: surgical interventions including tumor resection and liver transplantation, percutaneous interventions including ethanol injection and radiofrequency thermal ablation, transarterial interventions including embolization and chemoembolization, radiation therapy and drugs as well as gene and immune therapies. These therapeutic strategies have been evaluated in part in randomized controlled clinical trials that are the basis for therapeutic recommendations. Though surgery, percutaneous and transarterial interventions are effective in patients with limited disease (1-3 lesions, <5 cm in diameter) and compensated underlying liver disease (cirrhosis Child A), at the time of diagnosis more than 80% patients present with multicentric HCC and advanced liver disease or comorbidities that restrict the therapeutic measures to best supportive care. In order to reduce the morbidity and mortality of HCC, early diagnosis and the development of novel systemic therapies for advanced disease, including drugs, gene and immune therapies as well as primary HCC prevention are of paramount importance. Furthermore, secondary HCC prevention after successful therapeutic interventions needs to be improved in order to make an impact on the survival of patients with HCC. New technologies, including gene expression profiling and proteomic analyses, should allow to further elucidate the molecular events underlying HCC development and to identify novel diagnostic markers as well as therapeutic and preventive targets.

Viral hepatitis and hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. The incidence of HCC varies considerably with the geographic area because of differences in the major causative factors. Chronic hepatitis B and C, mostly in the cirrhotic stage, are responsible for the great majority of cases of HCC worldwide. The geographic areas at the highest risk are South-East Asia and sub-Saharan Africa, here hepatitis B is highly endemic and is the main cause of HCC. In areas with an intermediate rate of HCC such as Southern Europe and Japan, hepatitis C is the predominant cause, whereas in low rate areas such as Northern Europe and the USA, HCC is often related to other factors as alcoholic liver disease. There is a rising incidence in HCC in developed countries during the last two decades, due to the increasing rate of hepatitis C infection and improvement of the clinical management of cirrhosis.

METHODS

This article reviews the literature on hepatitis and hepatocellular carcinoma. The Medline search was carried out using these key words and articles were selected on epidemiology, risk factors, screening, and prevention of hepatocellular carcinoma.

RESULTS

Screening of patients with advanced chronic hepatitis B and C with hepatic ultrasound and determination of serum alfa-fetoprotein may improve the detection of HCC, but further studies are needed whether screening improves clinical outcome. Hepatitis B and C viruses (HBV/HCV) can be implicated in the development of HCC in an indirect way, through induction of chronic inflammation, or directly by means of viral proteins or, in the case of HBV, by creation of mutations by integration into the genome of the hepatocyte.

CONCLUSION

The most effective tool to prevent HCC is avoidance of the risk factors such as viral infection. For HBV, a very effective vaccine is available. Preliminary data from Taiwan indicate a protective effect of universal vaccination on the development of HCC. Vaccination against HBV should therefore be a health priority. In patients with chronic hepatitis B or C, interferon-alfa treatment in a noncirrhotic stage is protective for HCC development in responders, probably by prevention of cirrhosis development. When cirrhosis is already present, the protective effect is less clear. For cirrhosis due to hepatitis B, a protective effect was demonstrated in Oriental, but not in European patients. For cirrhosis due to hepatitis C, interferon-alfa treatment showed to be protective in some studies, especially in Japan with a high incidence of HCC in untreated patients. Virological, but also merely biochemical response, seems to be associated with a lower risk of development of HCC. As most studies are not randomized controlled trials, no definitive conclusions on the long-term effects of interferon-alfa in HBV or HCV cirrhosis can be established. Especially in hepatitis C, prospective studies should be performed using the more potent reference treatments for cirrhotics, namely the combination of peginterferon and ribavirin.

Screening for hepatocellular carcinoma

There is currently no evidence that screening patients at risk for hepatocellular carcinoma reduces mortality from the disease. Nonetheless, screening is widely practiced. Screening is a process that includes selecting patients, applying screening tests, deciding on recall policies, and subsequently proving or disproving the presence of cancer. The literature on screening for hepatocellular carcinoma is confusing at best, and does not adequately consider the many biases that result from uncontrolled and retrospective studies. Nonetheless, screening can be justified because it is likely that mortality is decreased by adequate treatment of small cancers, particularly in the era of liver transplantation. False-positive screening test results are common. Once an abnormal screening result is obtained there is little guidance from the literature as to how patients should be investigated further, nor about how to determine whether the screening test result was a false-positive. This should at minimum include short interval follow-up with CT scans and MRI's.

Treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours worldwide. The major etiologies and risk factors for HCC development are well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. Despite these scientific advances and the implementation of measures for early HCC detection in patients at risk, patient survival has not improved during the last three decades. This is due in part to the advanced stage of the disease at the time of clinical presentation, in part due to the limited therapeutic options. These fall into four main categories: (1) surgical interventions, including tumour resection and liver transplantation, (2) percutaneous interventions, including ethanol injection and radiofrequency thermal ablation, (3) transarterial interventions, including embolisation and chemoembolisation and (4) drugs as well as gene and immune therapies. These therapeutic strategies have been evaluated in part in randomised controlled clinical trials that are the basis for therapeutic recommendations. While surgery and percutaneous as well as transarterial interventions are effective in patients with limited disease (1-3 lesions, < 5 cm in diameter) and compensated underlying liver disease (cirrhosis Child A), at the time of diagnosis more than 80% patients present with multicentric HCC and advanced liver disease or comorbidities that restrict the therapeutic measures to best supportive care. In order to reduce morbidity and mortality from HCC, therefore, early diagnosis and the development of novel systemic therapies for advanced disease, including drugs, gene and immune therapies as well as primary HCC prevention are of paramount importance. Further, secondary HCC prevention after successful therapeutic interventions needs to be improved in order to make an impact on the survival of patients with HCC. New technologies, including gene expression profiling and proteomic analyses, should further elucidate the molecular events underlying HCC development and identify novel diagnostic markers as well as therapeutic and preventive targets.

Study of the effects of interferon a on several human hepatoma cell lines: analysis of the signalling pathway of the cytokine and of its effects on apoptosis and cell proliferation

BACKGROUND

Interferon alpha (IFNalpha), currently used for the treatment of chronic viral hepatitis, is also known to prevent the development of hepatocellular carcinoma (HCC), the mechanism of this action being still debatable.

AIMS

To study thoroughly in human hepatoma cell lines (HHL)--Hep3B, HepG2, HuH7, SKHep1, and Chang-Liver--submitted to rhIFNalpha, the signalling pathway of IFNalpha, the binding activity of the cytokine on specific gamma-activated sequence (GAS) and interferon-stimulated regulatory element (ISRE) nuclear sequences, and its effects on apoptosis and cell proliferation.

METHODS

The behaviour of signal transducer and activator of transcription (STAT)1, STAT2, p48(IRF9) and the binding of nuclear proteins were investigated by immunoblot and electro-mobility shift assay. Expression of some IFNalpha-dependent proteins--p21/(WAF1), inducible nitric oxide synthase, IRF1 and 2--were studied by immunoblot. Apoptosis and the cell cycle were studied by morphological and biochemical methods.

RESULTS

Transduction of INFalpha was unaltered, although there were some variations in the different HHL. Nuclear protein binding to GAS or ISRE showed that ISRE was mainly involved. Apoptosis did not occur. The cell cycle was slightly modified in HuH7. Three GAS- and/or ISRE-dependent proteins increased, suggesting that IFNalpha may have some biological effects on HHL.

CONCLUSIONS

The IFNalpha signalling pathway is functional in several HHL, but the cytokine has no apoptotic effect and a moderate anti-proliferative effect. This suggests that the preventive role of IFNalpha on HCC cannot be explained by an apoptotic and/or an anti-proliferative effect, but possibly by its action on several specific nuclear sequences that protect liver cells from transformation.

Potential of interferon-alpha in solid tumours: part 2

The second part of this review examines the use of recombinant interferon-alpha (rIFNalpha) in the following solid tumours: superficial bladder cancer, Kaposi's sarcoma, head and neck cancer, gastrointestinal cancers, lung cancer, mesothelioma and ovarian, breast and cervical malignancies. In superficial bladder cancer, intravesical rIFNalpha has a promising role as second-line therapy in patients resistant or intolerant to intravesical bacille Calmette-Guérin (BCG). In HIV-associated Kaposi's sarcoma, rIFNalpha is active as monotherapy and in combination with antiretroviral agents, especially in patients with CD4 counts >200/mm(3), no prior opportunistic infections and nonvisceral disease. rIFNalpha has shown encouraging results when used in combination with retinoids in the chemoprevention of head and neck squamous cell cancers. It is effective in the chemoprevention of hepatocellular cancer in hepatitis C-seropositive patients. In neuroendocrine tumours, including carcinoid tumour, low-dosage (</=3 MU) or intermediate-dosage (5 to 10 MU) rIFNalpha is indicated as second-line treatment, either with octreotide or alone in patients resistant to somatostatin analogues. Intracavitary IFNalpha may be useful in malignant pleural effusions from mesothelioma. Similarly, intraperitoneal IFNalpha may have a role in the treatment of minimal residual disease in ovarian cancer. In breast cancer, the only possible role for IFNalpha appears to be intralesional administration for resistant disease. IFNalpha may have a role as a radiosensitising agent for the treatment of cervical cancer; however, this requires confirmation in randomised trials. On the basis of current evidence, the routine use of rIFNalpha is not recommended in the therapy of head and neck squamous cell cancers, upper gastrointestinal tract, colorectal and lung cancers, or mesothelioma. Pegylated IFNalpha (peginterferon-alpha) is an exciting development that offers theoretical advantages of increased efficacy, reduced toxicity and improved compliance. Further data from randomised studies in solid tumours are needed where rIFNalpha has activity, such as neuroendocrine tumours, minimal residual disease in ovarian cancer, and cervical cancer. A better understanding of the biological mechanisms that determine response to rIFNalpha is needed. Studies of IFNalpha-stimulated gene expression, which are now feasible, should help to identify molecular predictors of response and allow us to target therapy more selectively to patients with solid tumours responsive to IFNalpha.

Treatment of chronic hepatitis C in nonresponders to previous therapy

About 55% to 60% of treatment-naïve patients fail to achieve a sustained virologic response after therapy with standard interferon and ribavirin. The use of polyethylene glycol-enhanced interferon (PEG-IFN) plus ribavirin for retreatment of this challenging group is currently being evaluated by several investigators. Although no sustained virologic response rates have been reported yet from these trials, reported on-treatment response rates for previous nonresponders range from 25% to 30%, and an early estimate of the sustained virologic response rate is about 11%. Outcomes for treatment of relapsers and interferon monotherapy nonresponders have been significantly better than those for combination nonresponders. On-treatment responses of 40% to 43% in previous combination therapy nonresponders are now being seen with the addition of amantadine (triple therapy), and sustained response rates with this regimen are awaited. Large trials are underway to evaluate the role of maintenance therapy for virologic nonresponders with advanced liver disease.

Treatment of chronic hepatitis C: a systematic review

This systematic review addressed 3 issues regarding current treatments for chronic hepatitis C: (1) efficacy and safety in treatment-naive patients; (2) efficacy and safety in selected subgroups of patients; and (3) effects on long-term clinical outcomes. Electronic databases were searched for articles from January 1996 to March 2002. Additional articles were identified by searching references in pertinent articles and recent journals and by questioning experts. Articles were eligible for review if they reported original human data from a study that used virological, histological, or clinical outcome measures. For data collection, paired reviewers assessed the quality of each study and abstracted data. This systematic review found that the combination of high-dose peginterferon and ribavirin was more efficacious than standard interferon and ribavirin in persons infected with hepatitis C virus (HCV) genotype 1 (sustained virologic response [SVR] rate: 42% vs. 33%) and that ranges of SVR rates were higher with peginterferon than standard interferon monotherapy in naïve patients (10% to 39% vs. 3% to 19%). Reports were consistent in showing treatment with interferon and ribavirin was more efficacious than interferon monotherapy in treatment-naive persons and previous nonresponders and relapsers. Studies were moderately consistent in showing that treatment decreases the risk for hepatocellular carcinoma (HCC). The evidence on treatment in important subgroups was limited by a lack of randomized controlled trials. Thus, the combination of peginterferon and ribavirin was the most efficacious treatment in patients with HCV genotype 1. Long-term outcomes were improved in patients with hepatitis C who achieved an SVR with treatment.

Treatment of chronic hepatitis C: a systematic review

This systematic review addressed 3 issues regarding current treatments for chronic hepatitis C: (1) efficacy and safety in treatment-naive patients; (2) efficacy and safety in selected subgroups of patients; and (3) effects on long-term clinical outcomes. Electronic databases were searched for articles from January 1996 to March 2002. Additional articles were identified by searching references in pertinent articles and recent journals and by questioning experts. Articles were eligible for review if they reported original human data from a study that used virological, histological, or clinical outcome measures. For data collection, paired reviewers assessed the quality of each study and abstracted data. This systematic review found that the combination of high-dose peginterferon and ribavirin was more efficacious than standard interferon and ribavirin in persons infected with hepatitis C virus (HCV) genotype 1 (sustained virologic response [SVR] rate: 42% vs. 33%) and that ranges of SVR rates were higher with peginterferon than standard interferon monotherapy in naïve patients (10% to 39% vs. 3% to 19%). Reports were consistent in showing treatment with interferon and ribavirin was more efficacious than interferon monotherapy in treatment-naive persons and previous nonresponders and relapsers. Studies were moderately consistent in showing that treatment decreases the risk for hepatocellular carcinoma (HCC). The evidence on treatment in important subgroups was limited by a lack of randomized controlled trials. Thus, the combination of peginterferon and ribavirin was the most efficacious treatment in patients with HCV genotype 1. Long-term outcomes were improved in patients with hepatitis C who achieved an SVR with treatment.

Prevention of liver cancer

Hepatocellular carcinoma (HCC) is among the most prevalent and deadly cancers worldwide. Prominent risk factors for HCC include viral hepatitis infection; dietary exposure to hepatotoxic contaminants such as aflatoxins; alcoholism; smoking; and male gender. This review highlights ongoing efforts in HCC prevention. Strategies include vaccination against, and treatment of, viral hepatitis infection. In addition to interferon alpha, an acyclic retinoid (all-trans-3,7,11, 15-tetramethyl-2,4,6,10,14-hexadecapentanoic acid), glycyrrhizin and ginseng are currently under clinical investigation for HCC prevention in Japanese hepatitis C patients. Several recent clinical studies in a Chinese region of pervasive aflatoxin contamination also support the approach of favorably altering aflatoxin metabolism and excretion using the chemopreventive agents oltipraz or chlorophyllin. Agents exhibiting chemopreventive efficacy in preclinical HCC models include vitamins A, D, and E, herbal extracts, a 5alpha-reductase inhibitor, green tea, and D-limonene. Efforts to elucidate the molecular lesions and processes underlying HCC development have identified several putative molecular targets for preventive interventions. These include genes and gene products controlling viral replication, carcinogen metabolism, signal transduction, cell-cycle arrest, apoptosis, proliferation, and oxidative stress.