Nonsurgical treatment of hepatocellular carcinoma

Molecular pathogenesis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common life-threatening malignancies in the world. This cancer generally arises within the boundaries of well-defined causal factors, of which viral hepatitis infection, aflatoxin exposure, chronic alcohol abuse, and nonalcoholic steatohepatitis are the major risk factors. Despite the identification of these etiological agents, hepatocarcinogenesis remains poorly understood. The molecular mechanisms leading to the development of HCC appear extremely complex and only recently have begun to be elucidated. Currently, surgical resection or liver transplantation offer the best chance of cure for the patient with HCC; however, these therapies are hindered by inability of many of these patients to undergo liver resection, by tumor recurrence and by donor shortages. A lack of suitable therapeutic strategies has led to a greater focus on prevention of HCC using antiviral agents and vaccination. Overall, the current outlook for patients with HCC is bleak; however, a better understanding of the molecular and genetic basis of this cancer should lead to the development of more efficacious therapies.

Chemical-shift MR imaging of acetic acid during percutaneous chemical ablation therapy: preliminary work

The purpose of this study was to test the hypothesis that chemical-shift magnetic resonance (MR) imaging may be used to map the distribution of acetic acid during percutaneous chemical ablation procedures. Chemical-shift MR imaging was performed with use of standard methods on a 1.5-T scanner. Phantom and ex-vivo data demonstrated focal increases in the observed signal in chemical-shift MR imaging that correlate well with the site of injection. Preliminary study in a patient with hepatoma revealed focal signal at the injection site. These preliminary results suggest that chemical-shift MR imaging may be used to visualize acetic acid distribution during percutaneous chemical ablation procedures.

Variant estrogen receptors and their role in liver disease

The liver presents estrogen receptors alpha and beta. As for breast cancer, a variant form of estrogen receptor alpha transcript (ER) has been described in hepatocellular carcinoma (HCC). It is derived by an exon 5-deleted transcript (vER), which lacks the hormone-binding domain of the receptor but, being intact in the DNA-binding domain, maintains constitutive transcriptional activity. HCCs presenting vER have an extremely aggressive clinical course and are unresponsive to the antiestrogen tamoxifen. On the other hand, megestrol, a drug able to block both the wild type and the variant form of ER, influence the clinical course of HCC presenting vER. The presence of vER is associated with elevated cancer cell proliferation rate.

Hepatitis C and hepatocellular carcinoma

Chronic hepatitis C infection (HCV) accounts for approximately 50% of the cases of hepatocellular carcinoma (HCC) in the United States. Cirrhosis or an advanced stage of fibrosis is the major risk factor of HCC; patients with cirrhosis are recommended to undergo surveillance with alpha-fetoprotein and ultrasound. Alpha interferon (IFN-alpha) is associated with a reduced risk of HCC in patients with chronic infection but insufficient data exist to recommend treatment of patients with cirrhosis and HCV for this reason alone. Resection and liver transplantation are the only "curative" therapies available. Advanced fibrosis or cirrhosis in patients with HCC limits the number of patients for whom resection is applicable. Moreover, the remaining liver is at high risk of developing a second primary tumor. Partial hepatic resection for hepatocellular carcinoma should be restricted to patients with well-compensated cirrhosis (Child's A class). Acceptable parameters include a single lesion not exceeding 5 cm, normal levels of bilirubin, and absence of portal hypertension. Liver transplantation is the best definitive treatment for HCV-infected patients who have small, localized HCC (solitary lesion not greater than 5 cm, or no more than 3 lesions, none of which are greater than 3 cm). Limitations of liver transplantation as a therapy for HCC are the scarcity of donor organs and the prolonged waiting time during which continued tumor growth occurs. Living donors can reduce waiting time and increase the number of patients treatable by transplantation. Chemoembolization and local ablation therapies have not been shown to confer survival benefits as primary treatments for HCC. The potential benefit of these procedures in controlling tumor growth to "bridge" patients to liver transplantation must be further investigated. Similarly, systemic chemotherapy and hormonal therapy do not generally produce a survival advantage. However, recent studies that used octreotide and combination doxorubicin/cisplatin/5-FU/interferon appear to be promising.