Hepatitis C virus: Epidemiology and clinical features of related cancer

Hepatitis C virus (HCV) affects about 3 % of the world population. The region with the highest prevalence is Africa with a prevalence of 5.3 %. Genotype 1 is the most commonly encountered of the six viral genotypes. With the implementation of testing of blood products in the early 1990s, injection drug use and transmission in health and para-health care settings are now the main mechanisms of infection. HCV infection is mostly asymptomatic and diagnosed at a chronic stage by detection of anti-HCV antibodies in the blood. Nucleic acid testing confirms active HCV infection. Chronic HCV is complicated by liver cirrhosis in 20-30 % of cases. Cirrhosis is a precursor condition for hepatocellular carcinoma. The risk of hepatocellular carcinoma is increased by 17- to 20-fold in chronic HCV patients and HCV causes 20-30 % of all liver cancers worldwide. The combination of pegylated-Interferon/Ribavirin is still the standard of care for chronic HCV-infected patients who are eligible for antiviral therapy. The addition of a protease inhibitor to pegylated-Interferon/Ribavirin combination improves the rate of sustained virological response (SVR) in patients infected with HCV genotype 1. Protease inhibitors are associated with numerous side effects and alternative therapies may soon become available. HCC is the third most common cause of cancer-related death worldwide. HCV-induced HCC is expected to become the dominant cause of liver cancers as vaccination against HBV is being implemented in almost all countries. HCV-induced HCC disproportionately affects low resource countries. HCV-induced HCC mostly develops in the cirrhotic liver with transformation of regenerative nodules into dysplastic nodules and then to HCC. Death in patients with advanced HCC mostly occurs by progression to liver failure. Ultrasonographic surveillance of cirrhotics for HCC has contributed to early diagnosis of HCC. New nodules detected by ultrasonography can be confirmed with high specificity by the finding of arterial enhancement and portal venous or venous phase washout on dynamic contrast enhanced CT or MRI. The Barcelona Clinic Liver Cancer (BCLC) staging system stratifies HCC into stages of increasing severity each with its recommended treatment. The shortcoming of this staging is the heterogeneity of patients with intermediate stage disease, leading to a lack of uniformity in the treatments applied to these patients. Liver transplantation is associated with the best survival outcomes for patients with HCV-induced HCC, but graft loss can occur due to recurrence of chronic HCV in the transplanted liver. The 5-year survival of HCV-induced HCC after liver resection ranges from 40 to 70 %, but is marked by tumor recurrence rates of up to 75 % at 5 years, due to the development of de novo tumors in the residual cirrhotic liver. The best strategy to prevent HCV-induced HCC is to prevent HCV infection and to treat chronic infection at the earliest opportunity to mitigate the risk of progression to cirrhosis.