Magnitude of and prediction for risk of hepatocellular carcinoma in patients with chronic hepatitis B taking entecavir or tenofovir therapy: A systematic review

Background and Aim Entecavir (ETV) and tenofovir disoproxil fumarate (TDF) have been shown to reduce incidence of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). This systematic review aims to evaluate the magnitude, change over time, and prediction of residual HCC risks in CHB patients treated with ETV/TDF therapy. Methods Available literature was systematically reviewed through searches of PubMed and EMBASE databases from January 1, 2006 to September 1, 2019, to identify cohort studies that reported HCC incidence in CHB patients during ETV/TDF therapy. Studies were screened by title and abstract and then evaluated for eligibility in terms of full text. Results We identified 141 studies for full-text review, and 34 were eligible for analysis. From 19 studies with data separated by cirrhosis status, the 5-year cumulative incidence of HCC was 0.5-6.9% in patients without cirrhosis, 4.5-21.6% in compensated cirrhosis, and 36.3-46.5% in decompensated cirrhosis. All four studies that addressed temporal changes in HCC risks consistently found the incidence rate decreased over time in patients with cirrhosis, although the findings were inconsistent in patients without cirrhosis. Six predictive scores were developed and validated to predict incident HCC during ETV/TDF therapy in CHB patients. Common scoring variables included age, sex, cirrhosis (fibrosis grade), and hepatic function. Conflicting results were reported in seven individual studies and two meta-analyses that compared ETV versus TDF. Conclusions The residual risk of HCC remains during ETV/TDF treatment in CHB patients with cirrhosis but declines over time. Risk stratification is attainable by validated predictive scores.