Risk calculators for hepatocellular carcinoma in patients affected with chronic hepatitis B in Asia.

Risk calculators are widely used in many clinical fields, and integrate several important risk factors through the conversion of a risk function into a single measure of risk. Several studies have been carried out to create risk calculators for the prediction of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). Most of them were hospital-based, with limited sample sizes and insufficient external validation. These study groups collaborated to establish the REACH-B risk score, which incorporated five clinical variables to predict HCC risk. This risk score was then validated in international clinical cohorts. Evidence suggests that quantitative serum HBsAg level provides additional predictability of HCC, especially in patients with low levels of hepatitis B virus DNA. This novel marker was incorporated into a risk calculator and was internally validated. This tool will hopefully be externally validated in the near future. Risk calculators can be used to support clinical practice, and to establish preventive measures; several "off-label" extension usages have also been implemented. Albeit beneficial, several precautions and discussions should be noted in using the risk calculators. The future development of risk calculators for CHB patients can be extended by applying them to additional CHB-related outcomes, and by incorporating emerging risk parameters.