Determining HCC Risk Among Patients with HBV and HCV
October 12, 2017 - MCI Canada
Hepatitis B (HBV) and Hepatitis C (HCV) have an established causal relationship with Hepatocellular carcinoma (HCC), and have the highest associated risk of all diseases for developing the cancer. However, many other factors are independently linked with risk of developing HCC, including gender, age, family history of HCC, alcohol intake, and the presence of cirrhosis, obesity, or type II diabetes. These factors, as well as individual viral and environmental factors, all interact with one another, making each patient’s risk for HCC unique, and assessing their risk level a complex process.
Most patients possess mixed risk profiles, making their chances of developing HCC difficult to predict. An evidence-based tool that accurately weighs risk factors to give a precise assessment would be extremely helpful in determining the necessity of HCC preventative treatment for individuals with HBV and HCV. Currently, hepatology risk calculators are able to do this with limited accuracy; as more sophisticated models are developed, a stronger diagnostic tool may become a reality.
Reliability of Risk Calculators in Hepatology
Several study groups have established prediction models to devise risk calculators for predicting HCC in patients with chronic HBV, incorporating prominent risk predictors into a single risk measurement system. The main issue with these initial models was the lack of external validation; to solve this problem, key study groups collaborated to establish an HCC risk score: REACH-B. REACH-B looks at common clinical variables—gender, age, serum ALT concentration, HBeAg status, and serum HBV DNA levels. It has accurately and consistently estimated risk of HCC in HBV patients at three, five, and ten years, predicted risks similar to those estimated by the Kaplan-Meier curve, and has since been validated in international clinical cohorts. This provides sufficient external validation of an HCC risk prediction tool for the first time.
Recent evidence suggests that a patient’s quantitative serum HBsAg level offers another layer of predictability of HCC, especially for patients with low HBV DNA levels. This new marker has been internally validated as a part of the risk calculator, with external validation hopefully coming soon.
Although the REACH-B score can be useful in clinical practice, a few precautions should be noted. Firstly, the risk score decreases in reliability when applied to cirrhotic patients. However, a precise risk assessment for cirrhotic patients may not be necessary, as cirrhosis itself is an important risk factor of HCC development in HBV and HCV patients. As well, the REACH-B score was established among patients not undergoing antiviral therapy, and therefore may not be considered accurate for those undergoing antiviral treatment.
Risk Assessment Informs Treatment Options
The HCC risk calculator is best used as a tool to support evidence-based decisions for management of HBV in patients and establish a plan for HCC prophylaxis. Treatment plans such as follow-up intervals, patterns of surveillance, and referrals can be personalized depending on a patient's individual HCC risk. A risk score can also be a platform that raises a patient's awareness of their own risk and may improve their willingness to receive appropriate therapy.
Risk assessment is also useful to the extent that it informs HCC prevention measures for individuals with HBV and HCV. High-risk patients may benefit from starting antiviral therapy to improve histology.
Determining HCC Risk Both an Art and a Science
Determining the risk of HCC for patients infected with HBV and HCV is complex, based on a multitude of variable patient, viral, and environmental risk factors. Risk calculators can help hepatologists to assess risk and help determine the need for prophylactic treatment, but may not be appropriate for all patients. As such, a variety of specialized tools and tests should help inform, but not solely decide, the best course of treatment for each unique individual.
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