How I Do It: Systemic Therapies for Primary Liver Cancers.

Primary liver cancer, which includes hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), remains a leading cause of cancer-related mortality worldwide. Systemic therapy, particularly immunotherapy, has significantly improved outcomes in advanced or unresectable cases in recent years and is increasingly being applied in earlier disease stages and in combination with local-regional treatments. Because imaging plays a critical role from diagnosis through treatment response assessment, radiologists must remain up to date with the evolving therapeutic landscape and its imaging manifestations. This article provides an updated overview of systemic therapies for HCC and iCCA and summarizes key findings from landmark clinical trials. While the Response Evaluation Criteria in Solid Tumors and its variants remain the standard assessment tools in clinical trials, assessing treatment response in daily practice can be more complex. This article outlines key considerations that radiologists should keep in mind when evaluating the response to systemic therapy in primary liver cancer. This assessment requires a comprehensive approach that goes beyond size changes, incorporating biologic effects such as necrosis and changes in vascularity. As systemic therapy becomes increasingly nuanced and personalized, radiologists play a vital role in informing treatment decisions, supporting multidisciplinary care, and optimizing patient outcomes.