Editor’s Note:
The diagnosis of liver cancer involves three aspects, including imaging, blood test results, and biopsy pathology results. Typically, the diagnosis of a tumor is confirmed only under a microscope after obtaining pathological tissue. However, liver cancer has its unique characteristics, and its diagnosis can be based on cirrhosis and confirmed through imaging tests such as computer tomography scans and magnetic resonance imaging. At the recently concluded 13th Asia-Pacific Primary Liver Cancer Expert Conference (APPLE 2023), Dr. Kathryn J. Fowler from the University of California, San Diego, shared insights from the perspective of a radiologist on the effectiveness and reliability of liver cancer imaging in clinical diagnosis, as well as the positive role of imaging in the classification and prognosis prediction of liver cancer patients. Hepatology Digest had the privilege of conducting an in-depth interview with Dr. Fowler at the conference, and we have compiled the content for our readers.
To what extent can clinical diagnosis of liver cancer rely on imaging?
Dr. Fowler: From the perspective of a radiologist, the clinical diagnosis of liver cancer can rely on imaging studies such as dynamic contrast-enhanced MR or CT (using multiphase contrast imaging). LI-RADS classification defines the diagnostic criteria for liver cancer in radiology, making the diagnosis more accurate. LI-RADS grading is primarily based on lesion diameter and four liver cancer-specific imaging features: arterial phase enhancement, washout in the venous phase, capsule appearance, and threshold growth. This grading is particularly useful for individuals at high risk of liver cancer, such as those with cirrhosis, chronic hepatitis B, or a family history of liver cancer. In these cases, we can reliably clinically diagnose liver cancer using LI-RADS grading, which categorizes liver cancer into 5 levels: LR1: definitely benign; LR2: probably benign; LR3: indeterminate; LR4: probably liver cancer; LR5: definitely liver cancer.
The application value of imaging features of liver cancer in classification and prognostic stratification
Dr. Fowler: Regarding whether imaging features have a positive role in the classification and prognosis of liver cancer, I firmly believe they do. Through retrospective, single-center studies, we have shown that the imaging features of liver cancer can help us understand what type of tumor it is, especially when it is a massive liver cancer, which may be associated with poorer histopathological subtypes and prognosis. Another example is in cases of liver cancer with extensive necrosis, recent literature reports that the macrotrabecular-massive hepatocellular carcinoma (MTM-HCC) subtype presents as intratumoral necrosis and ischemic areas in imaging, and its high recurrence rate may be related to vessels completely encapsulating tumor clusters (VETC). However, further multicenter, prospective, and methodological research is needed to fill these knowledge gaps and further clarify the role of imaging features in the classification and prognosis of liver cancer.
When is a biopsy needed for a definite diagnosis?
Dr. Fowler: So, when is a biopsy necessary? In cases where the lesion does not meet the LI-RADS grading criteria, there is a need for a pathological diagnosis. For example, when a patient presents with an LR4 lesion, indicating “probably liver cancer,” we would recommend a biopsy to confirm the diagnosis.
Introduction to recent research results and their clinical significance by your team in recent years
Dr. Fowler: As co-director of the Liver Imaging Group at the University of California, San Diego, I have been working with Dr. Claude Sirlin to primarily validate the accuracy of LI-RADS diagnoses in various scenarios and optimize response algorithms. In addition, our research includes screening and validation of quantitative imaging biomarkers for chronic liver diseases. For example, you may see proton density fat fraction (PDFF) used for accurate quantification of liver fat content in routine magnetic resonance imaging reports or R2* values for non-invasive assessment of liver iron content in cases of iron overload. These are relevant indicators that our team has helped develop and validate.
