Hepatocellular carcinoma (HCC) is a type of primary liver cancer. For individuals at an elevated risk of developing this disease, doctors recommend a structured monitoring program called surveillance. The purpose of surveillance is to detect cancer at an early stage, often before symptoms appear. Finding HCC when it is small increases the effectiveness of medical interventions and improves long-term health outcomes.
Identifying High-Risk Individuals
The greatest risk factor for developing hepatocellular carcinoma is cirrhosis. This condition results from long-term liver damage that leads to extensive scarring and impaired function. This scarring disrupts the liver’s normal cellular architecture, creating an environment where cancer can develop. All patients with cirrhosis, regardless of its cause, are considered candidates for regular HCC surveillance.
The conditions that lead to cirrhosis are varied, with common causes being chronic viral infections and metabolic diseases. Chronic hepatitis B and C are significant drivers of cirrhosis and cancer risk. Other frequent causes include alcohol-related liver disease from prolonged, heavy alcohol consumption, and nonalcoholic fatty liver disease (NAFLD). NAFLD is linked to obesity and can progress to a more severe inflammatory form called nonalcoholic steatohepatitis (NASH).
An exception to the “cirrhosis-first” rule involves individuals with chronic hepatitis B virus (HBV) infection. Unlike other liver diseases, HBV can directly cause cancer even in the absence of cirrhosis. The virus can integrate its genetic material into the DNA of liver cells, which can trigger cancerous changes. Because of this mechanism, surveillance is recommended for specific groups of hepatitis B patients even if their liver is not cirrhotic.
These non-cirrhotic HBV patient groups are defined by factors that correlate with a higher cancer risk. Medical guidelines specify these groups, which include Asian men over the age of 40 and Asian women over 50. Other factors that place a non-cirrhotic HBV patient into a surveillance program include having a family history of HCC or being of African ancestry.
The Surveillance Process
The standard approach for HCC surveillance involves a combination of non-invasive tests performed every six months. This timeframe is based on studies of HCC tumor doubling time, aiming to detect a new tumor before it grows too large for effective treatment. This biannual schedule is widely recommended by major medical organizations.
The primary imaging tool used is an abdominal ultrasound. During this procedure, a technician uses a handheld transducer to send high-frequency sound waves into the body, creating a real-time image of the liver. The test is painless, does not involve radiation, and its purpose is to identify any new nodules or suspicious areas within the liver.
Along with the ultrasound, a blood test is performed to measure the level of a protein called alpha-fetoprotein (AFP). AFP levels are normally low in healthy adults, but some HCC tumors produce the protein, leading to an elevated level in the bloodstream. The AFP test is not used alone for surveillance because its levels can be normal when cancer is present, or elevated for other reasons, such as liver inflammation.
The effectiveness of the ultrasound can be limited by certain patient factors. In individuals with obesity, excess abdominal tissue can make it difficult to produce a clear image of the entire liver. Similarly, in patients with advanced cirrhosis, extensive scarring can alter the liver’s texture, potentially obscuring small lesions. In cases where an ultrasound is inadequate, a doctor may use alternative imaging like a CT or MRI for surveillance.
Interpreting Surveillance Results
After a round of surveillance, the results guide the next steps. A negative, or normal, result is the most common outcome and means the ultrasound did not detect any suspicious liver nodules and the AFP level was normal. When results are negative, no immediate action is needed, and the individual continues with their established six-month surveillance schedule.
A positive, or abnormal, result from surveillance requires further attention but is not a diagnosis of cancer. An abnormal finding could be the appearance of a new nodule on the ultrasound or a significant rise in the AFP blood test level. These findings are indicators that a more detailed evaluation is necessary, as many nodules are benign and AFP levels can be elevated by inflammation.
These situations are referred to as false positives, where the initial screening test suggests a problem that is found not to be cancer after investigation. The purpose of surveillance is to be sensitive enough to catch potential cancers early, which means it will inevitably flag some benign findings. An abnormal result marks the beginning of a diagnostic process, not the end.
Follow-Up Diagnostic Procedures
When a surveillance test shows an abnormality, the medical team begins a focused diagnostic workup. The first step is more advanced imaging, such as multiphase contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI). These scans are more powerful than ultrasound and capture images of the liver at several points after a contrast dye is injected. This technique allows doctors to observe how blood flows into and out of the suspicious nodule compared to healthy liver tissue.
Hepatocellular carcinomas have a distinct blood supply pattern that can be identified on these scans. They receive most of their blood from the hepatic artery, causing them to appear bright in the early “arterial phase” of the scan. Subsequently, in later phases, the contrast dye washes out of the tumor more quickly than the surrounding liver tissue. This pattern of arterial enhancement followed by venous washout is a distinct feature of HCC and can provide a diagnosis without a biopsy.
If the imaging results from a CT or MRI are inconclusive or show atypical features, the final step is a liver biopsy. During a biopsy, a physician uses a thin needle to take a small sample of tissue from the suspicious nodule. This tissue is then examined under a microscope by a pathologist to make a definitive diagnosis and confirm if cancer cells are present.