What is the most common primary malignancy that leads to liver cancer?

Hepatocellular carcinoma (HCC) is recognized as the most common primary malignancy of the liver. It typically arises from hepatocytes and is most frequently associated with underlying liver diseases such as hepatitis B and C infection, cirrhosis, and excessive alcohol consumption. The prevalence of HCC has been increasing globally, particularly in regions with high rates of hepatitis infection.

In contrast to other options, cholangiocarcinoma primarily affects the bile ducts and is not a primary tumor of the liver itself. Pancreatic adenocarcinoma, while a significant cause of cancer mortality, primarily affects the pancreas and does not originate in the liver. Metastatic tumors refer to cancers that spread to the liver from other sites in the body, such as colon or breast cancers, but they are not classified as primary liver malignancies. Therefore, hepatocellular carcinoma stands out as the primary malignancy that leads to liver cancer, making it the correct answer in this context.