The 3 Most Common Liver Cancer Types

Liver cancer can come in different forms, and it can be confusing to differentiate one from another. Before we delve into the different liver cancer types, you should first understand the difference between primary liver cancer and secondary liver cancer. Primary liver cancer refers to cancer that starts in the liver, while secondary liver cancer refers to cancer that started somewhere else in the body, but has spread to the liver.

For primary liver cancer, exactly where in the liver it starts determines what type of liver cancer it is. This will affect the type of treatment plan your doctor might recommend.

Hepatocellular carcinoma (HCC)

The first and most common type of liver cancer is hepatocellular carcinoma, also known as hepatoma or HCC. HCC refers to cancer that starts in the main cells of the liver, which are called hepatocytes, and it accounts for 85% to 90% of all primary liver cancers. It tends to be more common in men. It is also more common in people who have cirrhosis, usually caused by damage to the liver from chronic viral hepatitis infections or prolonged alcohol consumption.

HCC can be further categorized into different subtypes based on the characteristics and features of the liver cancer tissue:

• Fibrolamellar
• Scirrhous
• Clear cell type
• Steatohepatitic
• Macrotrabecular massive (MTM)
• Chromophobe
• Neutrophil-rich
• Lymphocyte-rich

The differentiation between most of these subtypes generally does not affect the treatment methods or patient outcomes. The only exception would be the fibrolamellar variant. It is important to recognize that it tends to develop in people with healthy livers without cirrhosis, typically in teens and adults under the age of 40. It is worth noting, however, that fibrolamellar carcinoma is extremely rare, accounting for approximately 1% to 5% of all liver cancers, and tends to have a better prognosis as compared to the other subtypes.

Intrahepatic cholangiocarcinoma (bile duct cancer)

This type of liver cancer starts in the cells lining the bile ducts within the liver. It is less common than hepatocellular carcinomas, accounting for approximately 10% to 20% of all primary liver cancers. While it is considered a different type of liver cancer, intrahepatic cholangiocarcinomas are generally treated in the same way as hepatocellular carcinomas.

Some tumors have both hepatocellular and cholangiocellular elements. These are called mixed tumors. Also known as mixed hepatocellular cholangiocarcinomas (mHC-CC), these are very rare tumors, and little is known about their therapy and treatment outcomes, as data on them is scarce.

Angiosarcoma and hemangiosarcoma

These are cancers that start from the cells lining the blood vessels of the liver. These types are very rare, tend to be more fast-growing in nature and are often widely spread by the time they are discovered.

In most cases, the cause of liver sarcomas is unknown. Known causes or risk factors include exposure to certain chemicals, such as vinyl chloride and thorium dioxide, and inherited conditions such as hereditary hemochromatosis.

The liver is a common site for metastatic spreading of primary cancers from other parts of the body, as it filters large volumes of blood, making it more likely for those cancer cells to reach it through the bloodstream. Common primary sources include:

• Colorectal cancer
• Breast cancer
• Lung cancer
• Pancreatic cancer
• Stomach cancer

A key difference between primary liver cancer and secondary metastatic liver lesions is that the treatment of the latter would depend on the primary cancer type. For example, if the primary cancer is a breast cancer that has spread to the liver, it would still be treated as a breast cancer and not as a primary liver cancer.

It can certainly get overwhelming reading about the different types of liver cancer. However, the important thing is to understand that the liver cancer type and/or subtype can affect your treatment plan and patient outcome, but this will also depend on a variety of other factors, such as cancer stage and your overall health condition. Having a basic understanding of the type of liver cancer you have may help you start conversations with your doctor and ask relevant questions that may affect your decision-making in your treatment plan.