Primary liver cancer is cancer that forms in the tissues of the liver. Secondary liver cancer is cancer that spreads to the liver from another part of the body. Most liver cancer is secondary or metastatic.
Primary liver cancer, which starts in the liver, accounts for about 2 percent of cancers in the U.S., but up to half of all cancers in some developing countries. This is largely due to the prevalence of hepatitis, which predisposes a person to liver cancer. In the U.S., primary liver cancer strikes twice as many men as women, at the average age of 67.
The liver is one of the largest organs in the body. It has four lobes and fills the upper right side of the abdomen inside the rib cage.
Three of the many important functions of the liver are:
- To filter harmful substances from the blood so they can be passed from the body in stools and urine.
- To make bile to help digest fat that comes from food.
- To store glycogen (sugar), which the body uses for energy.
The following are risk factors for adult primary liver cancer:
- Having hepatitis B or hepatitis C. Having both hepatitis B and hepatitis C increases the risk even more.
- Having cirrhosis, which can be caused by hepatitis (especially hepatitis C), drinking large amounts of alcohol for many years, or being an alcoholic.
- Having metabolic syndrome, a set of conditions that occur together, including extra fat around the abdomen, high blood sugar, high blood pressure, high levels of triglycerides and low levels of high-density lipoproteins in the blood.
- Having liver injury that is long-lasting, especially if it leads to cirrhosis.
- Having hemochromatosis, a condition in which the body takes up and stores more iron than it needs. The extra iron is stored in the liver, heart, and pancreas.
- Eating foods tainted with aflatoxin (poison from a fungus that can grow on foods, such as grains and nuts, that have not been stored properly).