October is Liver Cancer Awareness Month, which makes this a good time to learn more about liver cancer.

More than 42,000 new cases of primary liver cancer and intrahepatic bile duct cancer will be diagnosed in the U.S. this year, and more than 30,000 people will die of these diseases, according to the American Cancer Society.

Liver cancer is cancer that begins in the cells of your liver, which is a football-sized organ in the upper right portion of your abdomen. The liver is essential for digesting food and ridding your body of toxic substances.

Intrahepatic bile duct cancer, which sometimes is classified as a type of liver cancer, occurs in the parts of the bile ducts within the liver. Bile ducts carry bile, a digestive fluid, and they connect your liver to your gallbladder and small intestine.

Cancer that spreads to the liver is more common than cancer that begins in the liver cells. Cancer that begins in another area of the body, such as the colon, lung or breast, and then spreads to the liver is called metastatic cancer rather than liver cancer. This type of cancer is named after the organ in which it began, such as metastatic colon cancer to describe cancer that begins in the colon and spreads to the liver.

Sometimes the cause of liver cancer is known, such as with chronic hepatitis infections. But sometimes liver cancer happens in people with no underlying disease, and it's not clear what causes it. Factors that increase the risk of liver cancer include chronic infection with hepatitis B or hepatitis C, diabetes, and excessive alcohol consumption.

Treatment for primary liver cancer depends on the severity of the disease, as well as your age, overall health and personal preferences. Treatment options can include surgery; localized treatments, including radiofrequency ablation, cryoablation and chemoembolization; radiation therapy; targeted drug therapy; immunotherapy; and chemotherapy.

Connect with others talking about living with liver cancer, treatments and more in the Cancer support group on Mayo Clinic Connect, an online patient community moderated by Mayo Clinic.