Liver cancer explained

Where is the liver?

The liver is the largest organ in the body. It lies under the lower part of the rib cage on the right hand side of the body but it stretches across the middle about as far as the left nipple (see figure). When the liver gets larger, which can often happen when it is diseased, your doctor may be able to feel its lower edge below the rib cage. He might ask you to take a deep breath which can make the liver easier to feel.

What does the liver do?

The liver performs many important functions in the body. It produces bile, which is not only needed to digest certain foods, but also helps to absorb several important vitamins. It is helpful to think of the liver as a ‘factory’ which manufactures many important proteins and other chemical substances that the body needs to work normally. The liver helps regulate the energy and fluid stores in the body, and also processes many of the body’s waste products (or toxins) to render them harmless.

What is cancer?

The body is made up of billions of tiny cells whose growth is very carefully controlled. Cancers can be thought of as a collection of abnormal cells that have escaped from growing under this normal control. At first, the collection of abnormal cells is tiny and too small to be seen on an X-ray or scan. Usually cancers do not produce any symptoms until they have grown in size.

What types of liver cancer are there?

Some cancers begin in the cells of the liver itself – these are called primary liver cancer. More commonly, cancers start in cells in other organs of the body but then spread to the liver – this is called secondary liver cancer. Your doctor may use the term ‘liver metastasis’ (which is another way of saying that cancer has spread to the liver). It is possible for there to be several cancer deposits (metastases) in the liver.

There is more than one sort of primary liver cancer. One such type starts within the cells which make up most of the liver tissue – this is known as a hepatoma, or sometimes hepatocellular carcinoma (HCC for short).

Another type begins in the cells which line the tubes (or ducts) that carry the bile out of the liver – this bile duct cancer is known as a cholangiocarcinoma. Hepatomas usually occur in people who have an underlying liver disease, such as scarring of the liver (also known as cirrhosis) and can be a long-term result of chronic hepatitis. There is no association between cirrhosis and the development of cholangiocarcinoma.

However, in the UK, secondary liver cancer is about 30 times more common than these primary liver cancers. Secondary cancer occurs in people who have a primary cancer which has begun elsewhere. The usual sites in the body where primary tumours develop before spreading to the liver include the lung, breast, large bowel,
stomach and pancreas. Cancer cells usually spread to the liver from the primary tumour through the bloodstream.

Other, much less common, types of cancers can occur in the liver. These grow at different speeds. Your doctor will explain if you have one of these sorts of tumour.