1) Overview :-
The liver is a very important organ in the human body. It is placed under right ribs just under the right lung. The most important function of the liver is to convert food into energy and filtering and storing blood. The liver plays a pivotal role in the detoxification of blood, i.e. removal of toxins produced in the body due to metabolic activity of the body. The liver receives blood from two sources, the hepatic artery supplies the liver with blood from the heart that is rich in oxygen and the portal vein carries nutrient rich blood from the digestive organs. Liver also produces clotting agents necessary for clotting the blood when the body is injured. It secrets bile into the intestines, to help absorb nutrients. The liver is made up of several different types of cells. This is why there are several types of malignant (cancerous) and benign (non-cancerous) tumors that can form in the liver.
Benign tumors :-
(i) Hemangioma – The most common type of benign tumor of the liver, starts in blood vessles. Because most hemangiomas of the liver cause no symptoms, they do not need treatment. Some however may need to be surgically removed.
(ii) Hepatic adenomas – These are benign tumors of hepatocytes (the main type of liver cell). Most cause no symptoms and do not need treatment. However, some eventually cause symptoms, such as abdominal pain, a mass in the abdomen, or blood loss. Because there is a risk that the tumor could rupture, and a small risk that it would eventually develop into liver cancer, most experts usually recommend surgical removal if possible.
(iii) Focal nodular hyperplasia – This is a tumor growth of several cell types. Although FNH tumors are benign, it can be difficult to tell them apart from true liver cancers, and they sometimes are surgically removed when diagnosis is unclear.
Malignant tumors: –
(i) Hepatocellular carcinoma :- It is the most common form of liver cancer occurring. It is on numerous occasions called hepatoma because it comes from the hepatocytes. It accounts for about 75% of primary liver cancers.
(ii) Cholangeocarcinomas :- This accounts for 10 to 20% of primary liver cancers. These are also called intrahepatic (starting with the liver) Cholangeocarcinomas. These cancer starts in the small bile ducts within the liver.
(iii) Angiosarcomas and hemangiosarcomas: – These are rare cancers that begin in the blood vessles of the liver. Exposure to various chemicals such as vinyl chlorides or thorium oxide, and radioactive elements like radium or poisons like arsenic are known to cause these types of cancers. Angiosarcomas grow rapidly, by the time they are detected the growth is too large to be surgically removed.
(iv) Hepatoblastoma: – This is a very rare kind of cancer that developes in children, usually up to five years of age. If detected early this cancer is highly treatable.
(2) Symptoms: –
Signs and symptoms in liver cancers are not present until the last stage when cancer has spread. Many signs and symptoms are relatively non-specific, they can be caused by other cancers or non-cancerous diseases. However the following symptoms may require attention.
(i) Unexplained, unintentional weight loss.
(ii) Anorexia – persistent lack of appetite.
(iii) Liver enlargement or a mass that can be felt in the area of liver.
(iv) Persistent abdominal pain.
(vi) Hyperglycemia – Some liver hormones may cause hyperglycemia ( high blood calcium levels). This can lead to weakness.
(vii) Hypoglycemia – Low blood sugar levels, which can lead to fainting.
(viii) Gynecomastia – Enlargement of breasts in men, and shrinking of testis.
(ix) Aseitis – Water retention in the abdominal area. Many patients are seen with these symptoms.
(3) Risk factors
(i) Gender – Hepatocellular carcinoma is predominantly more common in males than in females.
(ii) Chronic viral hepatitis – Chronic (long term) infection with hepatitis B virus or Hepatitis C virus is an important liver cancer risk factor. These infections are responsible for making liver cancer the most common type of cancer in the world.
(iii) Cirrhosis – Cirrhosis is the result of scar tissue formation in the liver. This can often lead to cancer. Most liver cirrhosis occurs in people who abuse alcohol. But, Hepatitis B and C are also major causes of liver cirrhosis. Another cause is excessive iron in liver.
(iv) Tobacco use – A link has been established between tobacco use and liver cancer. Combined with alcohol tobacco is very potent in causing cancer.
(v) Inherited metabolic diseases – Certain metabolic diseases can also lead to cirrhosis. People with hemochromatosis, absorb too much iron from their food. They are more likely to develop cirrhosis because of the high levels of iron in their liver.
(vi) Aflatoxins – These cancer causing substances are produced by a fungus that contaminates crops. Long term exposure may cause Hepatocellular carcinoma.
(vii) Arsenic – Chronic exposure to drinking water contaminated with naturally occurring arsenic such as that from wells, increases the risk of liver cancer.
(4) Metastasis: –
Mostly when cancer is found in the liver, it did not start there but spread, or metastasized from a cancer that developed in the other organs of the body such as pancreas, colon, stomach, breast, or lung, and metastasized to the liver. These tumors are named after their primary site of occurrences and are further known as metastasis. For example, cancer that started in the lung and spread to the liver is called metastatic lung cancer with spread to the liver.
(5) Diagnosis: –
The following methods are used by modern science in the diagnsis of liver cancer.
(ii) Computed tomography (CT)
(iii) Magnetic resonance imaging (MRI)
(vii) Alpha-fetoprotein blood test.
(6) Staging: –
(i) Stage 1 – The tumor may be small or large but has not affected blood vessles.
(ii) Stage 2 – There may be many tumors of large size but blood vessles are not yet affected.
(iii) Stage 3-a – There are several tumors, and at least one is larger than 5 cms. And a tumor invades a branch of major liver blood vessles. (Portal vein or Hepatic vein)
(iv) Stage 3-b – A tumor invades a nearby organ or a tumor has penetrated the lining of the liver.
(v) Stage 3-c – The cancer has invaded nearby lymph nodes.
(vi) Stage 4 – The cancer has spread to other parts of the body.