What is Liver Cancer?
What is Liver Cancer?
The liver is the largest intra-abdominal organ of the human body. It is situated under the right rib , below right lung and is divided into two lobes. The liver has several important functions in the human body like secreting bile into the intestines to help absorption of nutrients , breaking down toxins like drugs and alcohol in the blood, which then passes through urine and stool. It also has the job of making most of the blood clotting factors that help in stopping excessive bleeding at the time of a cut or injury.
The liver is composed of a number of cells called hepatocytes. It is also made up of many other types of cells which include blood vessels and cells that are found in the lining of bile ducts. Bile ducts are small tube-like structures that extend out of the liver and carry a substance called bile which has the role of breaking down fats. Bile is also carried by the bile ducts from the liver to the gallbladder and intestines.
The different types of cells that are found in the liver can form different types of tumors. These tumors can either be cancerous (malignant) or non- cancerous (benign). The treatment of liver cancer depends on a number of factors like the kind of tumor, the cause of the tumor, number and size. Each of these tumors have a different prognosis.
Liver cancer can be of three primary categories, benign liver tumors, primary liver cancer, and secondary or metastatic liver cancer.
- Benign liver tumors are tumors that sometimes grow large enough to create problems. These tumors, however, don’t grow into the nearby tissue or organs and do not spread to distant sites. Most of these tumors can be treated with surgery.
- Primary liver cancer is the cancer that starts in the liver
- Secondary liver cancer is cancer that has spread to the liver from another part of the body like the pancreas, colon, stomach, lung or breast. The tumors in secondary lung cancer are named based on the primary site or area in which the cancer was found.
What are the different types of Liver Cancer?
The different types of cells that are found in the liver can form different types of tumors. These tumors can either be cancerous (malignant) or non-cancerous (benign). The treatment of liver cancer depends on the kind of tumor, the cause, number and size of the tumor. Each of these tumors have different prognosis.
Liver cancer can be of three primary categories, benign liver tumors, primary liver cancer and secondary or metastatic liver cancer.
Primary liver cancer
Primary liver cancer is the kind of cancer that has originated in the liver. Primary liver cancer consists of different types like hepatocellular carcinoma, intrahepatic cholangiocarcinoma, angiosarcoma, hemangiosarcoma, and hepatoblastoma.
Hepatocellular carcinoma
Hepatocellular carcinoma is the most common type of primary liver cancer. In this type of primary liver cancer the cancer mainly develops in the main cells of the liver that are known as hepatocytes. It is seen to be more common in people who have a damaged liver from conditions like cirrhosis. Hepatocellular cancer can also have different growth patterns like some begin as a small single tumor that later grows larger. The second growth pattern is when there are many small cancer nodules throughout the liver and it is not just a single tumor.
Intrahepatic cholangiocarcinoma
A few cancers that start in the liver are intrahepatic cholangiocarcinomas. This type is also known as bile duct cancer. The cancer starts in the cells that line the bile duct. Most cholangiocarcinomas start in the bile ducts outside the liver.
Angiosarcoma and hemangiosarcoma
These are very rare cancers that start in cells that line the blood vessels. These type of cancers are mostly seen in people who are exposed to chemicals like vinyl chloride and thorotrast. These cancers can also be caused due to exposure to arsenic or radium or even due to inherited conditions. These tumors grow fast and spread widely to be surgically removed so the most common treatment options are chemotherapy and radiation.
Hepatoblastoma
This is a very rare type of cancer that is usually seen in children below the age of 4. Hepatoblastomas originate from immature liver precursor cells. Treatment for this kind of cancer is usually surgery with chemotherapy.
Secondary liver cancer
Secondary liver cancer is also known as metastatic liver cancer and means that the cancer has spread from somewhere else in the body to the liver. The tumors that are found in secondary liver cancer are named and treated based on the site of origin or their primary site.
Benign liver tumors
Benign tumors can also grow large enough to cause problems for people. However, these tumors don’t grow into the nearby tissues nor do they spread to distant sites. Benign liver tumors are of three types:
1. Hemangioma
These type of tumors start in the blood vessels and most do not cause any kind of symptoms. Sometimes these tumors can cause bleeding and may need to be removed surgically.
2. Hepatic adenoma
These type of tumors start from the main liver cells, which are known as hepatocytes. Most don’t cause any symptoms and do not need treatment but however there are some that can cause symptoms like pain and swelling in the abdomen. If these tumors burst they cause severe blood loss and most doctors recommend surgically removing these type of tumors to prevent such complications.
3. Focal nodular hyperplasia
Focal nodular hyperplasia is a tumor like growth that is made up of several cells like hepatocytes, bile duct cells and connective tissue cells. Though these tumors are benign it is hard to differentiate them from cancerous tumors and for this reason, doctors recommend removing them especially when the diagnosis is unclear.
What are the signs and symptoms of Liver Cancer?
The signs and symptoms of liver cancer usually do not show up until the cancer is in its later stages, but sometimes they can show up early too. It is important to go to the doctor once the first symptoms appear as there might be chances of getting the cancer diagnosed and treated earlier and better. The most common symptoms of liver cancer are listed below.
- Right upper abdominal pain
- Nausea or vomiting
- Weight loss
- Feeling full after a small meal
- Loss of appetite
- Enlarged liver
- Enlarged spleen
- Swelling or fluid build up in the abdomen
- Jaundice
- Itching
What are the causes of Liver Cancer?
A risk factor is known as a factor that increases a person’s chance of developing cancer. Risk factors often influence the development of cancer but don’t directly cause it. If you have a few risk factors it is always better to speak to your doctor about it. So that necessary health and lifestyle changes can be made. It is also important to know that having a few risk factors or even several of them does not mean that a person will definitely develop cancer as studies have shown that some people who develop cancer have few or no known risk factors.
Studies have linked several risk factors to liver cancer and these include:
Gender
In women, hepatocellular carcinoma is seen to be more common and this is mainly due to a number of factors like lifestyle and other health conditions which can be risk factors that are mentioned below.
Chronic viral hepatitis
Chronic infection with the hepatitis B virus or hepatitis C virus is the most common risk factor for liver cancer worldwide. These infections can lead to cirrhosis of the liver. It is also important to know that these infections can spread from person to person through unprotected sex, contaminated needles, childbirth and even through blood transfusion.
Tobacco
Smoking increases the risk of developing liver cancer. Current smokers have a higher risk of developing liver cancer than former smokers. However, smokers, in general, are at a higher risk of developing liver cancer than nonsmokers.
Alcohol use
Heavy alcohol use has been the leading cause of cirrhosis which has been linked to an increased risk of developing liver cancer.
Arsenic
Arsenic that has contaminated drinking water has been linked to increasing the risk developing of liver cancer for the person who consumes the water for a long period of time.
Obesity
Being overweight can increase the risk of developing liver cancer because being obese has been linked to liver conditions such as fatty liver and cirrhosis.
Type 2 diabetes
Type 2 diabetes has been linked to an increased risk of developing liver cancer as most people who have type 2 diabetes are overweight and being overweight has been linked to having other liver conditions.
Anabolic steroids
Anabolic steroids are male hormones that are used by some athletes for increased strength. Prolonged use has been linked to developing hepatocellular cancer.
Rare diseases
Certain rare conditions like Wilson disease and glycogen storage disease can increase the risk of developing liver cancer.
Cirrhosis
People with cirrhosis are at an increased risk of developing liver cancer. Cirrhosis is a condition in which liver cells get damaged and these cells are replaced by scar tissue.
Non-alcoholic fatty liver disease
People who have little or no alcohol can also develop fatty liver disease. Non-alcoholic fatty liver disease is commonly seen in people who are obese or overweight and has been seen to increase the risk of developing liver cancer.
Primary biliary cirrhosis
In primary biliary cirrhosis, the bile ducts are damaged are distorted and this can further lead to cirrhosis. People with advanced primary biliary cirrhosis are at a higher risk of developing liver cancer.
Inherited metabolic diseases
A few inherited metabolic diseases can lead to cirrhosis. People who have a condition known as hereditary hemochromatosis absorb too much iron from the food. The iron settles in tissues throughout the body and even in the liver. If too much of iron settles in the liver it can damage the liver and can cause cirrhosis and liver cancer.
What are the stages of Liver Cancer?
After diagnosis of liver cancer, one of the most important procedure done is staging. Staging refers to the extent of the cancer and how far it has spread. Liver cancer staging is very important as it can help doctors determine the kind of treatment that is required.
The liver cancer staging is done based on the TNM system of staging.
The TNM system of staging has the following factors:
Tumor (T): This determines how large the cancer has grown or if there is more than one tumor in the liver or if the cancer has reached nearby structures in the liver like the veins.
Lymph node s (N): This factor indicates if the cancer has spread to the lymph nodes.
Metastasis (M): This factor refers to whether the cancer has spread to other parts of the body.
Liver cancer staging is done usually based on the results of the biopsies, physical exam and imaging tests. If surgery is conducted, the pathological state is determined by examining the tissue that was removed during the surgery.
Classification of liver cancer stages
Liver cancer is classified into four stages, that are listed below:
Stage 1
Also known as the earliest stage of liver cancer, at this stage the cancer has not grown out to the blood vessels and there is only a single tumor. Stage 1 is also further divided into stage 1a and state 1b.
Stage 2
At stage 2 the single tumor has grown into the blood vessels of the liver.
Stage 3
Stage 3 is a little more advanced than stage 2 and consists of stage 3a and stage 3b and each substage states how big the tumor has grown and how far the cancer has spread.
Stage 4
Stage 4 is the most advanced stage of liver cancer and this stage is divided into two substances stage 4a and stage 4b and this stage is also known as metastatic liver cancer which means the cancer at this stage has spread to nearby lymph nodes and distant organs.
How do I know if I have Liver Cancer?
If some symptoms of liver cancer are present, there are different kinds of tests that have to be done to diagnose liver cancer. During the diagnosis of liver cancer, the doctor may take into consideration the person’s overall health and medical history. It is important to tell the doctor if there is a previous history of alcohol abuse or hepatitis B or hepatitis C infection. During the diagnosis, there are different tests that might be conducted like:
Imaging tests
Imaging tests use X-rays or magnetic waves to get a view of the internal organs. Imaging tests such as an abdominal CT scan or MRI is used to get a view of the liver and other organs.
Computed tomography (CT) scan
A CT scan creates a three-dimensional picture of inside the body using X-rays that are taken from different angles. A special kind of dye is also used to make the image clearer. The dye can be injected into the patient’s veins or can be given as a liquid to swallow. Triple phase CT scans are preferred.
Magnetic Resonance Imaging (MRI)
The MRI scan unlike the X-ray uses magnetic waves to give a detailed image of the internal parts of the patient’s body. The MRI is also known to detect the tumor size and a dye called a contrast medium is injected into the patient’s veins to give a more detailed view.
Liver Biopsy
A biopsy is sometimes the only way to be certain if cancer is present. A biopsy is a procedure where a sample tissue is removed and is looked at under a microscope to see if it is cancerous. In a liver biopsy, a small piece of the liver tissue is taken and examined under a microscope to see if cancer is present. In most cases of a liver biopsy, the technique of a needle biopsy is used where a thin needle is passed through the abdomen and into the liver to obtain a sample of the tissue. Sometimes a laparoscopic biopsy may also be performed where a small thin tube with a camera is used and this allows the doctor to have a view of the liver and internal organs
Alpha-fetoprotein (AFP) Blood test
The levels of alpha-fetoprotein is usually seen to be high in the blood of fetuses but it comes down after birth. The level of AFP is high in adults who have liver disease or cancer. If the levels of AFP are seen to be very high in adults who already have a liver tumor, it can be a sign that cancer is present. However, this test cannot be fully relied on to diagnose the early stages of liver cancer {insert secondary article hyperlink here}, as the levels of AFP maybe normal and it may be raised in other infective conditions also.
Liver function tests
Liver function tests are done during a diagnosis to check the health of the liver by measuring the liver proteins, enzymes and bilirubin in the blood.
How is Liver Cancer treated?
After diagnosis and staging the next important step is treatment. There are several treatment options for liver cancer and they are listed below.
Surgery
There are two types of surgery that can be performed for liver cancer. One is a resection which is a partial removal of the tumor and the other is a liver transplant. The treatment option if surgery is known to be the only reasonable cure for liver cancer.
Partial hepatectomy
The removal of a part of the liver is known as a partial hepatectomy. This kind of a surgery is usually considered if only a single tumor is present and if the tumor has not grown into the blood vessels of the liver. This surgery is also only conducted if the patient has good liver function and is healthy enough for surgery.
Liver transplant
Liver transplant can be an option for those people who have tumors that cannot be surgically removed. In general it is used to treat patients with small tumors but this option can also be used to treat patients with resectable cancers.
Tumor ablation
An ablation is the process of destroying the tumor without removing it. These techniques are used in people who have few small tumors and also for those who are not healthy enough for surgery.There are several techniques that can be used and they include
Radiofrequency ablation (RFA)
In the procedure of a radio-frequency ablation, high energy radio waves are used to kill tumors. A CT scan or ultrasound is used to guide a needle like instrument through the skin and into the tumor. An electric current is passed to the tip of the instrument, releasing high frequency radio waves that heat the tumor and kill the cells.This method is helpful in tumors upto 5 cm and away from blood vessels.
Cryoablation
A cryoablation is a procedure that uses extreme cold to destroy a diseased tissue. The procedure is performed using hollow needles through which cooled thermally conductive fluids are circulated. The cryoprobes are positioned adjacent to the target in such a way that the freezing process will destroy the affected tissue.This method is helpful in tumors upto 5 cm.
Ethanol ablation
In this process ethanol (alcohol) is injected directly into the tumor to kill the cells. This procedure is also known as percutaneous ethanol injection. This can be repeated multiples times.
Microwave ablation
In this procedure, microwaves are transmitted through a probe and heat is used to destroy the tumor.
Chemotherapy
Chemotherapy is the use of cytotoxic or anti cancer drugs to kill cancer cells. The most common ways used to give chemotherapy include the intravenous method where the tube is placed into the vein using a needle or the chemotherapy drugs can be taken orally by the patient. Chemotherapy may be given after surgery to kill any remaining cancer cells.
Liver cancer resists most if the drugs used in chemotherapy. There are some chemotherapy drugs that are seen to be most effective in the case if liver cancer big even these drugs shrink only a small portion of the tumors and the responses of these drugs often don’t last very long.
Hepatic Artery infusion
Hepatic artery infusion is mainly done for liver cancer because of the poor response systemic chemotherapy has. In the procedure of a hepatic artery infusion the chemo drugs are directly connected to the hepatic artery. The chemo is given directly to liver but the liver breaks it down before it reaches the other parts of the body. This kind of a procedure allows more chemo to reach the tumor without increasing side effects. Some studies have found that the hepatic artery infusion is the best method to shrink tumors but more research is needed in the area. However, this method requires a catheter to be placed surgically in the hepatic artery and some liver cancer patients are unable to tolerate the surgery.
Targeted therapy
Targeted therapy is the kind of therapy that targets cancer cells including specific genes, proteins or even the tissue environment that contributes to the growth of cancer cells. This type of treatment blocks the growth and spread of cancer cells while limiting the damage that is done to healthy cells. There are different types of targeted therapies which that are used, they include:
Anti-angiogenesis therapy
A kind of targeted therapy that focuses on stopping angiogenesis, which is the process of making new blood cells. The tumor needs nutrients from the blood cells to survive and the goal of anti-angiogenesis therapy is to starve the tumor.
Epidermal growth factor receptor (EGFR) inhibitors
An EGFR inhibitor is a kind of targeted therapy and studies have found that blocking the epidermal growth factor receptor may be beneficial for blocking or slowing down the growth of tomor.
Radiation therapy
Radiation therapy is the kind of treatment that uses high energy rays to kill cancer cells. There are different types of radiation therapy like:
External Beam Radiation Therapy (EBRT)
In this type of radiation, the radiation is focused from outside the body through a machine. The process is a lot like getting an X-ray and the amount of radiation given depends on different factors. Radiation is usually given over a course of few days. External beam radiation cannot be given on high doses as liver cells are quite sensitive to radiation and the normal tissue might get damaged in the process. The procedure of radiation is painless and lasts for very less time, however, getting the patient ready for radiation takes longer as the radiation team will have to mark correct angles to aim the radiation beams at.
With radiation having newer techniques, doctors have found targeting tumors easier while reducing side effects.
Stereotactic body radiotherapy
In this kind of radiation therapy very focused beams of high does radiation are aim at the tumor from many angles. To precisely target the radiation, the body is put into a specially designed body frame for each treatment.
Radioembolization
In this procedure, tumors in the liver are treated by injecting small amounts of radioactive beads into the hepatic artery. In this procedure small amounts of radiation are given and it only travels a short distance.
Immunotherapy
Immunotherapy is the kind of treatment that uses drugs that enables a person immune system to fight and destroy cancer cells.
Liver cancer can be prevented by reducing a person’s exposure to the most known risk factors. The preventive measures to be taken for liver cancer include:
Limiting the use of tobacco and alcohol
Drinking alcohol in moderation or not drinking at all can lower the risk of developing cirrhosis which in turn can prevent liver cancer. Limiting the use of tobacco or quitting all together is ideal as smoking has been linked to liver cancer and quitting can reduce the risk of developing it.
Healthy weight
Getting to or staying at a healthy weight is important as obesity has been linked to liver conditions like fatty liver disease and diabetes which can cause liver cancer. The only way to prevent these conditions and lower the risk of developing liver cancer is to lead an active and healthy lifestyle.
Avoiding and treating hepatitis
The most well-known risk factor of liver cancer is known to be the hepatitis B and hepatitis C viral infections. These viruses can spread from person to person through contaminated needles, blood transfusion, and unprotected sex. Some of these infections can be prevented by having protected sex and by not sharing needles. A vaccine can be used to prevent developing a hepatitis infection and it is recommended that all children and adults should be immunized . It is also recommended that blood banks check for these kind of viruses before taking blood from a person. Treatment is recommended for a person who is infected by the virus as treatment can reduce the risk of developing liver cancer. There are also a number of drugs that are available to treat hepatitis B or hepatitis C and these are used to reduce the number of viruses in the blood and lessen the liver damage. These drugs can also help to reduce the risk of cirrhosis and liver cancer.
Limit exposure to cancer-causing chemicals
Changing the way grains are stored can reduce the exposure to aflatoxins. Aflatoxins are a kind of fungus that can contaminate grains like peanuts and they grow in a warm environment. Prolonged exposure to aflatoxins can cause cancer.
Treating inherited diseases
Certain inherited diseases are the cause of cirrhosis in the liver and this can lead to liver cancer. It is of utmost importance to find these inherited diseases and treat them the right way to prevent the development of liver cancer.
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