by Dr S. Y. Chong
The liver plays an essential role in regulating life processes. Before birth, it serves as the main organ of blood formation. Thereafter, its primary functions are to refine and detoxify everything you eat, breathe, and absorb through your skin. The liver is a silent, faithful partner and does not complain UNTIL advanced damage has occurred.
Primary Liver Cancer
Primary liver cancer is the fifth most common cancer in the world. Primary liver cancer refers to cancer that originates from the cells of the liver. This is different from metastatic liver cancer, which refers to the invasion of cancer cells from another organ such as the breast and lungs spreading to the liver.
Of the 600,000 new cases diagnosed annually worldwide, approximately 400,000 come from China, Japan, Taiwan, and South Korea combined. It is the sixth most common cancer in Malaysia, affecting more men than women, and occurring between the ages of 50 and 60.
The causes of liver cancer depend on many factors. A key step in the progression to liver cancer is scarring of the liver due to liver cell damage (cirrhosis). This scarring can be caused by hepatitis B or C infection, alcohol abuse, aflatoxins (a mould that grows on foods such as peanuts, rice, and wheat that has been stored in a hot and humid environment), as well as rare diseases that lead to chronic inflammation of the liver, such as Wilson’s disease or haemochromatosis.
In Asia, the key risk factor for liver cancer is chronic hepatitis B infection. It is spread mainly via blood, sexual contact, and between mother and foetus during pregnancy. Whilst the majority of people who have acute hepatitis B will overcome the infection, the virus can linger in about 10% of patients for up to 6 months. Such patients are known as hepatitis B carriers or have chronic hepatitis B infection, depending on levels of virus in the blood and liver enzyme levels.
As chronic hepatitis B infection will lead to liver cell damage and cirrhosis, it is essential to follow-up closely with these patients and provide appropriate antiviral treatment to them.
A hepatitis B vaccination programme has been in place in Malaysia since 1989 to prevent hepatitis B infection. It is also essential to vaccinate newborns as 90% of infections in this group will result in chronic infection. If you have a relative with hepatitis B or liver cancer, it is important to get yourself screened to determine your status.
For hepatitis C, major routes of transmission include administration of infected therapeutic blood products and intravenous drug abuse. However, all blood products are now routinely screened for the virus. There is no vaccine for hepatitis C.
Alcohol use or overuse may increase a person's chances of developing liver cancer. Approximately 15% of all alcoholics will develop cirrhosis. In carriers of the hepatitis B or C virus, alcohol consumption also greatly increases the risk of developing cancer. Patients with viral hepatitis are strongly advised to refrain from consuming alcohol.
Signs and Symptoms
Signs and symptoms of liver cancer tend to appear at later stages of the disease. These include abdominal pain on the right side (just under the right ribcage), weight loss, fatigue, easy bruising or bleeding, enlarged abdomen or yellow skin and eyes (jaundice). Physicians may be able to feel a lump in the abdomen upon examination.
In the diagnosis of liver cancer, a range of blood tests complement the observation of physical signs and symptoms. These include liver function tests that measure the level of various enzymes produced by the liver and other parameters such as albumin and bilirubin.
In liver cancer patients, liver enzyme levels as well as the liver-specific tumour marker, alpha-feto protein, is often abnormally high.
CT and MRI scans are also used to detect liver tumours. These scans help pick up on the presence of the vascular (blood-supply) pattern typical to liver cancer.
In cases where a tumour is under 2cm in size, a liver biopsy may be done to enable early confirmatory diagnosis. This involves extracting samples of tumour tissue with a fine-needle syringe under guidance of an ultrasound or CT scan. The samples are then sent to a histopathology laboratory to confirm diagnosis of primary liver cancer.
Small tumours that are detected early can be successfully treated with surgery. This is the treatment of choice for patients with uncomplicated solitary tumours and if the cancer has not spread beyond the liver.
Liver transplant is another optimal therapeutic option for large and complicated lesions as it removes the entire tumour and underlying cirrhosis. However, the availability of donor organs is limited. Moreover, patients commonly present at a stage that is too late even for this option.
These are treatment options that damage or kill the tumour directly. They include :
Percutaneous ethanol injection
Involving the injection of pure alcohol into the tumour to destroy the tumour tissue, this treatment is used when the disease is locally advanced and the patient is not suitable for surgery. This approach is more effective in small tumours that are less than 3cm in diameter.
For patients who have tumours between 2cm and 5cm in diameter and are not suitable for surgery, an effective treatment would be to destroy the tumour tissue through heat from electrodes inserted directly into the tumour.
Trans-arterial chemo-embolisation (TACE)
TACE is a type of chemotherapy that supplies strong anti-cancer drugs directly to the liver. Unlike the traditional systemic infusion of chemotherapy into the blood vessels, TACE has the advantage of confining high concentrations of the drug to the tumour, depriving it of its needed blood supply by blocking arterial supply to the tumour (embolisation), which in turn leads to the damage or death of the tumour cells.
TACE is suitable for patients with inoperable liver cancer where the tumour has not invaded the main blood vessel of the liver or spread beyond the liver.
Until recently, there has been a lack of effective systemic agents that increase the survival of patients with liver cancer. Systemic therapy may be oral or intravenous agents that are aimed at destroying cancer cells. However, these therapies affect the whole body. Conventional chemotherapy regimens have not been found to be particularly effective as response rates are low with no survival advantage.
The increasing knowledge of the molecular processes involved in the progression of the liver tumour over more recent years has led to the development of targeted therapies. Currently, one such agent known as sorafenib has been approved in Malaysia for the treatment of patients with advanced liver cancer. Taken orally, sorafenib acts by preventing the generation of new blood vessels within the tumour, effectively slowing down or stopping tumour growth. It has been proven to extend the survival of selected patients with advanced, inoperable liver cancer.
Liver cancer is a complex disease with many causative factors. However, in Malaysia, hepatitis B is the single most important risk factor in the development of this disease and vaccination as well as surveillance programmes are vital in reducing the incidence of liver cancer.
Whilst there are a few treatment modalities, early detection is the best way to effectively treat and prolong survival. However, even in advanced liver disease, there is still hope with molecular targeted therapies and much research is still being done in this area.
More info on LIVER CANCER here.
2:32 PM Kanser Hati