Hepatocellular Carcinoma ( HCC )

hepatocellular carcinoma - HCC

What is liver cancer (hepatocellular carcinoma - HCC)?

Liver cancer (hepatocellular carcinoma) is a Cancer arising from the liver. It is also known as primary liver cancer or hepatoma. The liver is made up of different cell types (for example, bile ducts, blood vessels, and fat-storing cells). However, liver cells (hepatocytes) make up 80% of the liver tissue. Thus, the majority of primary liver cancers (over 90 to 95%) arises from liver cells and is called hepatocellular cancer or carcinoma.
When patients or physicians speak of liver cancer, however, they are often referring to cancer that has spread to the liver, having originated in other organs (such as the colon, stomach, pancreas, breast, and lung). More specifically, this type of liver cancer is called metastatic liver disease (cancer) or secondary liver cancer. Thus, the term liver cancer actually can refer to either metastatic liver cancer or hepatocellular cancer. The subject of this article is hepatocellular carcinoma, which I will refer to as liver cancer.

What is the problem of the liver cancer?

Liver cancer is the fifth most common cancer in the world. A deadly cancer, liver cancer will kill almost all patients who have it within a year. In 1990, the World Health Organization estimated that there were about 430,000 new cases of liver cancer worldwide, and a similar number of patients died as a result of this disease. About three quarters of the cases of liver cancer are found in Southeast Asia (China, Hong Kong, Taiwan, Korea, and Japan). Liver cancer is also very common in sub-Saharan Africa (Mozambique and South Africa).
The frequency of liver cancer in Southeast Asia and sub-Saharan Africa is greater than 20 cases per 100,000 population. In contrast, the frequency of liver cancer in North America and Western Europe is much lower, less than five per 100,000 population. However, the frequency of liver cancer among native Alaskans is comparable to that seen in Southeast Asia. Moreover, recent data show that the frequency of liver cancer in the U.S. overall is rising. This increase is due primarily to chronic Hepatits C , an infection of the liver that causes liver cancer.

What are the population characteristics (epidemiology) of liver cancer?

In the U.S. the highest frequency of liver cancer occurs in immigrants from Asian countries, where liver cancer is common. The frequency of liver cancer among Caucasians is the lowest, whereas among African-Americans and Hispanics, it is intermediate. The frequency of liver cancer is high among Asians because liver cancer is closely linked to hepatitis B chronic infection. This is especially so in individuals who have been infected with chronic hepatitis B for most of their lives. If you take a world map depicting the frequency of chronic hepatitis B infection, you can easily superimpose that map on a map showing the frequency of liver cancer.
The initial presentation (symptoms) of liver cancer in patients in areas of high liver cancer frequency is quite different from that seen in low frequency areas. Patients from high frequency areas usually start developing liver cancer in their 40s, and the cancer is usually more aggressive. That is, the liver cancer presents with severe symptoms and is inoperable (too advanced for surgery) at the time of diagnosis. Also, in these areas, the frequency of liver cancer is three to four times higher in men than in women, and most of these patients are infected with chronic hepatitis B. In contrast, liver cancer in lower risk areas occurs in patients in their 50s and 60s and the predominance of men is less striking.




What is the natural history of liver cancer?

The natural history of liver cancer depends on the stage of the tumor and the severity of associated liver disease (for example, cirrhosis) at the time of diagnosis. For example, a patient with a 1 cm tumor with no cirrhosis has a greater than 50% chance of surviving three years, even without treatment. In contrast, a patient with multiple tumors involving both lobes of the liver (multicentric tumors) with decompensated cirrhosis (signs of liver failure) is unlikely to survive more than six months, even with treatment.
What are the predictors of a poor outcome? Our knowledge of the prognosis is based on studying many patients with liver cancer, separating out their clinical characteristics, and relating them to the outcome. Grouped in various categories, the unfavorable clinical findings include;
• Population characteristics (demographics); male gender, older age, or alcohol consumption.
• Symptoms; weight loss or decreased appetite.
• Signs of impaired liver function; jaundice, ascites, or encephalopathy (altered mental state).
• Blood tests; elevated liver tests (bilirubin or transaminase), reduced albumin, elevated AFP, elevated blood urea nitrogen (BUN), or low serum sodium.
• Staging of tumor (based on imaging or surgical findings); more than one tumor, tumor over 3 cm (almost 1¼ inches), tumor invasion of local blood vessels (portal and/or hepatic vein), tumor spread outside of the liver (to lymph nodes or other organs).
There are various systems for staging liver cancer. Some systems look at clinical findings while others rely solely on pathological (tumor) characteristics. It makes the most sense to use a system that incorporates a combination of clinical and pathological elements. In any event, it is important to stage the cancer because staging can provide guidelines not only for predicting outcome (prognosis) but also for decisions regarding treatment.
The doubling time for a cancer is the time it takes for the tumor to double in size. For liver cancer, the doubling time is quite variable, ranging from one month to eighteen months. This kind of variability tells us that every patient with liver cancer is unique. Therefore, an assessment of the natural history and the evaluation of different treatments are very difficult. Nevertheless, in patients with a solitary liver cancer that is less than 3 cm, with no treatment, we can expect that 90% of the patients will survive (live) for one year, 50% for three years, and 20% for five years. In patients with more advanced disease, we can expect that 30% will survive for one year, 8% for three years, and none for five years.


What is fibrolamellar carcinoma?

Fibrolamellar carcinoma is an liver cancer variant that is found in non-cirrhotic livers, usually in younger patients between the ages of 20 and 40 years. In fact, these patients have no associated liver disease and no risk factors have been identified. The alpha-fetoprotein in these patients is usually normal. The appearance of fibrolamellar carcinoma under the microscope is quite characteristic. That is, broad bands of scar tissue are seen running through the cancerous liver cells. The important thing about fibrolamellar carcinoma is that it has a much better prognosis than the common type of liver cancer. Thus, even with a fairly extensive fibrolamellar carcinoma, a patient can have a successful surgical removal.

What's in the future for the prevention and treatment of liver cancer?

Prevention

Worldwide, the majority of liver cancer is associated with chronic hepatitis B virus infection. Today, however, all newborns are vaccinated against hepatitis B in China and other Asian countries. Therefore, the frequency of chronic hepatitis B virus in future generations will decrease. Eventually, perhaps in three or four generations, hepatitis B virus will be totally eradicated, thereby eliminating the most common risk factor for liver cancer.

Some retrospective (looking back in time) studies suggest that patients with chronic hepatitis C who were treated with interferon were less likely to develop liver cancer than patients who were not treated. Interestingly, in these studies, interferon treatment seemed to provide this benefit, even to patients who had less than an optimal antiviral response to interferon. Still, it remains to be seen whether the risk of developing cirrhosis and liver cancer is significantly decreased in prospectively (looking ahead) followed patients who responded to interferon.

One Japanese study has reported that a retinoid derivative (a compound related to vitamin A) was effective in preventing recurrence of liver cancer after resection of the liver. As of now, this compound is not available in the U.S. It would be of great interest to study the use of this compound in conjunction with other palliative therapy for liver cancer.

Treatment

Unfortunately, there have been no significant new developments in the treatment of liver cancer. Medical therapy remains a disappointment. Scientists are working hard, however, to address this problem. For example, anti-angiogenesis compounds, which inhibit blood vessel formation, may hold promise in the treatment of liver cancer since this tumor depends on a rich blood supply. Also, different ways to deliver drugs or treatment to the tumors are being investigated. This includes attaching radioactive material to antibodies that are directed at specific targets in liver cancer cells (immunotherapy).

Problem of the Liver Cancer

What is the problem of the Liver Cancer?

Liver cancer is the fifth most common cancer in the world. A deadly cancer, liver cancer will kill almost all patients who have it within a year. In 1990, the World Health Organization estimated that there were about 430,000 new cases of liver cancer worldwide, and a similar number of patients died as a result of this disease. About three quarters of the cases of liver cancer are found in Southeast Asia (China, Hong Kong, Taiwan, Korea, and Japan). Liver cancer is also very common in sub-Saharan Africa (Mozambique and South Africa).
The frequency of liver cancer in Southeast Asia and sub-Saharan Africa is greater than 20 cases per 100,000 population. In contrast, the frequency of liver cancer in North America and Western Europe is much lower, less than five per 100,000 population. However, the frequency of liver cancer among native Alaskans is comparable to that seen in Southeast Asia. Moreover, recent data show that the frequency of liver cancer in the U.S. overall is rising. This increase is due primarily to chronic Hepatits C , an infection of the liver that causes liver cancer.