There are two types of cancers that affect the liver, primary cancer and metastasized cancer (i.e. cancers originating in an organ other than the liver). There are several causes of liver cancer such as chronic hepatitis B and C infection, cirrhosis, diabetes, exposure to toxins and certain medications, alcoholism and smoking. Liver cancer generally affects the older population with a median age of onset of 60 years. It is the third most common cancer worldwide and approximately 564,000 new cases of liver cancer are diagnosed each year. What is most alarming are approximately all patients with liver cancer will succumb to the disease, thus the liver cancer prognosis is relatively poor compared to other cancers.
Why is liver cancer associated with a poor prognosis?
Liver cancer can go undetected for quite a long time before it is diagnosed. In fact, there are no specific symptoms of liver cancer and are often quite unnoticeable or mistaken for other liver diseases, such as infection or cirrhosis. Therefore, many patients are generally only diagnosed in later and more aggressive cancer stages. This contributes to the poor liver cancer prognosis that the majority of patients face. It is important to note that the survival rate of liver cancer patients is skewed due to the lack of early diagnostics. Since survival is directly associated with the liver cancer stage and severity of liver disease, 50 percent of patients with a small localized tumor without liver disease survive for at least 3 years, even without treatment, where as patients with multiple liver lobe involvement and signs of liver disease and/or failure barely survive more than 6 months.
What can predict poor outcome in liver cancer patients?
Prognosis depends on the stage of the cancer and the extent of liver disease. Certain factors can influence liver cancer prognosis. First off, studies have shown that certain patient populations are at an elevated risk of developing liver cancer, as well as a poor prognosis. These populations include: patients of male gender, older age and/or alcoholics. Other medical factors can contribute to a poor prognosis. These include:
Hepatitis B infection
Hepatitis B is a viral infection of the liver that causes symptoms such as jaundice, dark urine, fatigue, nausea, vomiting and abdominal pain. While patients generally take months to recover from this condition without any serious complications, chronic infection is associated with the development of liver disease and liver cancer. In fact, 25% of patients chronically infected by hepatitis B die of either liver cancer or cirrhosis. Moreover, approximately 75% of hepatic cell carcinomas are linked to chronic hepatitis B infections. These cancers are almost always fatal, thus hepatitis B is associated with a poor prognosis for liver cancer patients.
Hepatitis C infection
Hepatitis C is a viral infection that affects the liver leading to liver inflammation. Studies have demonstrated that patients with hepatitis C are at an elevated risk of liver cancer. In fact, hepatitis C patients are 10 times more likely to develop liver cancer compared to the normal population. Moreover, both hepatitis B and C are considered the leading cause of liver cancer worldwide. In addition, approximately 5 percent of hepatitis C patients will die from liver cancer. Thus, hepatitis C is associated with an elevated risk of developing fatal liver cancer.
Cirrhosis is associated with the development of up to 80% of hepatocellular carcinoma cases. Moreover, 5 percent of cirrhosis patients develop advanced, multi-focal liver cancer. Thus, cirrhosis has been linked to the development of aggressive liver cancer. Moreover, the rate of successful surgical removal of liver tumors is linked to the extent of liver cirrhosis. Furthermore, patients with abundant cirrhosis of the liver can often be non-viable for liver resection.
Studies have demonstrated that liver cancer is associated with elevated levels of alpha-fetoprotein, a protein produced by the yolk sac and liver of a fetus. In adults, it is only elevated in cases of hepatocellular carcinoma, germ cell tumors and liver metastatic disease. In fact, approximately 70% of liver cancer patients have elevated alpha-fetoprotein levels. It is important to note that elevated alpha-fetoprotein levels have been associated with a poor liver cancer prognosis. Studies have shown that patients with elevated alpha-fetoprotein levels have a significantly shorter median survival compared to alpha-fetoprotein negative patients.
Blumberg BS et al. The relation of infection with Hepatitis B agent to primary hepatic carcinoma. American Journal of Pathology 81(3): 669-682, 1975.
Tsukuma H et al. Risk factors for hepatocellular carcinoma among patients with chronic liver disease. New England Journal of Medicine 328(25): 1797-1801, 1993.
Izumi R et al. Alpha-fetoprotein production by hepatocellular carcinoma is prognostic of poor patient survival. Journal of Surgical Oncology 49(3): 151-155, 1992.
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