Liver cancer

Liver cancer is the uncontrolled growth of malignant liver cells.

The liver is an organ located in the upper right region of the abdomen below the diaphragm and above the stomach.

Liver cancer can be classified into:

• Primary: Malignant tumor that starts in the liver
  • Hepatocellular carcinoma (about 80-90% of primary liver cancers): This is the most common liver cancer in adults.
  • Intrahepatic cholangiocarcinoma or bile duct cancer (about 10% of primary liver cancers): It starts in the bile ducts inside the liver.
  • Hepatic sarcomas (about 0.5 to 2% of primary liver tumors): It is extremely rare. It begins in cells lining the blood vessels of the liver.
  • Hepatoblastoma: This type of liver cancer is common in children under 4 years old. Hepatoblastoma is very rare and tumor cells are similar to fetal liver cells.
• Secondary or metastatic: The tumors start in another organ and spread (metastasize) to the liver.

Without any doubt, hepatocellular carcinoma is the most common type of liver cancer. When the term “liver cancer” is used alone, it usually refers to hepatocellular carcinoma. This type of liver cancer results from a malignant transformation of hepatocytes (the cells that constitute the liver).

Clinically, hepatocellular carcinoma usually is presented as multiple nodules throughout the liver, but sometimes it may be only a single mass. As it grows, the nodules can infiltrate, compress, or metastasize other tissues through the bloodstream.

Hepatocellular carcinoma, the most frequent type of liver cancer, is more common in people over 50 years old and has a higher prevalence in men than in women. The incidence of liver cancer is 5-15 cases per 100,000 people.

Globally, the incidence rate is highest in Southeast Asia and Sub-Saharan Africa.

Liver cancer is the sixth most common type of cancer and the third leading cause of death due to cancer.

The exact cause of the malignant transformation of hepatocytes is still unknown. However, the following risk factors may predispose to suffer liver cancer:

• Previous cirrhosis (chronic and irreversible liver disease)
• Chronic infection with the hepatitis B and C viruses
• Hemochromatosis (excessive iron accumulation in the body)
• Aflatoxin B1, a natural carcinogen produced by a type of fungus called Aspergillus sp.
• Vinyl chloride
• HIV coinfection
• Obesity, diabetes mellitus and metabolic syndrome

Thanks to the ultrasound screening of high-risk populations, liver cancer can be diagnosed in early stages when it has not yet produced any symptom.

However, when symptoms are present is because the tumor is already advanced. The most common symptoms are:

• Abdominal pain
• Mass in the right upper quadrant (right abdominal region)
• Yellowing of the skin (jaundice)

Another less frequent symptom is the accumulation bloody fluid in the abdomen (bloody ascites).

In advanced liver cancer, curative treatments are not very promising.

The first step to detect a hepatocellular carcinoma is to perform an abdominal ultrasound. This technique may also serve as a screening tool.

In case of finding a mass in the liver bigger than 1 cm, an imaging scan (CT-Computerized Tomography or MRI-Magnetic Resonance) should be performed.

To confirm the diagnosis, a biopsy of the mass must be analyzed under a microscope to determine the presence of malignant cells.

During the initial stages, several therapeutic strategies are used with curative purposes, such as:

• Surgical resection (treatment of choice)
• Ablation (removal) of the mass by radiofrequency
• Liver transplant surgery using a living or cadaver donor

With advanced liver cancer, palliative care is recommended to improve the symptoms and quality of life:

• Chemoembolization of the tumor, trying to reduce the blood supply to the tumor and reduce the volume.
• Immunotherapy
• Chemotherapy
• Pain control, diet, psychological treatment

When the tumor is detected in early stages and curative treatment is possible, the 5-year survival rate is 70%.

However, in advanced stages, the survival rate is very low. The treatment in these cases only helps to improve the quality of life of the patient.