Liver cancer originates from abnormal cell growth within the liver. It is classified as either primary, starting in the liver itself, or secondary (metastatic), when cancer from another part of the body spreads to the liver. This article will focus on primary liver cancer.
The most common type is hepatocellular carcinoma (HCC), which develops from the main liver cells called hepatocytes. Rarer types include cholangiocarcinoma, starting in the bile ducts, and hepatoblastoma, which primarily affects young children. Primary liver cancer is a significant health concern and one of the leading causes of cancer-related deaths worldwide.
Causes and Risk Factors
The development of primary liver cancer is linked to chronic liver disease and damage. A major cause is long-term infection with the Hepatitis B (HBV) or Hepatitis C (HCV) virus. These viruses cause chronic inflammation and cellular injury over many years, significantly increasing the risk of cancerous changes and accounting for most cases globally.
Cirrhosis, a condition where scar tissue replaces healthy liver tissue, is another predominant risk factor. It impedes the liver’s function and can be caused by chronic hepatitis or long-term, excessive alcohol consumption. Heavy alcohol use is a direct contributor to cirrhosis and also elevates liver cancer risk on its own.
Nonalcoholic fatty liver disease (NAFLD) is a growing concern. This condition involves excess fat accumulation in the liver and can progress to nonalcoholic steatohepatitis (NASH), causing inflammation and cell damage. NASH can lead to cirrhosis and is an independent risk factor for liver cancer.
Less common risk factors include exposure to aflatoxins and certain inherited metabolic diseases. Aflatoxins are poisons from a fungus that can contaminate foods like corn and nuts. Inherited conditions such as hemochromatosis, which causes excess iron storage in the body, can also damage the liver and increase cancer risk.
Symptoms and Early Detection
Primary liver cancer often produces no noticeable symptoms in its initial stages. When signs do appear, they are often a result of the tumor growing or underlying liver disease worsening. A common initial symptom is pain or a feeling of fullness in the upper right abdomen below the ribs.
As the cancer progresses, a person might experience unexplained weight loss, a lack of appetite, or feeling very full after a small meal. General fatigue, weakness, and nausea are also common. A sign of declining liver function is jaundice, a yellowing of the skin and eyes caused by a buildup of bilirubin.
Other symptoms can include abdominal swelling from fluid buildup (ascites), itchy skin, and a hard lump under the right rib cage. Some liver tumors produce hormones that lead to high blood calcium levels, causing confusion, or low blood sugar levels, resulting in fatigue.
Regular screening is important for individuals in high-risk groups, as early-stage cancer is often asymptomatic. People with risk factors like cirrhosis or chronic hepatitis may undergo periodic surveillance. These screenings can help detect cancer at an earlier, more treatable stage.
The Diagnostic and Staging Process
Confirming a diagnosis involves tests to evaluate the liver’s health and structure. The process begins with blood tests, including liver function tests (LFTs) to measure proteins and enzymes that indicate how well the liver is working. Another blood test measures levels of alpha-fetoprotein (AFP), a protein that can be elevated in people with liver cancer.
Imaging studies provide detailed pictures of the liver. An ultrasound is often the first test used, followed by more detailed computed tomography (CT) or magnetic resonance imaging (MRI) scans. These scans reveal the size, number, and location of tumors and help determine if the cancer has invaded nearby blood vessels.
A liver biopsy, where a small tissue sample is removed from the tumor with a needle for examination, may be necessary for a definitive diagnosis. A biopsy is not always required, especially if findings from blood tests and imaging scans are conclusive.
Once confirmed, the cancer is staged to determine its extent and guide treatment. The Barcelona Clinic Liver Cancer (BCLC) system is most common. It considers the tumor’s size and number, cancer spread, the patient’s liver function, and their general health. The BCLC system classifies the cancer into stages from very early (Stage 0) to end-stage (Stage D), linking each stage to appropriate treatments.
Liver Cancer Treatment Approaches
Treatments are categorized based on their goal, whether it is to remove the cancer, control its growth locally, or manage it when it has spread.
Treatments with Curative Intent
For early-stage, confined liver cancer, surgical removal offers the best chance for a cure. A partial hepatectomy is a procedure where the portion of the liver with the tumor is removed. The liver’s ability to regenerate allows the remaining portion to regrow and resume its functions.
A liver transplant is another curative option. This involves removing the entire diseased liver and replacing it with a healthy donor liver. Transplantation is considered for patients with small tumors who are not candidates for a partial hepatectomy, often due to poor liver function from cirrhosis. Strict criteria must be met to ensure the cancer has not spread beyond the liver.
Localized Treatments
When surgery is not an option, therapies can target and destroy tumors directly within the liver. Ablation uses extreme temperatures to kill cancer cells. Radiofrequency ablation (RFA) uses high-energy radio waves to heat the tumor, while cryoablation freezes it. These imaging-guided procedures are most effective for smaller tumors.
Embolization therapies work by cutting off the blood supply to the tumor, which is primarily derived from the hepatic artery. In transarterial chemoembolization (TACE), chemotherapy drugs are delivered to the tumor through the artery, which is then blocked to trap the drugs. A similar technique, radioembolization, delivers tiny radioactive beads to the tumor.
Systemic Therapies
For advanced liver cancer that has spread, systemic therapies that travel through the bloodstream are used. Targeted therapy uses drugs designed to attack specific molecules involved in cancer cell growth and survival. These medications can help slow the progression of advanced liver cancer.
Immunotherapy is a systemic treatment that helps the body’s immune system attack cancer cells. Some cancer cells have proteins that allow them to hide from the immune system. Immunotherapy drugs block these proteins, allowing immune cells to find and destroy the cancer. These therapies are a standard approach for treating advanced liver cancer.
Prognosis and Survival Rates
Survival rates are statistical estimates of the percentage of people with the same cancer type and stage who are alive after a set period, usually five years. These rates are based on population data and cannot predict an individual’s outcome. The 5-year relative survival rates are often categorized by how far the cancer has spread.
For liver cancer that is localized (has not spread outside the liver), the 5-year relative survival rate is highest. The rate decreases if the cancer has spread to nearby tissues or lymph nodes (regional). The lowest survival rate is for distant cancer, where it has metastasized to faraway parts of the body.
These statistics are averages, and individual outcomes can vary. Patients with early-stage cancer eligible for curative treatments like surgery or a liver transplant often have much better outcomes. Continuous advancements in detection and treatment are leading to improved survival for patients with liver cancer.