Table of Contents
Liver cancer definition
Liver Cancer – malignant growths in the LIVER – may be primary (originates in the liver) or secondary (metastasizes, or spreads, from other locations in the body). Primary liver cancer is less common than metastatic liver cancer. Most primary liver cancer develops as a complication of chronic HEPATITIS B or hepatitis C INFECTION, conditions that repeatedly damage liver tissue, and arises from the liver’s workhorse cells, the hepatocytes.
Hepatocytes continually regenerate; researchers believe the continued replication of the hepatitis VIRUS eventually creates changes in the processes of regeneration (cellular DNA alterations) that cause hepatocyte growth to become uncontrolled. Primary liver cancer is rare in people who have otherwise healthy livers. Because of its rich BLOOD supply and numerous functions related to blood filtration, the liver is a common site for metastatic cancers.
Symptoms of Liver Cancer and Diagnostic Path
Liver cancer typically does not present symptoms until the cancer is quite advanced, and even then symptoms often are vague. Such symptoms might include upper ABDOMINAL PAIN, ASCITES (fluid accumulation in the abdominal cavity), NAUSEA, lack of appetite, and JAUNDICE. The diagnostic path typically includes blood tests to assess liver function and hepatitis status, abdominal ULTRASOUND or COMPUTED TOMOGRAPHY (CT) SCAN, and PERCUTANEOUS LIVER BIOPSY.
Some doctors advocate regular testing to measure blood levels of ALPHA FETOPROTEIN (AFP), a protein that many liver tumors produce, in people who are at high risk for developing liver cancer (such as those who have chronic hepatitis or severe CIRRHOSIS). However, there is no consensus within the medical community as to the effectiveness of AFP screening for those not at high risk because numerous factors cause erroneous test results.
Treatment Options and Outlook
Treatment for liver cancer depends on whether the cancer is primary or secondary. Treatment for secondary liver cancer is generally palliative, aiming to relieve symptoms such as pain. For primary liver cancer, surgical removal of the tumor is the preferred option. However, people who have longstanding cirrhosis may have too much damage for the liver to remain functional after surgery. Large or multiple tumors also are difficult to remove without causing substantial damage to the remaining liver tissue. The surgeon may use RADIOFREQUENCY ABLATION or chemical ablation to kill tumor cells without removing the tumor; this is primarily a palliative treatment. LIVER TRANSPLANTATION is occasionally an option when the liver cancer is primary, small, and well contained.
Conventional external-beam RADIATION THERAPY often is not very successful in altering the course of liver cancer to increase survival, though it can shrink liver tumors to relieve pain and other symptoms. A precise technique for targeting liver tumors with radiation, three-dimensional conformal radiation therapy (3DCRT), shows promise for improving the therapeutic value of radiation therapy in liver cancer. Similarly, conventional CHEMOTHERAPY is not very effective against this cancer, though in some people directly infusing chemotherapy agents into the hepatic ARTERY, called hepatic artery infusion (HAI) chemotherapy, has therapeutic benefit.
Because liver cancer tends to be either well advanced or metastatic at the time of its diagnosis, the overall outlook remains among the least positive despite the numerous advances in cancer treatments overall. The five-year survival rate, the standard measure for cancer treatment success, is about 30 percent when surgery can remove the tumor and about 5 percent when surgery is not a viable treatment option. Prevention efforts offer the greatest opportunity for defeating liver cancer.
What causes liver cancer – risk factors
The most significant risk factor for this cancer is infection with chronic hepatitis B or hepatitis C. Other circumstances that increase risk include cirrhosis, LIVER DISEASE OF ALCOHOLISM, exposure to hepatotoxic chemicals (especially arsenic, which remains a contaminant in water supplies throughout the United States as a result of past industrial waste practices, and the industrial chemical vinyl chloride), and smoking in combination with alcohol abuse.
|RISK FACTORS FOR LIVER CANCER|
|anabolic steroid use||arsenic exposure (chronic)|
|hepatitis B infection (chronic)||HEPATITIS C INFECTION (chronic)|
|LIVER DISEASE OF ALCOHOLISM||smoking and alcohol abuse in combination|
|vinyl chloride exposure||WILSON’S DISEASE|
Risk Factors and Preventive Measure
The single most important preventive measure for liver cancer is hepatitis vaccination to prevent hepatitis B infection and appropriate measures to limit exposure to hepatitis C. People who already have chronic hepatitis, cirrhosis, or other conditions that increase the risk for liver cancer, the herb MILK THISTLE (silymarin) may help protect the liver from further damage. Other preventive measures include avoiding circumstances associated with liver cancer, notably excessive alcohol consumption. Though the number of people who develop primary liver cancer is rising, it remains less common than metastatic (secondary) liver cancer.
See also CANCER PREVENTION; CANCER TREATMENT OPTIONS AND DECISIONS; CELL STRUCTURE AND FUNCTION; ENVIRONMENTAL HAZARD EXPOSURE; HEAVY-METAL POISONING; HEPATITIS PREVENTION; METASTASIS; OCCUPATIONAL HEALTH AND SAFETY; SURGERY BENEFIT AND RISK ASSESSMENT.