Liver cancer, also known as hepatic cancer, primary hepatic cancer, or primary hepatic malignancy, is cancer that starts in the liver. Liver cancer can be primary in which the cancer starts in the liver, or it can be liver metastasis, or secondary, in which the cancer spreads from elsewhere in the body to the liver. Liver metastasis is the more common of the two liver cancers.
Primary liver cancer is globally the sixth-most frequent cancer and the fourth-leading cause of death from cancer. In 2018, it occurred in 841,000 people and resulted in 782,000 deaths globally. Higher rates of liver cancer occur where hepatitis B and C are common, including Asia and sub-Saharan Africa. Males are more often affected with hepatocellular carcinoma (HCC) than females. Diagnosis is most frequent among those 55 to 65 years old.
The leading cause of liver cancer is cirrhosis due to hepatitis B, hepatitis C, or alcohol. Other causes include aflatoxin, non-alcoholic fatty liver disease and . The most common types are HCC, which makes up 80% of cases and intrahepatic cholangiocarcinoma. The diagnosis may be supported by blood tests and medical imaging, with confirmation by tissue biopsy.
Given that there are many different causes of liver cancer, there are many approaches to liver cancer prevention. These efforts include immunization against hepatitis B, hepatitis B treatment, hepatitis C treatment, decreasing alcohol use, decreasing exposure to aflatoxin in agriculture, and management of obesity and diabetes. Cancer screening is recommended in those with chronic liver disease. For example, it is recommended that people with chronic liver disease who are at risk for hepatocellular carcinoma be screened every 6 months using ultrasound imaging.
Because liver cancer is an umbrella term for many types of cancer, the signs and symptoms depend on what type of cancer is present. Symptoms can be vague and broad. Cholangiocarcinoma is associated with sweating, jaundice, abdominal pain, weight loss, and hepatomegaly. Hepatocellular carcinoma is associated with abdominal mass, abdominal pain, vomiting, anemia, back pain, jaundice, itching, weight loss and fever.
Treatment options may include surgery, targeted therapy and radiation therapy. In certain cases, ablation therapy, embolization therapy or liver transplantation may be used.
In terms of HCC diagnosis, it is recommended that people with risk factors (including known chronic liver disease, cirrhosis, etc.) should receive screening ultrasounds. If the ultrasound shows a focal area that is larger than 1 centimeter in size, patients should then get a triple-phase contrast-enhanced CT scan or MRI scan. HCC can then be diagnosed radiologically using the Liver Imaging Reporting and Data System (LI-RADS). There is also a variant type of HCC that consists of both HCC and cholangiocarcinoma.
Even with Hepatectomy, prognosis is poor with most individuals not living longer than six months after diagnosis. Only 3% of individuals live longer than two years.
HBV and HCV can lead to HCC, because these viral infections cause massive inflammation, fibrosis, and eventual cirrhosis occurs within the liver. In addition, many mutation and epigenetics changes are formed in liver cells during HCV and HBV infection, which is a major factor in the production of the liver tumors. The viruses induce malignant changes in cells by altering gene methylation, affecting gene expression, and promoting or repressing cellular signal transduction pathways. By doing this, the viruses can prevent cells from undergoing a programmed form of cell death (apoptosis) and promote viral replication and persistence.
HBV and HCV also induce malignant changes by causing DNA damage and genomic instability. This involves the generation of reactive oxygen species, expression of proteins that interfere with DNA repair enzymes, and HCV induced activation of a mutator enzyme.
, chemicals sometimes found in the blood of people with cancer, can be helpful in diagnosing and monitoring the course of liver cancers. High levels of alpha-fetoprotein (AFP) in the blood can be found in many cases of HCC and intrahepatic cholangiocarcinoma. Of note, AFP is most useful for monitoring if liver cancers come back after treatment rather than for initial diagnosis. Cholangiocarcinoma can be detected with these commonly used tumor markers: carbohydrate antigen 19-9 (CA 19–9), carcinoembryonic antigen (CEA) and cancer antigen 125 (CA125). These tumor markers are found in primary liver cancers, as well as in other cancers and certain other disorders.
Secondary prevention includes both cure of the agent involved in the formation of cancer (carcinogenesis) and the prevention of carcinogenesis if this is not possible. Cure of virus-infected individuals is not possible, but treatment with antiviral drugs can decrease the risk of liver cancer. Chlorophyllin may have potential in reducing the effects of aflatoxin.
Tertiary prevention includes treatments to prevent the recurrence of liver cancer. These include the use of surgical interventions, chemotherapy drugs, and antiviral drugs.
Treatments include surgery, medications, and ablation methods. There are many chemotherapeutic drugs approved for liver cancer including: atezolizumab, nivolumab, pembrolizumab, regorafenib. Increasingly, immunotherapy agents (also called targeted cancer therapies or precision medicine) are being used to treat hepatobiliary cancers.
Recent advances in liver cancer treatment are exploring T cells engineered with chimeric antigen receptors (CARs) targeting glypican-3 (GPC3), such as GAP T cells, showing potential in addressing GPC3-positive tumors, especially in pediatric liver cancers.
Percutaneous ablation is the only non-surgical treatment that can offer cure. There are many forms of percutaneous ablation, which consist of either injecting chemicals into the liver (ethanol or acetic acid) or producing extremes of temperature using radio frequency ablation, microwaves, laser ablation or cryotherapy. Of these, radio frequency ablation has one of the best reputations in HCC, but the limitations include inability to treat tumors close to other organs and blood vessels due to heat generation and the heat sink effect, respectively. In addition, long-term of outcomes of percutaneous ablation procedures for HCC have not been well studied. In general, surgery is the preferred treatment modality when possible.
Systemic chemotherapy are not routinely used in HCC, although local chemotherapy may be used in a procedure known as transarterial chemoembolization (TACE). In this procedure, drugs that kill cancer cells and interrupt the blood supply are applied to the tumor. Because most systemic drugs have no efficacy in the treatment of HCC, research into the molecular pathways involved in the production of liver cancer produced sorafenib, a targeted therapy drug that prevents cell proliferation and angiogenesis. Sorafenib obtained FDA approval for the treatment of advanced hepatocellular carcinoma in November 2007. This drug provides a survival benefit for advanced HCC.
Transarterial radioembolization (TRACE) is another option for HCC. In this procedure, radiation treatment is targeted at the tumor. TRACE is still considered an add on treatment rather than the first choice for treatment of HCC, as dual treatments of radiotherapy plus chemoembolization, local chemotherapy, systemic chemotherapy or targeted therapy drugs may show benefit over radiotherapy alone.
Ablation methods (e.g. radiofrequency ablation or microwave ablation) are also an option for HCC treatment. This method is recommended for small, localized liver tumors as it is recommended that the area treated with radiofrequency ablation should be 2 centimeters or less.
60% of cholangiocarcinomas form in the perihilar region and photodynamic therapy can be used to improve quality of life and survival time in these un-resectable cases. Photodynamic therapy is a novel treatment that uses light activated molecules to treat the tumor. The compounds are activated in the tumor region by laser light, which causes the release of toxic reactive oxygen species, killing tumor cells.
Systemic chemotherapies such as gemcitabine and cisplatin are sometimes used in inoperable cases of cholangiocarcinoma.
Radio frequency ablation, transarterial chemoembolization and internal radiotherapy (brachytherapy) all show promise in the treatment of cholangiocarcinoma and can sometimes improve Biliary, which can decrease the symptoms a patient experiences.
Radiotherapy may be used in the adjuvant setting or for palliative treatment of cholangiocarcinoma.
Chemotherapy, including cisplatin, vincristine, cyclophosphamide, and doxorubicin are used for the systemic treatment of hepatoblastoma. Out of these drugs, cisplatin seems to be the most effective.
Given that HCC is the most-common type of liver cancer, the areas around the world with the most new cases of HCC each year are Northern and Western Africa as well as Eastern and South-Eastern Asia. China has 50% of HCC cases globally, and more than 80% of total cases occur in sub-Saharan Africa or in East-Asia due to hepatitis B virus. In these high disease burden areas, evidence indicates the majority of the HBC and HCV infections occur via perinatal transmission (also called mother-to-child transmission). However, it is important to note that the risk factors for HCC varies by geographic region. For example, in China, Hepatitis B and aflatoxin are the largest risk factors; whereas, in Mongolia, it is a combination of Hepatitis and high levels of alcohol use that are driving the high levels of HCC.
In terms of intrahepatic cholangiocarcinoma, we currently do not have sufficient epidemiological data because it is a rare cancer. According to the United States National Cancer Institute, the incidence of cholangiocarcinoma is not known. Cholangiocarcinoma also has a significant geographical distribution, with Thailand showing the highest rates worldwide due to the presence of liver fluke.
In the United States, there were 42,810 new cases of liver and intrahepatic bile duct cancer in 2020, which represents 2.4% of all new cancer cases in the United States. There are about 89.950 people who have liver and intrahepatic liver cancer in the United States. In terms of mortality, the 5-year survival rate for liver and intrahepatic bile duct cancers in the United States is 19.6%. In the United States, there is an estimated 1% chance of getting liver cancer across the lifespan, which makes this cancer relatively rare. Despite the low number of cases, it is one of the top causes of cancer deaths.
Classification
Hepatocellular carcinoma
Intrahepatic cholangiocarcinoma
Angiosarcoma and hemangiosarcoma
Hepatoblastoma
Metastasis to liver
Children
Causes
Viral infection
Cirrhosis
Aflatoxin
Nonalcoholic steatohepatitis (NASH) and Nonalcoholic fatty liver (NAFL)
Other risk factors in adults
Children
Diagnosis
Prevention
Treatment
General considerations
Hepatocellular carcinoma
Intrahepatic cholangiocarcinoma
Hepatoblastoma
Angiosarcoma and hemangiosarcoma
Epidemiology
External links
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