Liver metastases is a secondary liver tumor that has arisen as a result of the spread of malignant cells from the primary focus located in another organ. It is accompanied by nonspecific symptoms of cancer (hyperthermia, weight loss and appetite), an increase in the liver and its soreness during palpation. In the later stages, the liver becomes lumpy, ascites, progressive jaundice and hepatic encephalopathy occur. The diagnosis is made taking into account anamnesis, clinical symptoms, results of laboratory and instrumental studies. Treatment – chemotherapy, embolization, radiofrequency ablation, surgery.
ICD 10
C79.8 Secondary malignant neoplasm of other specified localizations
General information
Liver metastases is the most common metastatic lesion in oncological diseases. It is observed in about 1/3 of patients with malignant tumors of various localization. It is detected in every second patient suffering from stomach cancer, colon cancer, lung cancer and breast cancer. In the initial stages, it is asymptomatic, which makes timely diagnosis difficult, especially with the simultaneous latent course of the primary tumor.
Until recently, liver metastases was considered inoperable regardless of the type, size, localization and number of secondary foci, but nowadays this point of view is gradually being revised. Treatment is carried out by specialists in the field of oncology, gastroenterology and abdominal surgery.
Causes
Liver metastases is especially common in visceral neoplasms, since blood from the abdominal organs enters the liver through the portal vein system. It is a common complication of stomach cancer, pancreatic cancer, gallbladder cancer and rectal cancer. At the same time, malignant cells can enter the liver and from organs that are not drained by the portal vein system. Liver metastases often occurs with lung cancer, melanoma and breast cancer, and is often diagnosed with ovarian cancer, prostate cancer and kidney tumors.
Malignant neoplasms that rarely metastasize to the liver include bladder cancer, pharyngeal cancer, oral cancer and skin cancer. In some cases, metastatic liver cancer can be difficult to distinguish from the primary tumor of the organ. It is possible to suspect a secondary lesion in such cases by the early appearance of ascites caused by the contamination of the abdominal cavity with malignant cells. Patients with secondary neoplasm in the liver often die from cancerous peritonitis, not having time to live to a significant increase in the organ.
Pathanatomy
In metastatic liver cancer, nodular forms predominate. Foci can be either single or multiple, localized in the center of the liver or on its surface. The diameter of metastases ranges from a few millimeters to several centimeters. With multiple foci of liver metastases, the so–called “chestnut” liver can be detected – an organ covered with numerous neoplasms resembling hazelnuts. Sometimes secondary tumors develop mainly in the center of the organ, are not detected by palpation and become visible only on the incision.
The histological structure of liver metastases usually corresponds to the structure of the primary focus. Most metastases are whitish nodes of rounded or irregular shape. In primary ovarian cancer, multiple light foci of soft consistency with clear contours are usually detected in the liver. In clear cell kidney cancer, the consistency of the nodes of liver metastases practically does not differ from the consistency of normal organ tissue. The nodes are light brown, the contours are clear. In primary endocrine neoplasms, the color of metastases ranges from whitish or yellowish to dark brown. The consistency is slightly denser than liver tissue. As in other cases, metastases have clear contours.
Less often, there is a discrepancy between the pathoanatomical characteristics of the primary tumor and liver metastases, due to differences in the degree of differentiation of malignant cells. Sometimes histological differentiation of primary and metastatic foci is a difficult task due to the similarity of the structure of the primary process in the liver and tumors of extrahepatic localization. A similar problem may arise, for example, when distinguishing between adenocarcinoma metastases of the digestive tract and cholangiocellular liver cancer having a similar structure.
Symptoms
In the early stages, liver metastases is asymptomatic. Patients may show common signs of cancer: weakness, fatigue, fever, decreased appetite and weight loss. Palpation determines a slight increase in the liver. The liver is dense, sometimes painful. In some cases, noise is detected during auscultation. Possible enlargement of the spleen.
Jaundice is usually absent or mild, with the exception of liver metastases located near the biliary tract. An increase in the level of lactate dehydrogenase and alkaline phosphatase is detected. Early ascites often occurs due to simultaneous peritoneal insemination. In the late stages of metastatic liver cancer, there is a pronounced enlargement of the organ, increasing jaundice and hepatic encephalopathy. Many patients do not have time to live up to these symptoms. The cause of death is cancerous peritonitis caused by multiple metastases in the abdominal cavity.
Diagnostics
The diagnosis is established on the basis of anamnesis (the presence of cancer), complaints, objective examination data, results of instrumental and laboratory studies. Patients with suspected metastatic liver cancer are referred for ultrasound and CT. In most cases, these techniques are quite effective, however, with small metastases and liver changes caused by benign tumors and chronic diseases of a non-tumor nature, diagnostic difficulties are possible.
To assess hepatic functions, a biochemical blood test is prescribed. In doubtful cases, liver metastases is confirmed on the basis of liver biopsy results. To improve the accuracy of diagnosis, a biopsy can be performed under the control of ultrasound or during laparoscopy.
In addition, a patient with liver metastases is referred for abdominal ultrasound, chest X-ray, CT of the brain and other studies to identify secondary neoplasms in other organs. If liver metastases are detected during the initial treatment, and the main oncological disease is asymptomatic, an extended examination is prescribed.
Treatment
Surgical methods
For a long time, liver metastases was considered as evidence of a near fatal outcome. Due to the peculiarities of the structure and vascularization of the organ, surgical interventions were associated with a high operational risk, so liver resections were very rarely performed in the first half of the twentieth century. The improvement of surgical techniques and the emergence of new methods of treatment has made it possible to change the approach to the treatment of metastatic liver cancer, although the problem of increasing life expectancy in this pathology remains extremely relevant.
The best long-term results of surgical treatment are observed in patients with colon cancer. Unfortunately, only about 10% of liver metastases is operable at the time of diagnosis. In other cases, operations are not indicated due to too large a tumor, the proximity of the neoplasm to large vessels, a large number of foci in the liver, the presence of metastases of extrahepatic localization or the severe condition of the patient.
In recent years, the list of indications for surgical intervention in liver metastases has expanded. Sometimes oncologists recommend resection in the presence of metastases not only in the liver, but also in the lungs. The operation is performed in two stages: first, the focus in the liver is removed, then in the lung. Statistical data on the change in life expectancy with such interventions are not yet available.
Antitumor therapy
In inoperable metastatic liver cancer, chemotherapy is indicated. Patients are prescribed 5-fluorouracil (sometimes in combination with calcium folinate), oxaliplatin. The average life expectancy after drug treatment ranges from 15 to 22 months.
In some cases, chemotherapy can reduce tumor growth and perform surgery for liver metastases which was considered inoperable before treatment. Resection becomes possible in about 15% of patients. The average life expectancy is the same as for initially operable tumors. In all cases, after removal of metastatic liver cancer in the long term, new secondary foci may appear in various organs. With operable hepatic metastases, repeated resection is performed. In case of metastatic lesion of other organs, chemotherapy is prescribed.
Minimally invasive methods
Along with classical surgical interventions and chemotherapy, for liver metastases, embolization of the hepatic artery and portal vein, radioablation, cryodestruction and the introduction of ethyl alcohol into the neoplasm area are used. As a result of embolization, the nutrition of the tumor is disrupted, necrotic changes occur in the tissues. Simultaneous administration of chemotherapy drugs through a catheter allows you to create a very high concentration of drugs in the tissue of the neoplasm, which further increases the effectiveness of the technique. Chemoembolization can be used as an independent method of treating metastatic liver cancer or used at the stage of preparing the patient for organ resection.
The purpose of radiofrequency ablation, cryodestruction and administration of ethyl alcohol is also the destruction of tumor tissue. Experts note the prospects of these techniques, but do not report statistical data on the change in survival after their use, so it is difficult to assess the long-term results so far.
Forecast
Resection of a single metastasis up to 5 cm in size can increase the average five-year survival rate of patients with rectal cancer to 30-40%. With multiple lesions, the prognosis after surgical treatment of metastatic liver cancer is less favorable, however, with the removal of all foci, it is possible to achieve an average three-year survival rate of 30%. Mortality in the postoperative period is 3-6%. In primary malignant tumors of other localizations, with the exception of rectal cancer (lung cancer, breast cancer, etc.), the prognosis after resections of hepatic metastases is less optimistic.
The mortality rate of patients with metastatic liver cancer using minimally invasive methods is about 0.8%. In advanced cases, when surgical treatment, chemotherapy, embolization, radioablation or cryodestruction is impossible due to the severe condition of the patient, symptomatic agents are prescribed to mitigate the manifestations of the disease. The life expectancy of metastatic liver cancer in such cases usually does not exceed several weeks or months.