Hepatocellular carcinoma, i.e. malignant tumor of liver, can be divided into two categories: primary and secondary. Primary liver malignant tumors originate from epithelial or mesenchymal tissues of the liver, and the former is called primary liver cancer, which is a highly prevalent and extremely harmful malignant tumor in China. Secondary or metastatic hepatocellular carcinoma refers to malignant tumors originated from multiple organs of the whole body invading into the liver. It is usually seen in liver metastasis of malignant tumors of stomach, biliary tract, pancreas, colorectum, ovary, uterus, lung, breast and other organs. Causes and clinical manifestations of hepatocellular carcinoma Causes of hepatocellular carcinoma The etiology and exact molecular mechanism of primary hepatocellular carcinoma are still incompletely understood, and it is currently believed that its pathogenesis is a multifactorial, multistep and complex process. Epidemiologic and experimental research data show that hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, aflatoxin, drinking water pollution, alcohol, cirrhosis of the liver, sex hormones, nitrosamines, trace elements and so on are related to the development of liver cancer. Secondary hepatocellular carcinoma (metastatic hepatocellular carcinoma) can form the disease through different ways, such as transferring with blood, lymphatic fluid or directly infiltrating the liver. Clinical manifestations of liver cancer 1. Primary liver cancer (1) Symptoms Early-stage liver cancer often has nonspecific symptoms, while symptoms of middle and late-stage liver cancer are more common. Common clinical manifestations include pain in the liver area, abdominal distension, poor appetite, fatigue, emaciation, progressive liver enlargement or epigastric mass, etc. Some patients may have low-grade fever, jaundice, diarrhea, upper gastrointestinal tract bleeding, or acute abdominal manifestations after rupture of liver cancer, etc. There are also patients with inconspicuous or only manifestations of acute abdomen. Some patients may have low-grade fever, jaundice, upper gastrointestinal bleeding, acute abdomen after rupture of liver cancer, etc. There are also patients with inconspicuous symptoms or metastatic symptoms. （Early liver cancer often has no obvious positive signs or only resembles signs of cirrhosis. In middle and advanced stage, liver cancer usually shows signs such as enlarged liver, jaundice, ascites and so on. In addition, those who are combined with cirrhosis often have liver palms, spider nevus, enlarged male breast and lower limb edema. When extrahepatic metastasis occurs, the corresponding signs of each metastatic site may appear. (3) Common complications include upper gastrointestinal bleeding, rupture and bleeding of liver cancer, liver and kidney failure. (1) Clinical manifestations of primary tumor are mainly seen in patients with no history of liver disease. Liver metastasis is still in the early stage, and no corresponding symptoms appear, while the symptoms of primary tumor are obvious in the middle and late stages. Secondary hepatocellular carcinoma in such patients is mostly found in the examination and follow-up of primary treatment. (2) Clinical manifestations of secondary hepatocellular carcinoma Patients usually complain of dullness, distension, discomfort or vague pain in the epigastric or hepatic region, and with the development of the disease, patients may have fatigue, poor appetite, emaciation, or fever, etc. On physical examination, patients may have symptoms in the middle and upper abdomen. During physical examination, enlarged liver can be detected in the middle and upper abdomen, or hard nodules with hard texture and tenderness, and patients with advanced stage may have anemia, jaundice and ascites. The clinical manifestations of these patients are similar to those of primary liver cancer, but the development is relatively slow and the degree is relatively mild. Most of them are suspected to have metastasis during various examinations of the liver, and the primary tumors are found during further examinations or surgical exploration. Some patients cannot find the primary tumor after various examinations. (3) Clinical manifestations of both primary tumor and secondary liver cancer are mainly seen when the primary tumor and metastatic cancer of liver are not in early stage, and the patients not only have symptoms and signs similar to those of primary liver cancer, but also have clinical manifestations caused by the primary tumor, such as change of defecation habit, stool character and blood in stool in liver metastasis from colorectal or rectal cancer. Laboratory examination for primary liver cancer (1) Serum marker test for liver cancer ① Serum alpha-fetoprotein (AFP) has relative specificity in diagnosing this disease. The diagnosis of hepatocellular carcinoma can be considered if continuous serum AFP ≥400μg/L is determined by radioimmunoassay and pregnancy and active liver disease can be excluded. About 30% of patients with hepatocellular carcinoma are clinically negative for AFP. If AFP heterogeneous body is detected at the same time, the positive rate can be significantly increased. ② Blood enzymology and other tumor markers examination of liver cancer patients’ serum γ-glutamyl transpeptidase and its isoenzymes, abnormal prothrombinogen, alkaline phosphatase, lactate dehydrogenase isoenzymes can be higher than normal. However, they lack specificity. (2) Imaging examination ①Ultrasonography can show the size, shape, location of the tumor and whether there is cancer thrombus in the hepatic vein or portal vein, and its diagnostic compliance rate can reach 90%. ②CT examination has high resolution and the diagnostic conformity rate of liver cancer can be more than 90%, and it can detect tiny cancer foci with a diameter of about 1.0cm. ③ MRI has similar diagnostic value with CT, and is better than CT in differentiating benign and malignant intrahepatic space-occupying lesions, especially hemangiomas. ④ Selective abdominal artery or hepatic artery angiography has a low resolution of about 1cm in vascularized cancers, and its positivity rate can reach 90% in small hepatocellular carcinomas <2.0cm. ⑤ Liver puncture with needle aspiration cytology under the guidance of B-mode ultrasound and fine needle puncture can help to improve the positive rate. Most patients with secondary liver cancer have tumor markers within normal range, but a few liver metastatic cancers from stomach, esophagus, pancreas and ovary may have elevated AFP. Symptomatic patients are often accompanied by elevated ALP and GGT. Elevated carcinoembryonic antigen (CEA) is helpful in the diagnosis of liver metastatic cancer, and the positive rate of CEA is as high as 60%～70% in liver metastasis of colorectal cancer. Selective hepatic angiography can find lesions with a diameter of 1cm. Selective abdominal or hepatic arteriography mostly shows less vascular tumors; CT shows unevenly mixed isointense or low-density occupations, typically showing "bull's-eye" sign; MRI examination of liver metastatic carcinoma often shows uniform signal intensity, clear margins, multiple occurrence, and a few of them have "target" sign or "target" sign. MRI examination of liver metastatic cancer usually shows uniform signal intensity, clear margins, multiple, and a few have "target" sign or "bright ring" sign. Diagnosis of hepatocellular carcinoma According to the cause of disease, clinical manifestations and examination results, different cases can be diagnosed clearly. Treatment of liver cancer Individualized comprehensive treatment according to different stages of liver cancer is the key to improve therapeutic effect; treatment methods include surgery, hepatic artery ligation, hepatic artery chemoembolization, radiofrequency, cryotherapy, laser, microwave, as well as chemotherapy and radiotherapy. Biological therapy and traditional Chinese medicine are also widely used in the treatment of liver cancer. Surgery is the first choice and the most effective way to treat liver cancer. Surgery is the first choice and the most effective method to treat liver cancer. Surgical methods include radical hepatectomy, palliative hepatectomy and so on. For liver cancer that cannot be resected, intraoperative hepatic artery ligation, hepatic artery chemoembolization, radiofrequency, freezing, laser, microwave and other treatments can be used according to specific conditions, which have certain curative effect. Primary liver cancer is also one of the indications for liver transplantation. 2. Chemotherapy treatment If the cancer is found to be unresectable by caesarean section or as a follow-up treatment of palliative resection of tumor, hepatic artery and/or portal vein pump (subcutaneous buried perfusion device) can be used for regional chemoembolization; for those who can not be resected by surgery, radiological interventional therapy can be used to selectively intubate into the hepatic artery through femoral artery and inject embolic agent (commonly used, such as iodized oil) and chemoembolization of anticancer drugs, some of the patients can thus obtain the treatment of surgical resection. Some patients can get the chance of surgical resection. Radiotherapy For patients with good general condition, good liver function, no cirrhosis, no jaundice, ascites, hypersplenism and esophageal varices, limited cancer, no distant metastasis and not suitable for surgical resection or recurrence after surgery, radiotherapy can be used. 4. Biological therapy: Commonly used treatments include immune ribonucleic acid, interferon, interleukin-2, thymic peptide, etc., which can be applied jointly with chemotherapy. 5.Chinese medicine treatment Adopting the method of diagnosis and treatment, attacking and complementing at the same time, often used in conjunction with other therapies. In order to improve the body's resistance to disease, improve the general condition and symptoms, reduce the adverse effects of chemotherapy and radiotherapy.