Primary liver cancer (PLC, hereinafter referred to as liver cancer) is a common malignant tumor. Because of insidious onset, no or no obvious symptoms in early stage, and rapid progress, most patients have reached locally advanced stage or distant metastasis when diagnosed, which makes treatment difficult and prognosis very poor. Primary liver cancer mainly includes different pathological types such as hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma-intrahepatic cholangiocarcinoma mixed type, which have obvious differences in their pathogenesis, biological behavior, histological morphology, clinical manifestations, treatment methods and prognosis; since HCC accounts for more than 90% of them, what this article refers to “The etiological factors of liver cancer in China mainly include hepatitis virus infection, food aflatoxin contamination, long-term alcohol abuse and blue-green algae toxin contamination of rural drinking water, other liver metabolic diseases, autoimmune diseases and cryptogenic liver disease or cryptogenic cirrhosis. Routine surveillance screening indicators include serum alpha-fetoprotein (AFP) and liver ultrasonography (US). Screening is generally performed at 6-month intervals for men ≥40 years of age or women ≥50 years of age with HBV and/or HCV infection, alcoholism, comorbid diabetes mellitus, and a family history of liver cancer at high risk. It is generally accepted that AFP is a relatively specific tumor marker for HCC, and persistent elevation of AFP is a risk factor for the development of HCC. Subclinical pre-stage of hepatocellular carcinoma refers to the period from the beginning of the lesion to the diagnosis of subclinical hepatocellular carcinoma, when the patient has no clinical symptoms and signs and is difficult to detect clinically, usually about 10 months. In the subclinical stage (early stage) of hepatocellular carcinoma, the tumor is about 3-5 cm, most patients still have no typical symptoms, and the diagnosis is still difficult, mostly detected by serum AFP census for about 8 months on average, during which a few patients can have symptoms related to chronic underlying liver disease such as epigastric stuffiness, abdominal pain, weakness and loss of appetite. Main manifestations: (1) Pain in the liver area. Pain in the right upper abdomen is the most common and is an important symptom of the disease. It is often intermittent or persistent vague, dull or distending pain, which increases with the development of the disease. If the tumor invades the diaphragm, the pain may spread to the right shoulder or the right back; the tumor growing backward to the right may cause pain in the right lumbar region. The cause of pain is mainly due to the tumor growth which makes the liver envelope tense. Sudden onset of severe abdominal pain and peritoneal irritation sign may be caused by peritoneal irritation due to rupture and bleeding of subperitoneal cancer nodules. (2) Loss of appetite. Symptoms such as epigastric fullness after meals, indigestion, nausea, vomiting and diarrhea are easy to be ignored because of the lack of specificity. (3) Wasting and weakness. The whole body is weak, and a few advanced patients may present a cachectic condition. (4) Fever. It is more common, mostly persistent low fever, around 37.5-38℃, or irregular or intermittent, persistent or chilling fever, similar to liver abscess, but no chills before fever, and antibiotic treatment is ineffective. The fever is mostly cancer fever, which is related to the absorption of tumor necrotic material; sometimes it can be caused by cholangitis due to the compression or invasion of bile duct by cancer, or fever due to other infections combined with weakened resistance. (5) Symptoms of extrahepatic metastases. For example, lung metastasis can cause cough and hemoptysis; pleural metastasis can cause chest pain and bloody pleural effusion; bone metastasis can cause bone pain or pathological fracture, etc. (6) Jaundice, bleeding tendency (gingival, nasal bleeding and subcutaneous bruises), upper gastrointestinal bleeding, hepatic encephalopathy and hepatic and renal failure are often seen in advanced stage patients. (7) Paraneoplastic syndrome, which is a syndrome of endocrine or metabolic disorders caused by the abnormal metabolism of liver cancer tissue itself or the multiple effects of cancer tissue on the body. The clinical manifestations are diverse and lack of specificity, including spontaneous hypoglycemia, erythrocytosis, hyperlipidemia, hypercalcemia, precocious puberty, gonadotropin secretion syndrome, cutaneous porphyria, abnormal fibrinogenemia and carcinoid syndrome, but they are relatively rare. Infiltration and metastasis: (1) Intrahepatic metastasis: initially, hepatocellular carcinoma is mostly intrahepatic metastasis, easily invading the portal vein and its branches and forming tumor embolus, which will cause multiple metastases in the liver after shedding. If the stem branch of portal vein is obstructed, it will often cause or aggravate the existing portal hypertension. (2) Extrahepatic metastasis: ①Lung metastasis is the most common, but it can also be metastasized to pleura, adrenal gland, kidney and bone. (2) Lymphatic metastasis, the most common metastasis is from the hilar lymph nodes, but also to the pancreas, spleen and para-aortic lymph nodes, and occasionally to the supraclavicular lymph nodes. Occasionally, the metastasis can be planted in the peritoneum, diaphragm and thorax, causing bloody abdominal and thoracic effusions; in women, ovarian metastases can occur, forming larger masses. Common complications: (1) Upper gastrointestinal bleeding: Hepatocellular carcinoma often has hepatitis and cirrhosis background with portal hypertension, and portal vein and hepatic vein cancer embolus can further aggravate portal hypertension, so it often causes bleeding from varices of middle and lower esophagus or gastric fundus. If cancer cells invade the bile duct, it may cause biliary bleeding, vomiting blood and black stool. Some patients may bleed extensively due to gastrointestinal mucosa erosion, ulceration and coagulation dysfunction, and heavy bleeding may lead to shock and hepatic coma. (2) Hepatorenal nephropathy and hepatic encephalopathy (hepatic coma): In advanced stage of hepatocellular carcinoma, especially diffuse hepatocellular carcinoma, hepatic insufficiency or even failure can occur, causing hepatorenal syndrome (HRS), i.e. functional acute renal failure (FARF), which mainly manifests as Significant oliguria and decreased blood pressure with hyponatremia, hypokalemia, and azotemia, often progressive in nature. Hepatic encephalopathy (HE), i.e. hepatic coma, is often a manifestation of end-stage hepatocellular carcinoma and is often induced by gastrointestinal bleeding, massive diuretics, electrolyte disorders and secondary infections. (3) Rupture and bleeding of hepatocellular carcinoma nodes: It is the most urgent and serious complication of hepatocellular carcinoma. Therefore, gentle palpation is recommended during clinical examination and no forceful pressure should be applied. The rupture of cancer nodules can be confined to the subhepatic peritoneum, causing acute pain and rapid enlargement of the liver, and soft masses can be palpated locally. A small amount of bleeding can be manifested as bloody peritoneal fluid, while a large amount of bleeding can lead to shock or even rapid death. (4) Secondary infection: Patients with hepatocellular carcinoma have weakened resistance due to long-term consumption and bed-rest, especially after chemotherapy or radiotherapy when their white blood cells are reduced, which can easily be complicated by various infections, such as pneumonia, intestinal infection, fungal infection and sepsis.