Gastric cancer patients’ complaints and symptoms are often non-specific and can be easily confused with other gastrointestinal diseases, and the clinical symptoms of gastric cancer patients at different ages and stages of disease are slightly different. How to diagnose gastric cancer early based on the complaints, physical examination and relevant auxiliary examinations at the time of consultation is the key to improve the cure rate and prognosis. 1.First Diagnosis Symptoms 111 Epigastric pain is the most common symptom of gastric cancer. It is often regarded as gastritis, ulcer disease, etc. It can be temporarily relieved after appropriate treatment, but it will recur within a short period of time. If the disease progresses further, the symptoms will be aggravated, and the pain will be frequent and may radiate to the lower back, which is the middle and late stage of the disease. 112 Loss of appetite, emaciation and weakness This is another common but non-specific symptom, but sometimes it can be the first symptom of gastric cancer. This group of symptoms may be caused by cachexia due to disease consumption, or may be caused by abdominal distension and discomfort after eating and automatic food restriction. 113 Nausea and vomiting In the early stage, the symptoms may be only a feeling of fullness or mild nausea after eating, which is often caused by tumor obstruction or gastric dysfunction. 114 Hemorrhage and black stool are caused by ulcer formation and tumor erosion of submucosal blood vessels, which may appear in the early stage of the lesion. 115 Other symptoms: The tumor in the cardia may have a feeling of unpleasant eating in the early stage, which may progress to dysphagia and food reflux. Acute perforation caused by gastric cancer may lead to pain in the whole abdomen and symptoms of peritonitis. Some patients may have diarrhea, constipation and lower abdominal discomfort, and fever may also occur. Since the symptoms of gastric cancer patients are often non-specific, it is very important to take a detailed medical history as much as possible. 21111 Abdominal pain The typical stomach pain of gastric cancer is not rhythmic and cannot be relieved by eating, but when the lesion first starts, it only feels discomfort in the upper abdomen, and the symptoms can be temporarily relieved after appropriate treatment as gastritis or ulcer disease. Pain in the posterior sternum or precordial region indicates tumor in the cardia or esophagogastric junction; increasing pain and persistent pain often indicates invasion of the entire stomach wall, and is usually seen in ulcerative cancer; when gastric cancer invades the pancreas, the pain is severe and radiates to the back; total abdominal pain or peritonitis often indicates gastric perforation caused by the tumor. 21112 Gastric dysfunction The presence of choking on food or difficulty in swallowing indicates that the tumor is mostly located around the cardia; vomit is overnight food with putrid odor, which indicates a tumor in the gastric sinus with pyloric obstruction; vomiting coffee-like liquid or passing tarry stool indicates that the cancer has broken down or invaded the blood vessels and caused bleeding; any elderly patient without a history of gastric disease must be alerted to the possibility of gastric cancer once black stool appears. 21113 Systemic conditions Loss of appetite, emaciation, and weakness should be considered as possible gastric cancer when they occur together with symptoms of stomach pain and hepatitis can be excluded. Some patients may have hypothermia and anemia, which should be taken seriously. 212 Physical examination Vital signs such as temperature, pulse, respiration, and blood pressure are routine, and in addition, the following areas should be examined. 21211 Skin and mucous membranes Pale skin and lid conjunctiva may indicate anemia due to tumor bleeding; tumor involving the hepatic hilum may cause yellow staining of the skin and sclera. 21212 Superficial lymph nodes Enlarged left supraclavicular lymph nodes suggest distant metastasis through the thoracic duct; in rare patients, left axillary lymph nodes may be metastatic. 21213 Abdominal examination A dilated gastric pattern in the upper abdomen with audible tremors suggests pyloric obstruction; large tumors in the pylorus and anterior wall of the stomach may be detected as a mass in the upper abdomen; in female patients, a pushable mass in the lower and middle abdomen often suggests Krukenberg’s tumor; tumors may also metastasize to the umbilicus via the hepatic ligament and form a periumbilical mass; membranous metastases may present with ascites; perforation may present with total metastasis. In the case of perforation, the tumor may present with total abdominal pain and peritonitis. 21214 Anal examination In advanced gastric cancer with pelvic implantation, nodules can be found in the rectal fossa of the bladder (uterus) on rectal examination. 21215 Other small intestine or mesenteric metastasis may cause partial or complete intestinal obstruction by narrowing the intestinal cavity. 21311 Routine blood and stool tests to find out whether the patient has anemia or gastrointestinal bleeding. 21312 Biochemical immunoassay Carcinoembryonic antigen (CEA), tissue peptide antigen (TPA), CA19-9, CA74-2, etc. may be elevated in gastrointestinal tumors, but they lack specificity and can only be used as an auxiliary basis for diagnosis. 214 Imaging 21411 X-ray gastric double contrast imaging can clearly show the fine structure of gastric mucosa, which is unique for the diagnosis of gastric cancer, especially for the early diagnosis of gastric cancer. The niche is nodular at the base, with a concentration of surrounding mucosa, or it may appear only as a fusion of gastric cells. CT examinations, especially spiral CT, can provide valuable information on the localization, characterization, gross staging, muscle and plasma membrane involvement, invasion of adjacent organs (pancreas, liver), and lymph node metastasis of gastric cancer. 21413 Ultrasound and MRI are useful in determining the progressive gastric cancer and clinical stage, but have limited clinical value in the examination and diagnosis of gastric cancer. 215 Endoscopic examination 21511 Visual observation Early gastric cancer may appear as localized elevated lesions, mucosal depression and erosion or only redness, pallor, roughness and loss of luster of the mucosa. In some cases, due to diffuse infiltration of cancerous tissues, the gastric wall becomes thicker, stiffer, the gastric cavity becomes narrower, and gastric peristalsis disappears, which is called “leather-like” gastric cancer. 21512 Biopsy The lesion is removed by endoscopy with biopsy forceps and sent for pathological examination. Most of the elevated carcinomas are differentiated carcinomas, and the carcinoma tissues are growing continuously. 21513 Cytological examination Cytological examination under direct endoscopy can be verified with biopsy results by collecting cells after biopsy by inserting a cytological brush through the endoscopic biopsy jaws, rubbing or turning the brush repeatedly at the lesion, then retreating the brush to the lower opening of the biopsy hole and retreating the brush together and sending two smears for examination. Cells may also be collected by suction rinsing. The clinical diagnosis of gastric cancer can be made when the history, physical examination and laboratory examination are consistent with the characteristics of gastric cancer and the occupying lesion is detected by X-ray air-barium double imaging or endoscopy, but the final diagnosis of gastric cancer must be based on biopsy or cytological examination. The incidence of gastric cancer has been on the rise recently. Based on the above diagnostic steps, patients with suspected gastric cancer can be screened out and further adjuvant examinations can be performed on the premise of detailed medical history and complete physical examination, so as to achieve early diagnosis and treatment, and avoid missed diagnosis and misdiagnosis. In addition, we believe that patients with the following symptoms should be particularly alert to gastric cancer: (1) patients with a past history of chronic gastric disease should be taken seriously if they have a recent history of loss of appetite, emaciation and anemia; (2) patients over 40 years of age with no previous history of gastric disease should be considered for gastric cancer or other gastric tumors if they suddenly develop vomiting blood and black stool, except for bleeding from ruptured esophageal varices caused by portal hypertension; (3) Age 40 years or older, with previous diagnosis of chronic atrophic gastritis or atypical hyperplasia, should be reviewed promptly when symptoms worsen recently with epigastric distention, vague pain, loss of appetite and significant weight loss; (4) With previous history of chronic gastric disease, positive fecal occult blood (++) found during fecal occult blood test, which lasts for more than 2 weeks, there may be persistent bleeding lesions in the stomach, which should raise the alert for gastric cancer.