Stomach cancer is a common malignant tumor originating from the stomach, and the mortality rate in China is the highest among all kinds of cancers. Its occurrence may be related to certain diseases of the stomach, carcinogenic substances in food and genetic factors. Clinically, it mainly manifests as epigastric distention and discomfort, vague pain, loss of appetite, anorexia, progressive anemia and emaciation, masses can be found in the upper abdomen during the progressive stage, and fecal occult blood continues to be positive. Surgical radical resection is the most effective method to treat gastric cancer. Therefore, early diagnosis is the key. Postoperative chemotherapy should also be given attention because it can prolong survival and has obvious effects on preventing liver metastasis. (I) Symptoms: 1. Early gastric cancer: there may be no obvious symptoms or only epigastric discomfort, atypical epigastric pain, loss of appetite, fullness and belching. Few may have black stool or vomiting blood. There may be no obvious physical signs. 2.Progressive middle stage cancer: (1) progressive emaciation, anemia, hypoproteinemia, swelling, cachexia; (2) persistent epigastric pain; (3) vomiting blood and black stool; (4) pancreatic and gastric base cancer may have difficulty in swallowing; pylorus cancer may have pyloric obstruction; (5) abdominal masses may be found, hard and painful; (6) if metastasis occurs, the left supraclavicular lymph nodes may be enlarged or appear (6) if metastasis occurs, the left supraclavicular lymph node may be enlarged or the liver may be enlarged, hard and have uneven surface, and even ascites may appear. If the tumor spreads to the pelvis, it may cause ovarian mass or enlarged lymph nodes beside the anus. (2) Diagnostic basis: 1. Early stage may have no symptoms and signs; or indigestion symptoms may appear; or the symptoms of original gastric ulcer may be aggravated, and abdominal pain may lose rhythm, mostly persistent, and the symptoms are not relieved by treatment of ulcer disease. 2. In the middle and late stages, weight loss, progressive anemia, low fever, palpable mass in the epigastrium with pressure pain, enlarged left supraclavicular lymph nodes, ascites and cachexia may be present. 3, there may be dysphagia or pyloric obstruction performance. 4.Barium X-ray examination: (1) barium filling defect; (2) pyloric stenosis; (3) stiffness of the affected gastric wall and loss of peristalsis; (4) narrowing of the gastric shape or narrowing of the gastric lumen; (5) niche shadow of more than 2.5 cm in diameter in the greater or lesser curvature of the stomach, with the bottom within the gastric contour. (5) Cancer cells can be seen in gastric exfoliated cell blood examination. 6.Gastroscopy can see mucosal elevation, mass, ulcer and other lesions, and biopsy or brushing can confirm the diagnosis. (C) Treatment methods: Treatment principles 1. Surgery is the main treatment, supplemented by medical treatment; 2. chemotherapy radiotherapy with surgery, emphasizing postoperative chemotherapy; 3. symptomatic treatment. Specific methods1. Surgery is still the main treatment method for gastric cancer and the only way to potentially cure it, but surgery as a local treatment method has its shortcomings. In order to improve the efficacy of surgical treatment and make up for the shortcomings of surgery, it is necessary to implement integrated treatment combined with chemotherapy and radiotherapy.2.Chemotherapy: it is applicable to pre-, intra- and post-operative and inoperable advanced gastric cancer, and often adopts inter-exhaustive, multi-course and combined drugs. FAM (combination of mitomycin, 5-fluorouracil and adriamycin), ELF (combination of formyltetrahydrofolate, 5-fluorouracil and pedialyte), etc. During chemotherapy, regular blood check, strengthen nutrition and supportive therapy. 3.Radiotherapy: the application of gas pedal has certain efficacy and is suitable for preoperative, intraoperative and postoperative radiotherapy of gastric cancer. (If radical surgery can be performed before metastasis occurs, the curative effect is better, especially when the cancer tissue has not yet invaded the muscular layer and plasma layer, the five-year survival rate is the highest. Therefore, all patients with clinically confirmed or highly suspected diagnosis of gastric cancer, except for those with distant metastasis or poor general condition who cannot tolerate surgery, should be explored by abdominal dissection. For progressive cancer, except for cases with extensive spread of cancer, as long as the general condition and technical conditions permit, even if radical resection cannot be performed, all or most of the primary foci should be removed to relieve symptoms. In cases where the cancer cannot be removed and is accompanied by pyloric obstruction, short-circuit surgery – gastrojejunostomy or gastrostomy – is feasible to relieve symptoms. The following measures can help the prevention, early detection and timely treatment of gastric cancer (1) Pay attention to dietary hygiene, eat less smoked and fried food, quit smoking and drinking, eat more vitamin E rich fruits and vegetables, store food well, and process and cook properly; (2) Treat chronic atrophic gastritis, especially those with intestinal hyperplasia and atypical hyperplasia, gastric ulcer, pernicious anemia, gastric polyp, etc. actively and conduct gastroscopy regularly to detect and treat cancer in time.