With the improvement of living standard and change of lifestyle as well as the aggravation of environmental pollution, the incidence of tumors is also increasing. Many malignant tumors, early detection, early diagnosis and early treatment of gastrointestinal tumors is an important element in tumor prevention and treatment. Among the gastrointestinal tumors, gastric cancer is one of the most common tumors. So what are the current gastric cancer detection methods? Physical examination for people with high risk of gastric cancer 1. Doctors conduct comprehensive physical examination on patients, whether they have obvious wasting, jaundice (yellowing of skin and eyes) and obvious abdominal distension. 2. The patient is examined by touch, such as touching the neck, to determine whether there are obvious lymph node metastases in the neck. 3.Touch the abdomen to determine whether there is pressure pain, obvious abdominal mass, enlargement of liver and spleen, etc. Sometimes it is also necessary to perform anal finger examination to determine whether there is a mass inside the anus and whether there is blood in the anus and rectum, etc. 4.To determine whether there is intestinal obstruction, a stethoscope is needed for abdominal auscultation to be used. Gastroscopy Gastroscopy is the most reliable method for screening gastric cancer, and for early detection of gastric cancer, gastroscopy is the internationally accepted method. Many people are afraid of gastroscopy because they think that gastroscopy is very painful, and some patients do not take the examination at the early stage of upper gastrointestinal tumor, so the diagnosis is delayed until the late stage when the cancer is confirmed. In conclusion, early detection and early diagnosis of gastric cancer are the basis of early treatment and the fundamental guarantee to reduce and minimize the deterioration of gastric cancer. If it has been diagnosed, it should be treated as soon as possible according to medical advice. The current gastroscopic examinations are 1. General electron gastroscopy: EG endoscopic manifestations are insidious and not obvious, mainly the rough feeling of mucosa, easy bleeding when touched, patchy congestion and mucosal erosion. Typical gastric cancer is shown as nodules, masses, uneven cancerous ulcers, etc. under the microscope. 2.Ultrasound endoscopy: The application of a small probe with high frequency (20MHz) can show the depth and extent of lesion infiltration more clearly. EUS can also be used for accurate staging of gastric cancer, so as to guide treatment; it can also be used for postoperative follow-up to detect residual or recurrent cancer. Due to the limitation of ultrasound beam penetration distance, the large part of the right lobe of liver, the retroperitoneum and mesenteric lymph nodes below the superior mesenteric vessels in the abdominal cavity cannot be detected by EUS, so EUS cannot provide conclusive diagnosis of distant metastases. In recent years, with the continuous development of science and technology, some new gastroscopic diagnostic techniques have gradually emerged and are being gradually promoted and tried in clinical practice, accumulating experience and knowledge. These new techniques are: 1. Pigmented endoscopy: pigmented endoscopy refers to the auxiliary use of pigmented preparations and dyes on the basis of routine endoscopic examination to increase the contrast between lesions and normal tissues, so as to make the morphology and scope of lesions clearer, thus improving the visual detection of gastric cancer, guiding biopsy and treatment, and increasing the detection rate of lesions. 2. Magnification endoscopy: Magnification endoscopy can magnify the endoscopic image tens to hundreds of times, which can clearly show the microstructural changes such as the opening of glandular ducts and microvessels in the mucosa of gastrointestinal tract. :3.Fluorescence endoscopy: the principle is that compounds in biological tissues react with specific wavelengths of luminescent substances and can emit special fluorescent signals. The biochemical characteristics of benign and malignant lesions are different, and there is specificity in the corresponding fluorescence spectra. Fluorescence endoscopy can clearly show the early tumors of the gastrointestinal tract and the degree of mucosal infiltration, but the specificity for superficial gastric tumors is not strong. 4.Infrared electronic endoscopy: The advantage is that infrared light can penetrate into tissues. Using electronic endoscopy with far-infrared light source of 780-840 nm, the morphology of fine blood vessels of mucosa can be seen, which can be used to distinguish mucosal carcinoma, submucosal carcinoma and progressive carcinoma; it can also clearly show the condition of blood vessels under the gastric mucosa. Imaging examination 1.Barium meal imaging: conventional barium meal is not enough to show the microstructure of gastric mucosa, nowadays, double contrast barium meal examination is mainly used to detect various types of EGC, including small gastric cancer and micro gastric cancer with the maximum diameter of cancer foci < 1 cm or even 0.5 cm. Endoscopy should be performed when there is suspicious finding. 2.CT: CT can better observe the situation inside and outside the gastrointestinal tract and whether there is metastasis in distant organs, and has unique diagnostic effect on gastrointestinal tumors growing mainly outside the wall or between the walls, which is obviously better than endoscopy and gastrointestinal imaging. Spiral CT can improve the detection rate and precise tumor staging of gastrointestinal tract tumors by relying on thickness changes, abnormal enhancement and thickening of the gastrointestinal wall and mucosal changes, and CT simulation endoscopy can visualize in three dimensions and accurately measure the size of lesions, and the combination with gastroscopic biopsy can improve the correct diagnosis rate of EGC.