In the process of continuous development and progress in the treatment of gastric cancer, the understanding of the pattern of lymph node metastasis of gastric cancer has been gradually advanced. Early gastric cancer’s anterior lymph node navigation surgery is the result of this understanding process. The lymphatic reflux network of the stomach is very rich and complex. In the early years, Sappey made a specimen of lymphatic reflux network in the gastric wall and fixed the lymphatic system in the submucosa, muscular layer, and subplasma layer of the stomach by injecting a solution containing mercury, and after peeling off the plasma membrane and other tissues, the lymphatic network was shown to be interwoven and covered the entire gastric wall in a fine grid. The lymphatic reflux outside the gastric wall is also very complex. The blood supply vessels of the stomach are very rich, and in addition to the trunk of the left and right gastric arteries, the left and right gastric omental arteries, and several short gastric arteries, the posterior gastric artery and the left subphrenic artery are also involved in the blood supply of the stomach. Some of the veins of the gastric wall are accompanied by arteries of the same name, while others have variations, such as the right gastroretinal vein injecting into the superior mesenteric vein via the gastrocolic trunk, and the esophageal branch of the left gastric vein anastomosing with the inferior vena cava. The lymphatic reflux of the abdominal organs mainly follows the venous direction, but intraoperative lymphography reveals that the lymphatic fluid from the gastric wall can also reflux against the arterial direction, for example, the main direction of lymphatic reflux through the subpyloric lymph node (No.6) is not only along the venous reflux to the superior mesenteric vein (No.14v), but also against the gastroduodenal artery to the anterior lymph node of the common hepatic artery (No.8a), and then to the peri-abdominal artery lymph nodes (No.9). In this way, many lymphatic vessels running along veins, along variant veins, and against many arteries intertwine to form a complex lymphatic reflux network outside the gastric wall. The lymphatic network inside the stomach wall in the form of a fine grid and the complex reflux pathways outside the stomach wall form a huge and rich lymphatic reflux system of the stomach. The incidence of such lymph node metastasis in the right side of the cardia is about 10%, such as subpyloric lymph node metastasis in cardia and sinus cancer. The lymphatic reflux system of stomach is very complex and difficult to be described and summarized by a simple method, so people’s research and understanding of the law of lymph node metastasis of gastric cancer lags far behind that of colon cancer, which has a relatively single blood supply and a relatively simple lymphatic reflux system. The Japanese scholars formulated the “Statute for the management of gastric cancer” by imitating the lymph node metastasis pattern of colon cancer, and revised the statute continuously according to the deepening understanding of lymph node metastasis in clinical practice, and anatomically divided the lymph nodes related to gastric cancer metastasis into 16 groups for labeling to observe and study the metastasis pattern. For example, No.8 around the common hepatic artery was further divided into 8a and 8p (anterior and posterior lymph nodes of the common hepatic artery), and No.14 around the superior mesenteric vessels was further divided into 14a and 14v (lymph nodes around the superior mesenteric artery and vein). peripheral lymph nodes). The complex lymphatic reflux system of the stomach can only be described in detail with a more detailed grouping of lymph nodes, which is cumbersome and inconvenient for clinical application, but plays an important role in studying and revealing the pattern of lymph node metastasis in gastric cancer. After extensive lymph node dissection surgery, the distribution of metastatic lymph nodes is recorded in detail according to the groups of lymph nodes marked in the Statute for the Management of Gastric Cancer, and the distribution characteristics of metastatic lymph nodes of gastric cancer at different sites and with different pathological characteristics are summarized according to the results of a large number of cases, which becomes the basic method to study the pattern of lymph node metastasis. The results obtained by this research method are also the most accurate and reliable. For more than half a century, the treatment of early gastric cancer with standardized surgery has achieved satisfactory results. How to reasonably reduce the scope of surgery, lower the surgical trauma and preserve the function of some organs without affecting the therapeutic effect has become one of the hot spots of clinical research on gastric cancer. In areas where there are more cases of early gastric cancer, this kind of reduction surgery for early gastric cancer is as important as the research on the comprehensive treatment of progressive gastric cancer. Summarizing the results and patterns of lymph node metastasis, it is found that the lymph node metastasis in early gastric cancer does not exceed 20%, and very few distant metastases occur, so the reasonable reduction of the perigastric lymph node clearance becomes one of the main contents of the study of gastric cancer reduction surgery. Initially, when performing reduction surgery, we mostly adopted indirect methods to determine lymph node metastasis and its extent, based on the lymph node metastasis pattern summarized from previous surgical results, and judged lymph node metastasis from factors such as site, size, general type and differentiation degree of early gastric cancer. In recent years, based on the understanding of lymph node metastasis for many years, people have borrowed the experience of research and application of sentinel lymph nodes in malignant melanoma, breast cancer, especially colon cancer, and combined with the concept of gastric cancer reduction surgery, the diagnosis of lymph node metastasis has developed from indirect judgment to direct detection, and started the sentinel lymph node navigation surgery for early gastric cancer. It can be said that the study of early gastric cancer sentinel lymph nodes is a high overview of the law of early gastric cancer lymph node metastasis and a sublimation of the process of exploring the law of gastric cancer lymph node metastasis over the years. Sentinel node is the lymph node that receives lymphatic reflux from tumor first. In 1977, Cabanas in South America studied the lymph node metastasis pattern of penile cancer cases by lymphangiography and found that the contrast agent first flowed into the superficial lymph nodes in the abdominal wall. In 1992, Monton studied the sentinel lymph nodes in malignant melanoma, and in 1993, Krag studied the sentinel lymph nodes in breast cancer by radioisotope method, which attracted the attention of academia and made sentinel node navigation surgery more and more important in the treatment of many solid tumors. In the treatment of many solid tumors, early stage lymph node navigation plays an increasingly important role. In the treatment of gastric cancer, sentinel lymph node navigation surgery for early gastric cancer has also been greatly developed. The lymph node metastasis of gastric cancer is very complex, and it is not easy to grasp its pattern, and it is difficult to generalize it by simple methods, while sentinel lymph node navigation surgery tries to generalize the status of lymph node metastasis by simple and rapid biopsy of individual lymph nodes. It is only suitable for the treatment of early-stage gastric cancer where the incidence of lymph node metastasis is low and the pattern is easy to grasp. At present, the tracer method is mostly used to find the sentinel lymph nodes, in which the tracer is injected near the lesion to show the lymphatic metastasis pathway of the primary lesion, and the lymph node that accumulates the tracer first is obtained as the sentinel lymph node for rapid biopsy to determine whether the lymph node has metastasis. Tracer is mainly a traditional method to observe the lymphatic reflux pathway of gastric cancer intraoperatively, and there are two types of methods: pigmentation method and isotope method. The pigment can be methylene blue, patent blue, ink, indocyanine green, microparticle activated carbon and other dyes, which are injected into the submucosa around the lesion via endoscopy before surgery, or injected into the subplasma layer around the lesion during surgery to find the first stained lymph node. Since the stomach is an intra-abdominal organ, unlike retroperitoneal and interperitoneal organs such as the pancreas and rectum, the whole stomach can be observed without much separation, so the pigmentation method has the advantages of simplicity and ease in exploring the anterior lymph nodes of gastric cancer. However, there are still many problems in clinical implementation, such as the pigment will spread and fade over time and must be observed within a limited period of time; the observation of staining results will be subjective; the amount of injected pigment will affect the display of the lymphatic system, and more injected amount will show more lymph nodes, while less injected amount will show less lymph nodes, etc. Radioisotope method is to use radioisotope to label colloid that is easily absorbed by lymphatic tissue, inject it locally, and search for lymph nodes with a detector. It is also possible to use radioisotope labeled monoclonal antibodies for gastric cancer and inject them locally or intravenously to accumulate in the primary and metastatic foci, and to detect them with a handheld detector, which can detect deep lymph nodes covered by thicker fatty tissue, and the results are more objective. A combination of the two methods has also been applied, which is thought to further improve the accuracy of detection. Two large multicenter prospective studies are currently underway in Japan on the pigmentation and radioisotope methods, and if the results of this study are satisfactory, then sentinel lymph node biopsy will likely become an important step in open surgery. The results of detecting anterograde lymph nodes also reflect many of the complexities of lymph node metastasis in gastric cancer that are different from those in breast and colon cancer. Almost all reports suggest multiple rather than single anterograde lymph nodes in gastric cancer, which also illustrates the multidirectional and random nature of gastric cancer lymph node metastasis in a fine lattice-like lymphatic return system that cannot be summarized by a single lymph node. In addition, not all of the anterior lymph nodes appear around the primary focus, and sometimes they are directly shown in the station 2 lymph nodes, such as the lymph nodes around the left gastric artery and common hepatic artery, and some are even station 3 lymph nodes, which is consistent with the phenomenon of partial jumping metastasis of gastric cancer lymph nodes. If the detection means are insufficient, such as insufficient amount of dye injected by pigmentation method to show the jumping metastasis lymph nodes, it will be missed and lead to serious consequences. Many other factors affect the accuracy of the results during the detection process. Previous studies have found that when lymphatic reflux pathways were observed by gastric wall injection of activated charcoal, the black staining rate of cancer metastatic lymph nodes was lower than that of those without metastasis, and the common lymphatic reflux pathways were blocked and closed by cancer metastasis, and the uncommon reflux pathways were easily black stained. Histologically metastatic cancer cells occupy less than 2/3 of the lymph nodes before the lymph nodes are black stained, and the direction of lymphatic return stained by pigmentation does not fully represent the direction of lymphatic metastasis of cancer. This may be one of the main reasons for the false negatives in many reported results. Intraoperative rapid biopsy is also an important aspect affecting the accuracy of detection of anterior lymph nodes. The traditional method of diagnosing lymph node cancer metastasis is to observe the largest section of lymph nodes after HE staining. In recent years, with immunohistochemistry, RT-PCR (reverse transcription polymerase chain reaction), serial sections and other techniques, it was found that many lymph nodes diagnosed as negative for cancer metastasis by traditional methods still have micro-metastasis of cancer, suggesting the inadequacy of traditional diagnostic methods. The diagnosis of the pathological status of the lymph node is directly related to the decision of surgery and patient’s prognosis, so it is also crucial to improve the accuracy of intraoperative rapid biopsy. Rapid immunohistochemistry has been reported for the detection of anterior lymph nodes during surgery. Many domestic and international reports have shown that the accuracy of diagnosis of sentinel lymph nodes in gastric cancer is more than 95%, but there are false negatives, and the risk of cancer recurrence is traded for the reduction of lymph node dissection, rapid postoperative recovery and improved quality of life in gastric cancer reduction surgery. The consequences of false-negative results are severe for the patient and are not permissible for anterior lymph node navigation. Theoretically, in any solid cancer, there exists the sentinel lymph nodes that first collect lymphatic fluid from the cancerous tissue, and even if there are multiple of them at the same time, these sentinel lymph nodes should be the real first stop lymph nodes in the pathological process of cancer metastasis and can represent whether the cancer has lymph node metastasis or not. However, there is still no ideal clinical detection method that can truly reveal the pathological process of lymph node metastasis in gastric cancer, grasp the pattern of lymph node metastasis fundamentally, and reveal all the sentinel lymph nodes. The various tracing methods currently used only reveal the local lymphatic reflux pathways of the stomach, and they are likely to be incomplete and not necessarily representative of the true cancer metastasis pathways. For more than half a century, it is because the pathological process of lymphatic metastasis of gastric cancer cannot be truly grasped fundamentally that the lymphatic return system of the stomach has been described anatomically in detailed groups and stations to observe the metastasis of gastric cancer. If very ideal detection means are available in clinical practice, which can truly reveal the pathological process of lymphatic metastasis of gastric cancer, then anterior lymph node navigation will be applicable to all lymph node dissection of gastric cancer, and various anatomical lymph node groupings and substations will lose their significance. Because of the complexity of the gastric lymphatic reflux system, and because there are still many shortcomings in various methods for detecting anterior lymph nodes, the implementation of anterior lymph node navigation in gastric cancer surgery must still be very cautious and limited to the treatment of early gastric cancer with low incidence of lymph node metastasis, and many issues are still in the research stage. To promote the application of sentinel lymph node navigation in clinical practice, firstly, the accuracy of detection methods should be improved, including various aspects such as detection of sentinel lymph nodes and rapid biopsy. Secondly, regarding the current detection means, in order to improve the safety of surgery and reduce the harm of false negatives, the experience and results of previous surgeries should be referred to when necessary, and the lymph node metastasis status should be indirectly inferred from the site, size, general type, and differentiation degree of early gastric cancer based on the statistical results of previous bulk cases to make up for the shortage of detection means. In addition, the time for detecting anterior lymph nodes should not be too long, and the prolongation of surgery time is contrary to the original purpose of reduction surgery. The concept of sentinel lymph nodes is a high overview of the lymph node metastasis pattern of gastric cancer, and it is the first step to study the lymph node metastasis pattern from the pathological metastasis pathway based on the previous anatomical observation of lymph node metastasis pattern. With the improvement of the accuracy of the detection method and the deeper research on the sentinel lymph nodes, sentinel lymph node navigation will have a good development prospect in the treatment of gastric cancer.