Gastric cancer is the fifth most common malignant tumor worldwide, with adenocarcinoma accounting for more than 95% of cases. East Asia is a high-incidence region, and Helicobacter pylori infection is a key factor driving the progression of precancerous lesions. Owing to the lack of specific symptoms in the early stages, more than 80% of gastric cancer cases in Asia are diagnosed at an advanced stage, resulting in an overall 5-year survival rate of approximately 35%. However, when detected early and treated with endoscopic resection, the 5-year survival rate can exceed 90%. Eradication of H. pylori infection and the widespread implementation of high-quality endoscopic screening remain the most effective strategies for reducing the burden of gastric cancer.
· Persistent Helicobacter pylori infection, with an attributable risk of approximately 60%–80%
· A high-salt diet; frequent consumption of pickled and smoked foods; and insufficient intake of fresh vegetables and fruits
· Smoking and heavy alcohol consumption
· Chronic atrophic gastritis, intestinal metaplasia, and dysplasia
· Pernicious anemia and Epstein–Barr virus (EBV) infection
· Hereditary diffuse gastric cancer associated with CDH1 gene mutations and a positive family history
The classic Correa cascade describes the pathogenesis of intestinal-type gastric cancer: Helicobacter pylori infection initiates chronic superficial gastritis, which progressively evolves into chronic atrophic gastritis, intestinal metaplasia, dysplasia, and ultimately adenocarcinoma. During this process, factors such as smoking, high salt intake, and exposure to N-nitroso compounds further aggravate DNA damage and epigenetic alterations. Diffuse-type gastric cancer is primarily associated with loss of cell adhesion caused by CDH1 gene inactivation and typically exhibits infiltrative growth patterns.
Early gastric cancer may present only with nonspecific dyspeptic symptoms, such as dull epigastric pain, bloating, belching, and acid reflux, which are easily overlooked. In advanced stages, patients may develop persistent epigastric pain unrelated to meals, loss of appetite, significant weight loss, melena, or hematemesis. Gastric cardia cancer may cause retrosternal discomfort or dysphagia, whereas pyloric cancer often presents with vomiting of retained food. In late-stage disease, ascites, enlargement of the left supraclavicular lymph node (Virchow’s node), anemia, and cachexia may be observed.
· Surgery: Early intramucosal gastric carcinoma can be treated with endoscopic submucosal dissection (ESD), thereby preserving gastric function. For resectable advanced gastric cancer, laparoscopic or open radical gastrectomy with D2 lymph node dissection is the standard surgical approach. Perioperative chemotherapy or stage-based postoperative adjuvant chemotherapy can further improve the curative resection rate and long-term outcomes.
· Minimally invasive therapy:Endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) are curative minimally invasive procedures for early gastric cancer. In advanced cases complicated by pyloric or cardia obstruction, endoscopic placement of self-expanding stents can rapidly restore oral intake. Intraluminal laser ablation, photodynamic therapy, and argon plasma coagulation may be used to control local bleeding or provide palliative tumor debulking.
· Chemoradiotherapy: Concurrent chemoradiotherapy can be used for downstaging and local control in patients with unresectable locally advanced gastric cancer. Postoperative adjuvant chemotherapy is the standard treatment for stage II–III disease. Palliative chemotherapy is administered to prolong survival and alleviate symptoms in advanced-stage patients.
· Targeted and immunotherapy: For HER2-positive gastric cancer, the addition of anti-HER2 targeted therapy to chemotherapy can improve therapeutic efficacy. Immune checkpoint inhibitors, guided by the assessment of PD-L1 expression, microsatellite instability-high (MSI-H) status, or mismatch repair deficiency (dMMR), are used in advanced disease and may result in durable tumor regression.
· Other treatments: All patients should be tested for Helicobacter pylori and undergo eradication therapy when indicated to reduce the risk of metachronous gastric cancer. Nutritional support, psychological counseling, and adjunctive traditional Chinese medicine may help improve appetite, nutritional status, and overall quality of life.
High-definition gastroscopy combined with chromoendoscopy and magnifying endoscopy is essential for the detection of early gastric cancer, while histopathological examination of biopsy specimens remains the gold standard for diagnosis. Endoscopic ultrasound can accurately assess the depth of tumor invasion and the status of perigastric lymph nodes. Molecular markers, including HER2, PD-L1, and microsatellite instability (MSI) status, should also be evaluated. Contrast-enhanced CT of the abdomen together with chest imaging is used to assess distant metastases. For high-risk populations, intensive gastroscopic screening every 1–2 years is recommended.
