Screening methods for gastric precancerous lesions

Gastric cancer, as a common malignant tumor worldwide, poses a serious threat to human health. The development of gastric cancer is a long process, usually starting from precancerous lesions and gradually developing into cancer. Therefore, screening for gastric precancerous lesions is particularly important. This article will introduce you to the screening methods for gastric precancerous lesions in detail.

1. Serological screening

Serological screening is a non-invasive and simple method to assess the risk of gastric cancer by detecting biomarkers in the blood. Commonly used serological markers include:

Serum pepsinogen (PG ): It is divided into two types: PGI and PGII. PGI is mainly secreted by the chief cells of the fundic glands, and PGII is secreted by the gastric and duodenal cells. When the gastric mucosa atrophies, the PG level will decrease. Therefore, by detecting the ratio of PGI to PGII (PGR), it is helpful to assess the risk of gastric cancer.

Gastrin-17 (G-17) : Secreted by the gastric antral G cells, the level of G-17 increases when the gastric mucosa atrophies.

Helicobacter pylori-immunoglobulin G antibody (Hp-IgG) : Hp infection is an important risk factor for gastric cancer, and Hp-IgG testing helps assess whether Hp infection exists.

MG7 antigen (MG7-Ag) : It is a specific monoclonal antibody associated with gastric cancer, and its expression level gradually increases in precancerous lesions.

The combined detection of these serological markers can improve the sensitivity and specificity of diagnosis.

2. Helicobacter pylori detection

Helicobacter pylori (HP) infection is an important risk factor for gastric cancer. HP infection can cause chronic inflammation of the gastric mucosal surface and is associated with the development of gastric mucosal atrophy and intestinal metaplasia. Therefore, HP detection is an essential test in the screening of gastric precancerous lesions. Commonly used detection methods include:

Urea breath test : It is simple to operate, highly accurate and non-invasive, and is the most recommended method in clinical practice.

Histology or serum HP antibody testing : Evaluate the presence of HP infection by endoscopic biopsy or blood testing.

Saliva or stool HP antigen test : can also be used to detect HP infection.

3. Imaging Examination

Gastric cancer precancerous lesions often have no obvious positive signs in imaging examinations. However, for patients suspected of gastric cancer, imaging examinations can help evaluate the depth of tumor infiltration, lymph node metastasis, and distant metastasis. Commonly used imaging examination methods include:

CT : Can show the location, size, depth of invasion and lymph node metastasis of the tumor.

MRI : It helps to evaluate the relationship between the tumor and surrounding tissues, and is particularly suitable for evaluating the depth of gastric cancer infiltration and lymph node metastasis.

Ultrasound : High-frequency ultrasound probes can be used to observe the structure of the stomach wall and blood flow, which helps to detect early gastric cancer.

IV. Endoscopic screening

Endoscopic examination is the most important screening method for gastric precancerous lesions, which can visually observe the gastric mucosa and perform biopsy. Ordinary white light endoscopy is a preliminary screening method, but high-definition chromoendoscopy can significantly improve the accuracy of diagnosis. High-definition chromoendoscopy sprays dye onto the surface of the gastric mucosa to be observed and locally magnifies it, making the contrast between the lesion tissue and the surrounding normal tissue more obvious. Combined with pathological biopsy, it is the most effective method for detecting precancerous conditions or precancerous lesions of the gastric mucosa. It is recommended to use ordinary white light endoscopy for initial screening and use high-definition chromoendoscopy for detailed examination of suspicious lesions. In addition, electronic staining technologies such as narrow band imaging technology (NBI) and endoscopic electronic spectroscopic image processing (FICE) can also help improve diagnostic accuracy.

5. Liquid Biopsy

Liquid biopsy is an emerging non-invasive detection method that assesses tumor risk by analyzing circulating tumor components. Commonly used liquid biopsy markers include circulating tumor DNA (ctDNA), exosomes, and microRNA (miRNA). These tumor components released into the peripheral circulation by solid tumors or metastases provide a reference for early tumor diagnosis, efficacy evaluation, and recurrence prediction. For example, circulating miRNA-196a can distinguish between precancerous lesions, low-grade intraepithelial neoplasia, high-grade intraepithelial neoplasia, and early gastric cancer patients and healthy controls, providing evidence to support the screening value of liquid biopsy in precancerous lesions. However, the application of liquid biopsy in the screening of gastric precancerous lesions is still in the research stage, and it is recommended to combine liquid biopsy with other detection methods to improve diagnostic accuracy.

Screening for gastric precancerous lesions is crucial for early detection and treatment of gastric cancer. Methods such as serological screening, Helicobacter pylori testing, imaging examinations, endoscopic screening, and liquid biopsy provide multiple ways to assess the risk of gastric cancer. For high-risk people aged 45 years and above, regular gastroscopy screening should be performed. Combining multiple detection methods can improve the sensitivity and specificity of diagnosis. For suspicious lesions, a pathological biopsy is recommended to confirm the diagnosis. In addition, a healthy lifestyle and eating habits are also important measures to prevent gastric cancer.