Lymph node metastasis in early gastric cancer: A review of risk stratification and surgical decision-making

Table 1 Comparison of major approaches for lymph node metastasis assessment in early gastric cancer

Approach	Detection target	Advantages	Limitations	Applicable patients	Current level of evidence
CT	Suspicious lymph nodes and distant disease before treatment	Widely available; useful for routine preoperative staging and assessment	Limited sensitivity for small or microscopic metastases; mainly depends on nodal size and morphology	Patients undergoing routine preoperative staging, especially those with suspicious nodes or high-risk features	Widely used, but limited in detecting micrometastatic LNM in EGC
EUS	Depth of gastric wall invasion and morphology of surrounding lymph nodes	Provides high-resolution visualization of gastric wall layers; useful for estimating invasion depth; EUS-guided biopsy may provide pathological confirmation in selected cases	Operator-dependent; more accurate for T staging than N staging; small metastatic nodes may be missed	Patients requiring pretreatment assessment of invasion depth before ESD or further evaluation of suspicious lymph nodes	Mainly used for depth assessment; provides supportive evidence for LNM assessment
PET-CT/FAPI PET	Metabolically active nodal or distant disease	Provides metabolic and anatomical information	Low sensitivity for EGC and micrometastatic disease; inflammatory or fibrotic uptake may cause false-positive findings	Selected patients with suspected advanced disease, distant metastasis, or inconclusive conventional imaging	PET-CT has selective value; FAPI PET remains promising but insufficiently validated in EGC
Sentinel lymph node mapping	Sentinel lymph nodes for pathological assessment of LNM	May identify patients without nodal metastasis; may reduce unnecessary lymph node dissection; ICG enables real-time visualization	Gastric lymphatic drainage is complex; false-negative results may occur; procedures are not fully standardized	Selected EGC patients in experienced or high-volume centers	Supported in selected settings, but not yet a universally standardized routine pathway
Molecular biomarkers/multi-omics	Serum, tissue, genomic, transcriptomic, proteomic, immune, or stromal features associated with LNM	May provide biological information beyond imaging and reflect EMT, lymphangiogenesis or immune activity	Serum markers have low sensitivity in EGC; omics methods lack standardized protocols and sufficient clinical validation	EGC patients in exploratory or research settings	Exploratory; most evidence remains retrospective or early-stage
AI models	AI-assisted prediction of LNM based on clinical, imaging, or pathological data	May detect subtle patterns that are difficult to identify by conventional assessment	Often based on single-center or small datasets; limited interpretability and external validation	EGC patients in exploratory or adjunctive research settings	Promising in selected studies, but insufficient for independent routine clinical decision-making

CT: Computed tomography; EUS: Endoscopic ultrasound; PET-CT: Positron emission tomography-computed tomography; FAPI: Fibroblast activation protein inhibitor; AI: Artificial intelligence; LNM: Lymph node metastasis; ICG: Indocyanine green; EMT: Epithelial-mesenchymal transition; EGC: Early gastric cancer; ESD: Endoscopic submucosal dissection; PET: Positron emission tomography.