This study aims to develop and validate an artificial intelligence (AI) system that can predict whether lymph node metastasis has occurred in patients with gastric cancer before surgery. Using preoperative imaging and pathology data, the AI models will not only predict if metastasis is present but also identify which specific lymph node stations or individual lymph nodes are involved. All lymph nodes will be carefully removed during surgery and examined one by one with detailed pathological methods to ensure accurate diagnosis. The goal is to improve the accuracy of lymph node assessment and assist doctors in making better treatment decisions.

Inclusion Criteria:

• Age 18 years or older

Histologically confirmed gastric adenocarcinoma

Scheduled for curative-intent gastrectomy with lymphadenectomy

Completed preoperative imaging with contrast-enhanced CT or MRI

Available preoperative biopsy pathology report

Able and willing to provide written informed consent

Exclusion Criteria:

• Evidence of distant metastasis on preoperative imaging

Prior chemotherapy, radiotherapy, or major abdominal surgery

Severe comorbidities contraindicating surgery

Incomplete or poor-quality preoperative imaging or pathology data

Pregnancy or lactation

The study will enroll adult patients diagnosed with gastric adenocarcinoma who are scheduled to undergo curative-intent gastrectomy with lymphadenectomy. Participants must have completed preoperative imaging studies and histopathological evaluation. All enrolled patients will have individually retrieved lymph nodes evaluated by detailed pathological examination to provide a definitive reference for lymph node metastasis status.