The goal of this observational study is to learn about the overall disease status, diagnostic and therapeutic modalities, and prognosis of patients with gastric cancer liver metastasis(GCLM) in China. The investigators divided the participants into three groups( three types) of gastric cancer liver metastasis based onChinese c-GCLM classification system.The main question it aims to answer is:

1. How long do patients with GCLM live?
2. How different treatment modalities (surgery, chemotherapy, immunotherapy, targeted therapy and others) affect patients' prognosis of three type? All participants will be tracked for their physical condition.

This is a prospective, non-interventional, observational, multi-centre, real-world study designed to monitor the general condition, treatment pattern and prognosis of patients with GCLM. GCLM patients were divided into 3 types: Type I (resectable type), Type II (potentially resectable type), Type III (unresectable type). The patients' general information, past medical history, imaging results, laboratory tests, surgical and systemic therapy details will be recorded and analysed. The 2-year overall survival (OS) will be recorded as the primary endpoint. The different therapies (surgery, chemotherapy and immunotherapy) of GCLM, the effects of different therapies on prognosis including OS of type I, II and III; R0 resection rate and diease free survival (DFS) of type I; successful conversion rate and R0 resection rate and events free survival (EFS) of type II will be recorded as secondary endpoints.

This study involving human participants were reviewed and approved by the Ethics Committee of Chinese PLA General Hospital (No.S2023-724-02) and will be conducted according to the guidelines of the Declaration of Helsinki. Study findings will be disseminated through international peer-reviewed journal articles as well as public, academic presentations at national and international conferences.

Inclusion Criteria:

• aged ≥18 years
• gastric primary lesions confirmed by pathology and liver metastases confirmed by pathology or imaging (before, during, or after initial treatment)
• expected survival time of ≥ 12 weeks
• Eastern Cooperative Oncology Group Physical Status Score (ECOG PS score) of 0-2
• signed informed consent
• good compliance and ability to complete regular follow-up

Exclusion Criteria:

• heterochronous liver metastases
• multi-centra clinics with significant missing case information
• diagnosed, suspected or active autoimmune disease
• history of immunodeficiency
• history of allogeneic organ and haematopoietic stem cell transplantation
• pregnant or breastfeeding female patients
• uncontrolled co-morbidities, including but not limited to:
• a.HIV-infected (HIV-positive) patients
• b.severe infections that are active or poorly controlled clinically
• c.evidence of severe or uncontrolled systemic disease
• - severe psychiatric disease
• - severe neurological disease
• - epilepsy
• - dementia
• - unstable or uncompensated respiratory
• - cardiovascular
• - hepatic disease
• - renal disease
• - uncontrolled hypertension
• Abnormal coagulation in people with active bleeding or new thrombotic disease, on therapeutic doses of anticoagulants, or with bleeding tendencies.

The main study population was: patients diagnosed with liver metastases from gastric cancer who met the inclusion and exclusion criteria in China. Patient care in various tertiary hospitals throughout the country.