Gastric cancer is one of the most common cancers worldwide, especially in East Asia. Although surgery remains the main treatment, patients may experience postoperative complications and have varying long-term survival outcomes. Early identification of high-risk patients before surgery is important for improving treatment decisions and patient management.

This study aims to develop a prediction model based on routinely available preoperative blood test results and clinical characteristics to estimate the risk of postoperative complications and long-term survival in patients with gastric cancer. The model will be developed and validated using data from multiple medical centers.

By using easily accessible clinical information, this study seeks to provide a practical tool to help clinicians better assess patient risk before surgery, support personalized treatment planning, and improve overall patient outcomes.

Inclusion Criteria:

• patients aged ≥18 years;
• patients diagnosed with gastric cancer by pathological biopsy before surgery;
• patients without chemotherapy, radiotherapy, targeted and immunotherapy before enrolment;
• willing to participate in this study and sign the informed consent;
• complete clinical data.

Exclusion Criteria:

• patients with other primary malignant tumours other than gastric cancer;
• patients with systemic diseases such as severe cardiopulmonary insufficiency that affect the choice of treatment plan;
• patients who are not suitable for enrolment as assessed by the investigator;
• incomplete clinical data.

Patients diagnosed with gastric cancer and undergoing radical gastric cancer surgery at the First Hospital of Chongqing Medical University, the Second Hospital of Chongqing Medical University, and the Yongchuan Hospital of Chongqing Medical University.

None of the three clinical centres conducting the study allowed the disclosure of patient information and data sharing.