Different Cycles of Neoadjuvant PD-1 Blockades + Chemotherapy for Advanced Gastric Cancer

The Comparison of Different Cycles of PD-1 Blockades Combined with Chemotherapy As Neoadjuvant Therapy for Patients with Advanced Gastric Cancer

The goal of this observational study is to analyze the impact of different durations of neoadjuvant PD-1 inhibitor combined with chemotherapy on tumor regression and safety in patients with advanced gastric cancer. The main questions it aims to answer are:

• Does the duration of neoadjuvant treatment influence tumor regression grading (TRG)?
• How does treatment duration affect perioperative safety and clinical outcomes?

Participants who have previously undergone neoadjuvant PD-1 inhibitor combined with chemotherapy followed by surgery as part of their routine medical care will have their clinical data retrospectively reviewed and analyzed.

Inclusion Criteria:

• Non-bedridden patients aged 18-90 years;
• Histologically confirmed gastric or gastroesophageal junction adenocarcinoma by biopsy;
• Evaluated as resectable advanced gastric cancer via CT, MRI, or laparoscopic exploration;
• No prior anti-tumor treatments such as chemotherapy, radiotherapy, or immunotherapy;
• No history of other malignancies within the past 5 years;
• Received at least one cycle of PD-1 inhibitor combined with chemotherapy preoperatively, with no restrictions on the specific PD-1 inhibitor or chemotherapeutic agents;
• Underwent radical gastrectomy after neoadjuvant therapy;
• No severe underlying diseases.

Exclusion Criteria:

• Incomplete or inaccessible clinical and pathological data;
• Postoperative pathology confirming non-gastric or non-gastroesophageal junction adenocarcinoma;
• Distant metastases present prior to treatment;
• Concurrent diagnosis of other malignancies.