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.
Study Type
OBSERVATIONAL
Enrollment
300
Any PD-1 inhibitors combined with any chemotherapy regimen given before surgery for no more than 4 cycles
Any PD-1 inhibitors combined with any chemotherapy regimen given before surgery for no less than 5 cycles
Any type of surgical procedure for gastric adenocarcinoma patients in which part or all of the stomach is removed
Chinese PLA General Hospital
Beijing, China
RECRUITINGTumor Regression Grading (TRG)
Tumor Regression Grading (TRG) based on the Chinese Society of Clinical Oncology (CSCO) guidelines ranging from 0 (no residual tumor) to 3 (extensive residual tumor cells with no or minimal tumor cell necrosis), with higher scores indicating worse outcomes
Time frame: Approximately 1 week after surgery (when the pathology examination report available)
Safety
Adverse events during neoadjuvant therapy and postoperative complications
Time frame: From the start of neoadjuvant chemotherapy to 7 days after surgery
R0 resection
Complete removal of a tumor with no residual cancer cells at the surgical margins, confirmed by pathological examination
Time frame: Approximately 1 week after surgery (when the pathology examination report available)
Operative time
The total duration of a surgical procedure, measured from the first incision to the completion of wound closure
Time frame: On the day of the surgery (can be obtained immediately after the completion of the surgery)
Time to first flatus
The duration from the completion of surgery to the first passing of gas (flatus) by the patient
Time frame: From date of surgery until the date of first flatus, assessed up to 10 days post-surgery
Nutritional Risk Screening 2002 (NRS 2002)
The Nutritional Risk Screening 2002 (NRS 2002) is a scale used to assess the nutritional risk of hospitalized patients. The score ranges from 0 to 7, with higher scores indicating a higher risk of malnutrition. A score of 0 signifies no nutritional risk, while a score of 3 or higher indicates a significant nutritional risk that may require intervention.
Time frame: Approximately 1 week after completing all neoadjuvant therapy
YpTNM staging
Pathological classification used to assess cancer characteristics after neoadjuvant therapy, based on the American Joint Committee on Cancer (AJCC) Cancer Staging Manual 8th Edition.
Time frame: Approximately 1 week after surgery (when the pathology examination report available)
Dissected lymph node number
The total number of lymph nodes surgically removed and examined
Time frame: Approximately 1 week after surgery (when the pathology examination report available)
Positive lymph node number
The number of lymph nodes found to contain cancer cells upon pathological examination
Time frame: Approximately 1 week after surgery (when the pathology examination report available)
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