This is a single-center, retrospective clinical study to evaluate the efficacy and safety of tislelizumab combined with first-line chemotherapy in the treatment of HER2-negative advanced gastric cancer.

This study aims to include 60 HER-2 negative advanced gastric cancer patients who received first-line treatment with tislelizumab combined with chemotherapy in our hospital from November 1, 2020 to November 1, 2021. Clinicopathological data, blood tests and imaging data of the patients were collected. The primary endpoints evaluated were PFS and OS, and the secondary endpoints were ORR and safety. At the same time, ctDNA and peripheral cytokine status of patients as well as second-generation sequencing of tumor tissues at baseline were collected for the exploration of therapeutic efficacy related biomarkers.

Inclusion Criteria:

1. Patients with initially unresectable (locally advanced or metastatic) or postoperative recurrence of gastric adenocarcinoma or gastroesophageal junction adenocarcinoma confirmed by histopathology have not received any anti-tumor treatment for advanced gastric cancer in the past;
2. Pathological immunohistochemistry or FISH detection of gastric cancer tissue indicates negative Her-2;
3. Age range from 18 to 70 years old, regardless of gender;
4. The distance between postoperative recurrence and the end of neoadjuvant/adjuvant chemotherapy is more than 6 months;
5. If the patient experiences toxic side effects after receiving new adjuvant/adjuvant treatment, they need to recover from previous treatment toxic side effects to ≤ 1 level; According to the RECIST evaluation criteria, there should be at least one assessable lesion. Expected survival time ≥ 3 months;

7. ECOG score ≤ 2 points; 8. Main organ functions are basically normal, blood count (within 7 days): hemoglobin ≥ 90g/L, white blood cells ≥ 4.0 × 109/L, neutrophils ≥ 2.0 × 109/L, platelet ≥ 100.0 × 109/L. Total bilirubin 1.0 UNL, creatinine 1.0 × UNL, AST/ALT 2.5 UNL. Liver metastasis: ASAT/ALAT 5 UNL; 9. The electrocardiogram/cardiac function tests are basically normal.

Exclusion Criteria:

1. Suffering from undifferentiated gastric cancer or squamous cell carcinoma of the gastroesophageal junction and other pathological types of malignant tumors;
2. Have received anti-tumor treatment for gastric adenocarcinoma or adenocarcinoma at the junction of stomach and esophagus that can not be operated on for the first time or recur after operation, including but not limited to chemotherapy, Targeted therapy, immunotherapy, etc. (except for Thymosin and traditional Chinese medicine treatment);
3. Patients with other primary malignant tumors other than gastric cancer, excluding cured skin Basal-cell carcinoma and cervical Carcinoma in situ;
4. Patients with simple or combined brain metastasis;
5. Has experienced gastrointestinal perforation or fistula within 6 months prior to enrollment;
6. Patients who also suffer from other important organ diseases, including severe heart disease;
7. Complications such as uncontrollable moderate to massive ascites, active gastrointestinal bleeding, gastrointestinal perforation, gastrointestinal obstruction, etc;
8. Patients with chronic diseases such as hypertension, hyperglycemia, and COPD that are difficult to control;
9. Those who require antibiotics for systemic anti infection, active hepatitis, active pulmonary tuberculosis, and other diseases.

HER-2 negative, untreated patients with advanced gastric cancer.