Clinical Research Directory

Inclusion Criteria: * Age 18 to 75 years, regardless of sex, willing to participate in the study and able to provide written informed consent. Histologically confirmed gastroesophageal junction adenocarcinoma. Tumor classification meeting the definition of Siewert type I, II, or III gastroesophageal junction adenocarcinoma. Locally advanced, resectable or potentially resectable disease based on baseline imaging, with clinical stage cT2-4aN0-3M0 or cT1N+M0. No previous surgery, radiotherapy, chemotherapy, targeted therapy, or immunotherapy for the current gastroesophageal junction tumor. Measurable/evaluable primary tumor and/or regional lymph node lesions on baseline imaging. Considered suitable by a multidisciplinary team for sintilimab plus XELOX induction therapy, sintilimab plus capecitabine concurrent chemoradiotherapy, and optional sintilimab plus XELOX consolidation therapy, with the potential to undergo radical surgery. ECOG performance status of 0-1. Adequate major organ function to receive study treatment and subsequent surgery. Able to understand and comply with the study treatment, assessments, surgery, and follow-up procedures and provide written informed consent. Exclusion Criteria: * Patients considered unsuitable by the multidisciplinary team for neoadjuvant chemoradiotherapy, immunotherapy, or subsequent radical surgery. Definite distant metastasis, peritoneal dissemination, or other M1 disease. Previous surgery, radiotherapy, chemotherapy, targeted therapy, or immunotherapy for the current gastroesophageal junction tumor. Previous radiotherapy to the mediastinum, upper abdomen, or gastroesophageal junction region that may affect radiotherapy administration or safety assessment. Severe hypersensitivity to sintilimab, oxaliplatin, capecitabine, or related components. Unhealed gastrointestinal perforation, gastrointestinal fistula, active gastrointestinal bleeding, complete obstruction, or other severe gastrointestinal disease that may substantially increase treatment risk. Active autoimmune disease or a history of autoimmune disease requiring systemic immunosuppressive treatment that may increase the risk of immunotherapy. Grade ≥2 peripheral sensory neuropathy at baseline. Uncontrolled serious infection, including active hepatitis B, hepatitis C, HIV infection, or other infection considered clinically significant by the investigator. Serious cardiovascular or cerebrovascular events within 6 months before enrollment, uncontrolled arrhythmia, or NYHA class III-IV heart failure. Uncontrolled hypertension, severe hepatic or renal dysfunction, severe pulmonary disease, active interstitial lung disease, or other serious underlying disease that may affect treatment or surgical safety. Pregnant or breastfeeding women, or individuals of childbearing potential unwilling to use effective contraception during study treatment and for the protocol-specified period after the last dose. Other malignancy within the previous 5 years, except specified low-risk malignancies. Psychiatric disorders, substance abuse, or other conditions that may interfere with informed consent, treatment adherence, or follow-up. Participation in another interventional clinical study or any other condition considered inappropriate for study participation by the investigator.