study of adjuvant chemotherapy with or without pd-1 inhibitors and chemoradiotherapy in resected pn3 gastric (g) or gej adenocarcinoma

Conditions: Gastric Cancer

Summary: the purpose of the study is to evaluate the efficacy and safety of postoperative adjuvant chemotherapy with pd-1 inhibitors and chemoradiotherapy, in comparison with adjuvant chemotherapy only, in d2/r0 resected pn3 gastric or gastroesophageal junction adenocarcinoma. pd-1+crt cohort: a total of 216 patients will receive 6 weeks of pd-1 inhibitors and chemotherapy, then receive concurrent chemoradiotherapy, followed by 6 weeks of pd-1 inhibitors and chemotherapy, finally receive maintenance treatment of pd-1 inhibitors until (maximum 1year after radiotherapy). ct cohort: a total of 217 patients will receive 6 months of chemotherapy. the disease-free survival(dfs), overall survival(os) and adverse effects will be analyzed.


Eligibility criteria:
inclusion criteria: * eastern cooperative oncology group (ecog) performance status (ps) score of 0 or 1 * patients with expected survival time more than 6 months * patients after standard d2/r0 resection * postoperative histologically confirmed adenocarcinoma of the stomach or gej * positive lymph nodes more than 7, stage pn3 * patients without distant metastasis (m0) or m1 with abdominal exfoliated cell detection positive (cy1p0) * patients' physical condition and visceral function allows following adjuvant therapy, including chemotherapy, chemoradiotherapy and pd-1 inhibitor therapy. * patients' blood routine and biochemical indicators should meet the following standard: hb≥90g/l, anc≥1.5\*10\^9/l, plt≥100\*10\^9/l, alt \& ast≤2.5 u/l, tb ≤ 1.5 unl, serum creatinine\<1 unl. * patients who are willing to obey regimens during the study. * written informed consent is acquired before random entry, and patients should know that he/she has the right to quit, and following treatment won't be affected. * patients are willing to provide samples of blood and tissue. exclusion criteria: * patients with gross peritoneal metastasis (cy1p0 excluded) or distant metastasis. * patients who has received any anti-tumor therapy before surgery. * patients who had received radiotherapy for abdominal organs including stomach, liver, kidney, etc. * patients who had active systematic autoimmune diseases which need systematic treatment within 2 years before first medication in the study, substitutive therapy (such as thyroxine, insulin, etc) excluded. * patients diagnosed with immunodeficiency, or was receiving systematic glucocorticoid treatment or other immunosuppressive therapy within 7 days before medication, physiological dose of glucocorticoid is allowed (≤10 mg/d prednison or equivalent medication) * patients who have known severe allergic reaction (≥level 3) to anti-pd-1 monoclonal antibody, 5-fu, oxaliplatin or any auxiliary material. * patient diagnosed with other malignant tumor in the past 5 years, excluding radical basal cell carcinoma of the skin and/or radical resected carcinoma in situ. * patient with severe vital organ failure. * pregnant or lactation period * patient with known mental illness or drug abuse that may influence compliance. * patient with known hiv infection, or active tuberculosis. * untreated active hepatitis b * patient with active hcv infection * uncontrolled complications * other situations that might disturb study results and compliance.