Esophagogastric Junction Cancer

The purpose of this study is to evaluate the efficacy and safety of ONO-4578 in combination nivolumab and chemotherapy in participants with advanced or metastatic gastric cancer, esophagogastric junction cancer, or esophageal adenocarcinoma. Participants will: * Receive either ONO-4578 with nivolumab and chemotherapy or placebo with nivolumab and chemotherapy. * Make visits to the clinic for checkups and tests. * Answer questions about their health throughout the trial.

Definitive chemoradiotherapy is the standard of care in unresectable esophageal or esophagogastric cancer. A multidisciplinary approach, including chemotherapy and radiotherapy, is important for these patients. Morerover, molecular targeting agents does not show clear efficacy in EC up to now. Nowadays, the pace of development of cancer immunotherapies is accelerating. Clinical evidence of the efficacy of immune checkpoint inhibitors and adoptive immunotherapies herald the onset of a new era in cancer immunotherapy. There have also been recent developments to provide a promising frontier in extending the use of immunotherpay or targeting agents to radiotherapy. The purpose of this study was to explore the optimal treatment modalities including PD-1/PD-L1 antibody or targeted drug for patients with unresectable esophageal or esophagogastric junction cancer.

For locally advanced esophagogastric junction and gastric cancer, neoadjuvant chemotherapy can downstage T and N stage,treated distant micrometastases early , and finally improve the long-term survival. Combination of perioperative PD-1 antibody and chemotherapy for locally advanced esophagogastric junction and gastric cancer could be a novel therapy to increase response rate and reduce recurrence rate.Cadonilimab, a tetravalent bispecific antibody targeting PD-1 and CTLA-4, is designed to retain the efficacy benefit of combination of PD-1 and CTLA-4 and improve on the safety profile of the combination therapy. The aim of this study is to evaluate the efficacy and safety of cadonilimab Plus Chemotherapy for Locally Advanced Esophagogastric Junction and Gastric Cancer.

Magnetic resonance imaging (MRI) with functional features of diffusion weighted imaging (DWI) are advancing imaging technologies that have potential to overcome limitations of conventional staging methods, radiation treatment planning and the assessment of tumor response in esophageal or esophagogastric cancer. This study aimed to explore the value of MRI for the prediction of tumor response to chemoradiotherapy and accurate target volume delineation as compared to CT simulation for patients with unresectable or potentially resectable esophageal or esophagogastric cancer undergoing chemoradiotherapy. The average CT texture features are also extracted before and during treatment to establish a model to predict the prognosis or side effects (e.g. radiation pneumonitis or esophagitis) of patients.