Study of Hypofractionated Radiotherapy with Immunochemotherapy for Treating Advanced Gastroesophageal Junction Adenocarcinoma

What this Trial Is About

Researchers are investigating the safety and effectiveness of a treatment combining hypofractionated radiotherapy HFRT with immunochemotherapy ICT for patients who have locally advanced or metastatic unresectable gastroesophageal junction adenocarcinoma GEJA. This study aims to see if this combined approach can improve the objective response rate compared to immunochemotherapy alone while being safe and well-tolerated. The trial includes Phase Ib and Phase II stages to evaluate these aspects in detail. The treatment involves HFRT administered at different dose levels during Phase Ib to determine the recommended dose, which is then used in Phase II. The immunochemotherapy consists of a PD-1 inhibitor called Sintilimab given intravenously every three weeks and a chemotherapy regimen known as SOX, which includes Oxaliplatin infusion on Day 1 and oral S-1 taken for 14 days followed by a 7-day break. Participants are randomly assigned to either the combination of HFRT plus ICT or ICT alone. Participants will be closely monitored through various assessments including safety and tolerability within three months after HFRT, and evaluation of tumor response about four weeks after surgery to remove the primary lesion. Additional outcomes measured include surgical success rate, duration of response, progression-free survival, overall survival, adverse events up to 90 days after treatment, and quality of life assessments at multiple time points. The study is planned to continue follow-up for up to three years to gather comprehensive data on these outcomes.

Hypofractionated Radiotherapy Combined With Immunochemotherapy for Conversion Treatment of Gastroesophageal Junction Adenocarcinoma