[A Case of cy1 Advanced Gastric Cancer That Achieved CR after Chemotherapy Via an Enterostomy].

A 67-year-old male presented with severe epigastric pain in May 2023 and was diagnosed with Stage Ⅲ advanced gastric cancer(cStage Ⅲ)in June. Due to indistinct boundaries between lymph node #8a and the pancreas, non-resectional chemotherapy and enterostomy were performed during a diagnostic laparotomy. The diagnosis was updated to sStage Ⅳ with cy1. Beginning in July, the patient was administered SOX and nivolumab. Following 6 courses, CT scans in December revealed clearer boundaries, allowing for conversion surgery in January 2024. This surgery resulted in a pathological complete response(pCR), with no detectable malignant cells. Despite postoperative complications, the patient was discharged on day 34 and is currently receiving outpatient S-1 therapy. This case suggests that enterostomy may facilitate conversion surgery to achieve pCR, thereby providing a new treatment strategy for advanced gastric cancer.