[A Case of Gastric Perforation Due to an Unresectable Advanced Gastric Cancer That Achieved pCR after Conversion...

This case pertains to a 72-year-old man who visited the emergency department with a complaint of upper abdominal pain. On examination, we suspected gastric perforation due to gastric cancer and decided to perform emergency surgery. We performed laparoscopic omentoplasty and collected #4d lymph nodes that were enlarged on CT. The pathological diagnosis was lymph node metastasis. Based on CT findings, we determined it was Bulky N. For initial management, we performed 3 preoperative chemotherapy(SOX therapy)courses and staging laparoscopy. On surgery, extensive disseminated nodules on the abdominal wall, stomach wall, and liver surface were found, and ascites cytology revealed positive findings. Therefore, we did not perform primary lesion resection. Although the disseminated nodule did not pathologically show tumor cells, CY1 was found, resulting to a diagnosis of unresectable gastric cancer. Since the tumor was HER2 3+, we initiated SOX/trastuzumab therapy. After 16 courses, staging laparoscopy was performed as the lymph nodes had shrunk significantly. The results showed no tumor cells in ascites and the disseminated nodules, and laparoscopic total gastrectomy was subsequently performed. Pathological findings showed no tumor cells in the primary lesion or lymph nodes; therefore, a diagnosis of pathological complete response was made. Currently, the patient is alive without recurrence for 6 months after surgery.