[A Case of Long-Term Survival after Conversion Surgery following Systemic Chemotherapy for Peritoneal Dissemination-Positive Gastric Cancer].

A 60-year-old man was referred to our hospital after he was diagnosed with advanced gastric cancer. When he visited our hospital, upper gastrointestinal endoscopy revealed a type 3 tumor on the posterior wall of the middle greater curvature of the stomach, and histopathological examination revealed a well-differentiated adenocarcinoma(tub1). CT scan showed wall thickening with contrast effect in the middle part of the stomach. In the operation, the peritoneal lavage cytology was negative(CY0), but white nodules were found in the Douglas pouch, the great omentum, and mesentery, and the pathological examination showed adenocarcinoma(P1c). The patient was diagnosed as cT4aN0M1P1cCY0, Stage ⅣB and received S-1 plus CDDP therapy. After 4 courses of chemotherapy, the tumor was reduced. Staging laparoscopy showed no obvious peritoneal dissemination, and the peritoneal lavage cytology and scar nodules in the great omentum and Douglas pouch showed no evidence of malignancy(P0CY0). Therefore, the patient was able to have a conversion surgery, and underwent total gastrectomy with Roux-en-Y reconstruction and cholecystectomy. Pathological examination revealed type 3 tub1, ypT1bN0M0, pStage ⅠA, and the pathological effect of chemotherapy was Grade 1b. The patient was treated with S- 1 for 2 years as adjuvant chemotherapy, and the chemotherapy was terminated because no recurrence was observed by the CT and the laparoscopy. The patient has remained recurrence-free for a total of 10 years since then.