A Case of Type 4 Gastric Cancer with Peritoneal Dissemination in which a Pathological Complete Response was Obtained by SOX（S-1/L-OHP）Therapy

Abstract

A 65-year-old woman presented to our hospital with a high CEA level. Esophagogastroduodenoscopy showed Type 4 advanced gastric cancer extending from the upper body of the stomach to the angular region. Biopsy examination showed a moderately to poorly differentiated adenocarcinoma. On staging laparoscopy, peritoneal lavage cytology was positive, and peritoneal dissemination was found. The clinical stage was T4aN2M1 (PER) : Stage IVB. After five courses of SOX (S-1/L-OHP) were administered, the primary tumor and enlarged lymph nodes had shrunk, and the second-look staging laparoscopy was performed. Since peritoneal dissemination and cytology became negative, conversion surgery (laparoscopic total gastrectomy with D2 lymph node dissection) was performed. Histopathological examination showed that the tumor component in the primary tumor and the lymph nodes had disappeared. Histological effectiveness was Grade 3 (pathological complete response). The patient was discharged without postoperative complications. The patient has received S-1 as postoperative adjuvant chemotherapy and has had no recurrence 10 months after the operation.