Objective   This study aimed to develop a novel multidisciplinary treatment strategy combining neoadjuvant intraperitoneal-systemic chemotherapy protocol (NIPS) and peritonectomy.

  Methods   Gastric cancer patients with peritoneal carcinomatosis (PC) (n=96) were enrolled. Peritoneal wash cytology was performed before and after NIPS through a port system. For systemic chemotherapy, the patients were treated with 60mg/m² of oral S-1 for 21d, followed by a 1-week rest. For intraperitoneal chemotherapy, 30mg/m² of Docetaxel and 30mg/m² of cisplatin with 500 mL of saline were introduced through the port on d 1, 8, and 15. Two cycles of the NIPS regimen was conducted before surgery. Three weeks after NIPS, 82 eligible patients underwent complete cytoreductive surgery (CRS) by gastrectomy plus D2 dissection and peritonectomy.

  Results   Positive cytologic result was observed in 68patients treated with peritoneal washing before NIPS. The number was reduced to 47(69.1%) after NIPS. After NIPS, complete pathologic response on PC was observed in 30(36.8%) patients. Reduction of tumor stages occurred in12patients (14.6%). Complete cytoreduction was achieved in 58of the total patients (70.7%). Grade4 toxicities occurred in 9 cases, and the overall perioperative mortality rate was 3.7% (3/82). By multivariate analysis, complete cytoreduction and pathologic response were found to be independent factors for achieving a satisfactory survival rate.

  Conclusion   The optimal candidates for such multidisciplinary approach are patients with favorable pathologic response and PCI ≤6, among whom complete CRS could be achieved with peritonectomy.