Consensus Guideline for the Management of Gastric Cancer with Synchronous Peritoneal Metastases

Background. Gastric cancer with synchronous peritoneal metastases (GCPM) is a debilitating disease with limited treatment options. This manuscript describes an update of the 2018 Chicago Consensus Guidelines addressing the management of GCPM in line with most recent evidence. Methods. A clinical management pathway was updated through two rounds of a Delphi Consensus to assess agreement levels with pathway blocks. Supporting evidence underwent evaluation via a rapid literature review. Meta-analyses were performed where appropriate. Results. Overall, level of evidence in this disease subset was low to moderate. Of 124 participants in the first round, 109 (88%) responded in the second round. Strong consensus (>90%) was achieved in 6/8 (75%) blocks in round I and II. A multidisciplinary preoperative assessment and diagnostic laparoscopy should be offered to all patients, while patients with a high burden of disease or progression should undergo non-surgical management. Patients with stable/responsive disease and low peritoneal carcinomatosis index should subsequently be offered treatment with regional therapeutic interventions and cytoreductive surgery. In patients who are cytology positive, systemic therapy can be used to convert these patients to cytology negative, with subsequent surgery offered per the patient's goals of care. Meta-analysis of observational and randomized control trials revealed a survival benefit with the addition of intraperitoneal chemotherapy to cytoreductive surgery (HR 0.52). Conclusion. The consensus-driven clinical pathway for GCPMs offers vital clinical guidance for practitioners. There is a growing body of high-quality evidence to support management strategies and future clinical trials are eagerly awaited.