Abstract
Background: Gastric cancer with synchronous peritoneal metastases is a debilitating disease with limited treatment options. This article describes an update of the 2018 Chicago Consensus guidelines addressing the management of gastric cancer with synchronous peritoneal metastases in line with the 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 using a rapid literature review. Meta-analyses were performed as appropriate. Results: Overall, the 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 six of eight blocks (75%) in rounds 1 and 2. A multidisciplinary preoperative assessment and diagnostic laparoscopy should be offered to all patients, whereas patients with a high burden of disease or progression should undergo nonsurgical management. Patients with stable/responsive disease and a 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 them to cytology-negative, with subsequent surgery offered according to 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 (hazard ratio, 0.52). Conclusions: The consensus-driven clinical pathway for gastric cancer with synchronous peritoneal metastases 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.