The INDEPSO-ISPSM Consensus on Peritoneal Malignancies-Gastric Cancer Peritoneal Metastases

This manuscript reports the results of a consensus exercise that aimed to provide recommendations on issues related to the management of gastric peritoneal metastases (PM) for which evidence is limited. The modified Delphi technique was used. Twenty-four questions were framed on 8 main topics; preoperative work up, indications and patient selection for CRS, role of neoadjuvant chemotherapy, hyperthermic intraperitoneal chemotherapy in GC, management of patients with positive peritoneal cytology, Her2 positive and signet ring cell cancers, role of maintenance treatment and management of unresectable PM. A consensus was achieved if anyone option received > 70% votes. The response rate was 97.6% (42/43) in round I and 88.3% (38/43) in round II. Overall, a consensus was achieved on 20/24 (83.3%) questions and a strong consensus in 5/24 (20.8%). CRS was recommended in selected patients with PCI < / = 6 (82.93%), in specialized centers only (70.73%). HIPEC after CRS was recommended only in patients with a CC-0 resection (89.47%) including very selected patients with signet ring cell cancers (low PCI; good responders to systemic chemotherapy). Prophylactic HIPEC was recommended only in the setting of a clinical trial (87.80%). Systemic chemotherapy alone was recommended in patients with newly-diagnosed GC PM (70.73%). However pressurized intraperitoneal chemotherapy (PIPAC) was recommended by 60.98%. The panel recommends CRS and HIPEC in well selected patients of GCPM, including those with signet ring cells cancers. Intraperitoneal treatments for prophylaxis and treatment of newly-diagnosed PM were not recommended outside clinical trials. The results of this consensus including the recommendations on the extent of surgery like visceral resections and lymphadenectomy should be a useful resource for clinicians treating gastric PM.

The online version contains supplementary material available at 10.1007/s13193-025-02460-z.