Management of Gastric Cancer with Peritoneal Carcinomatosis

Introduction to Treatment Approaches

The National Comprehensive Cancer Network recommends palliative systemic chemotherapy as the standard approach for gastric cancer with peritoneal carcinomatosis, but cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) should be offered to highly selected patients with limited disease burden (PCI <6-7) at experienced centers, providing significant survival benefit over chemotherapy alone 1, 2

Patients with ECOG PS ≥3 or Karnofsky Performance Status <60% should be offered palliative/best supportive care only, as per the National Comprehensive Cancer Network guidelines 1
Patients with better performance status should consider systemic therapy with or without peritoneal-directed treatments based on disease burden, according to the National Comprehensive Cancer Network 1

Cytoreductive surgery + HIPEC represents the most aggressive curative-intent option and should only be performed at specialized centers with appropriate expertise, as recommended by the Gastric Cancer guidelines 2, 1
Patient selection criteria for CRS + HIPEC include limited peritoneal disease (PCI <6-7), good performance status, metachronous peritoneal carcinomatosis, and no extra-peritoneal unresectable metastases, as suggested by the Gastric Cancer and Journal of Clinical Oncology guidelines 2, 1, 3, 4
The ability to achieve complete cytoreduction (R0 resection) is crucial for CRS + HIPEC, according to the Praxis Medical Insights guidelines 5

Median overall survival with CRS + HIPEC is 11-24 months, compared to 5-6.5 months with surgery alone, as reported by the Journal of the National Comprehensive Cancer Network 1
The CYTO-CHIP phase III trial demonstrated median survival of 11 months with CRS + HIPEC versus 6.5 months with CRS alone (p=0.046), according to the Journal of the National Comprehensive Cancer Network 1

Systemic chemotherapy alone remains the standard for most patients with peritoneal carcinomatosis, with a median overall survival of 5-6 months, as reported by the Journal of Clinical Oncology 3, 4
Molecular testing, including HER2, PD-L1, CLDN18.2, and MSI/MMR status, is essential for guiding systemic therapy selection, as recommended by the National Comprehensive Cancer Network 1
Next-generation sequencing via validated assay should be considered, according to the National Comprehensive Cancer Network guidelines 1

PIPAC represents a novel palliative approach for patients not candidates for CRS + HIPEC, with a median overall survival of 15 months, as reported by the Journal of Clinical Oncology 3, 7, 4
PIPAC should only be performed within clinical trials, as recommended by the Journal of Clinical Oncology 3, 7, 4

Palliative gastrojejunostomy is beneficial for unresectable distal gastric cancer causing obstruction, as reported by the Gastric Cancer guidelines 2, 8
Endoscopic stenting is an effective alternative, especially for poor performance status patients, according to the Gastric Cancer guidelines 2, 8

Overestimating disease burden with CT imaging, as CT sensitivity for peritoneal metastases is only 28-51%, despite 97-99% specificity, as reported by the Praxis Medical Insights guidelines 9
Offering CRS + HIPEC to unselected patients, as this procedure should be restricted to patients with PCI <6-7, good performance status, and no extra-peritoneal disease at experienced centers only, as recommended by the Gastric Cancer and Journal of the National Comprehensive Cancer Network guidelines 2, 1
Pursuing reduction surgery based on outdated evidence, as the REGATTA trial definitively showed no benefit, and this approach should be abandoned outside of highly exceptional circumstances, according to the Gastric Cancer guidelines 2, 8
Performing PIPAC or experimental intraperitoneal chemotherapy outside clinical trials, as these approaches lack definitive evidence and should be restricted to research settings, as recommended by the Journal of Clinical Oncology 3, 7, 4
Failing to assess molecular markers, including HER2, PD-L1, CLDN18.2, and MSI/MMR testing, which are essential for guiding systemic therapy selection, as recommended by the National Comprehensive Cancer Network guidelines 1