[Treatment options for peritoneal metastases from hepato-pancreato-biliary tumors and neuroendocrine tumors].

Peritoneal metastasis (PM) in gastroenteropancreatic neuroendocrine tumors (GEP-NET) and hepato-pancreato-biliary (HPB) tumors has a low incidence and has rarely been studied as a stand-alone condition. The clinical relevance of PM in HPB tumors and GEP-NET arises from the fact that PM significantly worsens the prognosis of the underlying tumors. In GEP-NET, the particular situation is that PM has a negative prognostic impact compared to patients without metastases, which is not evident compared to patients with metastases in other locations. Complete surgical cytoreduction (CRS) is a curative treatment option for patients with PM in GEP-NET. Complete surgical resection should always be strived for, although patients may benefit from incomplete resection (70-90%) or resection of the primary tumor alone. Additional hyperthermic chemoperfusion (HIPEC) is currently not recommended. For nonresectable GEP-NET, systemic treatment is available that is oriented to the studies for generally metastasized GEP-NET. For PM in carcinomas of the bile duct and pancreatic carcinomas, there are no valid data or indications for CRS and HIPEC. In contrast, case series for PM in hepatocellular carcinoma (HCC) after CRS or CRS/HIPEC show good survival outcomes that justify a surgical approach under the condition of a complete resection. Patients with PM in GEP-NET and HCC should therefore be referred to a center for peritoneal tumor surgery to evaluate the option of complete CRS and use it as a curative option.