Updating the Surgical Management of Peritoneal Carcinomatosis in Patients with Neuroendocrine Tumors

Abstract

Well-differentiated digestive neuroendocrine tumors (NET) are a heterogeneous group of neoplasms usually associated with slow growth but a high rate of metastases, including peritoneal carcinomatosis (PC). Herein, we aimed to comprehensively review the current knowledge of PC in terms of implications for the management and prognosis of patients with NET, including the latest studies and expert statements. NET-derived PC concerns about 17% of NET patients and up to 30% of those with small intestine primary NET. It has an independent pejorative prognostic impact. The extent of PC in NET patients and its severity can be expressed by analogy to other malignancies. However, it must be placed in the context of NET disorders, which usually vary from other PC-related malignancies. Recently, a gravity PC score was proposed by a consensus European Neuroendocrine Tumor Society (ENETS) expert group, but it requires validation. In addition, the form of peritoneal involvement (nodular or fusiform/infiltrative) might influence its prognosis and management. Aggressive surgical management seems justified for subsets of NET-related PC but requires careful selection of the candidates most likely to benefit. Cytoreductive surgery prolongs survival, especially when the peritoneal lesions are completely resected. Too little is known about the benefit of hyperthermic intraperitoneal chemotherapy for NET-derived PC, but if it confers an advantage, it would have to be counterbalanced by its high morbidity.

Update on Surgical Management of Small Bowel Neuroendocrine Tumors

“…Peritoneal cavity is the third most common site of metastasis following lymph nodes and liver (81). The reported incidence of PC is approximately 13.6%.…”

“…Several patients present with 'frozen abdomen', especially in the pelvis, despite the absence of extensive liver metastatic disease (32). The presence of bulky disease in the peritoneal cavity is an ominous prognostic characteristic (81).…”

“…Surgical intervention in PC due to NETs remains debatable (81,82). However, it may be necessary for preventing serious complications such as bowel obstruction, mesenteric fibrosis, gastrointestinal bleeding, and portal vein hypertension (55).…”

“…CCR is the main prognostic factor for OS after surgery and is independent of the initial exten of PC (83). Thus, surgery should be opted for patients with anticipated low CCR score after the operation including, those with peritoneal carcinomatosis index <20, or abdominal gravity peritoneal carcinomatosis score (GPS)-A or GPS-B low (81).…”

“…The main limitation of HIPEC in this setting is that chemotherapy is used against tumors with a low proliferative rate (85). Added risk of morbidity and mortality should be also taken into consideration when HIPEC is considered simultaneously with another major surgery (81).…”