Principles of Surgical Management of Small Intestinal NET

SIMPLE SUMMARY: Small-intestinal neuroendocrine tumors (siNETs) account for 25% of gastroenteropancreatic NETs. A total of 89% of multiple tumors are located in the ileum, often within 100 cm of the ileocecal valve. According to current guidelines, all localized siNETs should be considered for radical resection with lymphadenectomy. The preoperative workout should focus on symptoms of carcinoid syndrome (flush, diarrhea, and cardiac failure). Morphological evaluation should include a CT scan with a thin-slice arterial CT, a PET/CT with 68 Ga, and a hepatic MRI. Levels of 24 h urinary 5-hydroxyindoleacetic acid are needed. Regarding surgery, the limiting component is the number of free jejunal branches allowing a resection without risk of short small bowel syndrome. In case of emergency surgery, there is expert agreement that it is not reasonable to initiate resection of the mesenteric mass without comprehensive workup and mapping. The challenge lies in the ability to propose a resection without imposing short small bowel syndrome on the patients. ABSTRACT: Introduction: Small-intestinal neuroendocrine tumors (siNETs) account for 25% of gastroenteropancreatic NETs. Multiple siNETs appear to develop in a limited segment of the small bowel (SB), 89% of them being located in the ileum, most often within 100 cm of the ileocecal valve (ICV). According to the European Neuroendocrine Tumor Society (ENETS) and the American Joint Committee on Cancer (AJCC), all localized siNETs should be considered for radical surgical resection with adequate lymphadenectomy irrespective of the absence of lymphadenopathy or mesenteric involvement. Surgical management of siNETs: The preoperative workout should include a precise evaluation of past medical and surgical history, focusing on the symptoms of carcinoid syndrome (flush, diarrhea, and cardiac failure). Morphological evaluation should include a CT scan including a thin-slice arterial CT, a PET/CT with 68 Ga, and a hepatic MRI in cases of suspected metastasis. Levels of 24 h urinary 5-hydroxyindoleacetic acid are needed. Regarding surgery, the limiting component is the number of free jejunal branches allowing a resection without risk of short small bowel syndrome. The laparoscopic approach has been poorly studied, and open laparotomy remains the gold standard to explore the abdominal cavity and entirely palpate the small bowel through bidigital palpation and compression. An extensive lymphadenectomy is required. A prophylactic cholecystectomy should be performed. In case of emergency surgery, current recommendations are not definitive. However, there is expert agreement that it is not reasonable to initiate resection of the mesenteric mass without comprehensive workup and mapping. Conclusion: The surgery of siNETs is in constant evolution. The challenge lies in the ability to propose a resection without imposing short small bowel syndrome on the patients. The oncological benefits supported in the literature led to recent changes in the recommendations of academic societies. The next steps remain the dissemination of reproducible quality criteria to perform these procedures.