Toward a Preoperative Classification of Lymph Node Metastases in Patients with Small Intestinal Neuroendocrine Tumors in the Era of Intestinal-Sparing Surgery.

ABSTRACT

INTRODUCTION: In patients with small intestinal neuroendocrine tumors (siNETs), surgical resection of the primary tumor and associated mesenteric lymph nodes (LNs) is recommended, but is not well standardized and can be risky in patients with superior mesenteric vessel involvement. OBJECTIVE: We aimed to evaluate the correlation between the length of resected small bowel and the number of removed LNs, and to propose a preoperative morphological classification of siNET-associated LNs. METHODS: The records of patients operated on for siNETs at two expert centers between August 2005 and November 2013 were analyzed. Two specialist radiologists reviewed the preoperative imaging and classified mesenteric LNs into five stages according to their proximity to the trunk and/or branches of the superior mesenteric artery. RESULTS: 72 patients were included. The mean number of removed LNs was 12 ± 15 and the length of removed small intestine was 53 ± 43 cm. No correlation existed between the length of small bowel resection and the number of removed LNs. Overall, 9 (12%), 13 (18%), 36 (50%), 14 (19%) and 0 patients were classified into LN stages 0, I, II, III and IV. The correlation rate between the two observers was 0.98. Patients with LN stage III (hardly resectable) had more removed LNs than those with LN stages 0, I or II (easily removable). CONCLUSION: Optimal lymphadenectomy is not always associated with extended small bowel resection. In the era of small bowel-sparing surgery, the preoperative classification of mesenteric LNs could help to standardize the surgical management of patients with siNETs.