Extent of Lymph Node Dissection for Small Bowel Neuroendocrine Tumors

The management of nodal disease remains controversial for small bowel neuroendocrine tumors (SB-NETs). Debates remain regarding the therapeutic role and extent of routine lymph node dissection (LND) for localized SB-NETs, as well as the need for aggressive resection of advanced loco-regional SB-NETs with mesenteric nodal masses. This review will address these questions regarding lymph node dissection for well-differentiated WHO grade 1 and 2 SB-NETs. In general, the aggressiveness and radicality of resection should be balanced against the length of bowel resected and post-operative functional outcomes. In localized SB-NETs with clinically negative lymph nodes, a nodal harvest of ≥ 8 lymph nodes provides accurate staging, but has not been shown to confer survival benefit. For loco-regional SB-NETs with clinically positive lymph nodes identified on imaging, 4 stages of nodal extent have been described: stage 1 nodes are located near to the intestinal border, stage 2 on arterial branches close to the origin of the SMA, stage 3 along the SMA itself, and stage 4 extend in the retroperitoneum under the pancreatic neck. In SB-NETs, every attempt should be made at resection of the primary tumor and the nodal mesenteric mass for curative-intent management and to prevent debilitating complications from mesenteric fibrosis. A mesenteric-sparing approach is favored to allow for resection for complex proximal nodal masses while preserving intestinal length and function. All patients with SB-NETs with nodal mesenteric mass should be assessed by a surgeon for resection; if deemed unresectable, consideration should be given to assessment in high-volume NETs centres to confirm proximal mesenteric-sparing resection is not feasible.