Pancreatic neuroendocrine tumors: Preoperative factors that predict lymph node metastases to guide operative strategy

BackgroundEnucleation and anatomic resection (central, distal, or pancreaticoduodenectomy) are surgical options for pancreatic neuroendocrine tumors. Depending on nodal-status, enucleation alone may not be oncologically appropriate. Preoperative factors predictive of nodal-involvement are not well defined. MethodsPatients who underwent curative-intent enucleation or resection of non-metastatic, well/moderately differentiated tumors at a single institution (2000-2014) were included. The aim was to determine factors associated with nodal-metastases and recurrence-free survival. ResultsOf 195 patients undergoing resection, 164 met inclusion-criteria. Lymphadenectomy was performed in 131 (80%), and 32 (24%) had nodal-metastases. Receiver-operative-characteristics analysis revealed tumor size 2cm was associated with nodal-involvement (AUC: 0.689; Sensitivity: 90%; Specificity: 53%). On multivariable analysis, male gender (OR: 3.16; 95%CI: 1.18-8.46; P=0.02), head/uncinate location (HR: 5.37; 95%CI: 2.07-13.96; P=0.001), and size 2cm (HR: 6.52; 95%CI: 1.75-24.30; P=0.005) were associated with nodal-positivity. Nodal-metastases (HR: 3.04; 95%CI: 1.04-8.91; P=0.043) and advanced T-stage (HR: 5.39; 95%CI: 1.46-19.95; P=0.012) were independently associated with decreased recurrence-free survival. Enucleation (n=17; 10%) had more positive margins and similar complication rates, pancreatic fistula rates, and lengths of stay as anatomic resections. ConclusionFor pancreatic neuroendocrine tumors, male gender, head/uncinate location, and size 2cm are associated with nodal-metastases. Nodal involvement is associated with decreased recurrence-free survival. Anatomic resection may be preferred in patients with these characteristics, as enucleation alone may under-stage patients and does not appear to be associated with an improved complication profile. J. Surg. Oncol. 2016;114:440-445. (c) 2016 Wiley Periodicals, Inc.