Supplementary Material for: Clinicoradiological Factors Predicting Lymph Node Metastasis in Patients with Nonfunctioning Pancreatic Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis

Introduction: Lymph node metastasis of nonfunctioning pancreatic neuroendocrine neoplasms (pNENs) potentially leads to poor survival. Given the contradictory results in the literature regarding factors associated with lymph node metastasis of nonfunctioning pNENs, we conducted a systematic review and meta-analysis to determine the preoperative predictors of lymph node metastasis. Methods: Original studies reporting factors associated with lymph node metastasis in patients with nonfunctioning pNENs were identified in PubMed, EMBASE, and Cochrane Library databases, and data from eligible studies were analyzed using random-effects meta-analysis to obtain pooled estimates of odds ratios (OR) and their 95% confidence intervals (CI). Results: Eleven studies were included. Tumor size (>2 cm or >2.5 cm; OR, 5.80 [95% CI, 4.07–8.25]) and pancreatic head location (OR, 1.75 [95% CI, 1.05–2.94]) were significant preoperative predictors of lymph node metastasis. Age (OR, 1.07 [95% CI, 0.68–1.68]) and male sex (OR, 1.12 [95% CI, 0.74–1.70]) were not significantly associated with lymph node metastasis. Conclusions: A large tumor size and pancreatic head location can be useful for planning optimal treatment in patients with nonfunctioning pNENs.