Clinical significance of the preoperative main pancreatic duct dilation and neutrophil-to-lymphocyte ratio in pancreatic neuroendocrine tumors (PNETs) of the head after curative resection

BACKGROUND: The present study aimed to investigate the prognostic significance of preoperative main pancreatic duct dilation and the neutrophil-to-lymphocyte ratio (PD-NLR) in pancreatic neuroendocrine tumors (PNETs) of the head after curative resection. METHODS: Sixty-four consecutive PNETs of the head that underwent curative resection were included in the study. Preoperative main pancreatic duct dilation (PD) was defined as a pancreatic duct dilation greater than 3 mm before surgery. Patients with both PD and an elevated NLR (> 3.13), with PD or elevated NLR, or neither of these characteristics were allocated a PD-NLR score of 2, 1, or 0, respectively. Univariate, multivariate and Kaplan-Meier analyses were used to calculate overall survival (OS) and disease-free survival (DFS). RESULTS: Preoperative PD-NLR score was correlated with tumor size (P = 0.005), T-stage (P = 0.016), lymph node metastasis (P < 0.001), distant metastasis (P = 0.005), type of hormone production (P = 0.006), perineural invasion (P = 0.014), and WHO classification (P < 0.001). Patients with a high PD-NLR score had a significantly poor OS and DFS relative to those with a low PD-NLR score (P < 0.001). In the multivariate analysis, PD-NLR score was an independent predictor of OS and DFS for PNET of the head (both P < 0.05). In the analyses of the various subgroups, preoperative PD-NLR score was also a predictor of OS and DFS. Additionally, the survival predictive capability of PD-NLR score was superior to that of WHO classification. CONCLUSIONS: Despite the retrospective nature and small sample size of the present study, the results suggest that preoperative PD-NLR score can serve as an independent prognostic marker of early survival in patients with PNETs of the head undergoing curative resection. Further large prospective studies are necessary to validate our findings.