title: Neutrophil-to-lymphocyte ratio predicts metachronous liver metastasis of pancreatic neuroendocrine tumors.
abstract: BACKGROUND
  Pancreatic neuroendocrine tumors (PNETs) are clinically malignant, having metastatic potential. Histological tumor grade is an accepted indicator of malignant potential, but noninvasive prognostic markers have not yet been identified. This study assessed whether the preoperative neutrophil-to-lymphocyte ratio (NLR) could predict clinical outcomes of PNET patients.
  
  
  METHODS
  Fifty-eight patients who underwent curative resection for PNETs between 2001 and 2015 were retrospectively evaluated. The correlations between the preoperative NLR and clinicopathological parameters, including patient baseline clinical characteristics, tumor progression, and postoperative oncological outcome were evaluated.
  
  
  RESULTS
  A high preoperative NLR was significantly associated with large tumor size (P = 0.0015) and high tumor grade (P < 0.0001). Overall survival and relapse-free survival of patients with a high NLR (≥2.4) were significantly shorter than those of patients with a low NLR (<2.4, P = 0.0481 and P < 0.0001, respectively). Multivariate analysis revealed that NLR ≥2.4 and tumor size ≥2 cm were independent predictors of postoperative recurrence (hazard ratio 6.012, P = 0.0035 and 6.760, P = 0.0049, respectively). Interestingly, a high NLR independently predicted postoperative liver, but not lymph node, metastasis.
  
  
  CONCLUSIONS
  In this patient series, a high NLR (≥2.4) was a noninvasive marker that independently predicted postoperative liver metastasis in patients with PNETs, and thereby could be clinically useful.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Arima
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Okabe
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hashimoto
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Chikamoto
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Nitta
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Higashi
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Kaida
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Yamamura
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kitano
authors.affiliation: Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University Hospital, Kumamoto, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Komohara
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Yo-Ichi
authors.initials: YI
authors.lastname: Yamashita
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Beppu
authors.affiliation: Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University Hospital, Kumamoto, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Takeya
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan. hdobaba@kumamoto-u.ac.jp.
authors.forename: Hideo
authors.initials: H
authors.lastname: Baba
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary*; D008207:Lymphatic Metastasis; D008214:Lymphocytes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D018358:Neuroendocrine Tumors / Q000473:pathology* / Q000601:surgery; D009504:Neutrophils / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Neutrophil-to-lymphocyte ratio; Pancreatic neuroendocrine tumor; Postoperative metachronous liver metastasis; WHO grade