title: Outcomes of resected nonfunctional pancreatic neuroendocrine tumors: Do size and symptoms matter?
abstract: BACKGROUND
  Nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) are rare tumors with highly variable outcome. Current guidelines recommend surveillance for small tumors (≤ 2 cm), but a scientific basis for such recommendation is scarce.
  
  
  METHODS
  Patients who underwent surgery for NF-PNET during 2001-2013 were identified from a prospectively maintained database and reviewed retrospectively.
  
  
  RESULTS
  Fifty-eight patients that had undergone an operative procedure for NF-PNET were identified. Forty-one patients (71%) were symptomatic. Median size of the tumor was 2.5 cm (range 0.9-12.0 cm). WHO 2010 grade was predictive of both overall- and disease-free survival (P < .001), whereas size alone was not. Twenty-four patients had a small NF-PNET (≤ 2 cm), of whom 16 were symptomatic and 8 asymptomatic. Seven patients with small symptomatic NF-PNETs showed signs of malignant behavior: 4 had lymph node metastases, 1 had liver metastases before surgery, 3 developed liver metastases, and 3 died of the disease. All 7 patients had either bile duct or pancreatic duct obstruction or both on preoperative imaging. On the contrary, patients with small asymptomatic NF-PNETs did not develop distant metastases nor died of disease.
  
  
  CONCLUSIONS
  The 2010 grading system from the World Health Organization can be used to predict survival. Symptomatic small NF-PNETs that caused bile and/or pancreatic duct obstruction had poor outcome. In contrast, asymptomatic small NF-PNETs seem to have benign course, and are candidates for surveillance.
authors.affiliation: Department of Abdominal Surgery, University of Helsinki, Helsinki University Hospital, Helsinki, Finland. Electronic address: ville.sallinen@helsinki.fi.
authors.forename: Ville
authors.initials: V
authors.lastname: Sallinen
authors.affiliation: Department of Abdominal Surgery, University of Helsinki, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Caj
authors.initials: C
authors.lastname: Haglund
authors.affiliation: Department of Abdominal Surgery, University of Helsinki, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Seppänen
mesh_terms: D000328:Adult; D000368:Aged; D002779:Cholestasis / Q000175:diagnosis; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D018358:Neuroendocrine Tumors / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D010180:Pancreatectomy / Q000379:methods*; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D047368:Tumor Burden; D014944:World Health Organization