title: Pancreatic neuroendocrine tumours: hypoenhancement on arterial phase computed tomography predicts biological aggressiveness.
abstract: BACKGROUND
  Contrary to pancreatic adenocarcinoma, pancreatic neuroendocrine tumours (PNET) are commonly hyperenhancing on arterial phase computed tomography (APCT). However, a subset of these tumours can be hypoenhancing. The prognostic significance of the CT appearance of these tumors remains unclear.
  
  
  METHODS
  From 2001 to 2012, 146 patients with well-differentiated PNET underwent surgical resection. The degree of tumour enhancement on APCT was recorded and correlated with clinicopathological variables and overall survival.
  
  
  RESULTS
  APCT images were available for re-review in 118 patients (81%). The majority had hyperenhancing tumours (n = 80, 68%), 12 (10%) were isoenhancing (including cases where no mass was visualized) and 26 (22%) were hypoenhancing. Hypoenhancing PNET were larger, more commonly intermediate grade, and had higher rates of lymph node and synchronous liver metastases. Hypoenhancing PNET were also associated with significantly worse overall survival after a resection as opposed to isoenhancing and hyperenhancing tumours (5-year, 54% versus 89% versus 93%). On multivariate analysis of factors available pre-operatively, only hypoenhancement (HR 2.32, P = 0.02) was independently associated with survival.
  
  
  CONCLUSIONS
  Hypoenhancement on APCT was noted in 22% of well-differentiated PNET and was an independent predictor of poor outcome. This information can inform pre-operative decisions in the multidisciplinary treatment of these neoplasms.
authors.affiliation: Department of Surgery, Division of Oncology, Stanford University Medical Center, Stanford, CA, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Worhunsky
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: Krampitz
authors.forename: Peter D
authors.initials: PD
authors.lastname: Poullos
authors.forename: Brendan C
authors.initials: BC
authors.lastname: Visser
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Kunz
authors.forename: George A
authors.initials: GA
authors.lastname: Fisher
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Norton
authors.forename: George A
authors.initials: GA
authors.lastname: Poultsides
mesh_terms: D000328:Adult; D000368:Aged; D002454:Cell Differentiation; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000401:mortality / Q000556:secondary / Q000601:surgery; D010180:Pancreatectomy; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome