title: Pancreatic neuroendocrine tumour grading on endoscopic ultrasound-guided fine needle aspiration: high reproducibility and inter-observer agreement of the Ki-67 labelling index.
abstract: OBJECTIVE
  Assessment of proliferation by the Ki-67 labelling index (Ki67-LI) is an important parameter of pancreatic neuroendocrine tumour (pNET) prognosis on resection specimens. Ki67-LI values for grading are not fully established on endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). The aim of the study was to determine the accuracy of Ki67-LI on EUS-FNA to predict a final grade of pNET and to analyse the relationship between cytological grading and progression-free survival (PFS).
  
  
  METHODS
  Between 1996 and 2010, 46 pNETs (33 were resected) from 45 patients were diagnosed by EUS-FNA. Ki67-LI was evaluated on cytological and histological material for each tumour and classified according to the 2010 WHO grading system.
  
  
  RESULTS
  A very good inter-observer agreement for Ki67-LI on EUS-FNA and surgical specimens, respectively, were obtained. Discrepancies were observed between histology and cytology, especially in grade 2 (G2) tumours, where cytology underestimated grading owing to tumour heterogeneity. Still, EUS-FNA was able to distinguish a poor prognostic group, as the actuarial PFS of cytological (c) G3 tumours was 10 ± 4 months versus 29 ± 7 and 68 ± 10 for cG2 and cG1 tumours, respectively (P < 0.0001).
  
  
  CONCLUSIONS
  This study attests the reproducibility of Ki67-LI of pNETs whether counted on cytology or histology with a very good inter-observer correlation. Determination of Ki67-LI on EUS-FNA of pNETs should be included systematically in their prognostic work-up.
authors.affiliation: Department of Pathology, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Weynand
authors.forename: I
authors.initials: I
authors.lastname: Borbath
authors.forename: V
authors.initials: V
authors.lastname: Bernard
authors.forename: C
authors.initials: C
authors.lastname: Sempoux
authors.forename: J-F
authors.initials: JF
authors.lastname: Gigot
authors.forename: C
authors.initials: C
authors.lastname: Hubert
authors.forename: V
authors.initials: V
authors.lastname: Lannoy
authors.forename: P H
authors.initials: PH
authors.lastname: Deprez
authors.forename: A
authors.initials: A
authors.lastname: Jouret-Mourin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D003581:Cytodiagnosis; D018572:Disease-Free Survival; D019160:Endosonography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D011379:Prognosis
keywords: Ki-67; Ki-67 labelling index; endoscopic ultrasound-guided fine needle aspiration; grading; neuroendocrine tumour; pancreas