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Pancreatic neuroendocrine tumour grading on endoscopic ultrasound‐guided fine needle aspiration: high reproducibility and inter‐observer agreement of the K i‐67 labelling index
Author(s) -
Weynand B.,
Borbath I.,
Bernard V.,
Sempoux C.,
Gigot J.F.,
Hubert C.,
Lannoy V.,
Deprez P. H.,
JouretMourin A.
Publication year - 2014
Publication title -
cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 48
eISSN - 1365-2303
pISSN - 0956-5507
DOI - 10.1111/cyt.12111
Subject(s) - medicine , grading (engineering) , reproducibility , endoscopic ultrasound , labelling , radiology , ultrasound , fine needle aspiration , neuroendocrine tumors , nuclear medicine , pathology , biopsy , chromatography , civil engineering , engineering , chemistry , criminology , sociology
Objectives Assessment of proliferation by the Ki‐67 labelling index ( K i67‐ LI ) is an important parameter of pancreatic neuroendocrine tumour ( pNET ) prognosis on resection specimens. K i67‐ 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 K i67‐ LI on EUS ‐ FNA to predict a final grade of p NET 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 K i67‐ LI on EUS ‐ FNA and surgical specimens, respectively, were obtained. Discrepancies were observed between histology and cytology, especially in grade 2 ( G 2) 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 c G 2 and c G 1 tumours, respectively ( P < 0.0001). Conclusion This study attests the reproducibility of K i67‐ LI of pNET s whether counted on cytology or histology with a very good inter‐observer correlation. Determination of K i67‐ LI on EUS ‐ FNA of pNETs should be included systematically in their prognostic work‐up.