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Evaluation of a new grading system for laryngeal squamous intraepithelial lesions—a proposed unified classification
Author(s) -
Gale Nina,
Blagus Rok,
ElMofty Samir K,
Helliwell Tim,
Prasad Manju L,
Sandison Ann,
Volavšek Metka,
Wenig Bruce M,
Zidar Nina,
Cardesa Antonio
Publication year - 2014
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.12427
Subject(s) - grading (engineering) , medicine , malignancy , confidence interval , laryngeal neoplasm , significant difference , radiology , oncology , carcinoma , civil engineering , engineering
Aims To verify the applicability, reproducibility and predictive value of a proposed unified classification (amended Ljubljana classification) for laryngeal squamous intraepithelial lesions ( SIL s). Methods and results Six internationally recognized experts and three pathologists from Ljubljana contributed to this study by evaluating a set of laryngeal SIL s using the new system: low‐grade SIL , high‐grade SIL , and carcinoma in situ ( CIS ). The overall agreement among reviewers was good. Overall unweighted and weighted κ‐values and 95% confidence intervals were 0.75 (0.65–0.84) and 0.80 (0.71–0.87), respectively. The results were stratified between the international reviewers and the Ljubljana pathologists. The former had good overall agreement, and the latter had very good agreement. Kaplan–Meier survival curves showed a significant difference ( P < 0.0001) between patients with low‐grade and high‐grade SIL s; 19 of 1204 patients with low‐grade SIL s and 30 of 240 patients with high‐grade SIL s progressed to malignancy in 2–15 years and in 2–26 years, respectively. Conclusions The proposed modification to the Ljubljana classification provides clear morphological criteria for defining the prognostic groups. The criteria facilitate better interobserver agreement than previous systems, and the retrospective follow‐up study demonstrates a highly significant difference in the risk of malignant progression between low‐grade and high‐grade SIL s.