Interobserver variability in the application of the novel IASLC/ATS/ERS classification for pulmonary adenocarcinomas

Abstract

Recently, a novel classification for pulmonary adenocarcinomas (ADCs) was published, the cornerstone of which is the quantification of growth patterns. Data on reproducibility in the routine diagnostic setting are lacking. 100 constitutive cases of lung ADC resection specimens from our archives were classified independently by five pulmonary pathologists and two residents according to the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification.The most frequent predominant pattern in our cohort was solid (37%), followed by acinar (35%), lepidic (20%), papillary (5%) and micropapillary (3%). k-values for the denomination of the predominant pattern revealed substantial agreement for pulmonary pathologists (k50.44-0.72) and fair agreement for residents (k50.38-0.47). Interobserver variability was significantly higher in cases with higher slide numbers (p50.028) and was considerably reduced after training. Intraobserver variability was low (k50.79-0.87). Papillary and micropapillary patterns were the most complicated patterns to evaluate, while evaluation of lepidic and solid tumour growth was straightforward.Our data imply that the novel classification of pulmonary ADC is applicable with acceptable interobserver variability if performed by specifically trained pathologists. Additional efforts are needed to harmonise the application of this novel and clinically important classification scheme of pulmonary ADC.

Accuracy of the IASLC/ATS/ERS histological subtyping of stage I lung adenocarcinoma on intraoperative frozen sections

“…However, pathologist regardless of experience showed comparable 'moderate' agreement for the primary pattern in stage IA tumors. In contrast, Warth et al 24 reported that thoracic pathologists showed 'substantial' agreement for the identification of predominant pattern on permanent sections, in contrast to pathologist in training with only 'fair' agreement. Possible reasons for this discordance could be related to different proportion of predominant histologic patterns between both study samples (our sample included more acinar-and papillarypredominant tumors and less lepidic-and solidpredominant tumors) and the fact that Warth et al 24 used permanent sections only.…”

EGFR,KRAS,BRAFandALKgene alterations in lung adenocarcinomas: patient outcome, interplay with morphology and immunophenotype

“…Therefore, reclassification of ADCs based on histomorphology [18] was a logical and essential step with highly significant prognostic and, probably, predictive value [9]. With this novel and largely reproducible [20,21] tool, linkage of the different ADC histotypes to diagnostic and predictive biomarkers as well as clinical characteristics is essential for a comprehensive interdisciplinary classification of ADC in the future [18]. Furthermore, different therapeutic targets were found to be associated with each other, implying combined inhibitory strategies for optimised treatment algorithms.…”

Correlation of radio- and histomorphological pattern of pulmonary adenocarcinoma

“…The prognostic impact of this classification has been confirmed in ADCs of various stages [9,10,12]. In preceding studies we could demonstrate that this classification system is a stage-independent predictor of overall (OS), disease-specific (DSS) and disease-free survival (DFS) [15], and is applicable with reasonable interobserver agreement [16]. Additionally, for the first time, we provided evidence that specific growth patterns might have impact on the outcome under adjuvant radio-and chemotherapeutic strategies [15].…”