Training increases concordance in classifying pulmonary adenocarcinomas according to the novel IASLC/ATS/ERS classification

Abstract

The International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS), and the European Respiratory Society (ERS) proposed a classification for lung adenocarcinomas (ADC) based on the predominant growth pattern. This classification has been shown to have prognostic and maybe even predictive impact. However, until now, the reproducibility of this classification has not been sufficiently demonstrated. Digital images of 40 selected ADC cases were shown twice to members of the Pulmonary Pathology Working Group of the German Society of Pathology. Each time a teledialogue-based survey on the classification was performed. Between the voting procedures, salient features of the novel classification were presented and discussed in detail by its members. The mean percentages of consensual votes per pattern ranged between 59.6 and 75 %, with lepidic and solid being the pattern with the most discordant and concordant votes, respectively. The other patterns ranged in between (papillary 65.8 %; acinar 67.8 %; micropapillary 74.2 %). The extent of disagreement decreased after the educational session. This decrease, however, was heterogeneous for the different patterns with acinar being the pattern with the strongest improvement. The overall number of abstentions decreased significantly after the educational session (p < 0.001) as well. The IASLC/ATS/ERS classification of lung ADC can be applied with reasonable consensus even for difficult cases in a nationwide context. The reproducibility evidently improves following educational sessions, even among experienced lung pathologists. Worldwide harmonization is clearly the next step on the way to a clinically meaningful, internationally accepted use of this novel prognostic and potentially predictive tool in lung pathology.

EGFR, KRAS, BRAF and ALK gene 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.…”

The IASLC Lung Cancer Staging Project: Background Data and Proposals for the Application of TNM Staging Rules to Lung Cancer Presenting as Multiple Nodules with Ground Glass or Lepidic Features or a Pneumonic Type of Involvement in the Forthcoming Eighth Edition of the TNM Classification

“…47 On the other hand, in a study of 40 difficult cases and 51 thoracic pathologists, consensus on the predominant subtype of adenocarcinoma was achieved initially in 51-74% (lepidic 57%, papillary 63%, acinar 51%, micropapillary 64% and solid 73%). 46 Training improved these results somewhat (consensus in 60-75%). 46 There is also interobserver variability in identifying the presence of invasion.…”

“…46 Training improved these results somewhat (consensus in 60-75%). 46 There is also interobserver variability in identifying the presence of invasion. 47 In a study involving 28 thoracic pathologists who evaluated 64 typical and difficult cases for the presence of invasion, complete agreement was seen in 10% of cases, and <10% discordance in 29% (3 point scale: probable and definite invasion, unclear, probably or definitely not invaded; κ = 0.55 for typical cases and 0.15 for difficult cases).…”

“…[45][46][47] In a study involving 100 consecutive adenocarcinoma cases and 5 dedicated thoracic pathologists, agreement on the predominant pattern was achieved in 66% (κ = 0.44-0.62). 45 In a study involving the evaluation of 19 typical cases for each of 5 adenocarcinoma subtypes by 26 thoracic pathologists, the predominant pattern was consistently identified in 92-100% of cases (except micropapillary with consensus in 62%).…”

Diagnose, Prognose und Prädiktion nicht-kleinzelliger Lungenkarzinome

“…Die Reproduzierbarkeit der Klassifikation wurde erstmals im Rahmen der AG Thoraxpathologie der Deutschen Gesellschaft für Pathologie untersucht. Hierbei zeigte sich, dass die Anwendung in der Routinediagnostik machbar erscheint, jedoch bei spezifischen Fragen der Musterinterpretation perspektivisch eine weitere Präzisierung erfolgen sollte [17,34]. Ein weiterer interessanter Aspekt der semiquantitativen Musteranalyse ergibt sich aus dem Aspekt, dass einige der Muster auch bildgeben, naturgemäß mit einigen technisch bedingten Einschränkungen, reproduzierbar sind und somit präoperativ im Rahmen von Verlaufsbeobachtungen als auch ggf.…”