Angela R Shih1, Hironori Uruga1,2, Emine Bozkurtlar3, Jin-Haeng Chung4, Lida P Hariri1, Yuko Minami5, He Wang6, Akihiko Yoshizawa7, Alona Muzikansky1, Andre L Moreira8, Mari Mino-Kenudson1. 1. Massachusetts General Hospital, Boston, MA, USA. 2. Toranomon Hospital, Tokyo, Japan. 3. Marmara University, Istanbul, Turkey. 4. Seoul National University, Bundang Hospital, Seongnam, Republic of Korea. 5. National Hospital Organization, Ibarakihigashi National Hospital, Ibaraki, Japan. 6. Temple University School of Medicine, Philadelphia, PA, USA. 7. Kyoto University Hospital, Kyoto, Japan. 8. NYU Langone Health, New York City, NY, USA.
Abstract
AIMS: The 2015 WHO classification for lung adenocarcinoma (ACA) provides criteria for adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (INV), but differentiating these entities can be difficult. As our understanding of prognostic significance increases, inconsistent classification is problematic. This study assesses agreement within an international panel of lung pathologists and identifies factors contributing to inconsistent classification. METHODS AND RESULTS: Sixty slides of small lung ACAs were reviewed digitally by six lung pathologists in three rounds, with consensus conferences and examination of elastic stains in round 3. The panel independently reviewed each case to assess final diagnosis, invasive component size and predominant pattern. The kappa value for AIS and MIA versus INV decreased from 0.44 (round 1) to 0.30 and 0.34 (rounds 2 and 3). Interobserver agreement for invasion (AIS versus other) decreased from 0.34 (round 1) to 0.29 and 0.29 (rounds 2 and 3). The range of the measured invasive component in a single case was up to 19.2 mm among observers. Agreement was excellent in tumours with high-grade cytology and fair with low-grade cytology. CONCLUSIONS: Interobserver agreement in small lung ACAs was fair to moderate, and improved minimally with elastic stains. Poor agreement is primarily attributable to subjectivity in pattern recognition, but high-grade cytology increases agreement. More reliable methods to differentiate histological patterns may be necessary, including refinement of the definitions as well as recognition of other features (such as high-grade cytology) as a formal part of routine assessment.
AIMS: The 2015 WHO classification for lung adenocarcinoma (ACA) provides criteria for adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (INV), but differentiating these entities can be difficult. As our understanding of prognostic significance increases, inconsistent classification is problematic. This study assesses agreement within an international panel of lung pathologists and identifies factors contributing to inconsistent classification. METHODS AND RESULTS: Sixty slides of small lung ACAs were reviewed digitally by six lung pathologists in three rounds, with consensus conferences and examination of elastic stains in round 3. The panel independently reviewed each case to assess final diagnosis, invasive component size and predominant pattern. The kappa value for AIS and MIA versus INV decreased from 0.44 (round 1) to 0.30 and 0.34 (rounds 2 and 3). Interobserver agreement for invasion (AIS versus other) decreased from 0.34 (round 1) to 0.29 and 0.29 (rounds 2 and 3). The range of the measured invasive component in a single case was up to 19.2 mm among observers. Agreement was excellent in tumours with high-grade cytology and fair with low-grade cytology. CONCLUSIONS: Interobserver agreement in small lung ACAs was fair to moderate, and improved minimally with elastic stains. Poor agreement is primarily attributable to subjectivity in pattern recognition, but high-grade cytology increases agreement. More reliable methods to differentiate histological patterns may be necessary, including refinement of the definitions as well as recognition of other features (such as high-grade cytology) as a formal part of routine assessment.
Authors: Andre L Moreira; Paolo S S Ocampo; Yuhe Xia; Hua Zhong; Prudence A Russell; Yuko Minami; Wendy A Cooper; Akihiko Yoshida; Lukas Bubendorf; Mauro Papotti; Giuseppe Pelosi; Fernando Lopez-Rios; Keiko Kunitoki; Dana Ferrari-Light; Lynette M Sholl; Mary Beth Beasley; Alain Borczuk; Johan Botling; Elisabeth Brambilla; Gang Chen; Teh-Ying Chou; Jin-Haeng Chung; Sanja Dacic; Deepali Jain; Fred R Hirsch; David Hwang; Sylvie Lantuejoul; Dongmei Lin; John W Longshore; Noriko Motoi; Masayuki Noguchi; Claudia Poleri; Natasha Rekhtman; Ming-Sound Tsao; Erik Thunnissen; William D Travis; Yasushi Yatabe; Anja C Roden; Jillian B Daigneault; Ignacio I Wistuba; Keith M Kerr; Harvey Pass; Andrew G Nicholson; Mari Mino-Kenudson Journal: J Thorac Oncol Date: 2020-06-17 Impact factor: 15.609