The IASLC Lung Cancer Staging Project: Proposals for Coding T Categories for Subsolid Nodules and Assessment of Tumor Size in Part-Solid Tumors in the Forthcoming Eighth Edition of the TNM Classification of Lung Cancer.
This article proposes codes for the primary tumor categories of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) and a uniform way to measure tumor size in part-solid tumors for the eighth edition of the tumor, node, and metastasis classification of lung cancer. In 2011, new entities of AIS, MIA, and lepidic predominant adenocarcinoma were defined, and they were later incorporated into the 2015 World Health Organization classification of lung cancer. To fit these entities into the T component of the staging system, the Tis category is proposed for AIS, with Tis (AIS) specified if it is to be distinguished from squamous cell carcinoma in situ (SCIS), which is to be designated Tis (SCIS). We also propose that MIA be classified as T1mi. Furthermore, the use of the invasive size for T descriptor size follows a recommendation made in three editions of the Union for International Cancer Control tumor, node, and metastasis supplement since 2003. For tumor size, the greatest dimension should be reported both clinically and pathologically. In nonmucinous lung adenocarcinomas, the computed tomography (CT) findings of ground glass versus solid opacities tend to correspond respectively to lepidic versus invasive patterns seen pathologically. However, this correlation is not absolute; so when CT features suggest nonmucinous AIS, MIA, and lepidic predominant adenocarcinoma, the suspected diagnosis and clinical staging should be regarded as a preliminary assessment that is subject to revision after pathologic evaluation of resected specimens. The ability to predict invasive versus noninvasive size on the basis of solid versus ground glass components is not applicable to mucinous AIS, MIA, or invasive mucinous adenocarcinomas because they generally show solid nodules or consolidation on CT.
Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York. Electronic address: travisw@mskcc.org.
William D
WD
Travis
Division of Thoracic Surgery, Keio University, School of Medicine, Tokyo, Japan.
Hisao
H
Asamura
Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Alexander A
AA
Bankier
Department of Pathology, Ichan School of Medicine at Mount Sinai, New York, New York.
Mary Beth
MB
Beasley
Thoracic Surgery, Yale School of Medicine, New Haven, Connecticut.
Frank
F
Detterbeck
Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania.
Douglas B
DB
Flieder
Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
Jin Mo
JM
Goo
Department of Radiology, University of Chicago, Chicago, Illinois.
Heber
H
MacMahon
Department of Radiology, New York University Langone Medical Center, New York University, New York, New York.
David
D
Naidich
Department of Histopathology, Royal Brompton and Harefield National Health Service Foundation Trust and Imperial College, London, United Kingdom.
Andrew G
AG
Nicholson
Pulmonary Critical Care and Sleep Medicine, Ichan School of Medicine, New York, New York.
Charles A
CA
Powell
Department of Radiology, Radboud University Nymegen Medical Center, Nymegen, The Netherlands.
Mathias
M
Prokop
Department of Thoracic Surgery, Hospital Universitari Mutua Terrassa, Terrassa, Barcelona, Spain; CIBERES Lung Cancer Group, Terrassa, Barcelona, Spain.
Ramón
R
Rami-Porta
Thoracic Surgery Service, Memorial Sloan Kettering Cancer Center, New York, New York.
Valerie
V
Rusch
Department of Thoracic and Vascular Surgery, Antwerp University Hospital, Edegem, Belgium.
Paul
P
van Schil
Department of Pathology and Molecular Diagnostics, Aichi Cancer Center Hospital, Nagoya, Japan.
Yasushi
Y
Yatabe
D000230:Adenocarcinoma / Q000473:pathology; D065311:Adenocarcinoma in Situ / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology*; D009367:Neoplasm Staging; D014057:Tomography, X-Ray Computed
Adenocarcinoma in situ; Lepidic predominant adenocarcinoma; Lung cancer; Lung cancer staging; Minimally invasive adenocarcinoma; TNM classification; Tumor size