title: The IASLC Lung Cancer Staging Project: Summary of Proposals for Revisions of the Classification of Lung Cancers with Multiple Pulmonary Sites of Involvement in the Forthcoming Eighth Edition of the TNM Classification.
abstract: Patients with lung cancer who harbor multiple pulmonary sites of disease have been challenging to classify; a subcommittee of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee was charged with developing proposals for the eighth edition of the tumor, node, and metastasis (TNM) classification to address this issue.
  
  
  
  A systematic literature review and analysis of the International Association for the Study of Lung Cancer database was performed to develop proposals for revision in an iterative process involving multispecialty international input and review.
  
  
  
  Details of the evidence base are summarized in other articles. Four patterns of disease are recognized; the clinical presentation, pathologic correlates, and biologic behavior of these suggest specific applications of the TNM classification rules. First, it is proposed that second primary lung cancers be designated with a T, N, and M category for each tumor. Second, tumors with a separate tumor nodule of the same histologic type (either suspected or proved) should be classified according to the location of the separate nodule relative to the index tumor-T3 for a same-lobe, T4 for a same-side (different lobe), and M1a for an other-side location-with a single N and M category. Third, multiple tumors with prominent ground glass (imaging) or lepidic (histologic) features should be designated by the T category of the highest T lesion, the number or m in parentheses (#/m) to indicate the multiplicity, and a collective N and M category for all. Finally, it is proposed that diffuse pneumonic-type lung cancers be designated by size (or T3) if in one lobe, T4 if involving multiple same-side lobes, and M1a if involving both lungs with a single N and M category for all areas of involvement.
  
  
  
  We propose to tailor TNM classification of multiple pulmonary sites of lung cancer to reflect the unique aspects of four different patterns of presentation. We hope that this will lead to more consistent classification and clarity in communication and facilitate further research in the nature and optimal treatment of these entities.
authors.affiliation: Department of Surgery, Yale University, New Haven, Connecticut. Electronic address: frank.detterbeck@yale.edu.
authors.forename: Frank C
authors.initials: FC
authors.lastname: Detterbeck
authors.affiliation: Department of Histopathology, Royal Brompton and Harefield National Health Service Foundation Trust and Imperial College, London, United Kingdom.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Nicholson
authors.affiliation: Department of Pathology, University of Colorado, Denver, Colorado.
authors.forename: Wilbur A
authors.initials: WA
authors.lastname: Franklin
authors.affiliation: Department of Diagnostic Imaging, Tel-Aviv University, Ramat Gan, Israel.
authors.forename: Edith M
authors.initials: EM
authors.lastname: Marom
authors.affiliation: Department of Pathology, Sloan-Kettering Cancer Center, New York, New York.
authors.forename: William D
authors.initials: WD
authors.lastname: Travis
authors.affiliation: Respiratory Medicine Service, Hôpital Louis Pradel, Hospices Civils de Lyon, Lyon, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Girard
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Arenberg
authors.affiliation: Cancer Research And Biostatistics, Seattle, Washington.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Bolejack
authors.affiliation: Department of Thoracic Surgery, New York University, New York, New York.
authors.forename: Jessica S
authors.initials: JS
authors.lastname: Donington
authors.affiliation: Department of Internal Medicine, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mazzone
authors.affiliation: Department of Internal Medicine, Yale University, New Haven, Connecticut.
authors.forename: Lynn T
authors.initials: LT
authors.lastname: Tanoue
authors.affiliation: Thoracic Surgery Service, Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Valerie W
authors.initials: VW
authors.lastname: Rusch
authors.affiliation: Cancer Research And Biostatistics, Seattle, Washington.
authors.forename: John
authors.initials: J
authors.lastname: Crowley
authors.affiliation: Division of Thoracic Surgery, Keio University, School of Medicine, Tokyo, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Asamura
authors.affiliation: Thoracic Surgery Service, Hospital Universitari Mutua Terrassa; Centros de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES) Lung Cancer Group, Terrassa, Barcelona, Spain.
authors.forename: Ramón
authors.initials: R
authors.lastname: Rami-Porta
mesh_terms: D000230:Adenocarcinoma / Q000145:classification* / Q000556:secondary; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification* / Q000473:pathology; D015201:Meta-Analysis as Topic; D009367:Neoplasm Staging / Q000592:standards*; D016609:Neoplasms, Second Primary / Q000145:classification* / Q000473:pathology; D011379:Prognosis
keywords: Lung cancer; Lung cancer staging; Multiple tumors; Non–small cell lung cancer; TNM classification