title: 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.
abstract: Application of tumor, node, and metastasis (TNM) classification is difficult in patients with lung cancer presenting as multiple ground glass nodules or with diffuse pneumonic-type involvement. Clarification of how to do this is needed for the forthcoming eighth edition of TNM classification.
  
  
  
  A subcommittee of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee conducted a systematic literature review to build an evidence base regarding such tumors. An iterative process that included an extended workgroup was used to develop proposals for TNM classification.
  
  
  
  Patients with multiple tumors with a prominent ground glass component on imaging or lepidic component on microscopy are being seen with increasing frequency. These tumors are associated with good survival after resection and a decreased propensity for nodal and extrathoracic metastases. Diffuse pneumonic-type involvement in the lung is associated with a worse prognosis, but also with a decreased propensity for nodal and distant metastases.
  
  
  
  For multifocal ground glass/lepidic tumors, we propose that the T category be determined by the highest T lesion, with either the number of tumors or m in parentheses to denote the multifocal nature, and that a single N and M category be used for all the lesions collectively-for example, T1a(3)N0M0 or T1b(m)N0M0. For diffuse pneumonic-type lung cancer we propose that the T category be designated by size (or T3) if in one lobe, as T4 if involving an ipsilateral different lobe, or as M1a if contralateral and that a single N and M category be used for all pulmonary areas of involvement.
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 Diagnostic Imaging, Tel-Aviv University, Ramat Gan, Israel.
authors.forename: Edith M
authors.initials: EM
authors.lastname: Marom
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Arenberg
authors.affiliation: Department of Pathology, University of Colorado, Denver, Colorado.
authors.forename: Wilbur A
authors.initials: WA
authors.lastname: Franklin
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, 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, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mazzone
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, 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: 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