title: The IASLC Lung Cancer Staging Project: Proposals for the Revisions of the T Descriptors in the Forthcoming Eighth Edition of the TNM Classification for Lung Cancer.
abstract: BACKGROUND
  An international database was collected to inform the 8 edition of the anatomic classification of lung cancer. The present analyses concern its primary tumor (T) component.
  
  
  METHODS
  From 1999 to 2010, 77,156 evaluable patients, 70,967 with non-small-cell lung cancer, were collected; and 33,115 had either a clinical or a pathological classification, known tumor size, sufficient T information, and no metastases. Survival was measured from date of diagnosis or surgery for clinically and pathologically staged tumors. Tumor-size cutpoints were evaluated by the running log-rank statistics. T descriptors were evaluated in a multivariate Cox regression analysis adjusted for age, gender, histological type, and geographic region.
  
  
  RESULTS
  The 3-cm cutpoint significantly separates T1 from T2. From 1 to 5 cm, each centimeter separates tumors of significantly different prognosis. Prognosis of tumors greater than 5 cm but less than or equal to 7 cm is equivalent to T3, and that of those greater than 7 cm to T4. Bronchial involvement less than 2 cm from carina, but without involving it, and total atelectasis/pneumonitis have a T2 prognosis. Involvement of the diaphragm has a T4 prognosis. Invasion of the mediastinal pleura is a descriptor seldom used.
  
  
  CONCLUSIONS
  Recommended changes are as follows: to subclassify T1 into T1a (≤1 cm), T1b (>1 to ≤2 cm), and T1c (>2 to ≤3 cm); to subclassify T2 into T2a (>3 to ≤4 cm) and T2b (>4 to ≤5 cm); to reclassify tumors greater than 5 to less than or equal to 7 cm as T3; to reclassify tumors greater than 7 cm as T4; to group involvement of main bronchus as T2 regardless of distance from carina; to group partial and total atelectasis/pneumonitis as T2; to reclassify diaphragm invasion as T4; and to delete mediastinal pleura invasion as a T descriptor.
authors.affiliation: *Department of Thoracic Surgery, Hospital Universitari Mútua Terrassa, University of Barcelona, and CIBERES Lung Cancer Group, Terrassa, Barcelona, Spain; †Cancer Research And Biostatistics, Seattle, Washington; ‡Department of Radiotherapy, Peter MacCallum Cancer Centre, Melbourne, Australia; §Department of Thoracic Surgery, Samsung Medical Center, Seoul, South Korea; ‖Department of Thoracic Surgery, Hospital Británico, Buenos Aires, Argentina; ¶Department of Thoracic Surgery, Cleveland Clinic, Cleveland, Ohio; #Department of Thoracic Surgery, Juntendo University, Tokyo, Japan; **Department of Internal Medicine and Pulmonology, Mayo Clinic, Rochester, Minnesota; ††Department of Pathology, Sloan-Kettering Cancer Center, New York, New York; ‡‡Guangdong Lung Cancer Institute, Guangdong, General Hospital & Guangdong Academy of Medical Sciences, Guangzhou, People's Republic of China; and §§Members of the IASLC Staging and Prognostic Factors Committee, Advisory Boards and Participating Institutions are listed in the Appendix.
authors.forename: Ramón
authors.initials: R
authors.lastname: Rami-Porta
authors.forename: Vanessa
authors.initials: V
authors.lastname: Bolejack
authors.forename: John
authors.initials: J
authors.lastname: Crowley
authors.forename: David
authors.initials: D
authors.lastname: Ball
authors.forename: Jhingook
authors.initials: J
authors.lastname: Kim
authors.forename: Gustavo
authors.initials: G
authors.lastname: Lyons
authors.forename: Thomas
authors.initials: T
authors.lastname: Rice
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Charles F
authors.initials: CF
authors.lastname: Thomas
authors.forename: William D
authors.initials: WD
authors.lastname: Travis
authors.forename: Yi-Long
authors.initials: YL
authors.lastname: Wu
mesh_terms: D000367:Age Factors; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification* / Q000473:pathology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012737:Sex Factors