title: The ground glass opacity component can be eliminated from the T-factor assessment of lung adenocarcinoma.
abstract: OBJECTIVE
  The radiological ground glass opacity (GGO) component of an adenocarcinoma pathologically reflects a non-invasive adenocarcinoma in situ (AIS). Measuring the tumour diameter to include the GGO component may overestimate the T factor. In this retrospective study, we evaluated the effect of the GGO component on the recurrence of an adenocarcinoma.
  
  
  METHODS
  We reviewed patients who underwent a surgical resection of a lung adenocarcinoma and were pathologically proven to be T1-2N0M0, from 1999 to 2009. We conducted four different types of analyses (multivariate analysis, receiver operating characteristic [ROC] analysis, survival analysis according to subcategories and survival analysis of propensity score-matched pairs) to evaluate the impacts of GGO and the solid component on recurrence.
  
  
  RESULTS
  The study included 241 patients, and there were 34 recurrences. Sixty-eight cases with AIS and minimally invasive adenocarcinoma exhibited 100% recurrence-free survival. A univariate and a multivariate analysis revealed that the maximum tumour diameter measured in the mediastinal window was a better prognostic factor than the maximum tumour diameter in the lung window. This finding was supported by an ROC curve analysis, a subgroup analysis and a propensity score-matched analysis. An ROC curve analysis revealed that GGO component exclusion resulted in improved prognostic performance for recurrence and pathological vessel invasion. A subgroup analysis and a propensity score-matched analysis demonstrated that tumours with similar solid component sizes and different GGO sizes exhibited equivalent recurrence-free survival.
  
  
  CONCLUSIONS
  The GGO component showed little influence on recurrence. Recurrence-free survival was solely dependent on the solid component size. A T factor measured by the solid component may be a more accurate prognostic parameter.
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. murakawa-tky@umin.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Murakawa
authors.forename: Chihiro
authors.initials: C
authors.lastname: Konoeda
authors.forename: Takuya
authors.initials: T
authors.lastname: Ito
authors.forename: Yuta
authors.initials: Y
authors.lastname: Inoue
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sano
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nagayama
authors.forename: Jun
authors.initials: J
authors.lastname: Nakajima
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D000077192:Adenocarcinoma of Lung; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019540:Area Under Curve; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology*; D011013:Pneumonectomy; D012372:ROC Curve; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods