title: Lung cancer with localized ground-glass attenuation represents early-stage adenocarcinoma in nonsmokers.
abstract: BACKGROUND
  Studies of lung cancer showing localized ground-glass attenuation (GGA) on thin-section computed tomography (TSCT) have been limited to resected stage IA adenocarcinomas. This study aimed to clarify the features of localized GGA cancer as a distinct clinicoradiological entity through a survey of lung cancers of all types.
  
  
  METHODS
  From 2000 through 2002, 492 patients with newly diagnosed stage I-IV lung cancer underwent TSCT at a single institution. The tumors were semiquantitatively classified into four groups on the basis of GGA area as a percentage of the whole tumor shadow (GGA ratio) on TSCT images: 100%, 99-50%, 49-1%, and 0%. The relationship between clinicopathological data and the GGA ratio, predictors of the presence of GGA, survival data, and prognostic factors were evaluated retrospectively.
  
  
  RESULTS
  All localized GGA cancers were adenocarcinomas (p < 0.05). A GGA component was not found in patients with advanced cancer (p < 0.05). GGA cancer was related to nonsmoking status (Odds ratio 6.17, p < 0.05). A threshold tumor size of 30 mm in GGA cancer (hazard ratio, 2.86; p < 0.01) and the GGA ratio (hazard ratio, 4.17; p < 0.01) were independent prognostic factors. Survival rates were higher in patients with a GGA ratio > or = 50% and stage IB lung cancer than in patients with a GGA ratio < 50% and stage IA lung cancer.
  
  
  CONCLUSIONS
  Localized GGA cancer, with presurgical prognostic factors of tumor size and GGA ratio, represents early-stage lung adenocarcinoma in nonsmokers.
authors.affiliation: Division of Medical Oncology, Department of Internal Medicine, Teikyo University School of Medicine, Itabashi-ku, Tokyo, Japan. seki@is.icc.u-tokai.ac.jp
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Seki
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sawada
authors.forename: Masao
authors.initials: M
authors.lastname: Nakata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inoue
authors.forename: Rieko
authors.initials: R
authors.lastname: Nishimura
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Segawa
authors.forename: Reishi
authors.initials: R
authors.lastname: Shibakuki
authors.forename: Kenji
authors.initials: K
authors.lastname: Eguchi
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D016015:Logistic Models; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012907:Smoking; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods