title: Prognostic value of tumor disappearance rate on computed tomography in advanced-stage lung adenocarcinoma.
abstract: BACKGROUND
  The proportion of tumor disappearance rate (TDR) on conventional computed tomography (CT) is associated with less aggressive biology, and patients with small peripheral adenocarcinoma accompanied by the TDR component showed better prognosis. These findings led us to the idea that even advanced-stage adenocarcinomas with a higher TDR in the primary lesion on CT might suggest slowly progressing cancer. This study was designed to determine the value of the TDR area in the primary site of advanced-stage lung adenocarcinoma with CT and correlate the CT findings with clinical outcome.
  
  
  METHODS
  In 103 patients with stage IIIB and IV lung adenocarcinoma, CT appearances and clinical data were reviewed retrospectively. Three methods were used in the evaluation of the TDR area: method I, consolidation on mediastinal windows/mass on lung windows > 75% or not; method II, maximum diameter on mediastinal windows/maximum diameter on lung windows (diameter ratio) > 75% or not; and method III, TDR area on lung windows > 25% or not.
  
  
  RESULTS
  In univariate analysis, patients with lung adenocarcinoma with TDR have a more favorable prognosis than those without TDR in all 3 methods (method I, P = 0.001; method II, P = 0.024; method III, P = 0.014; log-rank test). In multivariate analysis, a favorable prognosis in patients with adenocarcinoma with TDR was shown in method I (P = 0.015) and method III (P = 0.006).
  
  
  CONCLUSIONS
  As shown in patients with small peripheral lung adenocarcinoma, those with TDR on CT tended to have a good prognosis in contrast to those without TDR, even in patients with advanced-stage lung adenocarcinoma. Prospective study to confirm these results will be required.
authors.affiliation: Division of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Haraguchi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Satoh
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kikuchi
authors.forename: Katsunori
authors.initials: K
authors.lastname: Kagohashi
authors.forename: Hiroichi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Morio
authors.initials: M
authors.lastname: Ohtsuka
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000401:mortality*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D014057:Tomography, X-Ray Computed / Q000379:methods*