title: Progression of focal pure ground-glass opacity detected by low-dose helical computed tomography screening for lung cancer.
abstract: OBJECTIVE
  To clarify the progression of focal pure ground-glass opacity (pGGO) detected by low-dose helical computed tomography (CT) screening for lung cancer.
  
  
  METHODS
  A total of 15,938 low-dose helical CT examinations were performed in 2052 participants in the screening project, and 1566 of them were judged to have yielded abnormal findings requiring further examination. Patients with peripheral nodules exhibiting pGGO at the time of the first thin-section CT examination and confirmed histologically by thin-section CT after follow-up of more than 6 months were enrolled in the current study. Progression was classified based on the follow-up thin-section CT findings.
  
  
  RESULTS
  The progression of the 8 cases was classified into 3 types: increasing size (n = 5: bronchioloalveolar carcinoma [BAC]), decreasing size and the appearance of a solid component (n = 2: BAC, n = 1; adenocarcinoma with mixed subtype [Ad], n = 1), and stable size and increasing density (n = 1: BAC). In addition, the decreasing size group was further divided into 2 subtypes: a rapid-decreasing type (Ad: n = 1) and a slow-decreasing type (BAC: n = 1). The mean period between the first thin-section CT and surgery was 18 months (range: 7-38 months). All but one of the follow-up cases of lung cancer were noninvasive whereas the remaining GGO with a solid component was minimally invasive.
  
  
  CONCLUSIONS
  The pGGOs of lung cancer nodules do not only increase in size or density, but may also decrease rapidly or slowly with the appearance of solid components. Close follow-up until the appearance of a solid component may be a valid option for the management of pGGO.
authors.affiliation: Division of Thoracic Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwa-no-ha, Kashiwa, Chiba 277-8577, Japan. rkaki@east.ncc.go.jp
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Kakinuma
authors.forename: Hironobu
authors.initials: H
authors.lastname: Ohmatsu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kaneko
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kusumoto
authors.forename: Junji
authors.initials: J
authors.lastname: Yoshida
authors.forename: Kanji
authors.initials: K
authors.lastname: Nagai
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nishiwaki
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Tsuchiya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nishiyama
authors.forename: Eisuke
authors.initials: E
authors.lastname: Matsui
authors.forename: Kenji
authors.initials: K
authors.lastname: Eguchi
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Moriyama
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000000981:diagnostic imaging / Q000473:pathology; D000368:Aged; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed