title: Evolving Early Lung Cancers Detected During Follow-Up of Idiopathic Interstitial Pneumonia: Serial CT Features.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the CT characteristics of newly developed lung cancer on CT studies obtained during follow-up of idiopathic interstitial pneumonia (IIP) before the appearance of identifiable tumors to the time of detectable lung cancer and thereafter.
  
  
  METHODS
  The study sample included 66 cancers diagnosed in 63 patients with IIP and lung cancer (59 men, four women; median age, 64 years; range, 40-85 years) between October 1998 and July 2012. Two radiologists independently reviewed 193 CT scans, determined the earliest presence of cancer and IIP, and evaluated tumor size, lobar and axial location, shape, and tumor density. Delay in clinical diagnosis and doubling time were measured with first and second follow-up CT examinations.
  
  
  RESULTS
  Interobserver agreement was good (κ > 0.77). The median tumor size was 17 mm (range, 5-30 mm) for the 46 T1a and 20 T1b cancers. Most of the tumors (42 [63.6%]) were located in the lower lobes. Thirty-five tumors (53.0%) were at the interface between fibrotic cyst and normal lung, and 21 (31.8%) were in the midst of fibrotic lung cysts. Most of the tumors had a round or oval shape (52 [78.8%]) and were solid (62 [93.9%]). The median delay in diagnosis was 46 days (range, 8-760 days). The first median doubling time was 77 days (range, 15-525 days), and the second was 53 days (27-248).
  
  
  CONCLUSIONS
  New lung cancers during CT follow-up of IIP usually appear as small solid nodules with a round or oval shape. Most cancers are located at the interface between fibrotic cyst and normal lung or in the midst of fibrotic cysts of the lower lobes of subpleural lung.
authors.affiliation: 1 Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul 138-736, Korea.
authors.forename: Sang Young
authors.initials: SY
authors.lastname: Oh
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Kim
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Tai Sun
authors.initials: TS
authors.lastname: Park
authors.forename: Dong Soon
authors.initials: DS
authors.lastname: Kim
authors.forename: Chang-Min
authors.initials: CM
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054988:Idiopathic Interstitial Pneumonias / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: MDCT; early cancer detection; follow-up studies; idiopathic pulmonary fibrosis; interstitial; lung disease; lung neoplasms