title: Optimisation of volume-doubling time cutoff for fast-growing lung nodules in CT lung cancer screening reduces false-positive referrals.
abstract: OBJECTIVE
  To retrospectively investigate whether optimisation of volume-doubling time (VDT) cutoff for fast-growing nodules in lung cancer screening can reduce false-positive referrals.
  
  
  METHODS
  Screening participants of the NELSON study underwent low-dose CT. For indeterminate nodules (volume 50-500 mm(3)), follow-up CT was performed 3 months after baseline. A negative baseline screen resulted in a regular second-round examination 1 year later. Subjects referred to a pulmonologist because of a fast-growing (VDT <400 days) solid nodule in the baseline or regular second round were included in this study. Histology was the reference for diagnosis, or stability on subsequent CTs, confirming benignity. Mean follow-up of non-resected nodules was 4.4 years. Optimisation of the false-positive rate was evaluated at maintained sensitivity for lung cancer diagnosis with VDT <400 days as reference.
  
  
  RESULTS
  Sixty-eight fast-growing nodules were included; 40 % were malignant. The optimal VDT cutoff for the 3-month follow-up CT after baseline was 232 days. This cutoff reduced false-positive referrals by 33 % (20 versus 30). For the regular second round, VDTs varied more among malignant nodules, precluding lowering of the VDT cutoff of 400 days.
  
  
  CONCLUSIONS
  All malignant fast-growing lung nodules referred after the 3-month follow-up CT in the baseline lung cancer screening round had VDT ≤232 days. Lowering the VDT cutoff may reduce false-positive referrals.
  
  
  CONCLUSIONS
  • Lung nodules are common in CT lung cancer screening, most being benign • Short-term follow-up CT can identify fast-growing intermediate-size lung nodules • Most fast-growing nodules on short-term follow-up CT still prove to be benign • A new volume-doubling time (VDT) cut-off is proposed for lung screening • The optimised VDT cutoff may decrease false-positive case referrals for lung cancer.
authors.affiliation: Center for Medical Imaging-North East Netherlands, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
authors.forename: Marjolein A
authors.initials: MA
authors.lastname: Heuvelmans
authors.forename: Matthijs
authors.initials: M
authors.lastname: Oudkerk
authors.forename: Geertruida H
authors.initials: GH
authors.lastname: de Bock
authors.forename: Harry J
authors.initials: HJ
authors.lastname: de Koning
authors.forename: Xueqian
authors.initials: X
authors.lastname: Xie
authors.forename: Peter M A
authors.initials: PM
authors.lastname: van Ooijen
authors.forename: Marcel J W
authors.initials: MJ
authors.lastname: Greuter
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
authors.forename: Harry J M
authors.initials: HJ
authors.lastname: Groen
authors.forename: Rozemarijn
authors.initials: R
authors.lastname: Vliegenthart
mesh_terms: D000368:Aged; D055088:Early Detection of Cancer; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012017:Referral and Consultation; D012189:Retrospective Studies; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*