title: Interval lung cancers not detected on screening chest X-rays: How are they different?
abstract: BACKGROUND
  The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial provides us an opportunity to describe interval lung cancers not detected by screening chest X-ray (CXR) compared to screen-detected cancers.
  
  
  METHODS
  Participants were screened for lung cancer with CXR at baseline and annually for two (never smokers) or three (ever smokers) more years. Screen-detected cancers were those with a positive CXR and diagnosed within 12 months. Putative interval cancers were those with a negative CXR screen but with a diagnosis of lung cancer within 12 months. Potential interval cancers were re-reviewed to determine whether lung cancer was missed and probably present during the initial interpretation or whether the lesion was a "true interval" cancer.
  
  
  RESULTS
  77,445 participants were randomized to the intervention arm with 70,633 screened. Of 5227 positive screens from any screening round, 299 resulted in screen-detected lung cancers; 151 had potential interval cancers with 127 CXR available for re-review. Cancer was probably present in 45/127 (35.4%) at time of screening; 82 (64.6%) were "true interval" cancers. Compared to screen-detected cancers, true interval cancers were more common among males, persons with <12 years education and those with a history of smoking. True interval lung cancers were more often small cell, 28.1% vs. 7.4%, and less often adenocarcinoma, 25.6% vs. 56.2% (p<0.001), more advanced stage IV (30.5% vs. 16.6%, p<0.02), and less likely to be in the right upper lobe, 17.1% vs. 36.1% (p<0.02).
  
  
  CONCLUSIONS
  True interval lung cancers differ from CXR-screen-detected cancers with regard to demographic variables, stage, cell type and location. ClinicalTrials.gov number: NCT00002540.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Henry Ford Health System, Detroit, MI, United States. Electronic address: pkvale1@hfhs.org.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Kvale
authors.affiliation: Department of Public Health Sciences, Henry Ford Health System, Detroit, MI, United States. Electronic address: cjohnso1@hfhs.org.
authors.forename: Christine Cole
authors.initials: CC
authors.lastname: Johnson
authors.affiliation: Department of Community Health Sciences, Brock University, St. Catharines, Ontario, Canada. Electronic address: martin.tammemagi@brocku.ca.
authors.forename: Martin
authors.initials: M
authors.lastname: Tammemägi
authors.affiliation: National Cancer Institute, Bethesda, MD, United States. Electronic address: marcusp@mail.nih.gov.
authors.forename: Pamela M
authors.initials: PM
authors.lastname: Marcus
authors.affiliation: Department of Radiology, Henry Ford Health System, Detroit, MI, United States. Electronic address: zylak@rad.hfh.edu.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Zylak
authors.affiliation: Department of Radiology, Henry Ford Health System, Detroit, MI, United States. Electronic address: davidl@rad.hfh.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Spizarny
authors.affiliation: Department of Clinical Oncology, Marshfield Clinic, Marshfield, WI, United States. Electronic address: hocking.william@marshfieldclinic.org.
authors.forename: William
authors.initials: W
authors.lastname: Hocking
authors.affiliation: Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN, United States. Electronic address: travelermmo@yahoo.com.
authors.forename: Martin
authors.initials: M
authors.lastname: Oken
authors.affiliation: Information Management Services, Inc., Rockville, MD, United States. Electronic address: comminsj@imsweb.com.
authors.forename: John
authors.initials: J
authors.lastname: Commins
authors.affiliation: Westat, Inc., Rockville, MD, United States. Electronic address: lawrenceragard@westat.com.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Ragard
authors.affiliation: National Cancer Institute, Bethesda, MD, United States. Electronic address: pingh@mail.nih.gov.
authors.forename: Ping
authors.initials: P
authors.lastname: Hu
authors.affiliation: National Cancer Institute, Bethesda, MD, United States. Electronic address: bergc@mail.nih.gov.
authors.forename: Christine
authors.initials: C
authors.lastname: Berg
authors.affiliation: National Cancer Institute, Bethesda, MD, United States. Electronic address: prorokp@mail.nih.gov.
authors.forename: Philip
authors.initials: P
authors.lastname: Prorok
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008400:Mass Chest X-Ray; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D016017:Odds Ratio; D012307:Risk Factors; D012680:Sensitivity and Specificity
keywords: Chest X-ray screen-detected lung cancers; Chest radiograph; Lung cancer; PLCO Cancer Screening Trial; Pulmonary tumour; Screening interval lung cancers