title: Can CT Screening Give Rise to a Beneficial Stage Shift in Lung Cancer Patients? Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  To portray the stage characteristics of lung cancers detected in CT screenings, and explore whether there's universal stage superiority over other methods for various pathological types using available data worldwide in a meta-analysis approach.
  
  
  METHODS
  EMBASE and MEDLINE were searched for studies on lung cancer CT screening in natural populations through July 2015 without language or other filters. Twenty-four studies (8 trials and 16 cohorts) involving 1875 CT-detected lung cancer patients were enrolled and assessed by QUADAS-2. Pathology-confirmed stage information was carefully extracted by two reviewers. Stage I or limited stage proportions were pooled by random effect model with Freeman-Tukey double arcsine transformation.
  
  
  RESULTS
  Pooled stage I cancer proportion in CT screenings was 73.2% (95% confidence interval: 68.6%, 77.5%), with a significant rising trend (Ptrend<0.05) from baseline (64.7%) to ≥5 repeat rounds (87.1%). Relative to chest radiograph and usual care, the increased stage I proportions in CT were 12.2% (P>0.05), and 46.5% (P<0.05), respectively. Pathology-specifically, adenocarcinomas (66%) and squamous cell lung cancers (17%) composed the majority of CT-detected lung cancers, and had significantly higher stage I proportions relative to chest radiograph (bronchioloalveolar adenocarcinomas, 80.9% vs 51.4%; other adenocarcinomas, 58.8% vs 38.3%; squamous cell lung cancers, 52.3% vs 38.3%; all P<0.05). However, the percentage of small cell lung cancer was lower using CT than other detection routes, and no significant difference in limited stage proportion was observed (6.8% vs 10.8%, P>0.05).
  
  
  CONCLUSIONS
  CT screening can detect more early stage non-small cell lung cancers, but not all of them could be beneficial as there are a considerable number of indolent ones such as bronchioloalveolar adenocarcinomas. Still, current evidence is lacking regarding small cell lung cancers.
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Zixing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Yaoda
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Xue
authors.affiliation: Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Sui
authors.affiliation: Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.affiliation: National Institutes for Food and Drug Control, State Food and Drug Administration, Beijing, China.
authors.forename: Ruihong
authors.initials: R
authors.lastname: Shi
authors.affiliation: Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China.
authors.forename: Jingmei
authors.initials: J
authors.lastname: Jiang
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D016208:Databases, Factual; D055088:Early Detection of Cancer; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D009367:Neoplasm Staging; D055752:Small Cell Lung Carcinoma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed