title: CT scan screening for lung cancer: risk factors for nodules and malignancy in a high-risk urban cohort.
abstract: BACKGROUND
  Low-dose computed tomography (CT) for lung cancer screening can reduce lung cancer mortality. The National Lung Screening Trial reported a 20% reduction in lung cancer mortality in high-risk smokers. However, CT scanning is extremely sensitive and detects non-calcified nodules (NCNs) in 24-50% of subjects, suggesting an unacceptably high false-positive rate. We hypothesized that by reviewing demographic, clinical and nodule characteristics, we could identify risk factors associated with the presence of nodules on screening CT, and with the probability that a NCN was malignant.
  
  
  METHODS
  We performed a longitudinal lung cancer biomarker discovery trial (NYU LCBC) that included low-dose CT-screening of high-risk individuals over 50 years of age, with more than 20 pack-year smoking histories, living in an urban setting, and with a potential for asbestos exposure. We used case-control studies to identify risk factors associated with the presence of nodules (n=625) versus no nodules (n=557), and lung cancer patients (n=30) versus benign nodules (n=128).
  
  
  RESULTS
  The NYU LCBC followed 1182 study subjects prospectively over a 10-year period. We found 52% to have NCNs >4 mm on their baseline screen. Most of the nodules were stable, and 9.7% of solid and 26.2% of sub-solid nodules resolved. We diagnosed 30 lung cancers, 26 stage I. Three patients had synchronous primary lung cancers or multifocal disease. Thus, there were 33 lung cancers: 10 incident, and 23 prevalent. A sub-group of the prevalent group were stable for a prolonged period prior to diagnosis. These were all stage I at diagnosis and 12/13 were adenocarcinomas.
  
  
  CONCLUSIONS
  NCNs are common among CT-screened high-risk subjects and can often be managed conservatively. Risk factors for malignancy included increasing age, size and number of nodules, reduced FEV1 and FVC, and increased pack-years smoking. A sub-group of screen-detected cancers are slow-growing and may contribute to over-diagnosis and lead-time biases.
authors: Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, New York University School of Medicine, New York, New York, USA. alissa.greenberg@nyumc.org
authors: Alissa K
authors: AK
authors: Greenberg
authors: Feng
authors: F
authors: Lu
authors: Judith D
authors: JD
authors: Goldberg
authors: Ellen
authors: E
authors: Eylers
authors: Jun-Chieh
authors: JC
authors: Tsay
authors: Ting-An
authors: TA
authors: Yie
authors: David
authors: D
authors: Naidich
authors: Georgeann
authors: G
authors: McGuinness
authors: Harvey
authors: H
authors: Pass
authors: Kam-Meng
authors: KM
authors: Tchou-Wong
authors: Doreen
authors: D
authors: Addrizzo-Harris
authors: Abraham
authors: A
authors: Chachoua
authors: Bernard
authors: B
authors: Crawford
authors: William N
authors: WN
authors: Rom
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000000981:diagnostic imaging* / Q000401:mortality*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014505:Urban Population