title: Probability of cancer in pulmonary nodules detected on first screening CT.
abstract: BACKGROUND
  Major issues in the implementation of screening for lung cancer by means of low-dose computed tomography (CT) are the definition of a positive result and the management of lung nodules detected on the scans. We conducted a population-based prospective study to determine factors predicting the probability that lung nodules detected on the first screening low-dose CT scans are malignant or will be found to be malignant on follow-up.
  
  
  METHODS
  We analyzed data from two cohorts of participants undergoing low-dose CT screening. The development data set included participants in the Pan-Canadian Early Detection of Lung Cancer Study (PanCan). The validation data set included participants involved in chemoprevention trials at the British Columbia Cancer Agency (BCCA), sponsored by the U.S. National Cancer Institute. The final outcomes of all nodules of any size that were detected on baseline low-dose CT scans were tracked. Parsimonious and fuller multivariable logistic-regression models were prepared to estimate the probability of lung cancer.
  
  
  RESULTS
  In the PanCan data set, 1871 persons had 7008 nodules, of which 102 were malignant, and in the BCCA data set, 1090 persons had 5021 nodules, of which 42 were malignant. Among persons with nodules, the rates of cancer in the two data sets were 5.5% and 3.7%, respectively. Predictors of cancer in the model included older age, female sex, family history of lung cancer, emphysema, larger nodule size, location of the nodule in the upper lobe, part-solid nodule type, lower nodule count, and spiculation. Our final parsimonious and full models showed excellent discrimination and calibration, with areas under the receiver-operating-characteristic curve of more than 0.90, even for nodules that were 10 mm or smaller in the validation set.
  
  
  CONCLUSIONS
  Predictive tools based on patient and nodule characteristics can be used to accurately estimate the probability that lung nodules detected on baseline screening low-dose CT scans are malignant. (Funded by the Terry Fox Research Institute and others; ClinicalTrials.gov number, NCT00751660.).
authors.affiliation: Vancouver General Hospital, Vancouver, BC, Canada.
authors.forename: Annette
authors.initials: A
authors.lastname: McWilliams
authors.forename: Martin C
authors.initials: MC
authors.lastname: Tammemagi
authors.forename: John R
authors.initials: JR
authors.lastname: Mayo
authors.forename: Heidi
authors.initials: H
authors.lastname: Roberts
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Liu
authors.forename: Kam
authors.initials: K
authors.lastname: Soghrati
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yasufuku
authors.forename: Simon
authors.initials: S
authors.lastname: Martel
authors.forename: Francis
authors.initials: F
authors.lastname: Laberge
authors.forename: Michel
authors.initials: M
authors.lastname: Gingras
authors.forename: Sukhinder
authors.initials: S
authors.lastname: Atkar-Khattra
authors.forename: Christine D
authors.initials: CD
authors.lastname: Berg
authors.forename: Ken
authors.initials: K
authors.lastname: Evans
authors.forename: Richard
authors.initials: R
authors.lastname: Finley
authors.forename: John
authors.initials: J
authors.lastname: Yee
authors.forename: John
authors.initials: J
authors.lastname: English
authors.forename: Paola
authors.initials: P
authors.lastname: Nasute
authors.forename: John
authors.initials: J
authors.lastname: Goffin
authors.forename: Serge
authors.initials: S
authors.lastname: Puksa
authors.forename: Lori
authors.initials: L
authors.lastname: Stewart
authors.forename: Scott
authors.initials: S
authors.lastname: Tsai
authors.forename: Michael R
authors.initials: MR
authors.lastname: Johnston
authors.forename: Daria
authors.initials: D
authors.lastname: Manos
authors.forename: Garth
authors.initials: G
authors.lastname: Nicholas
authors.forename: Glenwood D
authors.initials: GD
authors.lastname: Goss
authors.forename: Jean M
authors.initials: JM
authors.lastname: Seely
authors.forename: Kayvan
authors.initials: K
authors.lastname: Amjadi
authors.forename: Alain
authors.initials: A
authors.lastname: Tremblay
authors.forename: Paul
authors.initials: P
authors.lastname: Burrowes
authors.forename: Paul
authors.initials: P
authors.lastname: MacEachern
authors.forename: Rick
authors.initials: R
authors.lastname: Bhatia
authors.forename: Ming-Sound
authors.initials: MS
authors.lastname: Tsao
authors.forename: Stephen
authors.initials: S
authors.lastname: Lam
mesh_terms: D019317:Evidence-Based Medicine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D015233:Models, Statistical; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging / Q000473:pathology; D011336:Probability; D011446:Prospective Studies; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed