title: Initial LDCT appearance of incident lung cancers in the ITALUNG trial.
abstract: OBJECTIVE
  To characterize early features of lung cancers detected with low-dose computed tomography (LDCT) screening.
  
  
  METHODS
  Two radiologists reviewed prior LDCTs in 20 incident cancers diagnosed at annual repeat screening rounds and 83 benign nodules observed in the ITALUNG trial.
  
  
  RESULTS
  No abnormality was observed in 3 cancers. Focal abnormalities in prior LDCT were identified in 17(85%) cancers (14 adenocarcinomas; 14 stage I). Initial abnormalities were intra-pulmonary in 10, subpleural in 4 and perifissural in 3. Average mean diameter was 9mm (range 4.5-18mm). Nine exhibited solid, 4 part-solid and 4 non-solid density. The margins were smooth and regular in 5 cases, lobulated in 6, irregular with spiculations in 3 and blurred in 3. Ten (59%) initial focal abnormalities had a round or oval nodular shape, but 7(41%) had a non-nodular complex (n=5) or "stripe-like" (n=2) shape. Bronchus sign was observed in 3 cases and association with cystic airspace in 2 cases. Non-solid density, complex or "stripe-like" shape, bronchus sign and association with cystic airspace had a specificity higher than 90%, but positive predictive value of every feature of incident lung cancers was low (range 10.4-50%).
  
  
  CONCLUSIONS
  The vast majority of cancers diagnosed at annual repeat show corresponding focal lung abnormalities in prior LDCTs. Perifissural location and non-nodular shape do not exclude the possibility of early lung cancer. Since specificity of the early features of incident lung cancer is incomplete and their positive predictive value is low, all focal pulmonary abnormalities detected in screened subjects should be re-evaluated in subsequent LDCTs.
authors.affiliation: Quantitative and Functional Radiology Research Programs at Meyer Children Hospital and Careggi Hospital of Florence, Florence, Italy; "Mario Serio" Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy. Electronic address: m.mascalchi@dfc.unifi.it.
authors.forename: Mario
authors.initials: M
authors.lastname: Mascalchi
authors.affiliation: Institute for Oncological Study and Prevention, Florence, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Picozzi
authors.affiliation: "Mario Serio" Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Falchini
authors.affiliation: Nuclear Medicine Unit, Le Scotte University Hospital, Siena, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Vella
authors.affiliation: Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Diciotti
authors.affiliation: Cardiopulmonary Department University Hospital, Pisa, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Carrozzi
authors.affiliation: Pneumonology Department, Careggi Hospital, Florence, Italy.
authors.forename: Andrea Lopes
authors.initials: AL
authors.lastname: Pegna
authors.affiliation: 2nd RadiologyUnit Cisanello University Hospital of Pisa, Pisa, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Falaschi
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D009367:Neoplasm Staging; D016032:Randomized Controlled Trials as Topic; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Low dose CT; Lung cancer; Screening