Frequency and distribution of incidental findings deemed appropriate for S modifier designation on low-dose CT in a lung cancer screening program

• Published in: Lung cancer (Amsterdam, Netherlands) Netherlands), 2018-06, Vol.120, p.1-6
• Main Authors: Reiter, Michael J., Nemesure, Allison, Madu, Ezemonye, Reagan, Lisa, Plank, April
• Format: Article
• Language: English
• Subjects: Aged; Calcinosis; Coronary Vessels - pathology; Early Detection of Cancer; Female; Humans; Incidental finding; Incidental Findings; Low-dose chest CT; Lung cancer screening; Lung Neoplasms - diagnosis; Lung-RADS S modifier; Male; Middle Aged; Observer Variation; Practice Guidelines as Topic; Retrospective Studies; Thorax - diagnostic imaging; Thorax - pathology; Tomography, X-Ray Computed - methods
• ISSN: 0169-5002; 1872-8332
• DOI: 10.1016/j.lungcan.2018.03.017

•Use of the Lung-RADS S modifier was common, present for 261 of 581 (45%) participants.•Coronary artery calcification was most frequent observation warranting S modifier.•Inter-observer variability between radiologists was substantial (kappa of 0.2).•Guidelines for all incidental findings on screening chest CT are clearly needed. To describe the frequency, distribution and reporting patterns of incidental findings receiving the Lung-RADS S modifier on low-dose chest computed tomography (CT) among lung cancer screening participants. This retrospective investigation included 581 individuals who received baseline low-dose chest CT for lung cancer screening between October 2013 and June 2017 at a single center. Incidental findings resulting in assignment of Lung-RADS S modifier were recorded as were incidental abnormalities detailed within the body of the radiology report only. A subset of 60 randomly selected CTs was reviewed by a second (blinded) radiologist to evaluate inter-rater variability of Lung-RADS reporting. A total of 261 (45%) participants received the Lung-RADS S modifier on baseline CT with 369 incidental findings indicated as potentially clinically significant. Coronary artery calcification was most commonly reported, accounting for 182 of the 369 (49%) findings. An additional 141 incidentalomas of the same types as these 369 findings were described in reports but were not labelled with the S modifier. Therefore, as high as 69% (402 of 581) of participants could have received the S modifier if reporting was uniform. Inter-radiologist concordance of S modifier reporting in a subset of 60 participants was poor (42% agreement, kappa = 0.2). Incidental findings are commonly identified on chest CT for lung cancer screening, yet reporting of the S modifier within Lung-RADS is inconsistent. Specific guidelines are necessary to better define potentially clinically significant abnormalities and to improve reporting uniformity.