Factors associated with the growth of ground-glass opacity nodules on chest computed tomography

Abstract

Background: As the clinical application of computed tomography (CT) has been increasing due to various clinical situations including national screening program, the incidental discovery of ground glass nodule (GGN) which was not seen in simple chest X-ray has been increasing. The natural history of GGN is not well defined and detailed guidelines for GGN assessment and follow-up schedules have not yet been established. The purpose of this study is to identify useful clinical indicators as well as radiologic factors for the course of GGN. Methods: We reviewed the retrospective data of GGN found on CT, performed at the tertiary university hospital. Variables of age, sex, underlying lung disease, the presence of malignancy or comorbidities, size, border and number of GGN, the presence of solid part within GGN, and growth rate over time were examined. Cox proportional hazards regression model was applied to identify the factors associated with the growth of GGN. Results: In a total of 504 patients, 916 GGN were detected on chest CT. The mean age was 59.6 years and sex of male was 37%. The mean follow-up time was 17.1 months. The growth of GGN was significantly associated with history of malignancy (adjusted hazard ratio [aHR] 1.77, 95% confidence intervals [CI] 1.05-2.99, p=0.032), solitary nodule (aHR 2.34, 95% CI 1.40-3.87, p=0.001) and longest diameter of nodules ≥ 10 mm (aHR=1.83, 95% CI 1.03-3.25, p=0.039). Conclusions: A prior history of malignancy, solidity of lesion, and diameter greater than 10 mm are likely to grow GGN. Those clinical indicators should be evaluated from the beginning of follow-up for GGN in order to determine the decision of tissue biopsy.