Clinical analysis of incidental discovery of pulmonary nodules with computed tomography: a retrospective cohort study.

Background: The increasing use of computed tomography (CT) for screening has led to a rising number of incidental pulmonary nodule detections. The incidental pulmonary nodule detection rates are well-documented in Western populations, but large-scale data from Chinese cohorts remain limited. Understanding the clinical characteristics of these lesions is crucial for the early diagnosis and management of potential malignancies. This study aimed to determine the prevalence of incidentally detected pulmonary nodules in routine Chinese practice, their malignant potential based on radiological characteristics, and the diagnostic outcomes of high-risk nodules. Methods: The study enrolled patients who underwent CT screening from February 2020 to February 2022, except for those with respiratory diseases or primary malignant tumors. Clinical and radiologic characteristics were retrospectively analyzed. Additionally, patients with high-risk lesions (noncalcified nodules ≥6 mm) were informed and followed up every 6 months until a clear pathological diagnosis was made. Results: The cohort (n=120,623) comprised 25.2% of individuals aged >65 years with 49.9% males, identifying 52.9% CT-positive (diameter ≥4 mm) cases, with 5.1% high-risk lesions. Among 5,482 followed cases, 343 underwent surgery or invasive diagnostics, confirming lung cancer in 310 (93.9% adenocarcinoma) after a 30-month median follow-up. Conclusions: CT screening demonstrates significant potential for incidental pulmonary nodule detection, with a subset exhibiting high malignancy risk. Our findings underscore the clinical value of targeted, risk-stratified screening over universal approaches in China.