Background A clinical trial (NCT03651986) is conducted to assess the performance of our previously established model based on cfDNA methylation sequencing (Liang, W. et al. J Clin Invest 2021;131(10): e145973) for early diagnosis of lung cancer.

Aims and Objective To report the prevalence and epidemiological characteristics of subjects in this trial at baseline.

Methods A prospective cohort of 10,560 subjects with incidental pulmonary nodules (IPNs) sized in 5-30 mm indicated by CT/LDCT were enrolled at 23 centers. The demographic, clinical, and CT imaging features of all cases at baseline were analyzed.

Results Totally 13,310 pulmonary nodules (PNs) were identified in 10,560 cases (mean [SD], 53.12 [11.88] years; 56.6% female; 71.3% never-smokers), including 4,997 (37.54%) solid nodules (SNs), 5,111 (38.40%) pure ground-glass nodules (pGGNs) and 3,202 (24.06%) mixed ground-glass nodules (mGGNs). 2,246 (1,814 malignant, 332 benign) PNs from 1,981 patients (53.9 [11.21] years; 60.6% female; 77.3% never-smokers) at high risk underwent surgical resection with definitive diagnosis at baseline. Up to 98.15% of female patients with malignant PNs were never-smoker. 76.7% of malignant PNs were GGNs and 58.8% of benign PNs were SNs. 92.78% of malignant PNs were lung adenocarcinoma and 87.54% (1,588) were at early stages (0-I). 46.99% (156) of benign PNs were inflammation. Gender, age, nodule size, location, types, lobulation, pleural traction, and vacuole signs were significant lung cancer risk factors (p<0.05).

Conclusions These findings describe a typical profile of IPN patients in China that form a foundation for future clinical management of IPN patients.