Characteristics of lung nodules detected by low-dose CT scan: Results from the French lung cancer screening study DEP...

DEP KP-80 is a real-world prospective study evaluating the effectiveness of organized lung cancer screening using low-dose chest CT (LDCT) across a French administrative department. Final results were published in 2024. The study, conducted from May 2016 to February 2020, included individuals aged 55-74 who were current or former smokers (within the past 15 years) with a smoking history of at least 30 pack-years. This ancillary analysis aimed to assess and compare the CT characteristics and demographic profiles of participants presenting with benign or malignant nodules within the first round of DEP KP-80 screening program.

We retrieved the characteristics of nodules and participants available from ADEMA80 across the first round of DEP-KP80 to investigate risk factors for malignancy.

Over the first screening round, a total of 809 nodules were identified in 348 of 945 participants (36.8%). The mean age was 61.6 ± 5.4 years, with 66.1% male participants. Nodules were solid in 86.2%, ground-glass in 9.1%, and part-solid in 4.6%. They were located in the upper lobes in 45.4% of cases, in the middle lobe in 13.1%, and in the lower lobes in 41.5%. Sizes were <5 mm in 41.3%, 5-10 mm in 47.5%, and >10 mm in 11.2%. Malignancy was confirmed in 35 nodules from 30 participants (8.6%). On multivariate analysis, multiplicity of nodules (at least five nodules) was predictive of benignity, while a diameter >10 mm was predictive of malignancy. No significant differences were found regarding age, sex, or nodule density.

This real-world lung cancer screening analysis shows that malignant pulmonary nodules tend to be solitary and larger than 10 mm in diameter. The multiplicity of nodules appears to be a factor of benignity and localization in the upper lobes a factor of malignancy, but these data did not reach significance in our study.