Characteristics of lung nodules detected by low-dose CT scan: Results from the French lung cancer screening study DEP KP-80

Abstract

Background

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.

Methods

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

Results

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.

Conclusion

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.