Abstract Background Solitary pure ground-glass nodules (pGGNs) are commonly detected on chest computed tomography (CT). Although they generally exhibit indolent biological behavior, they have a recognized potential for malignant transformation. Methods We conducted a prospective, multicenter cohort study enrolling 827 patients with solitary pGGNs measuring at least 4 mm in baseline diameter from two hospitals. Comprehensive baseline data—including demographic characteristics, clinical history, and detailed imaging features such as nodule diameter, volume, mass, CT attenuation values, and specific malignant signs—were systematically collected. Nodule progression was rigorously defined as meeting one or more of the following criteria: an increase in diameter of ≥ 2 mm, an increase in volume of ≥ 20%, or the emergence of a new solid component. Advanced artificial intelligence software was utilized to ensure consistent and quantitative image analysis. Results The study population had a mean age of 47.5 years, was predominantly female (71.2%), and had no significant history of smoking (88.4%). Nodules were most frequently located in the upper lobes (right upper lobe: 34%; left upper lobe: 30%), with a mean baseline diameter of 6.8 mm. Vascular penetration was the most observed malignant feature. Over the five-year follow-up period, the overall progression rate was 41.8%. Notably, when the volume increase criterion was excluded, the progression rate decreased significantly to 17.7%, underscoring the critical importance of volumetric assessment. Volume and mass demonstrated the most substantial changes, with a mean increase of nearly 50% over five years, whereas changes in diameter and mean CT attenuation were minimal. Rapid growth, defined as a volume doubling time (VDT) of ≤ 400 days, was infrequent, observed in only 2.5% of nodules, and was significantly associated with a personal history of tumors, larger baseline volume, and the presence of vascular penetration or pleural indentation. Complete nodule regression was rare, observed in only 4.1% of nodules during the first year and declining to less than 1% thereafter. Conclusion This prospective study confirms the slow progression of solitary pGGNs and establishes volumetric analysis as the most sensitive indicator for detecting progression, supporting its integration into standardized follow-up protocols to guide personalized management. This abstract is funded by: National Natural Science Foundation of China (CN) (82370100)
Li et al. (Fri,) studied this question.