Correlation between CT growth patterns and invasiveness progression in neoplastic subcentimeter sub-solid nodules

Size and/or attenuation growth of neoplastic sub-solid nodules (SSNs) potentially indicate progression in invasiveness. This study aims to clarify the correlation between growth patterns based on size and attenuation and the invasiveness progression in subcentimeter neoplastic SSNs. From December 2018 to October 2024, 530 patients with 629 neoplastic SSNs (initial diameter &lt;10 mm) were retrospectively enrolled. Based on CT changes (interval ≥3 months), the lesions were divided into four groups: I, no growth in size or attenuation; II, growth in both size and attenuation; III, growth only in size; and IV, growth only in attenuation. The relationship between growth patterns and pathological results was investigated, and the key CT indicators suggestive of invasiveness progression were determined. Lesions in groups I, II, III, and IV were 424 (67.4%), 76 (12.1%), 84 (13.4%), and 45 (7.1%), respectively. The invasive adenocarcinomas (IACs) and invasive lesions (ILs) were more prevalent in groups II (38.2%, 78.9%) and III (11.9%, 52.4%) compared to group I (3.8%, 34.0%) (all <i>p</i> &lt; 0.05). However, IACs (6.7%) and ILs (44.4%) in group IV were comparable to those in group I (all <i>p</i> &gt; 0.05). The tumor mass was a more effective indicator for predicting the progression to IAC and ILs in group II (area under the curve [AUC] = 0.85, 0.76) and group III (AUC = 0.75, 0.65) (all <i>p</i> &lt; 0.05). Regarding the subcentimeter SSNs, size growth, especially with concurrent attenuation increase, indicate a higher possibility of invasiveness progression, with mass being the primary predictor. Different growth patterns of subcentimeter neoplastic SSNs indicate varying degrees of invasiveness progression.Growth only in attenuation does not indicate significant progression in invasiveness.Size growth, especially with concurrent attenuation increasing, indicate a higher possibility of invasiveness progression.Mass is the primary indicator of invasiveness progression in those with size growth. Different growth patterns of subcentimeter neoplastic SSNs indicate varying degrees of invasiveness progression. Growth only in attenuation does not indicate significant progression in invasiveness. Size growth, especially with concurrent attenuation increasing, indicate a higher possibility of invasiveness progression. Mass is the primary indicator of invasiveness progression in those with size growth.