Positron Emission Tomography/Computed Tomography Radiomic Subtypes in Clinical Stage IA Pure-Solid Non-Small Cell Lung Cancer

Objective Clinical stage IA non–small cell lung cancer (NSCLC) with pure-solid appearance on computed tomography (CT) lacks additional reliable imaging biomarkers beyond tumor size and SUVmax. This study aimed to identify subtypes of clinical stage IA pure-solid NSCLC using positron emission tomography (PET)/CT-based radiomics and to assess their radiological, pathological, and prognostic differences. Methods This retrospective study included patients who underwent curative-intent resection for clinical stage IA pure-solid NSCLC with preoperative PET/CT. Radiomic features were extracted from tumors on PET/CT images. Robust, non-redundant, survival-related features were retained using intraclass correlation coefficient, Spearman correlation, and univariate Cox regression for recurrence-free survival (RFS). Consensus clustering was then applied to identify radiomic subtypes, which were comprehensively compared. Results Among 231 patients, two PET/CT radiomic subtypes, type 1 (N = 114) and type 2 (N = 117), were identified. Compared with type 1, type 2 showed higher CT attenuation and SUVmax, along with more frequent cavitation, air bronchogram, and pleural attachment (all P < 0.05). Type 2 exhibited more aggressive pathology, including higher pathological stage and more frequent occult lymph node metastasis and lymphovascular invasion (all P < 0.05). Type 2 was associated with worse RFS in the overall cohort (P = 0.005) and in subgroups with high SUVmax (P = 0.016) or larger tumors (P = 0.019). PET-derived Large Dependence Emphasis was the most discriminative feature for type 2 (area under the curve: 0.887). Conclusions PET/CT radiomics distinguishes two clinical stage IA pure-solid NSCLC subtypes with distinct radiological, pathological, and prognostic profiles.