Lymph Node Involvement and Radiologic Predictors of Invasiveness in Pure Ground-Glass Adenocarcinomas: The GORDON Study

Background: Pure ground-glass opacities (pGGOs) have been recognized as radiologic manifestations of early-stage lung adenocarcinomas, typically characterized by slow progression and a low risk of metastasis. The study evaluated the incidence of lymph node involvement in patients undergoing pGGO resection. Secondary objectives included assessing lymph node recurrence-free interval and correlating pGGO radiologic features with final histology. Methods: This multicenter retrospective study (January 2013-June 2024) included patients who underwent pulmonary resection and lymphadenectomy for pGGOs. Data were recorded in the GORDON (Ground-glass Opacities Retrospective Database for Oncological N-status) database. Histologic diagnosis, lymph node involvement, and recurrence were analyzed. Qualitative and quantitative radiologic features of invasive and noninvasive pGGOs were compared, and receiver operating characteristic curve analysis identified predictive variables for invasiveness. Results: Of 400 pGGOs, 346 (86%) were invasive adenocarcinomas, 40 (10%) were minimally invasive, and 14 (4%) were adenocarcinomas in situ. No lymph node metastases were detected. Nodal recurrence at 5 years was 0%. Invasive pGGOs showed larger radiologic diameter (22 vs 16 mm, P < .001), higher computed tomographic (CT) attenuation (-336 vs -562 Hounsfield units [HU], P < .001), higher difference CT values (-493 vs -313 HU, P < .001), and higher relative attenuation (P < .001). A combined receiver operating characteristic curve analysis identified a radiologic diameter of 18 mm and CT density of -390 HU as predictive cutoffs for invasiveness (area under the curve, 0.874). Conclusions: Adenocarcinomas presenting as pGGOs are low-risk lesions with rare lymph node involvement or recurrence, suggesting that lymphadenectomy may be unnecessary. Preoperative chest CT enables risk stratification of lesion invasiveness, supporting tailored therapeutic approaches.