Tumor spread through air spaces (STAS) is a predictor of occult lymph node metastasis in clinical stage IA lung adenocarcinoma

Abstract Introduction In patients with stage IA lung adenocarcinoma (ADC), sublobar resection and tumor spread through air spaces (STAS) are associated with high rates of locoregional recurrence, half of which occur within the regional lymph nodes (LNs). Our objective was to investigate the association between occult LN metastasis (ONM) and STAS and to assess their prognostic value in patients with clinical stage IA lung ADC. Methods The association between STAS and ONM was analyzed in patients who underwent lobectomy and LN dissection for clinical stage IA lung ADC (n=809). Multivariable logistic regression analysis was conducted to identify predictors of ONM. Site-specific recurrence by surgical procedure was investigated in patients with pathologic N0 disease (n=1055) using a competing-risks approach. Results ONM was identified in 129 patients (16%)—one-third of ONMs were located only in intrapulmonary nodes. STAS was more common in patients with ONM (67% vs. 39%; P Conclusion Presence of STAS predicts ONM in patients with clinical stage IA lung ADC and can help stratify risk of recurrence by extent and type of resection.