Predicting STAS in peripheral stage I lung adenocarcinoma: the incremental value of CT-based tumor disappearance
Haoran Du1, Yugang Ji2, Cong Liu3
1Department of Radiology, The Xuzhou Hospital Affiliated to Jiangsu University, Xuzhou, Jiangsu, 221000, People's Republic of China.
Background:
Tumor spread through air spaces (STAS) is a critical prognostic factor in peripheral stage I lung adenocarcinoma (LUAD) and substantially influences surgical decision-making. However, accurate preoperative prediction of STAS remains challenging. This study aimed to investigate the value of computed tomography (CT)-derived tumor disappearance rate (TDR) as a novel imaging biomarker for STAS prediction, and to evaluate the incremental benefit of combining TDR with consolidation tumor ratio (CTR) in part-solid nodules.
Methods:
This retrospective study enrolled 244 patients with peripheral stage I LUAD who underwent surgical resection at Xuzhou Hospital Affiliated to Jiangsu University between January 2022 and December 2023. The multivariate generalized additive model (GAM) was employed to characterize the adjusted dose-response relationship between TDR and STAS, with threshold effect analysis performed via the log-likelihood ratio test. The predictive performance of TDR, CTR, and the combined TDR-CTR index (COM) was compared using ROC curves, DeLong test, and bootstrap resampling validation.
Results:
STAS was identified in 51 (20.9%) patients. The STAS-positive group exhibited a significantly lower TDR compared with the STAS-negative group (0.26 +/- 0.32 vs. 0.51 +/- 0.44, P < 0.001). Multivariate analysis identified TDR and spiculation sign as independent risk factors for STAS. TDR demonstrated a non-linear association with STAS (P < 0.001), with a threshold value of 0.610. In the part-solid nodule subgroup, the combined TDR-CTR index achieved an AUC of 0.793 (95% CI: 0.654-0.932), significantly outperforming CTR alone (AUC = 0.525, P = 0.040). Bootstrap validation confirmed favorable stability. While promising in this exploratory subgroup analysis, further validation in larger cohorts is warranted due to the wide confidence interval of the combined TDR-CTR index.
Conclusions:
CT-derived TDR is a valuable biomarker for preoperative STAS risk stratification in peripheral stage I LUAD. The combined TDR-CTR index significantly enhances STAS prediction in part-solid nodules, addressing the limitations of CTR alone and supporting individualized surgical planning.