P2.09-04 The Clinicopathological Characteristics and Prognosis of Lung Cancer with Tumor Spread Through Air Spaces: A Meta-Analysis

Abstract

The clinicopathological characteristics of lung cancer with tumor spread through air spaces (STAS) has not been clearly characterized yet. Also, it is still not clear whether the presence of STAS correlated with worse prognosis in patients with lung cancer. Thus, we aim to systematically evaluate the clinicopathological characteristics and prognosis of the patients with or without STAS undergoing surgical resection for lung cancer. A comprehensive search of online databases was performed. Clinicopathological characteristics, 5-year RFS and OS rate were compared between 2 groups. Cumulative meta-analysis was performed to evaluate the temporal trend of pooled outcomes. Specific subgroups according to different types of lung cancer are examined. A total of 25 eligible studies including 8494 patients were recruited. STAS occurred in 2881 patients (34%) while non-STAS occurred in 5613 patients (66%). Overall, patients with STAS manifested significantly more aggressive characteristics, including lymphatic invasion (SMD=2.935; P=0.000), pleural invasion (SMD=2.329; P=0.000), vascular invasion (SMD=2.306; P=0.000) as well as lymph node metastasis (OR=3.510; P=0.000). Patients with STAS also correlated with significantly higher pathological stage (OR=2.216; P=0.003), T stage (OR=1.756; P=0.000), N stage (OR=2.395; P=0.000) and larger tumor size (OR=0.275; P=0.001). Meanwhile, the incidence of STAS was significantly associated with the micropapillary (OR=9.792; P=0.000) and solid patterns (OR=2.451; P=0.000). Moreover, the presence of STAS was related to male sex (OR=1.493; P=0.000), smoking history (OR=1.637; P=0.000) and necrosis (OR=2.300; P=0.000). As for the outcomes of the prognosis, patients with STAS linked with significant worse prognosis than those without STAS, including both 5-year RFS (HR=0.585; 95% CI: 0.486–0.684; P=0.000) and 5-year OS rate (HR=0.788; 95% CI: 0.596–0.980; P=0.000). The presence of STAS was associated with several invasive pathological characteristics, which might explain the worse prognosis in patients with STAS compared with those without STAS.