ABSTRACT
@#Objective To assess the specific clinicopathological characteristics as well as prognostic value of prognostic significance of spread through air spaces (STAS) in lung adenocarcinoma. Methods We systematically searched the databases of PubMed, EMbase and Web of Science databases from their date of inception to March 2019. The quality of the included literature was assessed by the Newcastle-Ottawa scale (NOS). The NOS of the study higher than 6 points was considered as high quality. Software of Stata 12.0 was used for meta-analysis. Results Twenty retrospective cohort studies involved with totally 6 225 patients were included. Quality of included studies was high with NOS score equal or higher than 6 points. STAS was associated with male sex, ever smoking history, abnormal carcino-embryonic antigen (CEA) level, air bronchogram negative, anaplasticlymphoma kinase (ALK) arrangement positive, epidermal growth factor receptor (EGFR) mutation positive, advanced pathological tumor stage and more invasive pathological adenocarcinoma subtypes. The presence of STAS indicated significantly poor recurrence free survival (RFS) (HR=1.960, 95%CI 1.718-2.237, P<0.001) as well as poor overall survival (OS) (HR=1.891, 95%CI 1.389-2.574, P<0.001). Further subgroup analyses showed that exhibiting tumor size including diameter less than 2 cm (HR=2.344, 95%CI 1.703-3.225, P<0.001) and diameter over 2 cm (HR=2.571, 95%CI 1.559-4.238, P<0.001), resection type including lobectomy (HR=1.636, 95%CI 1.258-2.127, P<0.001) and sublobar resection (HR=3.549, 95%CI 2.092-6.021, P<0.001) in stageⅠ adenocarcinoma suggested that STAS had a bad effect on RFS. Conclusion Presence of STAS is associated with more aggressive clinicopathological features and independently associated with worse RFS and OS in lung adenocarcinoma. STAS positive has a negative effect on RFS whatever the tumor size (including the diameter<2 cm or >2 cm) and resection types in stageⅠ adenocarcinoma.