Correlation between spread through air spaces (STAS) and other clinicopathological parameters in lung cancer.

Background: "Spread through airspace" (STAS) is defined as micropapillary clusters, solid nests or single cells of tumor extending beyond the edge of the tumor into the air spaces of the surrounding lung parenchyma. It is associated with reduced overall survival and disease-free survival. Assessment of STAS in lung cancer appears to be necessary to guide clinical interventions. However, data on the correlation between the status of STAS and other lung cancer clinicopathological parameters are scarce.

Methods: We reviewed 240 resected lung cancers and investigated the clinical significance of STAS in relation to other relevant lung cancer clinicopathological variables. We performed univariate and multivariate logistic regression analyses with STAS as a dependent variable.

Results: Of the total 240 patients, STAS was observed in 67 (27.9 %) of them. STAS is highly prevalent in adenocarcinoma with a micropapillary growth pattern (70.0 %) than in other lung cancer growth patterns. STAS was frequently reported in wedge resections (31.0%) than in lobectomy specimens (26.7 %). STAS was significantly associated with advanced pN stage (p < 0.001) and lymphovascular invasion (p = 0.005). In multivariate models, we found that lung cancers in the right lower lobe (RLL) (OR, 2.674; 95 % CI = 1.313-5.448, p = 0.007), micropapillary lung cancer growth pattern (OR = 5.199, 95 % CI = 1.220-22.162, p = 0.026), and pN2 stage (OR = 3.683, 95 % CI = 1.324-10.245, p = 0.013) serve as independent predictors for STAS.

Conclusion: Our findings suggest that the presence of STAS is associated with right lower lobe tumors, micropapillary adenocarcinoma, and pN2 tumor stage. Hence, it could serve as one of the prognostically significant histologic findings in lung cancer. It is thus valid to mandate reporting STAS status in CAP surgical pathology lung cancer case summaries.