Significance of Spread Through Air Spaces in Resected Lung Adenocarcinomas With Lymph Node Metastasis

Spread through air spaces (STAS) is a recently recognized invasive pattern of lung cancer defined by the World Health Organization as micropapillary clusters, solid nests, or single cells spreading within air spaces beyond the edge of the main tumor. Although STAS has been shown to be a significant prognosticator for the postoperative survival in early-stage lung cancer treated with limited resection, its prognostic impact on the survival in completely resected adenocarcinomas with lymph node metastasis remains unclear.

STAS was assessed in a total of 63 adenocarcinomas with lymph node metastasis in patients who underwent complete resection. STAS was defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. We evaluated the association between STAS and the clinicopathologic characteristics and the postoperative survival.

Among 63 patients, 31 (49.2%) and 32 (50.8%) had disease that was pathologically positive for N1 and N2, respectively. STAS was observed in 45 patients (73.0%) and was not significantly associated with any clinicopathologic characteristics. Patients with the STAS had significantly shorter recurrence-free survival (RFS) but not overall survival than those without STAS (P = .04 and P = .35, respectively). The 5-year RFS in patients with and without STAS was 25.1% and 56.7%, respectively. According to a multivariate analysis, positivity for STAS remained an independent prognostic parameter for RFS (hazard ratio = 3.09; 95% confidence interval, 1.47-7.16; P < .01).

STAS was predictive of a poor RFS in completely resected adenocarcinomas with lymph node metastasis.