Computed tomography features of resected lung adenocarcinomas with spread through air spaces

Spread through air spaces (STAS) is a recently recognized invasive pattern of lung cancer defined as "micropapillary clusters, solid nests, or single cells beyond the edge of the tumor into air spaces." Since STAS has been shown to be a significant prognosticator for the postoperative survival, predicting STAS preoperatively by computed tomography (CT) might help determine the optimum surgical procedures.

Information on STAS and preoperative CT was available in 327 patients with resected lung adenocarcinomas. STAS was defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. The association of STAS with CT characteristics, such as vascular convergence, ground-glass opacity (GGO), air bronchogram, notch, pleural indentation, spiculation, and cavitation, was analyzed.

Among the 327 patients with resected adenocarcinoma, 191 (58.4%) were positive for STAS. A univariable analysis demonstrated that STAS-positive adenocarcinomas were significantly associated with a larger radiologic tumor diameter (P = .02), the presence of vascular convergence (P < .01), notch (P < .01), pleural indentation (P = .03), spiculation (P < .01), and the absence of GGO (P < .01) compared with STAS-negative ones. In a multivariable analysis, the presence of notch (P = .01) and the absence of GGO (P < .01) were shown to be significantly associated with the STAS phenomenon. The odds ratio for STAS of notch-positive and GGO-negative adenocarcinomas against notch-negative and GGO-positive ones was 5.01 (P < .01).

The presence of notch and the absence of GGO were independently associated with the STAS phenomenon. These results will prove helpful in identifying STAS-positive adenocarcinoma by CT before surgical resection.