Computed Tomography Features of Lung Adenocarcinomas With Programmed Death Ligand 1 Expression

The development of immune checkpoint inhibitors against programmed death 1 has paved the way for a new era of treatment of lung cancer. Programmed death-ligand 1 (PD-L1) is expected to predict the response of immune checkpoint inhibitors in lung cancer. Predicting PD-L1 expression using a noninvasive method before immunotherapy would, therefore, help identify patients for whom immunotherapy can be successful.

A total of 394 patients with resected lung adenocarcinoma who had undergone preoperative thin-section computed tomography (CT) were analyzed for PD-L1 expression by immunohistochemistry and evaluated to determine the association between PD-L1 expression and CT characteristics, including convergence, surrounding ground glass opacity (GGO), air bronchogram, notching, pleural indentation, spiculation, and cavitation.

Of the 394 patients, 78 (19.8%) were positive and 316 (80.2%) were negative for PD-L1 expression. Univariate analysis demonstrated that PD-L1⁺ adenocarcinoma was significantly associated with the presence of convergence (P < .01), notching (P < .01), spiculation (P < .01), and cavitation (P < .01) and the absence of surrounding GGO (P < .01) compared with PD-L1^- cases. On multivariate analysis, the presence of convergence (P < .01) and cavitation (P < .01) and the absence of surrounding GGO (P = .02) and air bronchogram (P = .03) were significantly associated with PD-L1 expression.

PD-L1⁺ adenocarcinoma cases showed convergence and cavitation more frequently than did PD-L1^- cases. In contrast, surrounding GGO and air bronchogram were observed less frequently in PD-L1⁺ cases than in PD-L1^- cases. These results will prove helpful in identifying PD-L1-expressing adenocarcinoma by CT before immunotherapy.