Feasibility of intraoperative assessment of STAS in pathologic stage 1 lung adenocarcinomas in Chinese patients.

Background: Intraoperative assessment of tumor spread through air spaces (STAS) in early-stage lung adenocarcinomas (ADC) has been proposed to stratify patients for surgical management. However, data on the accuracy and reproducibility of detecting STAS on frozen sections (FS) and the prognostic value of STAS on FS remain limited and contradictory.

Methods: We conducted a retrospective study on the feasibility of intraoperative assessment of STAS by comparing the STAS patterns identified on FS and permanent sections from 524 patients diagnosed with pathologic stage 1 lung ADC. We also evaluated the association between STAS with patients' clinicopathological characteristics and their postoperative survival outcomes.

Results: STAS was identified in 117 out of 524 patients (22.3 %) on permanent sections. Patients with STAS identified on permanent sections experienced shorter progression-free survival (PFS; P = 0.042) and overall survival (OS; P = 0.005) compared to those without. STAS was identified in 87 out of 509 patients on FS. Patients with STAS detected on FS also had shorter PFS (P = 0.010) and OS (P < 0.001) than those without. Compared to permanent sections, STAS detection on FS yielded 66.7 % (74/111) sensitivity, 96.7 % (385/398) specificity, 85.1 % (74/87) positive predictive value, 91.2 % (385/422) negative predictive value, and 90.2 % (459/509) overall agreement. The kappa coefficient was 0.688 (P < 0.001).

Conclusions: Our results from a large series of Chinese patients with stage 1 lung ADC indicated that STAS was associated with poorer survival outcomes on both FS and permanent sections. FS is a highly specific method for assessing STAS in stage 1 lung ADC, but caution is warranted regarding false-positive results.