Comparison between sub-lobar resection and lobar resection for clinical stage IA (tumor size ≤ 2 cm) lung invasive mucinous adenocarcinoma with tumor spread through air spaces: A multi-center real-world study.

Background: Tumor spread through air spaces (STAS) has emerged as a significant prognostic factor in clinical stage IA (cIA) invasive mucinous adenocarcinoma (IMA) of the lung. However, it remains unclear whether sub-lobar resection (SR) offers survival outcomes comparable to those of lobar resection (LR) in this cohort. This study aimed to assess the efficacy of SR in patients with STAS-positive cIA (tumor size ≤2 cm) IMA using large-scale, multi-center, real-world data.

Methods: We retrospectively reviewed consecutive patients with peripheral cIA (≤2 cm) STAS-positive IMA who underwent SR or LR between 2012 and 2020 at seven high-volume institutions across five Chinese cities. The primary endpoint was overall survival (OS), and the secondary endpoint was recurrence-free survival (RFS). Propensity-score matching (PSM) was employed to mitigate selection bias.

Results: Among 567 included patients, PSM yielded 179 patients undergoing SR and 388 patients undergoing LR. Over a median follow-up of 6.2 years, SR demonstrated comparable 5-year OS (78.7 % versus 81.6 %, hazard ratio (HR) = 0.976, 95 % confidence interval (CI) = 0.693-1.375, P = 0.890) and RFS (69.0 % versus 71.8 %, HR = 1.017, 95 %CI = 0.752-1.376, P = 0.914) to LR. Subgroup analysis revealed that SR improved 5-year OS in patients aged ≥70 years (73.1 % versus 67.2 %, HR = 0.636, 95 %CI = 0.404-0.969, P = 0.040). Additionally, SR yielded similar outcomes in patients with visceral pleural invasion and exhibited a statistically nonsignificant trend toward lower survival in those with pathological N1-2 disease. Furthermore, LR, segmentectomy, and wedge resection yielded comparable 5-year OS and RFS.

Conclusion: Among patients with cIA (≤2 cm) STAS-positive IMA, SR provides 5-year OS and RFS outcomes comparable to LR and may confer a survival advantage among patients aged ≥70 years. These findings support the efficacy of SR and suggest that it should not be considered an adverse prognostic factor in this patient cohort.