Prognostic significance of tumor spread through air spaces in patients with stage IA part-solid lung adenocarcinoma after sublobar resection

Objectives The purpose of this study was to assess the clinicopathologic implications of tumor spread through air spaces (STAS) in patients with stage IA part-solid lung adenocarcinoma after sublobar resection. Materials and methods Medical records of patients with stage IA part-solid adenocarcinoma who underwent curative pulmonary resection between February 2009 and December 2016 were retrospectively reviewed. The clinicopathological features of STAS and its influence on postoperative recurrence and survival were investigated. Results Among the 115 patients with stage IA part-solid adenocarcinoma who underwent wedge resection, 20 (17.4 %) had STAS. The multivariable analysis showed presence of STAS [HR (hazard ratio), 9.447; p = 0.002) and a larger invasive component size (HR, 1.097; p = 0.034) were independent risk factors for recurrence. The 5-year freedom from recurrence rates were 62.4 % and 97.9 % in cases with and without STAS, respectively (p < 0.001), and the 5-year disease-free survival rates were 58.5 % and 97.9 % in cases with and without STAS, respectively (p < 0.001). The presence of STAS was associated with old age (p = 0.030), male gender (p = 0.023), acinar predominant histologic pattern (p = 0.004), presence of micropapillary pattern (p < 0.001), lymphovascular invasion (p < 0.001) and larger invasive component (p < 0.001). Conclusion STAS could be an important prognostic factor in patients with stage IA part-solid lung adenocarcinoma after sublobar resection. Effective preoperative evaluation and postoperative surveillance may help improve the outcome of patients with small part-solid nodules, particularly when accompanied by STAS.