P56.03 Prognostic Value of Tumor Spread Through Air Spaces in Patients With Lung Adenocarcinoma after Radical Surgery

Abstract

Tumor spread through air spaces (STAS) has been identified as an invasive pattern in lung adenocarcinoma (ADC), but the correlations between clinicopathologic features and STAS and the prognostic value of STAS have not been well studied in all stages of ADC with a lager sample size. The purpose of this study was to investigate these correlations and evaluate the prognostic value of STAS in patients with ADC after radical surgery. 988 patients with completely resected lung adenocarcinomas were reviewed. Recurrence-free survival (RFS) was defined as the time between the date of surgery to the date of disease recurrence or the last follow-up. Pearson’s chi-square test or Fisher exact test was used for comparing the relationship between STAS and clinicopathological features. The log-rank test was used to identify potential prognostic factors and multivariate Cox regression models were used to explore independent prognostic factors. Of the 988 patients, STAS was found in 328 (33.2%) patients. STAS was significantly frequent in patients with ever smoking (P=0.049), micropapillary-predominant (MPA) and solid-predominant adenocarcinoma (SPA) (P<0.001), N1-3 diseases (P<0.001), stage Ⅱ-Ⅲ (P<0.001), the presence of VPI (P<0.001), the presence of LVI (P<0.001) and the presence of NI (P<0.001). Univariate analysis revealed that patients with the presence of STAS had a significantly worse RFS in patients with stage Ⅰ(P=0.002), N0 diseases (P<0.001) and intermediate grade lung adenocarcinoma (Acinar-Predominant Adenocarcinoma; APA/ Papillary-Predominant Adenocarcinoma; PPA/Invasive Mucinous Adenocarcinoma; IMA) (P<0.001), but not in patients with stage Ⅱ-Ⅲ(P=0.96), N1-3 disease (P=0.90) and high grade lung adenocarcinoma (MPA/SPA) (P=0.35). Multivariate analysis demonstrated that STAS was an independent prognostic factor for RFS in patients with stage Ⅰ(P=0.018) and N0 diseases (P=0.011). Specially, STAS had independent prognostic significance for RFS in patients with intermediate grade lung adenocarcinoma (APA/PPA/IMA) of N0 diseases (P=0.009). Moreover, STAS status was a significantly prognostic factor for RFS in patients of N0 diseases after lobectomy (P=0.004) and sublobar resection (P=0.03) in univariate analysis. Multivariate analysis found that STAS status remained an independent predictor for RFS in patients of N0 diseases after lobectomy (P=0.008), but not in patients after sublobar resection (P=0.062). The presence of STAS is a significant risk factor for recurrence in N0 and stage ⅠADC patients. Moreover, it will significantly increase the risk of recurrence for patients with intermediate grade lung adenocarcinoma of N0 diseases. The presence of STAS is a high risk factor for recurrence in N0 patients after lobectomy or sublobar resection.