Prognostic impact of spread through air spaces in lung adenocarcinoma

OBJECTIVE: Spread through air spaces (STAS) is a pattern of invasion present in some adenocarcinomas (ADC). The goal of this study was to assess the impact of STAS in patients treated with different types of surgical resections and on the clinical outcome in patients with ADC of different diameters and with different degrees of nodal involvement. METHODS: A total of 109 patients were reviewed. Complete surgical resection with systematic nodal dissection was achieved in all patients. The median follow-up was 65 months (3-90 months). RESULTS: STAS was observed in 70 cases (64.2%); 13 patients (18.5%) had lymph node involvement (N1 and N2). Overall survival and progression-free survival were higher in patients without STAS (P= 0.042; P= 0.027). The presence of STAS in tumours <= 2 cm was a predictor of worse progression-free survival following sublobar resection compared to major resections (P= 0.011). Sublobar resection of NO STAS-positive tumours was associated with worse long-term survival compared to a major resection (P = 0.04). Statistical analyses showed that age >70 years and recurrence were independent variables for survival; smoking pack-years >20, sublobar resection and nodal involvement were independent variables for recurrence; and smoking pack-years >20 were independent variables for a history of cancer and pleural invasion for local recurrence. CONCLUSIONS: STAS seems to play a role in long-term survival, particularly for patients with N0 and tumours smaller than 2 cm. Further studies are necessary to validate this hypothesis.