High frequency of spread through air spaces in resected small cell lung cancer

Background/Aim: Spread through air spaces (STAS) is a novel invasive pattern of lung cancer, especially adenocarcinoma and squamous cell carcinoma. However, its frequency and significance in patients with resected small cell lung cancer (SCLC) remains unclear. Patients and Methods: A total of 30 patients with resected SCLC were analyzed for STAS. STAS was classified as either no STAS, low STAS (1-4 single cells or clusters of STAS), or high STAS (≥5 single cells or clusters of STAS). We evaluated the association between STAS and clinicopathological characteristics and postoperative survivals. Results: Among 30 patients, 5 (17%), 6 (20%) and 19 (63%) were classified as having no, low and high STAS, respectively. Fisher’s exact test demonstrated no significant associations between the positivity for STAS and clinicopathological characteristics. No significant differences were observed in recurrence-free and overall survival between STAS-negative/low and STAS-high patients. Conclusion: STAS was frequently observed in patients with resected SCLC.