Predictive factors for invasive adenocarcinoma in patients with clinical non-invasive or minimally invasive lung cancer

Background: Pure ground glass opacity (GGO) or part-solid GGO with small solid component (≤5 mm) are likely to be non-invasive or minimally invasive lung cancer. However, those lesions sometimes are diagnosed as invasive adenocarcinoma postoperatively. The aim of this study was to determine the predictors of invasive adenocarcinoma in clinical non- or minimally invasive lung cancer. Methods: From January 2010 to December 2017, 203 patients were diagnosed as clinical adenocarcinoma in situ (AIS) or minimally invasive adenocarcinoma (MIA) identified on chest computed tomography (CT) and they underwent surgical resection. A retrospective study was performed to analyze the prediction of invasive adenocarcinoma in clinical non- or minimally invasive lung cancer. Results: Of all clinical AIS or MIA patients, invasive adenocarcinoma was diagnosed in 55 patients (27.1%). In clinical AIS, invasive adenocarcinoma was diagnosed in 19 patients (17.9%) and 36 patients (37.1%) were diagnosed as invasive adenocarcinoma in clinical MIA (P=0.002). Tumor diameter and the presence of solid component were confirmed to be significant predictive factors for invasive adenocarcinoma in a multivariate analysis [hazard ratio (HR) 1.071, P=0.037; HR 2.573, P=0.005; respectively]. Conclusions: Large tumor size and the presence of solid component in clinical AIS or MIA are predictive factors for invasive adenocarcinoma. Therefore, early surgical intervention is recommended for those lesions.