FP06.01 Unexpected Aggressive Histological Component in Subsolid Lung Adenocarcinoma: Priority for Resection Without Delay

Introduction: Ground glass opacity (GGO)-containing small-sized adenocarcinoma of the lung can generally be expected to have a fair prognosis after resection. However, some of such tumors might contain a histological aggressive component that is related to poor prognosis. This study aimed to identify the predictors for the aggressive histological component in GGO-containing small-sized lung adenocarcinoma to screen the patients who should undergo resection without delay in the era of COVID-19. Methods: Of the 2,350 patients who underwent pulmonary resection for lung cancer at our institute between 2017 and 2020, we collected data of 501 patients with GGO-containing lung adenocarcinoma with a total diameter of ≤ 2 cm. Multivariable analysis was conducted to identify predictors for the presence of histological aggressive components. Results: Using a historical cohort, lymphovascular invasion and predominant micropapillary or solid patterns were identified as histological aggressive components that were related to poor prognosis in stage IA adenocarcinoma. Of the included 501 cases, 36 (7.2%) had at least one histological aggressive component. A multivariable analysis showed that consolidation/tumor ratio on high-resolution computed tomography > 0.5 (odds ratio [OR], 6.08;p 20 pack-years (OR, 2.69;p = 0.03) were predictors for the presence of histological aggressive component, with the sensitivity of 94.4%. Conclusion: Consolidation/tumor ratio > 0.5, SUVmax ≥ 1.5, and smoking history > 20 pack-years were predictors for the presence of a histological aggressive component in GGO-containing small-sized adenocarcinoma. These predictors may be useful for screening patients with a potentially high risk for poor prognosis and for setting priorities for resection in the era of COVID-19. Keywords: ground-glass opacity, consolidation/tumor ratio, prognosis