Pathologic Risk Factors for Recurrence in Early Stage Invasive Lung Adenocarcinoma with Tumor Spread through Air Spaces

초록

Introduction Tumor spread through air spaces (STAS) is a newly adopted pathologic pattern of invasion of cancer cell nests spreading into air spaces in the lung parenchyma adjacent to the border of the main tumor and well-known risk factor of recurrence. The aim of this study was to evaluate relevant pathologic risk factors in early stage lung adenocarcinoma containing tumor spread through air spaces (STAS) treated with surgical intervention. Methods Medical records of patients who underwent surgical resections for stage I (AJCC 8th edition) lung adenocarcinomas between 2012 and 2020 in our institutes were reviewed retrospectively. Patients who had invasive component less than 5mm (adenocarcinoma in situ and minimally invasive adenocarcinoma) or larger than 2cm and without STAS were excluded in this study. Pathologic risk factors for recurrence in enrolled patients were investigated. Results Among 201 patients who had invasive adenocarcinoma less than 2cm in size, 50 cases (24.9%) represent STAS and included in this study. The mean follow-up periods were 38.3 (±22.14, ranging 7.2 to 94.3) months and that of ages were 66.4 (±9.57, ranging 48 to 85). Recurrence rates were 8.7% (4 patients, 1 woman and 3 men). Three patients were died during follow-up periods and no one died due to lung cancer progression (Two because of cancer progression of other organs and one heart failure). The largest distance of STAS from tumor edge showed statistical significance (Odd ratio 2.8, 95% confidential interval 1.29 to 5.87 p=0.016), and patients with STAS more than 10 alveolar distances revealed statistical significance as recurrence risk factors in univariable analysis while other pathologic features including micropapillary patterns and invasive ratio were not. In multivariate analysis, only the largest distance from tumor edge showed statistical significance. 5-year recurrence free survival rates of patients with the largest distance of STAS from tumor edge less than 2mm were 96.3% and that of patients with larger than 2mm were 62.5%. Conclusions The presence of STAS and distance from the edge of tumor was important risk factors for recurrence in patients with early stage invasive lung adenocarcinoma treated with surgery.