The Effect of Resection Margin Distance and Invasive Component Size on Recurrence After Sublobar Resection in Patients With Small (≤2 Cm) Lung Adenocarcinoma

Background: When performing sublobar resection for lung cancer, the margin distance should exceed the tumor size. However, instead of total tumor size, the 8th edition TNM staging system has adopted the size of invasive component for the T stage. The aim of this study was to determine whether the prognosis was satisfactory when the resection margin distance was greater than the invasive component size instead of the total tumor size. Methods: From 2008 to 2017, 193 consecutive patients were diagnosed with lung adenocarcinoma (invasive component size ≤2 cm) and underwent sublobar resection. We analyzed risk factors for recurrence using clinicopathological factors including margin/invasive component ratio (resection margin distance/invasive component size). Results: Mean tumor size was 1.4 (±0.5) cm and the mean invasive component size was 0.8 cm (±0.5). In the multivariate analysis, neither resection margin distance (cm) nor margin/tumor ratio (resection margin distance/tumor size) was significant risk factors for recurrence. On the other hand, the margin/invasive component ratio (hazard ratio =0.035, p = 0.043) and the SUVmax (hazard ratio =1.993, p = 0.033) were significant risk factors for recurrence. Conclusions: When sublobar resection is performed for small (invasive component size ≤2 cm) adenocarcinomas of the lung, the resection margin distance should be larger than the invasive component size. Sublobar resection is not an appropriate treatment for lung adenocarcinoma with high SUVmax.