Figure 3.

Relationship between margin/tumor ratio and recurrence pattern after sublobar resection by tumor spread through air spaces (STAS) status. Margin/tumor ratio was defined as the ratio of surgical margin distance to tumor diameter. Patients who underwent sublobar resection with available surgical margin assessment were divided into two groups on the basis of STAS status: (A) STAS negative and (B) STAS positive. Each dot represents a patient and is plotted on the basis of tumor size (x-axis) and surgical margin (y-axis). Each patient (dot) is categorized into one of four groups on the basis of recurrence pattern: gray dot, no recurrence; red dot, locoregional recurrence; blue dot, distant recurrence; and purple dot, both locoregional and distant recurrence. A dot located in the area under the dotted diagonal line represents a patient whose surgical margin was smaller than their tumor diameter. The number of cases and 5-year cumulative incidence of recurrence (CIR) for each recurrence type are shown in the bottom table. Recurrence was rare (n=4, no locoregional recurrence) in patients with STAS-negative tumors (A) with margin/tumor ratio ≥1 (surgical margin ≥ tumor size, above the dotted diagonal line); in contrast, 14 patients with STAS-negative tumors with margin/tumor ratio <1 (surgical margin < tumor size, under the dotted diagonal line) had recurrence, of which 8 were locoregional. Among patients with STAS (B), >25% had recurrence at 5 years after surgery, regardless of margin/tumor ratio (margin/tumor ratio ≥1 vs. <1: 5-year CIR for any recurrence, 29% vs. 36%, P=0.3; only locoregional recurrence, 16% vs. 25%, P=0.3).