Optimal sublobar resection for c-stage I non-small cell lung cancer: significance of margin distance to tumor size ratio and margin cytology (Supplementary analysis of KLSG-0801): complete republication

Background: Sublobar resection for lung cancer is associated with a higher risk of recurrence than that of lobectomy; we evaluated the factors considered to be predictors of recurrence. Methods: By analyzing multicenter prospective studies of sublobar resection for patients with c-stage I non-small lung cancer who were unable to undergo lobectomy (KLSG-0801), we investigated the relationship between (1) tumor location (TL) and margin distance from the stump (MD), (2) the MD/tumor size (TS) ratio and prognosis, (3) and the margin cytology (MC) and prognosis. Results: The correlation between TS and MD was statistically significant in cases of easily resectable regions defined by Lewis’ classification (n = 18). However, there was no correlation in difficult-to-resect regions (n = 14). Among cases of recurrence, the MD/TS ratio was less than 1. The 3-year survival rate was 100% for patients with MD/TS > 1 (n = 12), 59.7% for patients with MD/TS ≤ 1 (n = 20) (p = 0.06), 88.1% in cases of negative MC (n = 18), and 20% in cases of positive MC (n = 5) (p = 0.001). Conclusion: Cases with positive MC had a significantly worse prognosis than those with negative MC. It may be difficult to secure an MD greater than the TS in a difficult-to-resect region according to Lewis’ classification.