Significance of R1-resection at the bronchial margin after surgery for non-small-cell lung cancer

OBJECTIVES: We aimed to evaluate the significance of microscopic residual disease at the bronchial resection margin (R1-BRM) after curative surgery for non-small cell lung cancer (NSCLC). METHODS: Retrospective review was performed on 1800 patients from 1994 to 2012. We compared recurrence and survival between 1740 patients with R0-resection at the BRM (R0-BRM) and 60 patients with R1-resection at the BRM (R1-BRM), comprising 18 cases of mucosal carcinoma in situ (R1-CIS) and 42 cases of extramucosal residual disease (R1-EMD). RESULTS: Stump recurrence occurred in 43 patients. The 5-year cumulative incidence of stump recurrence in group R0, R1-CIS and R1EMD was 3.1, 5.6 and 12.2%, respectively. Significant differences of stump recurrence were observed between the groups (R0 versus R1CIS, P = 0.008; R0 versus R1-EMD, P = 0.007). In Stage IB or II disease, the overall survival rate for R1-EMD was significantly lower than that for R0-BRM (P = 0.014), whereas the difference in overall survival rate between the R1-CIS group and the R0-BRM was not significant (P = 0.37). In Stage IIIA disease, the overall survival rates for R1-CIS (P = 0.87) and R1-EMD (P = 0.45) were not significantly different from that for R0-BRM. CONCLUSIONS: R1-BRM comprises a higher rate of stump recurrence, compared with that of R0-BRM. Herein, R1-EMD was associated with poor overall survival in Stage IB/II disease. In Stage IIIA disease, R1-BRM showed similar overall survival rate to that for R0-BRM, although the number of patients was too small to draw definitive conclusions thereon.