Distance between tumor and bronchial resection margin is an independent predictor of recurrence-free survival and overall survival in primary endobronchial neoplasm

Abstract

Background: The distance between tumor and bronchial resection margin (DBTM) had no clear standard in lung cancer surgery. We aimed to select the optimal cut-off value to provide a standard for surgery of the patients with primary endobronchial neoplasm.

Methods: We retrospectively analyzed patients with primary endobronchial neoplasm who underwent surgical resection between 2005 and 2012. The receiver operating characteristic curves and the Youden index were used to calculate the optimal cut-off value of the DBTM. Propensity score matching was applied to reduce selection bias. Survival was assessed with Kaplan-Meier analysis, log-rank test and Cox proportional hazards model.

Results: A total of 1048 patients comprised in the study cohort and 1.7 cm was determined the optimal cut-off value, including 531 grouped in DBTM ≤ 1.7 cm and 517 grouped in DBTM > 1.7 cm. Before propensity score matching, the 5-year recurrence-free survival was 38.7% in DBTM ≤ 1.7 cm group and 67.1% in DBTM > 1.7 cm (hazard ratio 0.48, P < 0.001), while the 5-year overall survival was 30.1% and 50.7%, respectively (hazard ratio 0.64, P < 0.001). After propensity score matching, the 5-year recurrence-free survival was 38.8% in DBTM ≤ 1.7 cm group and 66.1% in DBTM > 1.7 cm (hazard ratio 0.51, P < 0.001), while the 5-year overall survival was 34.7% and 50%, respectively (hazard ratio 0.81, P = 0.012). Multivariable cox model showed that the DBTM was an independent predictor for recurrence-free survival (hazard ratio 0.51, P = 0.001) and overall survival (hazard ratio 0.84, P = 0.026).

Conclusions: The DBTM was an independent predictor for outcomes in primary endobronchial neoplasm, and patients with the DBTM ≤ 1.7 cm should actively receive adjuvant therapy after surgery. The distance between tumor and bronchial resection margin (DBTM), the distance between the most proximal border of the macroscopic tumor and bronchial resection margin was measured by pathologist in the fresh specimens before formalin fixation. The DBTM less than 1.7cm had higher recurrence-free survival and overall survival and was an independent prognostic factor for patients with primary endobronchial neoplasm.

Keywords: Bronchial resection margin; Cut-off value; Overall survival; Recurrence-free survival.