Long-term Survival According to N Stage Diagnosed by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration in Non-small Cell Lung Cancer

Abstract

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is the main procedure for mediastinal staging. However, long-term survival analyses according to clinical nodal stage diagnosed by EBUS-TBNA (eN stage) have not been reported. The value of EBUS-TBNA has not been assessed through an analysis of survival in false-negative EBUS-TBNA cases.

Research question: What is the prognostic impact of eN stage in non-small cell lung cancer (NSCLC)? What is the survival rate in false-negative EBUS-TBNA cases?

Study design and methods: We retrospectively (January 2006 to December 2011) reviewed the medical records of patients with NSCLC who underwent EBUS-TBNA (± transesophageal approach) for initial staging (N = 1,089). Mediastinoscopy was not performed for EBUS-TBNA-negative cases. We performed 5-year survival analyses according to eN stage and treatment modality. Survival in false-negative EBUS-TBNA cases was compared with that in patients with pN0-1, including 941 non-EBUS-TBNA cases, during the same period.

Results: Among the 1,089 patients undergoing EBUS-TBNA (eN0-1: n = 681; eN2: n = 314; eN3: n = 94), we observed significant differences in survival between the eN stages (eN0-1 vs eN2: P < .0001; eN2 vs eN3: P = .0118; estimated 5-year overall survival [5YOS] rate: eN0-1 = 57.4%, eN2 = 23.2%, eN3 = 12.8%). Surgery cases had better survival than nonsurgery cases among patients with eN0-1 and eN2 (eN0-1/surgery vs eN0-1/no surgery: P < .0001; eN2/surgery vs eN2/no surgery: P < .0001). Among the patients with eN0-1, there were 55 false-negative cases (eN0-1/pN2-3, pN2: n = 54; pN3: n = 1). The 5YOS rates of patients with pN0, pN1, and eN0-1/pN2-3 were 76.4%, 56.0%, and 56.4%, respectively. Patients with eN0-1/pN2-3 had worse survival than patients with pN0 (P = .0061), whereas there was no significant difference compared with patients with pN1 (P = .9191).

Interpretation: Long-term survival significantly differed according to eN stage in NSCLC, highlighting the importance of EBUS-TBNA in NSCLC staging. False-negative EBUS-TBNA cases had favorable survival which was similar to that of patients with pN1, which may provide a rationale for performing surgery after negative EBUS-TBNA results.

Keywords: EBUS-TBNA; lung cancer; mediastinal staging; prognosis; survival.