The role of endobronchial ultrasound-guided transbronchial needle aspiration in stereotactic body radiation therapy for non-small cell lung cancer

Objective: To evaluate the diagnostic value of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in stereotactic body radiation therapy (SBRT) candidates and compare with computed tomography (CT) and positron emission tomography (PET). Methods: Inclusion criteria for this single institutional retrospective study were 1) biopsy-proven or suspicious NSCLC with diameter < 6 cm; 2) no distant metastasis; 3) EBUS-TBNA staging between April 2008 and November 2014; 4) SBRT eligible. CT and PET positive nodes were defined as short axis >= 1 cm and standardized uptake value >= 2.5, respectively. Node positive by clinical-pathologic confirmation (NPCP) was defined as confirmed malignancy by EBUS-TBNA or recurrence in hilar or mediastinal lymph nodes within one year after SBRT. The survival after SBRT was compared between radiologically node-positive, but EBUS-TBNA negative, patients (Case) and a matched cohort (tumor size; radiation dose; operability) who underwent SBRT without EBUS-TBNA staging (Control). Results: There were 35 eligible patients (mean age 77 +/- 8.2; mean diameter 2.5 +/- 1.0 cm). Thirty were medically inoperable. Twenty out of 24 patients with radiologically positive node(s) were negative by EBUS-TBNA. All eleven radiologically negative patients were NO following EBUS-TBNA. Thirty-one patients underwent SBRT. Per-person based sensitivity/specificity of CT, PET and EBUS-TBNA for NPCP were 42.9/64.3%, 100/64.3% and 57.1/100%, respectively. A 1:4 match was obtained. Regional failure-free survival (p = 0.71; HR = 0.88 95%CI 0.45-1.74) and disease-free survival (p = 0.77; HR = 1.10 95%CI 0.58-2.11) of the Case were not significantly different from the Control. Conclusion: Patients with radiographically positive lymph nodes can be considered for EBUS-TBNA and may remain candidates for SBRT.