Endoscopic Ultrasound-Guided Fine Needle Aspiration in Patients with Lung Cancer and Prior Negative Mediastinoscopy

Abstract

Background: Abnormal mediastinal lymph nodes (LNs) sampling is required prior to surgical resection in non-small cell lung cancer (NSCLC) patients. In patients with both anterior and posterior mediastinal LNs, the initial strategy to diagnose metastasis to ipsilateral (N2) or contralateral (N3) LNs remains unknown. Objectives: Our objectives were 1) To evaluate the yield of EUS-FNA in NSCLC patients with both anterior and posterior LNs that had prior negative mediastinoscopy. 2) To assess cost implications associated with alternative initial strategies: initial mediastinoscopy versus initial EUS-FNA. Methods: NSCLC patients first underwent thoracic CT, PET scan, and mediastinoscopy and then underwent EUS-FNA of the posterior mediastinal LNs. Reference standards included: thoracotomy with complete thoracic lymphadenectomy, repeat clinical imaging and/or long term clinical follow-up. A Monte Carlo cost-analysis model evaluated the expected costs and outcomes associated with staging of a hypothetical cohort of NSCLC patients presenting with enlarged anterior and posterior mediastinal LNs. Results: There were thirty-five lung cancer patients (median age of 65 years, 80% male). Of the 35 NSCLC patients who had a prior negative mediastinoscopy, 13 patients (37.1%) (95% CI: 21.5–55.1) had malignant LNs. Lower lobe masses were more likely to have malignant LNs as compared to upper lobe masses (OR = 6.8; 95% CI: 1.2–42.7, P = 0.03). All patients with N2/N3 disease received initial chemotherapy and/or radiation. EUS-FNA yielded one false negative result and no false positives. Final diagnoses were confirmed by surgery in 16 patients (45.7%). Accuracy of EUS-FNA (98.1%; 95% CI: 89.9–100.0) was significantly higher than CT (41.5%; p < 0.001) and PET (40%; p < 0.001). Initial EUS-FNA resulted in an average costs per patient of $1,867 (SD ± 4308) while initial mediastinoscopy cost $12,900 (SD ± 4164). If initial EUS-FNA is utilized rather than initial mediastinoscopy, there would be an average cost saving of $11,033 per patient evaluated. Conclusions: In NSCLC patients with both anterior and posterior LNs, starting with EUS-FNA would obviate the need for mediastinoscopy in over one-third of patients. EUS-FNA is an outpatient procedure that is less invasive, safer and less costly than mediastinoscopy. These finding have major implications on resource utilization in NSCLC patients undergoing invasive tissue sampling for preoperative staging.