What is the procedure for Endobronchial Ultrasound (EBUS) Transbronchial Needle Aspiration (TBNA) for staging lung cancer?

EBUS-TBNA Procedure for Lung Cancer Staging

For optimal lung cancer staging, EBUS-TBNA should be performed as the initial procedure over surgical staging, with sampling of at least three different mediastinal nodal stations (4R, 4L, 7) using either a 21- or 22-gauge needle with a minimum of 3 separate needle passes per sampling site. 1

Patient Preparation and Procedural Setup

• Sedation Options: Either moderate or deep sedation is acceptable for EBUS-TBNA procedures 1
• Equipment Required:
  • Linear EBUS bronchoscope with ultrasound transducer at the tip
  • 21- or 22-gauge dedicated EBUS-TBNA needle (both sizes provide equivalent diagnostic yield) 1
  • Ultrasound processor and monitor
  • Standard bronchoscopy equipment

Procedural Steps

1. Initial Assessment:

   • Review CT and/or PET-CT images to identify target lymph nodes
   • Identify abnormal mediastinal/hilar nodes (>10mm short axis on CT or FDG-avid on PET) 1

2. Bronchoscopic Examination:

   • Perform conventional bronchoscopy first to examine the airways
   • Switch to EBUS mode when ready to begin nodal assessment

3. Systematic Nodal Evaluation:

   • Complete assessment of mediastinal and hilar nodal stations 1
   • Prioritize sampling of at least three different mediastinal nodal stations (4R, 4L, 7) in patients with abnormal mediastinum by CT or CT-PET 1
   • For staging purposes, begin with N3 nodes (contralateral), then N2 nodes (ipsilateral mediastinal), and finally N1 nodes (hilar) to avoid contamination

4. Node Identification and Characterization:

   • Identify target lymph node using ultrasound
   • Evaluate ultrasonographic features (size, shape, borders, echogenicity)
   • Note: While ultrasonographic features can suggest malignant or benign diagnoses, tissue samples must still be obtained to confirm diagnosis 1

5. Sampling Technique:

   • Position the EBUS scope adjacent to the target lymph node
   • Insert the dedicated EBUS needle through the working channel
   • Deploy the needle through the airway wall into the lymph node under real-time ultrasound guidance
   • Perform at least 3 separate needle passes per sampling site 1
   • Sampling can be performed with or without suction (both approaches are acceptable) 1
   • For non-small cell lung cancer, obtain additional samples beyond those needed for diagnosis for molecular analysis 1, 2

6. Sample Handling:

   • Samples can be processed with or without rapid on-site evaluation (ROSE) 1
   • If ROSE is not available, a minimum of 3 separate needle passes per sampling site is recommended 1
   • Prepare samples for cytology, cell block, and if indicated, molecular testing

Special Considerations

• Combined Approach: For optimal staging, consider combining EBUS-TBNA with endoscopic (esophageal) ultrasound with fine needle aspiration (EUS-FNA or EUS-B-FNA) for more complete mediastinal assessment 1, 2

• Negative Results: If endosonography does not show malignant nodal involvement in patients with high clinical suspicion, subsequent surgical staging (mediastinoscopy) is recommended 1

• Centrally Located Tumors: For diagnostic purposes in patients with centrally located lung tumors not visible at conventional bronchoscopy, EBUS is recommended if the tumor is adjacent to larger airways 1

Training and Competency

• New trainees should follow a structured training curriculum including simulation-based training followed by supervised practice on patients 1
• Competency should be assessed using validated EBUS skills assessment tools 1
• For optimal endosonographic staging, endoscopists should be trained in both EBUS and EUS-B techniques 1

Common Pitfalls and How to Avoid Them

• Inadequate Sampling: Ensure at least 3 separate needle passes per site to maximize diagnostic yield 1
• False Negatives: When clinical suspicion is high but EBUS is negative, proceed to surgical staging 1
• Incomplete Staging: Sample at least three different mediastinal nodal stations (4R, 4L, 7) for thorough assessment 1
• Limited Access: Be aware that EBUS cannot access all lymph node stations (particularly stations 5 and 6); consider complementary EUS-FNA for these areas 2
• Insufficient Material for Molecular Testing: Obtain additional samples beyond those needed for diagnosis in NSCLC patients 1

EBUS-TBNA has revolutionized mediastinal staging with high sensitivity (88-92%) and specificity, providing a minimally invasive alternative to surgical staging with lower morbidity and cost 2, 3. When performed correctly, it significantly reduces the need for mediastinoscopy and prevents futile thoracotomies 4.