Endobronchial ultrasonography for positron emission tomography and computed tomography-negative lymph node staging in non-small cell lung cancer.

Background: Integrated positron emission tomography (PET) with computed tomography (CT) is a useful modality to investigate lymph node metastases for non-small cell lung cancer, but is less sensitive for normal-sized lymph nodes. We sometimes encounter cases with radiologically normal lymph nodes and unsuspected mediastinal metastases detected by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). However, few studies have investigated staging in patients with radiologically normal mediastina, and the accuracy of EBUS-TBNA staging for radiologically normal mediastina and hila is unclear.

Methods: This study was a retrospective, single-institution review of a prospectively maintained database at Chiba Cancer Center between May 1, 2008, and September 1, 2013. We analyzed 113 non-small cell lung cancer patients with both CT-negative and PET/CT-negative lymph nodes (N0) in preoperative nodal staging performed by EBUS-TBNA. After preoperative staging was performed, patients with either N0 or N1 clinical staging underwent surgery. Final N factors were determined by mediastinal lymphadenectomy.

Results: In our study, the overall rate of N2 disease was 17.6% (20 of 113). For nodal staging by EBUS-TBNA, the sensitivity, specificity, negative predictive value, and diagnostic accuracy were 35.0% (7 of 20), 100% (93 of 93), 87.7% (93 of 106), and 88.4% (100 of 113), respectively. There were no severe complications from EBUS-TBNA staging.

Conclusions: The overall rate of unsuspected N2 was not low. EBUS-TBNA was accurate and feasible for preoperative mediastinal nodal staging of non-small cell lung cancer with both CT-negative and PET/CT-negative lymph nodes. The sensitivity of EBUS-TBNA for radiologically normal mediastina and hila was low. Further investigations are required.