Endobronchial Ultrasound-guided Transbronchial Needle Aspiration Detection of PET-CT Negative Contralateral Hilar Lymph Node Metastasis in the Staging of Non-small cell Lung Cancer.

Abstract

Background: The detection rate of contralateral hilar involvement in NSCLC during EBUS-TBNA staging is not well established.

Methods: We conducted a retrospective observational single-center study of all EBUS-TBNA staging examinations performed from 2016 through 2020 to determine the incidence of PET and CT negative N3 hilar metastasis by EBUS-TBNA in patients with radiographic T1-T4, N0-N3, M0 NSCLC.

Results: A total of 516 patients underwent EBUS-TBNA sampling of contralateral hilar lymph nodes. Metastatic non-small cell lung cancer was detected in one or more contralateral hilar lymph node stations in 5 patients (0.97%). Four of these patients had radiographic N2 or N3 disease on PET imaging. Patients with mediastinal N2/N3 disease by PET scan were at higher risk of having occult contralateral hilar disease as compared with mediastinal N0/N1 by PET (P=0.017). In individuals radiographically staged as mediastinal N3 by CT scan, 14 (95% CI: 3-78) patients would need to undergo EBUS-TBNA sampling of a CT negative contralateral hilar lymph node to identify malignant involvement of the latter. In cases radiographically staged as mediastinal N3 by PET scan, 25 (95% CI: 6-141) patients would need to undergo EBUS-TBNA sampling of a PET-negative contralateral hilar lymph node to identify malignancy involvement in this location.

Conclusion: In patients with NSCLC undergoing EBUS staging for radiographic N0/N1 disease by PET, it is reasonable to not sample the contralateral hilar lymph node stations. In radiographic N2/N3 disease by PET or CT, sampling the contralateral hilar lymph node stations appears to be justified.