Integral mediastinal staging in patients with NON-SMALL cell lung cancer and risk factors for occult N2 disease.

Background: In patients with non-small cell lung cancer (NSCLC), the presence of abnormal hiliar lymph nodes (clinical N1; cN1), central tumor location and/or tumor size (diameter >3 cm) increases the risk of occult mediastinal metastasis (OMM). This study investigates prospectively the diagnostic value of an integral mediastinal staging (IMS) strategy that combines EndoBronchial Ultrasound-TransBronchial Needle Aspiration (EBUS-TBNA) and Video-Assisted Mediastinoscopy (VAM) in patients with NSCLC at risk of OMM.

Methods: Patients with NSCLC and radiologically normal mediastinum assessed non-invasively by positron emission tomography and computed tomography of the chest (PET-CT), and OMM risk factors (cN1, central tumor and/or >3 cm) underwent EBUS-TBNA followed by VAM if the former was negative. Those with negative IMS underwent resection surgery of the tumor.

Results: EBUS-TBNA identified OMM in 2 out of the 49 patients evaluated (4%) and VAM in 1 of the 47 patients with negative EBUS (2%). Two patients with a negative IMS had OMM at surgery. Overall, the prevalence of OMM was 10%. EBUS-TBNA has a sensitivity of 40%, a negative predictive value (NPV) of 93.6%, and negative likelihood ratio of 0.60 (95%CI:0.30-1.16). The risk of not diagnosing OMM after EBUS was 6% and after IMS was 4.4%.

Conclusion: Integral mediastinal staging in patients with NSCLC and clinical risk factors for OMM, does not seem to provide added diagnostic value to that of EBUS-TBNA, except perhaps in patients with cN1 disease who deserve further research.