External ValidatIon Trial of Aster: the Need for Surgical Staging After Echo-endoscopic Mediastinal Staging in Clinical N2/3 Lung Cancer
Background : The observation made by the ASTER investigators might be criticized as all
procedures were performed in highly experienced centers. To date, the number of
mediastinoscopies needed to detect one additional N2/3 disease in the routine clinical
practice of chest physician performing endosonography for mediastinal staging is unknown.
The investigators therefore seek to answer whether a negative endosonography should
routinely be followed by mediastinoscopy in day to day clinical practice.
Aim : As the use of endoscopic ultrasonography for mediastinal diagnosis and/or staging is
widely spread in Belgium, the investigators aimed to determine the number of
mediastinoscopies needed to detect one additional mediastinal lymph node invasion during
routine clinical practice.
Setting : centers in Belgium with EBUS-TBNA and/or EUS-FNA experience in at least 20
patients agreed to participate and will include their patients.
Design : Prospective national observational multicenter study. All patients with clinical
N2/3 disease based on CT and/or PET requiring invasive mediastinal staging will primarily
undergo invasive mediastinal staging with endosonography (EBUS +/- EUS). A subsequent
cervical mediastinoscopy will be performed in case no mediastinal lymph node involvement was
found with endosonography. Local surgeons perform these procedures according to their
institutional practice. Thoracotomy with mediastinal lymph node dissection will be the gold
standard for invasive mediastinal staging, in case no mediastinal lymph node metastases were
found during clinical staging including endosonography and mediastinoscopy.
Patients : The study will include 255 patients, based on the calculation of 15 consecutive
patients in each participating center, in order to validate the ASTER data.
Primary endpoint : The number of mediastinoscopies needed to detect one additional N2/3.
Secondary endpoints : The number of mediastinal lymph nodes stations sampled with
endosonography ; the median size of largest mediastinal lymph node sampled; characteristics
of mediastinal nodal disease missed by endosonography.
Allocation: Non-Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic
The number of mediastinoscopies needed to detect one additional N2/3
Universitaire Ziekenhuizen Leuven
Belgium: Ethics Committee