In the ASTER study, mediastinal staging was more accurate for patients randomised to combined endobronchial and endoscopic ultrasound, followed by surgical staging if endoscopy was negative, versus surgical staging alone. Here, we report survival, quality of life and cost effectiveness up to 6 months, for the UK, The Netherlands and Belgium, separately. Survival in the two arms of the study was similar. In all three countries, the endosonography strategy had slightly higher quality-adjusted life years over 6 months, and was cheaper. Therefore, based on clinical accuracy and cost effectiveness, we conclude that mediastinal staging should commence with endosonography.