- Consecutive patients with (suspected) NSCLC in whom invasive mediastinal staging is required based on presence of ACCP group B mediastinal lymph nodes and/or FDG-PET positive (visual interpretation of FDG uptake in mediastinal nodes as present) mediastinal lymph nodes (either ACCP group B or ACCP group D) in lymph node stations 2, 4, 7, 8 or 9 (see Appendix).