Lymph node SUVmax (N1) Lymph node SUVmax (N2) Lymph node SUVmax (N3) N1 lymph node size [mm] N2 lymph node size [mm] Visual PET score of mediastinal lymph nodes = 4? Age [years] Largest primary tumor diameter in transaxial plane [mm] Lung background SUVmean Mediastinal background SUVmean