Inclusion Criteria:  Age ≥ 18 years Newly diagnosis of stage I-IIIa NSCLC (higher stage could be considered, pending a multidisciplinary evaluation and approval). Baseline 18FFDG-PET-CT and ceCT Treatment according to good clinical practice  Exclusion criteria:  Unavailability of baseline images Diagnosis other than NSCLC at definitive pathology Surgery carried without complete resection or with no curative intent