External validation of the N descriptor in the proposed tumour-node-metastasis subclassification for lung cancer: the crucial role of histological type, number of resected nodes and adjuvant therapy. - Chiappetta M; Lococo F; Leuzzi G; Sperduti I; Petracca-Ciavarella L; Bria E; Mucilli F; Filosso PL; Ratto GB; Spaggiari L; Facciolo F; Margaritora S (European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, 2020)