Pitfalls in the actual tnm system for lung-cancer and their implications for curative radiotherapy (review)

The knowledge of lymphatic pathways of lung cancer as well as the prognostic significance of the involvement of each lymph node site is of paramount importance for diagnosis, staging and proper treatment indications. A modified TNM classification for lung cancer is proposed considering available data on: (i) survival of patients according to the actual TNM system; (ii) lymphatic drainage pattern; (iii) embryological development of the lymphatics in the thorax. Actual data on survival rate for N3 disease and stage IIIB are critically discussed. The involvement of the supraclavicular and/or contralateral hilar lymph nodes as well as the involvement of the contralateral mediastinal lymph nodes for the right situated lung cancer should be described as M1 (lymph) disease and thus classified as stage IV. The implications for curative irradiation are presented.