Fig. 2. Schema of central and peripheral locations. This diagram showed definition of central, peripheral and apical location of lung tumor. Tumors located at proximal bronchial tree (according to the Radiation Therapy Oncology Group) defined as centrally located tumor, tumor located above aortic arch defined as apically located tumor, and tumor located closer than 1 cm to chest wall defined as chest wall abutted. Except of these locations, others defined as peripherally located tumor.