Figure 2.

Proximal bronchial zone, or “no-fly zone,” of a centrally-located lung tumor. Definition of central tumor location as per RTOG 0236: tumors within 2 cm in all directions of the proximal bronchial tree, including the carina, right and left main bronchi, and bronchial tree to the second bifurcation. Updates to this definition include: (I) tumors within 2 cm of the proximal bronchial tree and abutting the mediastinum, pericardium, and spine; and (II) tumors within 2 cm in all directions of any mediastinal critical structure, including the esophagus, heart, spinal cord, great vessels, phrenic nerve, and recurrent laryngeal nerve. Adapted with permission from Timmerman et al. (45).