What exactly is a centrally located lung tumor? Results of an online survey

Rationale: Accurate mediastinal staging is a cornerstone in the management of patients with lung cancer. For patients with radiographically normal mediastinum, current lung cancer guidelines recommend invasive mediastinal staging when tumors are centrally located. However, definitions of central tumors are nonspecific, and there are discrepancies among guidelines (e.g., some use the inner onethird of the hemithorax, whereas others use the inner two-thirds). Objectives: To describe the definitions of central tumors used by pulmonologists and thoracic surgeons in their practices. Methods: An online questionnaire was e-mailed to members of the American Association for Bronchology and Interventional Pulmonology and members of the Cardiothoracic Surgery Network. Measurements and Main Results: A total of 218 participants completed our survey (12% response rate). Most common definitions for central tumors were: inner one-third of the hemithorax (55%), in contact with hilar structures (29%), and inner two-thirds of the hemithorax (15%). Of note, 29% of participants chose a definition fabricated specifically for this survey and not supported by guidelines. Regarding the method to delineate the thirds of the hemithorax, 182 (84%) participants chose a system of concentric lines arising in the hilum, whereas 31 (14%) chose straight lines in the sagittal plane of the chest. We found strikingly similar responses in members of both societies. Conclusions: A uniform definition of tumor centrality is currently lacking, and should be formulated. Studies using objective measurements that evaluate the ability of these different definitions of central lung tumors to predict N2 disease are needed to construct a clear and evidence-based definition.