Accurate and consistent regional lymph node classification (N) is an important element in the staging and multidisciplinary management of lung cancer. Regional lymph node definition sets—lymph node maps—have been created to standardize N. In 2009, the International Association for the Study of Lung Cancer (IASLC) introduced a lymph node map to supersede all pre-existing lymph node maps.
To study if, and how lung cancer specialists apply the IASLC lymph node map when classifying thoracic lymph nodes encountered on computed tomography (CT) during lung cancer staging.
Invitations were distributed to all members of the Fleischner Society, Society of Thoracic Radiology, General Thoracic Surgical Club, and the American Association of Bronchology and Interventional Pulmonology to participate in an anonymous, online image-based and text-based 20-question survey regarding lymph node classification for lung cancer staging on CT.
337 individuals responded (approximately 25% participation). Respondents consisted of self-reported thoracic radiologists (n=158), thoracic surgeons (n=102), and pulmonologists who perform endobronchial ultrasound (n=77). Half of the respondents (50%; 95% CI, 44%-55%) reported using the IASLC lymph node map in daily practice, with no significant differences between subspecialties. A disparity was observed between the IASLC definition sets and their interpretation and application on CT, in particular for lymph nodes near the thoracic inlet, anterior to the trachea, anterior to the tracheal bifurcation, near the ligamentum arteriosum, between the bronchus intermedius and esophagus, in the internal mammary space, and adjacent to the heart.
Use of older lymph node maps and inconsistencies in IASLC lymph node map definition interpretation and application may potentially lead to stage misclassification and suboptimal management of lung cancer in some patients.