Skip Navigation LinksHome > April 2010 - Volume 5 - Issue 4 > Response to Letter to the Editor
Journal of Thoracic Oncology:
doi: 10.1097/JTO.0b013e3181d43cdd
Letters to the Editor

Response to Letter to the Editor

Rusch, Valerie W. MD; Asamura, Hisao MD; Goldstraw, Peter MD

Free Access
Article Outline
Collapse Box

Author Information

Memorial Sloan-Kettering Cancer Center; New York, NY (Rusch)

National Cancer Center Hospital; Tokyo, Japan (Asamura)

Royal Brompton Hospital; London, UK; (Goldstraw)

Disclosure: The authors declare no conflicts of interest.

Back to Top | Article Outline

In Response:

We thank Ichimura et al.1 for their careful review of our article proposing a new international lymph node map for the staging of lung cancer (International Association for the Study of Lung Cancer [IASLC] lymph node map). They raise a question about the border between the upper and lower right paratracheal lymph nodes at levels 2R and 4R. We proposed that this border be defined as the intersection of the caudal margin of the innominate vein with the trachea. Ichimura et al. correctly pointed out that the orientation of the innominate vein to some degree is diagonal and proposed that a horizontal line drawn at either of the two points of the intersection of the vein with the trachea be used as the border between levels 2R and 4R lymph nodes. However, in developing the IASLC lymph node map, we explicitly intended to minimize the use of arbitrary nonanatomic and, thus, not easily reproducible boundaries between lymph node levels. Although somewhat diagonal in orientation, the inferior border of the innominate vein is easily visible by computed tomography, especially when intravenous contrast is used, and is an internationally reproducible landmark. Therefore, we feel that this is more accurate way to distinguish between levels 2R and 4R. As illustrated in Figure “B” of their article, some lymph nodes will overlap the borders between lymph node levels no matter how these are defined and will need to be labeled according to where they predominantly reside. The lymph node shown in Figure “B” is predominantly located below the caudal margin of the innominate vein and would, therefore, probably be most appropriately labeled as a 4R node.

The title of our article indicated that the IASLC map was a proposal for a new international lymph node map. We are grateful for the careful study of this proposal by other authors, because it is precisely through thoughtful commentary that this map may be improved in the future. Our principal intent was to develop international nomenclature that can now be used in the prospective IASLC (and other) lung cancer databases. This will permit future analyses that may refine the N-stage descriptors in the next (eighth) edition of the staging manuals.

Valerie W. Rusch, MD

Memorial Sloan-Kettering Cancer Center

New York, NY

Hisao Asamura, MD

National Cancer Center Hospital

Tokyo, Japan

Peter Goldstraw, MD

Royal Brompton Hospital

London, UK

Back to Top | Article Outline


1. Rusch VW, Asamura H, Watanabe H, et al; Members of IASLC Staging Committee. The IASLC lung cancer staging project: a proposal for a new international lymph node map in the forthcoming seventh edition of the TNM classification for lung cancer. J Thorac Oncol 2009;4:568–577.

© 2010International Association for the Study of Lung Cancer


Article Tools


Other Ways to Connect



Visit on your smartphone. Scan this code (QR reader app required) with your phone and be taken directly to the site.

 For additional oncology content, visit LWW Oncology Journals on Facebook.