© 2005 American Thoracic Society
Endoscopic Ultrasound Staging of Lung CancerTo the Editor:I wish to congratulate Dr. LeBlanc and colleagues on their recent article published in AJRCCM (1), but I would like to point out several key differences about their work relative to other published studies. Our group has published a nearly identical study in the area of endoscopic ultrasound staging (EUS) staging of lung cancer patients without evidence of enlarged mediastinal lymph nodes on CT (2). Both are prospective, controlled studies in similar populations comparing EUS to pathological staging. Both studies came to similar conclusions. In our study, the "yield" of EUS for detection of metastatic or unresectable disease was nearly identical (17/69 [25%] patients in our study, 18/72 [25%] patients in LeBlanc and coworkers' study). Both studies detected malignant mediastinal lymph nodes as well as extrathoracic metastases (left adrenal, celiac lymph nodes). The main difference between the studies was the overall accuracy of EUS. For both, the sensitivity was low, which is not surprising given the challenging group of patients (all with lymph nodes < 1 cm on CT). In our study the sensitivity was 61% and specificity 98%. In LeBlanc and colleagues' study the sensitivity was only 25% with specificity 100%. Why the difference in sensitivity? In my view, the key difference is the fact that LeBlanc and coworkers only sampled (by fine needle aspiration) lymph nodes which appeared malignant based on the EUS image. In our study, we sampled all visible lymph node stations including completely normal appearing ones. Other work by our group has suggested that the EUS image of a lymph node and tumor location (relative to the lymph node location) are poor predictors of nodal metastases (3). Even normal appearing lymph nodes can harbor metastatic disease and should be sampled at the time of EUS staging.
Based on these two large prospective studies, EUS clearly can detect metastatic disease and avoid surgical staging in The future of lung cancer staging indeed looks very bright with increasingly sensitive and decreasingly invasive methods of detecting and staging disease. Much work is to be done, but studies such as those by LeBlanc and colleagues are clearly on the "right track."
Mayo Clinic College of Medicine, Jacksonville, Florida FOOTNOTES Conflict of Interest Statement: M.B.W. receives research grants from Olympic Co., the manufacturer of EUS equipment. REFERENCES
This article has been cited by other articles:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
25% of lung cancer patients with "normal" mediastinal CT. Is this good enough to routinely recommend EUS in these patients? Given the alternatives of mediastinoscopy, or other surgical methods, I feel the answer is "yes," but we can and should still strive for better results. 
