Ann Thorac Surg 2005;80:1980-1981
© 2005 The Society of Thoracic Surgeons
Correspondence
Reply
Özcan Birim, MD,
Arie Pieter Kappetein, MD, PhD,
Ad J.J.C. Bogers, MD, PhD
Division of Cardiothoracic Surgery, Room BD 569, Erasmus MC, PO Box 2040, Rotterdam, 3000 CA, the Netherlands
(Email: a.kappetein{at}erasmusmc.nl).
To the Editor:
We extend our appreciation to Dr Detterbeck for his comments [1] on and interest in our recent investigation using meta-analysis and summary receiver operating characteristic curves to compare the reliability of positron emission tomographic (PET) and computed tomographic (CT) imaging for mediastinal staging of nonsmall cell lung cancer (NSCLC) [2]. Nowadays, among oncologists and thoracic surgeons, CT scanning is still considered the gold standard for noninvasive nodal staging, despite the low accuracy of the CT scan. However, in our meta-analysis we demonstrated that the accuracy of PET scanning for detecting mediastinal lymph node metastases was significantly higher in comparison with CT scanning.
In addition to the high accuracy of detecting mediastinal lymph nodes, PET scanning improves noninvasive clinical staging by detecting unexpected extrathoracic metastases without any evidence of metastases after conventional imaging, thus avoiding futile mediastinoscopy and eventually thoracotomy [3, 4].
In the work-up of staging for NSCLC, and considering a thoracotomy, a cervical mediastinoscopy is still considered the gold standard, providing a high positive and negative predictive value. Currently almost all national and international associations recommend a staging mediastinoscopy in patients with lymph nodes of more than 1 cm in short-axis diameter on the pre-therapeutic CT scan. However, have we forgotten that mediastinoscopy remains an invasive procedure, that accuracy of a mediastinoscopy is surgeon dependent, and maybe most important, that mediastinoscopy is not without morbidity and mortality [5, 6]?
Therefore, the question, "Can PET reduce the need for mediastinoscopy...?" is relevant to clinical practice. So we are now questioning the use of mediastinoscopy once a PET scan is performed. To eliminate mediastinoscopy, the PET scan should be at least as accurate as the mediastinoscopy. However, presently it is not. Although the PET scan does not eliminate mediastinoscopy, the PET scan does reduce the need for mediastinoscopy.
The low positive predictive value of the PET scan due to fluoro-deoxy-glucose uptake in inflammatory lymph nodes makes cytologic or histologic confirmation necessary in case of a positive mediastinum, being a known pitfall. With the high negative predictive value of the PET scan, a negative mediastinum on the PET scan can lead directly to thoracotomy, without further invasive preoperative staging. This implementation should be done with caution in case of patients with centrally located tumors, in case of positive central hilar N1-disease, and in case of bronchoalveolar cell carcinoma, due to the higher false-negative rate in these circumstances [7]. We realize that some occasional patient with a false-negative mediastinal PET scan will proceed to straightforward thoracotomy. In these cases, however, minimal N2 disease is found, in which a reasonable prognosis after surgical resection can be expected in comparison with patients with preoperative confirmed N2 disease [8]. An additional advantage of the PET scan in comparison with mediastinoscopy is that the PET scan can indicate suspected lymph nodes in stations not amenable to mediastinoscopy (eg, paraesophageal or supraclavicular).
Staging of the mediastinum using positron emission tomography is definitely better than staging using computed tomography alone, and therefore the PET scan has a definite role in noninvasive mediastinal staging independent of the availability and expertise in mediastinoscopy. In our view, the PET scan is able to reduce the need for mediastinoscopy and reduce the number of unnecessary thoracotomies. A clinician must always seek an accurate preoperative staging with a minimal need for invasive procedures. The use of PET scanning needs further validation in outcome studies. In a randomized design, these studies should examine whether positron emission tomography actually improves NSCLC management (eg, by decreasing the number of unnecessary invasive procedures or by improving the survival). In the future, fusion of the CT scan with the PET scan into one test may be helpful to further improve the diagnostic accuracy of these noninvasive imaging modalities.
We think that our considerations are not a matter of relearning lessons from the past, but are useful contributions to improvement of clinical staging of NSCLC patients. In that regard, we are making progress.
 |
References
|
|---|
- Detterbeck FC. Relearning the lessons of the pastare we making progress? (letter). Ann Thorac Surg 2005;80:1979-1980.[Free Full Text]
- Birim O, Kappetein AP, Stijnen T, Bogers AJ. Meta-analysis of positron emission tomographic and computed tomographic imaging in detecting mediastinal lymph node metastases in nonsmall cell lung cancer Ann Thorac Surg 2005;79:375-382.[Abstract/Free Full Text]
- Valk PE, Pounds TR, Hopkins DM, et al. Staging non-small cell lung cancer by whole-body positron emission tomographic imaging Ann Thorac Surg 1995;60:1573-1582.[Abstract/Free Full Text]
- Marom EM, McAdams HP, Erasmus JJ, et al. Staging non-small cell lung cancer with whole-body PET Radiology 1999;212:803-809.[Abstract/Free Full Text]
- Hommoud ZT, Anderson RC, Meyers BF, et al. The current role of mediastinoscopy in the evaluation of thoracic disease J Thorac Cardiovasc Surg 1999;118:894-899.[Abstract/Free Full Text]
- Gdeedo A, van Schil P, Corthouts B, van Mieghem F, van Meerbeeck J, van Marck E. Prospective evaluation of computed tomography and mediastinoscopy in mediastinal lymph node staging Eur Resp J 1997;10:1547-1551.[Abstract]
- Verhagen AFT, Bootsma GP, Tjan-Heijnen VCG, et al. FDG-PET in staging lung cancer. How does it change the algorithm? Lung Cancer 2004;44:175-181.[Medline]
- Vansteenkiste JF. PET scan in the staging of non-small cell lung cancer Lung Cancer 2003;42:S27-S37.
Top
References