Reply to the Letter to the Editor Entitled The IASLC Lung Cancer Staging Project: Revision Proposal of Pleural Effusion and Contralateral Nodule Staging, by V. Barbieri, P. Tassone, and P. Tagliaferri

Abstract

We read with interest the letter by Dr. Barbieri et al. regarding the recommendations for changes in the forthcoming edition of the tumor, node, metastasis (TNM) classification for lung cancer proposed by the International Staging Committee (ISC) of the International Association for the Study of Lung Cancer.1Barbieri V Tassone P Tagliaferri P The IASLC lung cancer staging project: revision proposal of pleural effusion and contralateral nodule staging.J Thorac Oncol. 2008; 3: 317Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar They raise two important issues: the suitability of the recommendation to reclassify malignant pleural effusion as M1a, and, therefore, stage IV; and the concern of classifying contralateral nodules as M1a, disregarding the possibility that some of these nodules may be second primary tumors. The criteria of the ISC to propose changes to the present TNM classification was based on survival differences and clinical judgment. The issues Dr. Barbieri et al. refer to in their letter were intensively discussed. For most proposals, more than one possibility was available, i.e., to retain the descriptor in the existing category, but identified by alphabetical subscripts, as Dr. Barbieri et al. propose, or to allow descriptors to move to a category containing other descriptors with a similar prognosis. Regarding malignant pleural effusion, it was thought that, in most cases, it was the consequence of metastatic spread in the pleura. Malignant pleural effusion, although confined to the chest, is treated as disseminated disease. These two facts favored the proposal to reclassify it as M1 disease, instead of maintaining it in the T4 category. However, the proposal of Dr. Barbieri et al. to reclassify it as T4b and transfer this category to stage IV is also valid was considered by the ISC, but was not chosen to avoid the complexity of the resulting TNM subsets. The problem with additional nodules in the same lobe, in another ipsilateral lobe, and in the contralateral lung is unsolved and will require a large number of well-registered cases. All of these nodules, now proposed to be classified as T3, T4, and M1a, respectively, can be second primaries, metastasis, or non-neoplastic disease. There rarely is preoperative pathologic diagnosis of these additional nodules and, even postoperatively, unless they have different cell types, second primaries and metastasis are practically impossible to differentiate with routine pathologic techniques. The ISC is well aware of this fact and for the prospective collection of data, which will be used to inform the eighth edition of the TNM classification, a detailed dataset has been designed, including molecular studies where they are available. We hope that the prospective project of the ISC will bring some light to this difficult problem. In the meantime, we must keep in mind that the TNM classification suggests but does not dictate a certain type of treatment for each TNM category. Therefore, the fact that contralateral nodules are classified as M1a disease does not preclude surgical treatment if both the primary tumor and the contralateral nodule are deemed completely resectable, and the patient is adequately fit for the planned operation. We know now that if the contralateral nodule is a second primary, it will have a better prognosis than a metastatic nodule; and if it is a metastasis, its prognosis will be better than that of metastasis outside the chest. We thank Dr. Barbieri et al. for their thoughtful comments and for their interest in lung cancer staging.