The Seventh Tumor, Node, Metastasis Staging System and Lung Cancer Treatment Choices: A Matter of Would, Could, and Should

Abstract

The Seventh edition of the tumor, node, metastasis (TNM) classification of lung neoplasms (TNM7) has been in use since January 1, 2010. This is the result of the hitherto unprecedented work of the International Staging Committee of the International Association for the Study of Lung Cancer (IASLC) led by Mr. Peter Goldstraw.1 Based on more than 100,000 case records, changes to TNM6 were proposed and validated. The effort was rewarded by adoption of the new classification by both the American Joint Committee on Cancer and the Union Internationale Contre le Cancer and resulted in a “seismic shift in lung cancer staging.”2 Most of the changes were in the T category3; the M1 category was adapted to M1a and M1b,4 whereas there were essentially no changes in the N categories.5 In this issue of Journal of Thoracic Oncology, Boffa et al.6 report on a study they performed to evaluate how much clinicians feel that a change in stage should lead to a change in management for a given patient. At four lung cancer symposia, clinicians were asked to give their preferred treatment strategy for three hypothetical case records. First, they were presented with each patient’s TNM6 stage and then with the new TNM7 stage designation. Not less than 77% of the respondents changed treatment intention in at least one case, despite the fact that the changes made to the lung cancer staging system as a result of the IASLC analyses were not based on treatment administered. Because of this, altering the treatment decisions based on upstaging or downstaging of a case is not really justified at this time. This article has limitations: a major one is the low number of surveyed clinicians and the low response rate (on average only 32% across the four meetings). Furthermore, the attendance to these meetings was quite heterogeneous, and no information on participants and their background or expertise was provided. It is nonetheless of interest because it is the first one to show that clinicians would change their treatment because of the TNM7 classification change. The article does raise the point that a change in TNM staging could potentially lead to changes in treatment, even if on theoretical grounds this should not be the case. In his editorial to the IASLC proposal in 2007, Dr. Silvestri previously pointed out that—apart from providing an anatomic description of the cancer to have groupings with similar prognosis—perhaps the most important rationale for staging is that stage dictates treatment and that treatment regimens vary considerably by stage.2 Indeed, most stage I cases in the IASLC database had a good prognosis because they had surgical resection (or radical radiotherapy if medically inoperable), illustrating the unavoidable link between any staging system and treatment. So, how do we deal with this issue of would, could, and should? One theoretical option is to stage according to TNM7 and temporarily look in terms of TNM6 for