Department of Thoracic Surgery, Royal Brompton and Imperial College, London, UK.
Disclosure: The author declares no conflict of interest.
Address for correspondence: Peter Goldstraw, MB FRCS, Department of Thoracic Surgery, Imperial College, London, Sydney Street, London, SW3 6NP, United Kingdom. E-mail: firstname.lastname@example.org
Disclaimer: Any Person/Department or Institution interested in contributing to the prospective data set is requested to e-mail email@example.com with “IASLC Staging Project” in the subject line.
The long-awaited 7th edition of tumor, node, metastasis (TNM) in Lung Cancer has now been published by the International Union Against Cancer and the American Joint Committee on Cancer. The changes to the 6th edition were based upon proposals from the International Staging Project of the International Association for the Study of Lung Cancer (IASLC).1 As required by the internal review processes of the two bodies that administer the TNM classification these proposals were finalized and submitted early in 2007. Since that time, the detailed proposals have been published in no less than 13 articles in the Journal of Thoracic Oncology.2–14 As chair of the International Staging Project I have made almost 50 presentations in 21 countries spanning 5 continents, and the other members of the committee have given many additional presentations. Surely, the most telegraphed changes to the TNM classification ever!
So what are the changes in the 7th edition? Broadly speaking they are:
a. Size cut points, in addition to the 3 cm cut point that traditionally separated T1 and T2 tumors, have been introduced at 2, 5, and 7 cm. T1 tumors are now subdivided into T1a and T1b around the 2 cm cut point. T2 tumors have been subdivided into T2a and T2b around the 5 cm cut point, and tumors >7 cm are now classified as T3.2
b. Cases in which additional tumor nodules are found have been reclassified. Those in the same lobe as the primary tumor are now classified as T3, those in the other ipsilateral lobe(s) are T4 and those in the opposite lung are now M1a.2,4
c. Cases associated with pleural or pericardial nodules/effusions have been reclassified from T4 to M1a.4
d. M1 disease due to distant metastases has been reclassified as M1b.4
e. The utility of the TNM classification in small-cell lung cancer has been confirmed in the largest data base of such cases ever established, treated by all modalities of care.7,14
f. The validity of TNM in Carcinoid tumors has been shown and these are now included, for the first time, within the TNM classification.9
g. A new IASLC nodal chart, with precise definitions, has been agreed, reconciling the previous differences between the Japanese and Mountain-Dresler charts. The concept of nodal “zones” has been introduced to make such classification relevant to those dealing with bulky nodal deposits that transgress the boundaries of individual nodal stations.12
h. For the first time we have introduced a precise definition of “visceral pleural invasion,” a long-standing T2 descriptor, with recommendations on the use of elastic stains to determine this feature.10
There are consequential changes to some stage groupings6:
a. The smaller T2 tumors, those >3 cm but ≤5 cm, become T2a, and T2a N1 M0 cases are down-staged from stage IIB to IIA.
b. The larger T2 tumors, those that are >5 cm but ≤7 cm become T2b and those tumors >7 cm become T3, are up-staged in the new TNM subsets they now join; T2b N0 M0 cases from stage IB to IIA, T3 N0 M0 from IB to IIB and T3 N1 M0 from IIB to IIIA.
c. Those cases with additional tumor nodules in the lobe of the primary, now T3 and not T4, will be down-staged from stage IIIB; if N1 or N2 to stage IIIA, and if N0 to stage IIB.
d. Those cases with additional tumor nodules in other ipsilateral lobe(s), now T4 and not M1, will be down-staged from stage IV; if N2 or N3 to stage IIIB, and if N0 or N1 to stage IIIA.
e. Tumors that are T4 due to other features will be down-staged if N0 or N1 from stage IIIB to stage IIIA.
f. Tumors associated with pleural or pericardial nodules/effusions become M1a instead of T4 and are consequently up-staged from IIIB to stage IV.
Some of these changes to the descriptors and stage groupings will have consequences for established treatment algorithms. Should those larger tumors that are node negative and which move from stage IB to stages IIA or IIB be considered for adjuvant chemotherapy after complete resection? The evidence to date has shown a survival benefit to such an approach in stage II cases15 but the evidence for this approach in stage IB is controversial and its use is unproven.16 We should remember that these trials were conducted at a time when stage II consisted of N1 cases, and trials will be necessary before one can assume such benefit in N0 cases. Similarly, there will be a greater emphasis on the role of surgery, probably in a multimodality setting, in cases that have been down-staged from stage IV or IIIB to IIIA or IIB. Common sense will restrict such calls to selected cases, but again trials will be needed to show the possible benefit of such surgery. We are in for an exciting time!
The IASLC has prepared a range of educational products to inform the lung cancer community of these changes. The Staging Handbook in Thoracic Oncology provides a handy pocket book describing the main features of the 7th edition, the more extensive Staging Manual in Thoracic Oncology contains additional background information, explanatory material and wider clarification such as that found in the TNM Supplement produced by the International Union Against Cancer.17 There are pocket laminates and larger posters providing an aide memoire of the key features. The IASLC has commissioned Dr. Aletta Frasier to produce drawings for a TNM Atlas of the new descriptors and a CT Atlas of axial, coronal and sagital images which are included in these publications. There will be a wealth of information on the IASLC web site (www.iaslc,org), available to members to down load, with PowerPoint presentations and supporting data and survival graphs.
The process by which TNM in Lung Cancer evolves has been changed irrevocably, and the IASLC has secured a central role in future revisions for the whole of the Thoracic Oncology community. The 7th edition of TNM is based upon the largest data base ever accrued, with global representation and cases treated by all modalities of care. There has been more extensive analysis, and internal and external validation never before used to support changes to the TNM classification. However, such a retrospective data base has its limitations and failings. There are shortcomings in the geographical accrual and still an unrepresentative dominance of surgically treated cases. The data were not collected for the primary purpose of TNM analysis and, with so many languages, quality control was limited. The routine use of PET scanning postdated the period of data collection. The IASLC proposes to improve these aspects in time for the 8th edition of TNM. A prospective data set has been agreed,11 funding has been secured for the 7-year cycle leading up to the 8th edition. A web-based data collection system is being developed and tested to make data submission easier for those who collaborate in this next phase. Data collection has been expanded to incorporate neuro-endocrine tumors18 and mesothelioma. However, ultimately the success of our efforts will depend upon the continued and expanded support we receive from colleagues around the world.
1. Goldstraw P, Crowley JJ, IASLC International Staging Project. The International Association for the Study of Lung Cancer International Staging Project on Lung Cancer. J Thorac Oncol
2. Rami-Porta R, Ball D, Crowley JJ, et al. The IASLC Lung Cancer Staging Project: proposals for the revision of the T descriptors in the forthcoming (seventh) edition of the TNM classification for lung cancer. J Thorac Oncol
3. Rusch VR, Crowley JJ, Giroux DJ, et al. The IASLC Lung Cancer Staging Project: proposals for revision of the N descriptors in the forthcoming (seventh) edition of the TNM classification for lung cancer. J Thorac Oncol
4. Postmus PE, Brambilla E, Chansky K, et al. The IASLC Lung Cancer Staging Project: proposals for revision of the M descriptors in the forthcoming (seventh) edition of the TNM classification for lung cancer. J Thorac Oncol
5. Groome PA, Bolejack V, Crowley JJ, et al. The IASLC Lung Cancer Staging Project: validation of the proposals for revision of the T, N and M descriptors and consequent stage groupings in the forthcoming (seventh) TNM classification for lung cancer. J Thorac Oncol
6. Goldstraw P, Crowley JJ, Chansky K, et al. The IASLC Lung Cancer Staging Project: proposals for revision of the stage groupings in the forthcoming (seventh) edition of the TNM classification for lung cancer. J Thorac Oncol
7. Shepherd FA, Crowley J, Van Houtte P, et al. The IASLC Lung Cancer Staging Project: proposals regarding the clinical staging of small-cell lung cancer in the forthcoming (seventh) edition of the TNM classification for lung cancer. J Thorac Oncol
8. Sculier JP, Chansky K, Crowley JJ, Van Meerbeeck J, Goldstraw P, IASLC International Staging Project. The impact of additional prognostic factors on survival and their relationship with the Anatomical Extent of Disease as expressed by the 6th edition of the TNM Classification of Malignant Tumours and the proposals for the 7th edition. J Thorac Oncol
9. Travis WD, Giroux DJ, Chansky K, et al. The IASLC Lung Cancer Staging Project: proposals for the inclusion of Carcinoid tumours in the forthcoming (seventh) edition of the TNM Classification for Lung Cancer. J Thorac Oncol
10. Travis WD, Brambilla E, Rami-Porta R, et al. Visceral pleural invasion: pathologic criteria and use of elastic stains: proposals for the 7th edition of the TNM Classification for Lung Cancer. J Thorac Oncol
11. Giroux DJ, Rami-Porta R, Chansky K, Crowley JJ, Groome PA, Postmus PE, et al. The IASLC lung cancer staging project: data elements for the prospective project. J Thorac Oncol
12. Rusch V, Asamura H, Watanabe H, et al. The IASLC Lung Cancer Staging Project: a proposal for a new international node map in the forthcoming seventh edition of the TNM classification for lung cancer. J Thorac Oncol
13. Chansky K, Sculier JP, Crowley JJ, et al. The IASLC lung cancer staging project: survival differences by cell type, gender, age and pTNM stage in surgically managed non-small cell lung cancer. J Thorac Oncol
14. Vallieres E, Shepherd FA, Crowley J, et al. The IASLC lung cancer staging project: proposals regarding the relevance of TNM in the pathological staging of small-cell lung cancer in the forthcoming (seventh) edition of the TNM classification for lung cancer. J Thorac Oncol
15. Pignon JP, Tribodet H, Scagliotti GV, et al. Lung adjuvant cisplatin evaluation: a pooled analysis by the LACE Collaborative Group. J Clin Oncol
16. Strauss GM, Herndon JE, Maddaus MA, et al. Adjuvant paclitaxel plus carboplatin compared with observation in stage IB non-small cell lung cancer: CALGB 9633 with the Cancer and Leukemia Group B, Radiation Therapy Oncology Group, and the North Central Cancer Treatment Group Study groups. J Clin Oncol
17. Wittekind C, Greene FL, Henson DE, Hutter RVP, Sobin LH. TNM Supplement: A Commentary on Uniform Use, 3rd Ed. New Jersey: Wiley-Liss, 2003.
18. Lim E, Goldstraw P, Nicholson AG, et al. Proceedings of the IASLC International Workshop on Advances in Neuroendocrine Tumors 2007. J Thorac Oncol