International Association For The Study Of Lung Cancer Staging Research Articles

IASLC Lung Cancer Staging Project: The New Database to Inform Revisions in the Ninth Edition of the TNM Classification of Lung Cancer

In the past 20 years, the International Association for the Study of Lung Cancer (IASLC) has been working on a global project to revise the TNM classification of lung cancer. The first and second phases of the staging projects proposed recommendations for revision of the TNM classification, which were adopted by the Union for International Cancer Control and the American Joint Committee on Cancer as their seventh and eighth editions of the TNM classifications of lung cancer. For the third phase of the IASLC Staging Project, a new database of lung cancer cases diagnosed between January 2011 and December 2019 has been established. The Staging and Prognostic Factors Committee of the IASLC is in charge of the process of proposing new recommendations. The newly established database consisted of 124,581 cases. The data were obtained from Asia and Australia (56.0%), Europe (24.7%), North America (15.7%), South/Central America (3.4%), and Africa and the Middle East (0.1%). After cases with incomplete data are excluded, 87,043 cases were enrolled in the analysis, of which 52,069 (59.8%) were invasive adenocarcinoma and 15,872 (18.2%) were squamous cell carcinoma. Both clinical and pathologic stages were available in 44,831 (51.5%) cases. Analyses of this database are expected to provide proposals for changing the TNM classification toward the ninth edition, which is scheduled to be in use in January 2024. This newly established global database on lung cancer is described to provide fundamental elements for revisions of the TNM rules for staging lung cancer.

The International Association for the Study of Lung Cancer Thymic Epithelial Tumor Staging Project: Unresolved Issues to be Addressed for the Next Ninth Edition of the TNM Classification of Malignant Tumors

Thymic epithelial tumors are presently staged using a consistent TNM classification developed by the International Association for the Study of Lung Cancer (IASLC) and approved by the Union for International Cancer Control and the American Joint Committee on Cancer. The stage classification is incorporated in the eight edition of the TNM classification of thoracic malignancies. The IASLC Staging and Prognostic Factors Committee (SPFC)—Thymic Domain (TD) is in charge for the next (ninth) edition expected in 2024. The present article represents the midterm report of the SPFC-TD: in particular, it describes the unresolved issues identified by the group in the current stage classification which are worth being addressed and discussed for the ninth edition of the TNM classification on the basis of the available data collected in the central thymic database which will be managed and analyzed by Cancer Research And Biostatistics. These issues are grouped into issues of general importance and those specifically related to T, N, and M categories. Each issue is described in reference to the most recent reports on the subject, and the priority assigned by the IASLC SPFC-TD for the discussion of the ninth edition is provided.

The International Association for the Study of Lung Cancer Staging Project: Methods and Guiding Principles for the Development of the Ninth Edition TNM Classification

IntroductionStage classification provides a consistent and concise nomenclature about the anatomic extent of the cancer. This is a fundamental cornerstone in the management of patients; it enables reporting results and facilitates comparing one treatment to another and judging how closely clinical trial results apply to an individual patient. A nomenclature must be relatively static; however, periodical refinement is needed to adjust to a changing landscape of clinical relevance. Changes must be well justified and thoughtfully developed to maintain the ability to communicate clearly and facilitate comparisons across time. MethodsFor thoracic malignancies (lung, pleura, thymus, and esophagus), the International Association for the Study of Lung Cancer (IASLC) has leveraged its worldwide multidisciplinary reach, permitting a sophisticated approach to this process. Refinement of stage classification for the ninth edition of TNM is underway; this article describes the approach adopted by the IASLC Staging and Prognostic Factors Committee. ResultsKey guiding principles include the ability to maintain communication over time, a classification that discriminates homogeneous cohorts of tumors consistently across the world in multiple settings, treatment approaches, and patient characteristics, including clinical relevance and practical applicability. The IASLC has again assembled a large international database to permit multifaceted analysis. Providing confidence that the classification performs consistently in multiple settings, treatments, and patients requires consistent discrimination in multiple subset analyses. Although observed outcomes of patients in the 2011 to 2019 database are essential, considerations about how the classification will be used are also important to ensure clinical relevance and applicability. ConclusionsThe strategy developed by the Staging and Prognostic Factors Committee is carefully designed to provide useful refinements to the stage classification of thoracic malignancies for the ninth edition of TNM classification of cancers.

Commemorating the Silver Anniversary of the International Association for the Study of Lung Cancer International Workshop on Intrathoracic Staging

Commemorating the Silver Anniversary of the International Association for the Study of Lung Cancer International Workshop on Intrathoracic Staging

Towards the 9th Edition of the Tumour, Node and Metastasis Classification of Lung Cancer. A Historical Appraisal and Future Perspectives.

Since 1966 the classification of anatomic extent of lung cancer, based on the primary tumour (T), the loco-regional lymph nodes (N) and the metastases (M) has been used in the management of lung cancer patients. Developed by Pierre Denoix, it was adopted by the Union for International Cancer Control and the American Joint Committee on Cancer. Clifton Mountain revised the second through the sixth editions based on a North American database of more than 5000 patients. For the seventh and the eighth editions, the International Association for the Study of Lung Cancer (IASLC) collected international databases of around 100,000 patients worldwide that allowed the introduction of innovations in both editions, namely the subdivision of the T and M categories based on tumour size and on the location and number of metastases, respectively. The revisions also showed the prognostic relevance of the quantification of nodal disease, and proposed recommendations on how to measure tumour size for solid lung cancers, part-solid adenocarcinomas, and for lung cancers removed after induction therapy. Despite the innovations, prognosis based on the anatomic extent is limited, because prognosis depends on factors related to the tumour, the patient and the environment. For the 9th edition, these factors, especially genetic biomarkers, will be combined in prognostic groups to refine prognosis at clinical and pathologic staging. To achieve this challenging objective, international cooperation is essential, and the IASLC Staging and Prognostic Factors Committee counts on it for the development of the 9th edition due to be published in 2024.

Towards the 9th Edition of the Tumour, Node and Metastasis Classification of Lung Cancer. A Historical Appraisal and Future Perspectives

Since 1966 the classification of anatomic extent of lung cancer, based on the primary tumour (T), the loco-regional lymph nodes (N) and the metastases (M) has been used in the management of lung cancer patients. Developed by Pierre Denoix, it was adopted by the Union for International Cancer Control and the American Joint Committee on Cancer. Clifton Mountain revised the second through the sixth editions based on a North American database of more than 5000 patients. For the seventh and the eighth editions, the International Association for the Study of Lung Cancer (IASLC) collected international databases of around 100,000 patients worldwide that allowed the introduction of innovations in both editions, namely the subdivision of the T and M categories based on tumour size and on the location and number of metastases, respectively. The revisions also showed the prognostic relevance of the quantification of nodal disease, and proposed recommendations on how to measure tumour size for solid lung cancers, part-solid adenocarcinomas, and for lung cancers removed after induction therapy. Despite the innovations, prognosis based on the anatomic extent is limited, because prognosis depends on factors related to the tumour, the patient and the environment. For the 9th edition, these factors, especially genetic biomarkers, will be combined in prognostic groups to refine prognosis at clinical and pathologic staging. To achieve this challenging objective, international cooperation is essential, and the IASLC Staging and Prognostic Factors Committee counts on it for the development of the 9th edition due to be published in 2024.

The IASLC Lung Cancer Staging Project: A Renewed Call to Participation.

Over the past two decades, the International Association for the Study of Lung Cancer (IASLC) Staging Project has been a steady source of evidence-based recommendations for the TNM classification for lung cancer published by the Union forInternational Cancer Control and the American Joint Committee on Cancer. The Staging and Prognostic Factors Committee of the IASLC is now issuing a call for participation in the next phase of the project, which is designed to inform the ninth edition of the TNM classification for lung cancer. Following the case recruitment model for the eighth edition database, volunteer site participants are asked to submit data on patients whose lung cancer was diagnosed between January 1, 2011, and December 31, 2019, to the project by means of a secure, electronic data capture system provided by Cancer Research And Biostatistics in Seattle, Washington. Alternatively, participants may transfer existing data sets. The continued success of the IASLC Staging Project in achieving its objectives will depend on the extent of international participation, the degree to which cases are entered directly into the electronic data capture system, and how closely externally submitted cases conform to the data elements for the project.

The IASLC Lung Cancer Staging Project: The New Database to Inform the Eighth Edition of the TNM Classification of Lung Cancer

The analyses of the retrospective database of the International Association for the Study of Lung Cancer (IASLC), consisting of more than 81,000 evaluable patients diagnosed with lung cancer between 1990 and 2000, formed the basis of recommendations to the Union for International Cancer Control and the American Joint Committee on Cancer for the revision of the sixth edition of the tumor, node, and metastasis (TNM) classification of lung cancer. However, despite the large number of patients, not all descriptors could be validated. This prompted a new collection of retrospective and prospective data to overcome the limitations of the original retrospective database. The new IASLC database has information on 94,708 new patients diagnosed of lung cancer between 1999 and 2010. They originated from 35 sources in 16 countries, and 4,667 were submitted via the online electronic data capture system. Europe contributed 46,560 patients, Asia: 41,705, North America: 4,660, Australia: 1,593, and South America: 190. After exclusions, 77,156 (70,967 with nonsmall cell lung cancer and 6,189 with small cell lung cancer) remained for analysis. This database will be analyzed according to established objectives for the T, the N, and the M components to inform the eighth edition of the TNM classification of lung cancer due to be published in 2016. The IASLC hopes for the continuing contribution of our partners around the world to improve the classification of anatomical extent of disease, but also to create prognostic groups in a parallel project of the IASLC Staging and Prognostic Factors Committee.

Response: A Critique of the International Association for the Study of Lung Cancer Lymph Node Map

We thank Pitson et al.1 for providing a detailed analysis of the International Association for the Study of Lung Cancer (IASLC) lymph node map from the viewpoint of radiation oncologists. The objectives of this map2 were to reconcile differences between the Japanese and MD-ATS (American Thoracic Society as modified by Mountain and Dresler) maps and to provide more specific anatomic definitions for each of the lymph node stations. Although the map was developed with multidisciplinary input from the IASLC Staging Committee including radiologists and radiation oncologists, additional thoughts are always welcome. We provide a few specific comments in response:

Impact of the New Lung Cancer Staging System for a Predominantly Advanced-Disease Patient Population

To investigate the feasibility and clinical impact of the 7th edition of the "Tumor, Node, Metastasis" (TNM) classification scheme in lung cancer as proposed by the International Association for the Study of Lung Cancer (IASLC) for non-small cell lung cancer. We evaluated the feasibility of the new staging system in our routine biweekly multidisciplinary lung cancer staging conference compared with the 6th TNM staging in a prospective manner from April 2008 to June 2009. The impact of IASLC staging versus the 6th TNM staging was observed at three levels: change in substaging, staging, and clinical management (based on the discussion within the staging conference). From 348 patients discussed during these conferences, 226 eligible non-small cell lung cancer patients newly diagnosed within the study period were reviewed and clinically staged. The majority were elderly (median age, 67 years) and men (58%). Of these, 23 patients had different staging, and four patients had different substaging in the IASLC staging compared with the 6th TNM staging. An impact on clinical management was seen in 2.7% (6 of 226) of these patients because of coding ipsilateral different-lobe metastasis as T4 instead of M1. The new staging system was clinically feasible and resulted in some (27 of 226, 12%) differences in staging. An impact on clinical decision making was occasionally seen within our institutional practice. Further studies are needed to investigate the comprehensive and long-term impact of the new staging system.

The revised TNM staging system and surgical strategies for non-small cell lung cancer

The International Association for the Study of Lung Cancer (IASLC) has presented the details of the IASLC/International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) Revised Staging Classification for Lung Cancer. The IASLC is the largest world-wide professional organization solely dedicated to reduce the worldwide burden of lung cancer. The IASLC recognizes that the staging classification will be most valuable and accurate if it is based on the evaluation of outcomes of large numbers of cases carefully collected and analyzed in an extensive worldwide database. The analyses of the T, N and M descriptors as well as the stage groupings were performed in 67,725 non-small cell lung cancer (NSCLC)patients. Survival was the primary outcome, measured from the date of diagnosis or date of protocol registration for clinical staging, or the date of surgery for pathologic staging. The remarkable efforts of the IASLC Staging Committee have resulted in an evidence-based, validated and robust revision of the international staging system for NSCLC. This landmark contribution will improve our care of patients and lays a strong foundation for future refinements based on an expanding knowledge of lung cancer behavior and biology. This review outlines the changes in the tumor, node, metastasis (TNM) descriptors and stage groupings anticipated in the official new stage classification system for NSCLC. Key words: Lung neoplasms; Neoplasms staging; Surgical procedures,operation

The IASLC Lung Cancer Staging Project: Data Elements for the Prospective Project

The International Association for the Study of Lung Cancer Retrospective Staging Project culminated in a series of recommendations to the International Union Against Cancer and to the American Joint Committee on Cancer regarding the seventh edition of the tumor, node, metastasis (TNM) classification for lung cancer. The International Staging Committee of the International Association for the Study of Lung Cancer now issues this call for participation in the Prospective Project designed to assess the validity of each component of T, N, and M, and other factors relevant to lung cancer staging and prognosis. In the Retrospective Project, the original data acquisition was typically motivated by interests other than staging. In contrast, the Prospective Project offers online data entry. Alternatively, participants may transfer existing data, provided core objectives are addressed. Cancer Research and Biostatistics will coordinate data management and analysis. The study population is newly diagnosed lung cancer patients. Data elements include patient characteristics, baseline laboratory values, first-line treatment, TNM plus supporting evidence, and survival. Pretreatment TNM will be collected for all cases; postsurgical TNM, if resection is attempted. T descriptors include size and degree of tumor extension, with further description of extent of visceral pleural invasion, venous invasion, carcinomatous lymphangitis, and pleural lavage cytology. M descriptors characterize the newly proposed M1a category and sites of distant metastases. Nodal station involvement is described by means of a newly proposed nodal map, facilitating international participation, and allowing further investigation of nodal zones. Successful collection and analysis of these data can be expected to yield unprecedented improvements in the utility and validity of lung cancer staging.

Application of the revised lung cancer staging system (IASLC Staging Project) to a cancer center population

The International Association for the Study of Lung Cancer (IASLC) proposed a revision to the Union Internationale Contre le Cancer (UICC-6) staging system for non-small cell lung cancer. The goal of our study was to compare these systems in patients undergoing surgery for non-small cell lung cancer to determine whether one system is superior in staging operable disease. Pathologic stages in 1154 patients undergoing complete resection over a 9-year period were analyzed. Patients were assigned a stage based on both IASLC and UICC-6 systems. We tested for statistically meaningful differences between the two staging systems using the Wilcoxon signed rank test and the permutation test. The IASLC system is more effective than the UICC-6 system at ordering and differentiating patients (P = .009). Application of the IASLC system resulted in 202 (17.5%) patients being reassigned to a different stage (P = .012), with the most common shifts occurring from IB to IIA and IIIB to IIIA. The 5-year and median survivals of the IASLC IIIA patients including those shifted from the UICC-6 IIIB were 37% and 35 months, respectively. Reclassifying UICC-6 IIIB to IASLC IIIA did not reduce survival for the newly characterized IIIA cohort. Our data confirm that the proposed IASLC staging system is more effective at differentiating stage than the UICC-6 system. Reclassifying patients from UICC-6 IIIB to IASLC IIIA will shift some patients from a stage previously considered unresectable to a stage frequently offered surgical resection. Further study and validation of the IASLC system are warranted.

Reporting lung cancer pathology specimens. Impact of the anticipated 7th Edition TNM Classification based on recommendations of the IASLC Staging Committee

Led by the International Association for the Study of Lung Cancer (IASLC), there are currently several major international collaborative projects underway that will have a significant impact on the future reporting of lung cancer pathology. In particular, the IASLC Staging Committee has just completed an analysis of >100,000 lung cancer cases, providing the basis for proposed revisions of the current TNM staging classification. The purpose of this review is not to provide a comprehensive document on recommendations for specimen processing, but rather to discuss how the anticipated changes in the 7th edition TNM will impact on specimen processing, specifically looking at tumour size, how to deal with multiple tumours and visceral pleural invasion. TNM staging of carcinoid tumours and small cell carcinoma is also discussed.

The IASLC Lung Cancer Staging Project: Proposals for the Inclusion of Broncho-Pulmonary Carcinoid Tumors in the Forthcoming (Seventh) Edition of the TNM Classification for Lung Cancer

In the 2003 Supplement for tumor, node, metastasis (TNM) Staging classification it states that TNM staging "applies to all types of carcinoma including small cell carcinoma; however, it does not apply to carcinoids." Despite this caveat, most publications on typical and atypical carcinoids use the TNM staging system for nonsmall cell carcinoma and are able to demonstrate prognostic significance for the different stages. For this reason, as the next TNM Staging proposal is being considered, we sought to investigate the carcinoid cases submitted to the International Association for the Study of Lung Cancer (IASLC) database, as well as the National Cancer Institute Surveillance Epidemiology and End Results (SEER). In the data collected for the IASLC Staging Project database over the time period 1990 to 2000, there were 513 broncho-pulmonary carcinoids. A total of 1619 broncho-pulmonary carcinoid cases diagnosed over the period 1990-2002 were analyzed from the SEER database, including 1437 surgical cases. Pathologic slides were not available for histologic review. Most of tumors in both the IASLC and SEER databases were Stage I (82% and 78%, respectively), as defined by the IASLC proposals for the 7th edition of TNM staging system. T status was a statistically significant predictor of survival for both the SEER data (p < 0.0001) and the IASLC database (p = 0.0156), though for different reasons. N status showed significant survival correlations in both data sets (p < 0.0001). The effect of M status was significant (p < 0.0001) within the SEER data and not studied in the IASLC cases, which were almost exclusively M0. We found that all three T, N, and M categories as defined for non-small cell lung cancer are generally useful for staging of pulmonary carcinoid tumors. Significant differences in survival for overall stages I versus II versus III/IV were identified in both data sets. Patients with multiple same lobe nodules had a 100% 5-year survival, which may be a reason to reevaluate their status in the IIB category in future analyses. In summary, the IASLC proposals for the 7th edition of TNM are helpful in predicting prognosis for broncho-pulmonary carcinoid tumors. It is the recommendation of the IASLC Staging project that TNM be applied to broncho-pulmonary carcinoid tumors. A prospective collection of data through an International Registry of Pulmonary Neuroendocrine Tumors planned by the IASLC will allow for further detailed analysis of staging data for broncho-pulmonary carcinoids.

Validation Study of the Proposed IASLC Staging Revisions of the T4 and M Non-small Cell Lung Cancer Descriptors Using Data from 23,583 Patients in the California Cancer Registry

We performed a validation study of the proposed International Association for the Study of Lung Cancer (IASLC) tumor, node, metastasis (TNM) and stage grouping revisions on advanced nonbronchioloalveolar carcinoma (non-BAC) non-small cell lung cancer (NSCLC). Twenty-three thousand five hundred eighty-three patients from the California Cancer Registry between 1999 and 2003 with histologically confirmed non-BAC NSCLC and complete TNM staging were identified and reclassified according to the IASLC proposed TNM revisions and new stage groupings. Twelve thousand nine hundred one stage IIIB and IV patients formed the primary analysis of the changes to T4 and M descriptors. Surveillance, Epidemiology, and End Results extent of disease codes were used to identify various T4 and M descriptors. Cox proportional hazards regression was used to calculate hazard ratios (HRs) among the stage groupings of the current and proposed staging system with adjustment for ethnicity, gender, age, histology, histologic grade, socioeconomic status, surgery, radiation, and chemotherapy. The proposed changes to the T4 and M descriptors were supported by overall survival analysis. T4 due to additional nodules had significant survival advantage over other T4 and M descriptors among non-BAC NSCLC and individual histology and warrants down-staging to T3. Pericardial effusion had survival similar to M1b patients. Cox proportional hazards regression analysis supports subdividing M descriptor into M1a (versus IASLC stage IA; HR = 4.90; 95% confidence interval: 4.49-5.34) and M1b (versus IASLC stage IA; HR = 6.84; 95% confidence interval: 6.30-7.44). IASLC has greatly improved the T4 and M descriptors allowing better prognostication of advanced non-BAC NSCLC. Pericardial effusion may be considered as M1b rather than M1a.

Validation of the Proposed International Association for the Study of Lung Cancer Non-small Cell Lung Cancer Staging System Revisions for Advanced Bronchioloalveolar Carcinoma Using Data from the California Cancer Registry

Recently, the International Association for the Study of Lung Cancer (IASLC) has proposed significant modifications to the existing TNM and stage grouping classifications affecting the T4 and M descriptors. We set out to validate this staging system for bronchioloalveolar carcinoma (BAC) cases using data from the California Cancer Registry (CCR). We identified 1909 patients from the CCR between 1999 and 2003 with histologically confirmed BAC and complete TNM staging and reclassified them according to the IASLC proposed staging revisions. There were 657 patients with stage IIIB and IV disease who formed the primary analysis of the changes to T4 and M descriptors. Surveillance Epidemiology and End Results (SEER) extent of disease codes (EOD) were used to identify various T4 and M descriptors. The primary outcome measured was overall survival (OS) for stage-specific comparisons of the existing to the proposed staging systems, using the Kaplan-Meier method. Multivariate survival analyses were performed using Cox proportional hazards ratios. Using the proposed criteria, 162 (25%) of the 657 patients with advanced BAC were reclassified: 73 patients with multiple lesions in the same lobe as T3 (stage II T3N0M0 [n = 53], stage IIIA T3N1-2M0 [n = 18], stage IIIB T3N3M0 [n = 1] or T3NXM0 [n = 1]); 89 patients with ipsilateral intrapulmonary metastasis were reclassified as T4 (stage IIIA T4N0-N1M0 [n = 54], stage IIIB T4N2-3M0 [n = 23] or T4NXM0 [n = 12]). Univariate and multivariate survival analysis of this validation set revealed an improved fit for the proposed IASLC staging system compared with the existing staging system. The proposed IASLC staging system modifications accurately reflect survival characteristics for BAC and represent an improvement compared with the existing staging system.

The 7th Edition of the TNM Classification for Lung Cancer: Proposals from the IASLC Staging Project

The purpose of this presentation is three-fold: (a) to inform the lung cancer community of the proposals submitted by the International Association for the Study of Lung Cancer (IASLC) to the International Union Against Cancer (UICC) and the American Joint Committee on Cancer (AJCC) for the Lung Cancer section of the forthcoming (7th) Edition of the TNM Classification of Malignant Tumours, (b) to stimulate discussion within the lung cancer community ahead of these revisions being enacted, and (c) to describe to the wider oncological community the IASLC Lung Cancer Staging Project in the hope that it might provide a useful template by which revisions to the TNM Classification for other tumours could be better informed. This last issue will entail a description of the development of TNM staging in lung cancer, which, inevitably will be somewhat critical of the pre-existing process for revision. The UICC has sought to improve this and the previous speaker will address their process for change initiative. However, the relevant specialist associations and National groups can help to inform such revisions by stimulating collaborative, international efforts for data collection.

Complete resection in lung cancer surgery: proposed definition

To propose an internationally accepted definition of complete resection in lung cancer surgery. The International Association for the Study of Lung Cancer (IASLC) Staging Committee created the Complete Resection Subcommittee in 2001 to work on an international definition of complete resection in lung cancer surgery. The previous definitions of complete resection and the rules of the International Union Against Cancer regarding the TNM residual tumor classification, together with a thorough review of the pertinent literature, and the input of the members of the IASLC Staging Committee were considered in order to get an international consensus on the definition of complete resection in lung cancer surgery. Complete resection requires all of the following: free resection margins proved microscopically; systematic nodal dissection or lobe-specific systematic nodal dissection; no extracapsular nodal extension of the tumor; and the highest mediastinal node removed must be negative. Whenever there is involvement of resection margins, extracapsular nodal extension, unremoved positive lymph nodes or positive pleural or pericardial effusions, the resection is defined as incomplete. When the resection margins are free and no residual tumor is left, but the resection does not fulfill the criteria for complete resection, there is carcinoma in situ at the bronchial margin or positive pleural lavage cytology, the term uncertain resection is proposed. The proposed definitions of complete, incomplete and uncertain resections are clear and reproducible in an international setting to study their prognostic impact prospectively.

Staging small cell lung cancer: Veterans Administration Lung Study Group versus International Association for the Study of Lung Cancer—what limits limited disease?

Small cell lung cancer (SCLC) is usually classified into a two-stage system, limited (LD) and extensive disease (ED). However, the criteria for these two categories remain controversial. The widely used Veterans Administration Lung Study Group (VALG) definition of LD includes patients with primary tumor and nodal involvement limited to one hemithorax. In contrast, the International Association for the Study of Lung Cancer (IASLC) recommends that LD should additionally include all patients without distant metastasis. As a consequence, since treatment modalities for LD and ED could be different, individual clinical outcome of SCLC patients may be influenced by the staging system chosen. Among 109 consecutive SCLC patients treated in our clinic between 1989 and 1999 (mean age 68±9.1 years, 81% male) 23 patients (21%) could be either classified as LD or ED (LD-ED), depending on the staging system used. The prognosis of this overlapping group (LD-ED: median survival 291 days) was not statistically different from patients with limited disease defined by VALG criteria (LD-VALG: 385 days, log–rank test P=0.42). On the other hand the survival difference between LD-ED patients and the ED-IASLC population was relevant (ED-IASLC: 208 days, P=0.05), indicating that LD-ED patients should rather be included in the LD category. This is further supported by the results of a multivariate Cox regression analysis with all clinically relevant data. Only stage as defined by IASLC criteria was an independent prognostic factor in the likelihood-ratio-forward (hazard ratio=1.94, CI=1.26–2.99; P=0.005) and backward model (hazard ratio=1.76, CI: 1.12–2.76; P=0.012), confirming the higher discriminatory power of the IASLC definition. In conclusion, the IASLC staging criteria for SCLC patients have a higher prognostic impact and are therefore preferable in clinical practice and future therapeutic trials.