The International Association for the Study of Lung Cancer Pleural Mesothelioma Staging Project: Proposal for Revision of the TNM Stage Groupings in the Forthcoming (Ninth) Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The eighth edition of the TNM classification of pleural mesothelioma (PM) saw substantial changes in T and N components and stage groupings. The International Association for the Study of Lung Cancer collected data into a multinational database to further refine this classification. This ninth edition proposal incorporates changes proposed in the clinical (c)T component but not the pathologic T component, to include size criteria, and further refines TNM stage groupings for PM. METHODS: Data were submitted through electronic data capture or batch transfer from institutional databases. Survival was measured from diagnosis date. Candidate stage groups were developed using a recursive partitioning and amalgamation algorithm applied to all cM0 cases for clinical stage and subsequently for pathologic stage. Cox models were developed to estimate survival for each stage group. RESULTS: Of 3598 submitted cases, 2192 were analyzable for overall clinical stage and 445 for overall pathologic stage. Recursive partitioning and amalgamation generated survival tree on overall survival outcomes restricted to cM0, with newly proposed (ninth edition) cT and cN component-derived optimal stage groupings of stage I (T1N0), II (T1N1; T2N0), IIIA (T1N2; T2N1/2; any T3), IIIB (any T4), and IV (any M1). Although cT and pathologic T descriptors are different in the ninth edition, aligning pathologic stage groupings with clinical stage produced better discrimination than did retaining eighth edition pathologic stage groupings. CONCLUSIONS: To our knowledge, this revision of the clinical TNM classification for PM is the first to incorporate the measurement-based proposed changes in cT category. The pathologic TNM aligns with clinical TNM.

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for the "N" Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The International Association for the Study of Lung Cancer developed an international database to inform potential revisions in the ninth edition of the TNM classification of diffuse pleural mesothelioma (PM). This study analyzed the clinical and pathologic N categories to determine whether revisions were indicated relative to the eighth edition staging system. METHODS: Of 7338 PM cases diagnosed from 2013 to 2022 and 3598 met all inclusion criteria for planned analyses. Data on 2836 patients without metastases were included in this study. Overall survival (OS) was measured from date of diagnosis. Patients were included regardless of whether they received neoadjuvant treatment. For the pathologic N analysis, patients who underwent resection (extrapleural pneumonectomy or pleurectomy/decortication) were included. N subgroups were analyzed and OS assessed by the Kaplan-Meier method. RESULTS: The existing eighth edition N categories were performed adequately in the ninth edition data set. A median OS advantage was noted for clinical and pathologic N0 versus N1 patients: 23.2 versus 18.5 and 33.8 versus 25.0 months, respectively. Patients with resected pN0 had a 3-year OS of 48%. No difference in OS was noted for single- versus multiple-station nodal metastases. The number of nodal stations sampled at the time of resection was not associated with a difference in OS. CONCLUSIONS: Data regarding clinical and pathologic N categories corroborate those used in the eighth edition. No changes in the N categories are recommended in the ninth edition of PM staging system.

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for Revisions of the "T" Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma.

INTRODUCTION: The primary tumor (T) component in the eighth edition of pleural mesothelioma (PM) staging system is based on pleural involvement and extent of invasion. Quantitative assessment of pleural tumor has been found to be prognostic. We explored quantitative and qualitative metrics to develop recommendations for T descriptors in the upcoming ninth edition of the PM staging system. METHODS: The International Association for the Study of Lung Cancer prospectively collected data on patients with PM. Sum of maximum pleural thickness (Psum) was recorded. Optimal combinations of Psum and eighth edition cT descriptors were assessed using recursive binary splitting algorithm, with bootstrap resampling to correct for the adaptive nature of the splitting algorithm, and validated in the eighth edition data. Overall survival (OS) was calculated by the Kaplan-Meier method and differences in OS assessed by the log-rank test. RESULTS: Of 7338 patients submitted, 3598 were eligible for cT analysis and 1790 had Psum measurements. Recursive partitioning identified optimal cutpoints of Psum at 12 and 30 mm, which, in combination with extent of invasion, yielded four prognostic groups for OS. Fmax greater than 5 mm indicated poor prognosis. cT4 category (based on invasion) revealed similar performance to eighth edition. Three eighth edition descriptors were eliminated based on low predictive accuracy. Eighth edition pT descriptors remained valid in ninth edition analyses. CONCLUSION: Given reproducible prognostication by Psum, size criteria will be incorporated into cT1 to T3 categories in the ninth edition. Current cT4 category and all pT descriptors will be maintained, with reclassification of fissural invasion as pT2.

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for Revision of the TNM Stage Groups in the Forthcoming (Ninth) Edition of the TNM Classification for Lung Cancer.

INTRODUCTION: The TNM classification of lung cancer is periodically revised. The International Association for the Study of Lung Cancer collected and analyzed a new database to inform the forthcoming ninth edition of the TNM classification. The results are herewith presented. METHODS: After exclusions, 76,518 patients from a total of 124,581 registered patients were available for analyses: 58,193 with clinical stage, 39,192 with pathologic stage, and 62,611 with best stage NSCLC. The proposed new N2 subcategories (N2a, involvement of single ipsilateral mediastinal or subcarinal nodal station, and N2b, involvement of multiple ipsilateral mediastinal nodal stations with or without involvement of the subcarinal nodal station) and the new M1c subcategories (M1c1, multiple extrathoracic metastases in one organ system, and M1c2, multiple extrathoracic metastases in multiple organ systems) were considered in the survival analyses. Several potential stage groupings were evaluated, using multiple analyses, including recursive partitioning, assessment of homogeneity within and discrimination between potential groups, clinical and statistical significance of survival differences, multivariable regression, and broad assessment of generalizability. RESULTS: T1N1, T1N2a, and T3N2a subgroups are assigned to IIA, IIB, and IIIA stage groups, respectively. T2aN2b and T2bN2b subgroups are assigned to IIIB. M1c1 and M1c2 remain in stage group IVB. Analyses reveal consistent ordering, discrimination of prognosis, and broad generalizability of the proposed ninth edition stage classification of lung cancer. CONCLUSIONS: The proposed stages for the ninth edition TNM improve the granularity of nomenclature about anatomic extent that has benefits as treatment approaches become increasingly differentiated and complex.

The International Association for the Study of Lung Cancer Pleural Mesothelioma Staging Project: Expanded Database to Inform Revisions in the Ninth Edition of the TNM Classification of Pleural Mesothelioma.

The International Association for the Study of Lung Cancer collaborated with the International Mesothelioma Interest Group to propose the first TNM stage classification system for diffuse pleural mesothelioma in 1995, accepted by the Union for International Cancer Control and the American Joint Committee on Cancer for the sixth and seventh edition stage classification manuals. The International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee Mesothelioma Domain developed and analyzed an international registry of patients with pleural mesothelioma and updated TNM descriptors for the eighth edition of the stage classification system. To inform revisions for the forthcoming ninth edition of the TNM stage classification system, data submission was solicited for patients diagnosed between 2013 and 2022 with expanded data elements on the basis of the first project's exploratory analyses, including pleural thickness measurements, updated surgical nomenclature, and molecular markers. The resulting database consisted of a total of 3598 analyzable cases from Europe, Australia, Asia, North America, and South America, with a median age of 71 years (range: 18-99 y), 2775 (77.1%) of whom were men. With only 1310 patients (36.4%) undergoing curative-intent operations, this iteration of the database includes far more patients treated nonsurgically compared with prior. Four separate manuscripts on T, N, M, and stage groupings submitted to this journal will summarize analyses of these data and will serve collectively as the primary source of the proposed changes to the upcoming ninth edition of the pleural mesothelioma stage classification system.

The International Association for the Study of Lung Cancer Staging Project for Lung Cancer: Proposals for the Revision of the M Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Lung Cancer.

INTRODUCTION: This study analyzed all metastatic categories of the current TNM classification of NSCLC to propose modifications of the M component in the next edition (ninth) of the classification. METHODS: A database of 124,581 patients diagnosed between 2011 and 2019 was established; of these, 14,937 with NSCLC in stages IVA to IVB were available for this analysis. Overall survival was calculated using the Kaplan-Meier method, and prognosis was assessed using multivariable-adjusted Cox proportional hazards regression. RESULTS: The eighth edition M categories revealed good discrimination in the ninth edition data set. Assessments revealed that an increasing number of metastatic lesions were associated with decreasing prognosis; because this seems to be a continuum and adjustment for confounders was not possible, no specific lesion number was deemed appropriate for stage classification. Among tumors involving multiple metastases, decreasing prognosis was found with an increasing number of organ systems involved. Multiple assessments, including after adjustment for potential confounders, revealed that M1c patients who had metastases to a single extrathoracic organ system were prognostically distinct from M1c patients who had involvement of multiple extrathoracic organ systems. CONCLUSIONS: These data validate the eighth edition M1a and M1b categories, which are recommended to be maintained. We propose the M1c category be divided into M1c1 (involvement of a single extrathoracic organ system) and M1c2 (involvement of multiple extrathoracic organ systems).

Completeness of Resection and Long-Term Survival of Patients Undergoing Resection for Pathologic T3 NSCLC: An International Association for the Study of Lung Cancer Analysis.

INTRODUCTION: Currently, tumors with different histopathologic characteristics and oncologic outcomes comprise the T3 category of the eight edition TNM classification for lung cancers. To better understand the T3 category, we evaluated completeness of resection and long-term survival in patients undergoing resection for T3 NSCLC. METHODS: The International Association for the Study of Lung Cancer 1999 to 2010 database was queried for patients with pathologic T3N0M0 NSCLC who underwent lobectomy or pneumonectomy. The primary outcome evaluated was overall survival (OS) stratified by T3 descriptors and completeness of resection. RESULTS: Of 1448 patients with T3N0M0 tumors, 1187 (82.0%) had a single descriptor defining them as T3. T3 tumors with chest wall infiltration (CWI) or parietal pleura infiltration (PL3) had the highest rates of incomplete resection (9.8% and 8.4%, respectively), and those classified as T3 by size only had the lowest rate of incomplete resection (2.9%). Individual T3 descriptors were associated with significant differences in OS (p = 0.005). When tumors with similar survival and complete resection rates were grouped, patients with T3 tumors characterized by size or the presence of a separate nodule (SN) in the same lobe had better 5-year OS than patients with tumors characterized by PL3 or CWI (size/SN 60% versus CWI/PL3 53%, p = 0.017) independent of completeness of resection. CONCLUSIONS: Significant differences in 5-year OS were associated with size, SN, PL3, or CWI T3 descriptors. Subdividing pathologic T3N0M0 tumors according to the presence or absence of CWI or PL3 may increase the prognostic accuracy of tumor staging.

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for the Revisions of the T-Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Lung Cancer.

INTRODUCTION: An international database was created by the International Association for the Study of Lung Cancer to inform on the ninth edition of the TNM classification of lung cancer. The present analyses concern its T component. METHODS: Data on 124,581 patients diagnosed with lung cancer from January 1, 2011 to December 31, 2019 were submitted to the International Association for the Study of Lung Cancer database. Of these, 33,982 met the inclusion criteria for the clinical T analysis, and 30,715 met the inclusion criteria for the pathologic postsurgical analysis. Survival was measured from the date of diagnosis or operation for clinically and pathologically staged tumors, respectively. T descriptors were evaluated in univariate analysis and multivariable Cox regression analysis adjusted for age, sex, pathologic type, and geographic region. RESULTS: Comprehensive survival analysis revealed that the existing eighth edition T component criteria performed adequately in the ninth edition data set. Although pathologic chest wall or parietal pleura involvement (PL 3) yielded a worse survival compared with the other T3 descriptors, with a similar survival as T4 tumors, this difference was not observed for clinical chest wall or PL 3 tumors. Because of these inconsistent findings, no reallocation of chest wall or PL 3 tumors is advised. CONCLUSIONS: The T subcommittee members proposed not to implement any changes and keep the current eighth-edition T descriptors for the ninth edition.

The International Association for the Study of Lung Cancer Staging Project for Lung Cancer: Proposals for the Revision of the N Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Lung Cancer.

INTRODUCTION: The accurate assessment of nodal (N) status is crucial to the management and prognostication of nonmetastatic NSCLC. We sought to determine whether the current N descriptors should be maintained or revised for the upcoming ninth edition of the international TNM lung cancer staging system. METHODS: Data were assembled by the International Association for the Study of Lung Cancer on patients with NSCLC, detailing both clinical and pathologic N status, with information about anatomical location and individual station-level identification. Survival was calculated by the Kaplan-Meier method and prognostic groups were assessed by a Cox regression analysis. RESULTS: Data for clinical N and pathologic N status were available in 45,032 and 35,009 patients, respectively. The current N0 to N3 descriptors for both clinical N and pathologic N categories reflect prognostically distinct groups. Furthermore, single-station N2 involvement (N2a) exhibited a better prognosis than multistation N2 involvement (N2b) in both clinical and pathologic classifications, and the differences between all neighboring nodal subcategories were highly significant. The prognostic differences between N2a and N2b were robust and consistent across resection status, histologic type, T category, and geographic region. CONCLUSIONS: The current N descriptors should be maintained, with the addition of new subdescriptors to N2 for single-station involvement (N2a) and multiple-station involvement (N2b).

The International Association for the Study of Lung Cancer Pleural Mesothelioma Staging Project: Updated Modeling of Prognostic Factors in Pleural Mesothelioma.

INTRODUCTION: The International Association for the Study of Lung Cancer developed an international pleural mesothelioma database to improve staging. Data entered from 1995 to 2009 (training data set) were analyzed previously to evaluate supplemental prognostic factors. We evaluated these factors with new clinical data to determine whether the previous models could be improved. METHODS: Patients entered into the database from 2009 to 2019 (validation cohort) were assessed for the association between previous prognosticators and overall survival using Cox proportional hazards regression with bidirectional stepwise selection. Additional variables were analyzed and models were compared using Harrell's C-index. RESULTS: The training data set included 3101 patients and the validation cohort, 1733 patients. For the multivariable pathologic staging model applied to the training cohort, C-index was 0.68 (95% confidence interval [CI]: 0.656-0.705). For the validation data set (n = 497), C-index was 0.650 (95% CI: 0.614-0.685), and pathologic stage, histologic diagnosis, sex, adjuvant therapy, and platelet count were independently associated with survival. Adding anemia to the model increased the C-index to 0.652 (95% CI: 0.618-0.686). A basic presentation model including all parameters before staging yielded a C-index of 0.668 (95% CI: 0.641-0.695). In comparison, the European Organization for Research and Treatment of Cancer model yielded C-indices of 0.550 (95% CI: 0.511-0.589) and 0.577 (95% CI: 0.550-0.604) for pathologic staging and presentation models, respectively. CONCLUSIONS: Although significant predictors differed slightly, the International Association for the Study of Lung Cancer training model performed well in the validation set and better than the model of the European Organization for Research and Treatment of Cancer. International collaboration is critical to improve outcomes in this rare disease.

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 Lung Cancer Staging Project: Overview of Challenges and Opportunities in Revising the Nodal Classification of Lung Cancer.

The status of lymph node involvement is a major component of the TNM staging system. The N categories for lung cancer have remained unchanged since the fourth edition of the TNM staging system, partly because of differences in nodal mapping nomenclature, partly because of insufficient details to verify possible alternative approaches for staging. In preparation for the rigorous analysis of the International Association for the Study of Lung Cancer database necessary for the ninth edition TNM staging system, members of the N-Descriptors Subcommittee of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee reviewed the evidence for alternative approaches to categorizing the extent of lymph node involvement with lung cancer, which is currently based solely on the anatomical location of lymph node metastasis. We reviewed the literature focusing on NSCLC to stimulate dialogue and mutual understanding among subcommittee members engaged in developing the ninth edition TNM staging system for lung cancer, which has been proposed for adoption by the American Joint Committee on Cancer and Union for International Cancer Control in 2024. The discussion of the range of possible revision options for the N categories, including the pros and cons of counting lymph nodes, lymph node stations, or lymph node zones, also provides transparency to the process, explaining why certain options may be discarded, others deferred for future consideration. Finally, we provide a preliminary discussion of the future directions that the N-Descriptors Subcommittee might consider for the 10th edition and beyond.

Oncologic Outcomes of Patients With Resected T3N0M0 Non-small Cell Lung Cancer.

In the eighth edition TNM staging, the T3N0M0 category represents a heterogeneous group of non-small cell lung cancers (NSCLC). This study aims to compare the oncologic outcomes associated with individual T3 features. We performed a single-institution, retrospective analysis of 280 consecutive patients with pT3N0M0 NSCLC. Multivariate regression models were used to estimate associations of clinical factors with oncologic outcomes. The patients were grouped according to their T3 features into 4 prognostic groups: chest wall infiltration (CWI-PG), largest diameter >5 cm and ≤7 cm (Size-PG), presence of a satellite nodule (SN-PG), and all other T3 features. Overall survival (OS) and progression-free survival (PFS) were estimated using Kaplan-Meier and Cox proportional hazard analyses. Tumors were most often classified as T3N0M0 by size (156 patients, 55.7%), and the highest rate of incomplete resection occurred in patients with CWI (n = 7, 25.9%). In multivariate analysis, CWI (hazard ratio [HR] 2.45, 95% confidence interval [CI] 1.36, 4.44), incomplete resection (HR 3.01, 95% CI 1.29, 7.05), and age >65 (HR 1.6; 95% CI 1.08, 2.38) were independently associated with worse OS, and female sex was associated with better OS (HR 0.6, 95% CI 0.42, 0.87). The CWI-PG had poorer OS when compared with each of the other prognostic groups (P < 0.05), and the Size-PG had inferior OS when compared with the SN-PG (P = 0.039). This single-center study demonstrated significant differences in OS and PFS between patients with different T3 classifying features and suggest that further subdivision of the T3 category should be considered.

The IASLC Lung Cancer Staging Project: Analysis of Resection Margin Status and Proposals for Residual Tumor Descriptors for Non-Small Cell Lung Cancer.

OBJECTIVE: Our aim was to validate the prognostic relevance in NSCLC of potential residual tumor (R) descriptors, including the proposed International Association for the Study of Lung Cancer definition for uncertain resection, referred to as R(un). METHODS: A total of 14,712 patients undergoing resection with full R status and survival were analyzed. The following were also evaluated: whether fewer than three N2 stations were explored, lobe-specific nodal dissection, extracapsular extension, highest lymph node station status, carcinoma in situ at the bronchial resection margin, and pleural lavage cytologic examination result. Revised categories of R0, R(un), R1, and R2 were tested for survival impact. RESULTS: In all, 14,293 cases were R0, 263 were R1, and 156 were R2 (median survivals not reached, 33 months, and 29 months, respectively). R status correlated with T and N categories. A total of 9290 cases (63%) had three or more N2 stations explored and 6641 cases (45%) had lobe-specific nodal dissection, correlated with increasing pN2. Extracapsular extension was present in 62 of 364 cases with available data (17%). The highest station was positive in 942 cases (6.4%). The pleural lavage cytologic examination result was positive in 59 of 1705 cases (3.5%): 13 had carcinoma in situ at the bronchial resection margin. After reassignment because of inadequate nodal staging in 56% of cases, 6070 cases were R0, 8185 were R(un), 301 were R1, and 156 were R2. In node-positive cases, the median survival times were 70, 50, and 30 months for R0, R(un) (p < 0.0001), and R1 (p < 0.001), respectively, with no significant difference between R0 and R(un) in pN0 cases. CONCLUSIONS: R descriptors have prognostic relevance, with R(un) survival stratifying between R0 and R1. Therefore, a detailed evaluation of R factor is of particular importance in the design and analyses of clinical trials of adjuvant therapies.

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 for International 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.

Recommendations for uniform definitions of surgical techniques for malignant pleural mesothelioma: a consensus report of the international association for the study of lung cancer international staging committee and the international mesothelioma interest group.

INTRODUCTION: Extrapleural pneumonectomy has been well defined; however, surgeons vary regarding the surgical extent and goals of "pleurectomy/decortication" (P/D). We explored mesothelioma surgeons' concepts of P/D with the aim of unifying surgical nomenclature. METHODS: A web-based survey was administered to surgeons who operated on malignant pleural mesothelioma (MPM) for diagnosis, staging, palliation, or cytoreduction. One hundred thirty surgeons from 59 medical centers were included. Surgeons who did not perform surgery for MPM within the last year were excluded. RESULTS: There were 62 (48%) respondents from 39 medical centers in 14 countries. The mean number of patients with MPM seen annually at each medical center was 46, and the mean annual number of cytoreductive procedures performed per surgeon was 8. Most (88%) agreed that the goal of cytoreductive surgery should be macroscopic complete resection of tumor. P/D was defined as resection of parietal and visceral pleura with the aim of achieving macroscopic complete resection by 72% of respondents. If the diaphragm or pericardium required resection, 64% preferred the term "radical P/D," whereas "P/D" (40%) or "total pleurectomy" (39%) was preferred if these structures were not removed. Most surgeons believed that extrapleural pneumonectomy (90%) or "radical P/D" (68%) could provide adequate cytoreduction, whereas only 23% thought that P/D could. CONCLUSIONS: There was significant variation regarding surgical nomenclature for procedures for MPM. The International Staging Committee of the International Association for the Study of Lung Cancer and the International Mesothelioma Interest Group recommend that P/D should aim to remove all macroscopic tumor involving the parietal and visceral pleura and should be termed "extended" P/D when the diaphragm or pericardium is resected.

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.