The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for Revision of the Classification of Residual Tumor After Resection for the Forthcoming (Ninth) Edition of the TNM Classification of Lung Cancer.

INTRODUCTION: The goal of surgical resection is to completely remove a cancer; it is useful to have a system to describe how well this was accomplished. This is captured by the residual tumor (R) classification, which is separate from the TNM classification that describes the anatomic extent of a cancer independent of treatment. The traditional R-classification designates as R0 a complete resection, as R1 a macroscopically complete resection but with microscopic tumor at the surgical margin, and as R2 a resection that leaves gross tumor behind. For lung cancer, an additional category encompasses situations in which the presence of residual tumor is uncertain. METHODS: This paper represents a comprehensive review of evidence regarding these R categories and the descriptors thereof, focusing on studies published after the year 2000 and with adjustment for potential confounders. RESULTS: Consistent discrimination between complete, uncertain, and incomplete resection is revealed with respect to overall survival. Evidence regarding specific descriptors is generally somewhat limited and only partially consistent; nevertheless, the data suggest retaining all descriptors but with clarifications to address ambiguities. CONCLUSION: On the basis of this review, the R-classification for the ninth edition of stage classification of lung cancer is proposed to retain the same overall framework and descriptors, with more precise definitions of descriptors. These refinements should facilitate application and further research.

The International Association for the Study of Lung Cancer (IASLC) Staging Project for Lung Cancer: Recommendation to Introduce Spread Through Air Spaces as a Histologic Descriptor in the Ninth Edition of the TNM Classification of Lung Cancer. Analysis of 4061 Pathologic Stage I NSCLC.

INTRODUCTION: Spread through air spaces (STAS) consists of lung cancer tumor cells that are identified beyond the edge of the main tumor in the surrounding alveolar parenchyma. It has been reported by meta-analyses to be an independent prognostic factor in the major histologic types of lung cancer, but its role in lung cancer staging is not established. METHODS: To assess the clinical importance of STAS in lung cancer staging, we evaluated 4061 surgically resected pathologic stage I R0 NSCLC collected from around the world in the International Association for the Study of Lung Cancer database. We focused on whether STAS could be a useful additional histologic descriptor to supplement the existing ones of visceral pleural invasion (VPI) and lymphovascular invasion (LVI). RESULTS: STAS was found in 930 of 4061 of the pathologic stage I NSCLC (22.9%). Patients with tumors exhibiting STAS had a significantly worse recurrence-free and overall survival in both univariate and multivariable analyses involving cohorts consisting of all NSCLC, specific histologic types (adenocarcinoma and other NSCLC), and extent of resection (lobar and sublobar). Interestingly, STAS was independent of VPI in all of these analyses. CONCLUSIONS: These data support our recommendation to include STAS as a histologic descriptor for the Ninth Edition of the TNM Classification of Lung Cancer. Hopefully, gathering these data in the coming years will facilitate a thorough analysis to better understand the relative impact of STAS, LVI, and VPI on lung cancer staging for the Tenth Edition TNM Stage Classification.

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 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).

Video-assisted mediastinoscopic lymphadenectomy (VAMLA): Mature results for staging non-small cell lung cancer with normal mediastinum.

OBJECTIVES: The aim of this study is to analyze the accuracy of video-assisted mediastinoscopic lymphadenectomy (VAMLA) and the unsuspected (u) N2/3 rates in patients with non-small cell lung cancer (NSCLC) and normal mediastinum by integrated positron emission tomography-computed tomography. METHODS: Prospective observational single-center study of 603 consecutive VAMLAs from 2010 to 2022. EXCLUSION CRITERIA: other indications (n = 32), tumors different from NSCLC (n = 91), and clinical (c) N2/3 tumors by positron emission tomography-computed tomography (n = 46). Systematic nodal dissection was the gold standard to validate negative VAMLAs. Those patients with negative VAMLA and missing reference standard test were excluded. uN2/3 rates were analyzed in the global series and in the subgroups of tumors according to their clinical nodal and tumor categories. Pathologic findings were reviewed, and staging values were calculated. RESULTS: Three hundred eighty-three patients with cN0/1 NSCLC underwent VAMLA. Staging values of VAMLA were: sensitivity, 0.98 (95% CI, 0.92-0.99); negative predictive value, 0.99 (95% CI, 0.98-1); and diagnostic accuracy, 0.99 (95% CI, 0.98-1). The uN2/3 rate for the whole series (N = 383) was 18.8%. The uN2/3 rates according to presurgical nodal and tumor categories determined by positron emission tomography computed tomography were: 3.6% (4 out of 111) in cT1N0; 16.3% (18 out of 110) in cT2N0; 10.25% (4 out of 39) in cT3N0; and 32% (7 out of 22) in cT4N0. Forty-two percent (39 out of 93) in cN1; complication rate was 7%. CONCLUSIONS: This series of NSCLC with normal mediastinum staged by VAMLA demonstrates a high accuracy of this technique and a high rate of uN2/3 disease (specially in cN1 and cT4N0). VAMLA could be considered the reference staging procedure for staging cN0/1 NSCLC.

The International Association for the Study of Lung Cancer Thymic Epithelial Tumors Staging Project: Proposals for the N and the M Components for the Forthcoming (Ninth) Edition of the TNM Classification of Malignant Tumors.

INTRODUCTION: Stage classification is an important underpinning of management in patients with cancer and rests on a combination of three components-T for tumor extent, N for nodal involvement, and M for distant metastases. This article details the revision of the N and the M components of thymic epithelial tumors for the ninth edition of the TNM classification of malignant tumors proposed by the Thymic Domain of the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee. METHODS: The N and M components of the eighth edition staging system were verified by a large international collaborative data source through a data-driven analysis. A total of 9147 cases were included for analysis, including 7662 thymomas, 1345 thymic carcinomas, and 140 neuroendocrine thymic tumors. RESULTS: Lymph node involvement rates were 1.5% in thymomas and 17.6% and 27.7% in thymic carcinomas and neuroendocrine thymic tumors, respectively. Rates of lymph node metastasis were increasingly higher in tumors with higher T stage and higher-grade histologic type. Survival analysis validated the differences in the N and M categories proposed in the eighth edition staging system. Good discrimination in overall survival was detected among pathologic (p)N and pM categories in patients with thymoma and thymic carcinoma. CONCLUSIONS: No changes are proposed from the eighth edition for the N and M components. The proposed stage classification will provide a useful tool for management of the disease among the global thymic community.

EBUS-TBNA for mediastinal staging of centrally located T1N0M0 non-small cell lung cancer clinically staged with PET/CT.

BACKGROUND AND OBJECTIVE: To evaluate the diagnostic accuracy and clinical usefulness of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for mediastinal staging of centrally located T1N0M0 non-small cell lung cancer (NSCLC) clinically staged with positron emission tomography/computed tomography (PET/CT). METHODS: We conducted a study that included patients with centrally located T1N0M0 NSCLC, clinically staged with PET/CT who underwent EBUS-TBNA for mediastinal staging. Patients with negative EBUS-TBNA underwent mediastinoscopy, video-assisted mediastinoscopic lymphadenectomy (VAMLA) and/or lung resection with systematic nodal dissection, that were considered the gold standard. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), overall accuracy of EBUS-TBNA for diagnosing mediastinal metastases (N2 disease) and the number needed to treat (NNT: number of patients needed to undergo EBUS-TBNA to avoid a case of pathologic N2 disease after resection) were calculated. RESULTS: One-hundred eighteen patients were included. EBUS-TBNA proved N2 disease in four patients. In the remaining 114 patients who underwent mediastinoscopy, VAMLA and/or resection there were two cases of N2 (N2 prevalence 5.1%). The sensitivity, specificity, NPV, PPV and overall accuracy for diagnosing mediastinal metastases (N2 disease) were of 66%, 100%, 98%, 100% and 98%, respectively. The NNT was 31 (95% CI: 15-119). CONCLUSION: EBUS-TBNA in patients with central clinically staged T1N0M0 NSCLC presents a good diagnostic accuracy for mediastinal staging, even in a population with low prevalence of N2 disease. Therefore, its indication should be considered in the management of even these early lung cancers.

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 Thymic Epithelial Tumors Staging Project: An Overview of the Central Database Informing Revision of the Forthcoming (Ninth) Edition of the TNM Classification of Malignant Tumors.

INTRODUCTION: In 2014, a TNM-based system for thymic epithelial tumors was proposed. The TNM stage classification system was published as a result of a joint project from the International Association for the Study of Lung Cancer and the International Thymic Malignancy Interest Group for the eighth edition of the American Joint Commission on Cancer and the Union for International Cancer Control stage classification system. The Thymic Domain of the Staging and Prognostic Factors Committee of the International Association for the Study of Lung Cancer received the mandate to make proposals for the ninth edition of the TNM stage classification. METHODS: A central thymic database was collected by the Cancer Research And Biostatistics with the contribution of the major thymic associations in the world. RESULTS: A total of 11,347 patients were collected. Submitting organizations were the following: Japanese Association for Research in the Thymus, European Society of Thoracic Surgeons, Chinese Alliance for Research in Thymoma, Korean Association for Research in the Thymus, International Thymic Malignancy Interest Group, and Réseau tumeurs THYMiques et Cancer. Additional contributions came from centers in the United States, United Kingdom, Turkey, Australia, Spain, and Italy. A total of 9147 cases were eligible for analysis. Eligible cases for analysis came from Asia and Australia (5628 cases, 61.5%), Europe (3113 cases, 34.0%), and North America (406 cases, 4.4%). CONCLUSIONS: This report provides an overview of the database that has informed the proposals for the updated T, N, and M components and the stage groups for the ninth TNM of malignant tumors.

The International Association for the Study of Lung Cancer Thymic Epithelial Tumor Staging Project: A Re-Assessment of the International Thymic Malignancy Interest Group/International Association for the Study of Lung Cancer Lymph Node Map for Thymic Epithelial Tumors for the Forthcoming Ninth Edition of the TNM Classification of Malignant Tumors.

INTRODUCTION: A lymph node map is the pillar on which accurate assignment and documentation of nodal classification stands. The International Thymic Malignancy Interest Group created the first map for thymic epithelial malignancies in conjunction with the eighth edition of the TNM classification, representing the first official TNM classification of thymic epithelial malignancies. The map was based on clinical experience and published studies, but it was largely empirical because of limited available data. Dissemination of the map and implementation of a standard thymic stage classification across the world in 2017 have provided more consistent and granular data. METHODS: More than twice as many cases of node involvement are available for analysis in the current database compared with that of the eighth edition database, allowing validation of many aspects of the eighth edition map. This article details the process and considerations for refinement of the thymic map for the ninth TNM used by the Thymic Domain of the Staging and Prognostic Factors Committee of the International Association for the Study of Lung Cancer. The committee evaluated a large international collaborative data set, published anatomical and clinical studies pertaining to lymph node spread from thymic epithelial tumors, in conjunction with the analysis underlying refinements of the TNM components for the ninth edition TNM classification. RESULTS: The node map boundaries of the N1 and N2 categories remain unchanged. Visual clarifications have been added to the nomenclature of nodal stations within these regions. CONCLUSIONS: On the basis of the recommendation to keep the N component unchanged for the ninth edition TNM classification, the lymph node map remains unchanged as well; however, clarifications have been added to facilitate clinical use.

The International Association for the Study of Lung Cancer Thymic Epithelial Tumors Staging Project: Proposal for a Stage Classification for the Forthcoming (Ninth) Edition of the TNM Classification of Malignant Tumors.

INTRODUCTION: A TNM-based system for all types of thymic epithelial tumors was introduced in the eighth edition of the TNM classification of thoracic malignancies. The Thymic Domain of the Staging and Prognostic Factors Committee of the International Association for the Study of Lung Cancer, composed of multispecialty international experts, was charged to develop proposals for the ninth edition. This article outlines the proposed definitions for the T, the N, and the M components and their combination into stage groups. METHODS: A large central database of 11,347 patients with thymic epithelial tumors was assembled thanks to the contribution of the major thymic organizations worldwide and analyses were carried out for the T, the N, and the M components and the stage groups. Overall survival was the outcome measure for patients with completely and incompletely resected tumors, and recurrence for those with complete resection. When the number of patients was sufficient, analyses were performed separately for thymomas, thymic carcinomas, and neuroendocrine thymic tumors. RESULTS: Tumor size is included in the T1 category as T1a (≤5cm) and T1b (>5 cm); the mediastinal pleura is dropped as a T descriptor; invasion of the lung or phrenic nerve is reclassified as T2 (instead of T3). No changes are proposed for the N and the M components from the eighth edition. The stage groups remain the same. CONCLUSIONS: The proposed changes for the ninth edition of the TNM classification set the stage for further progress in the future for these rare tumors.

The International Association for the Study of Lung Cancer Thymic Epithelial Tumor Staging Project: Proposal for the T Component for the Forthcoming (Ninth) Edition of the TNM Classification of Malignant Tumors.

INTRODUCTION: A TNM-based stage classification system of thymic epithelial tumors was adopted for the eighth edition of the stage classification of malignant tumors. The Thymic Domain of the Staging and Prognostics Factor Committee of the International Association for the Study of Lung Cancer developed a new database with the purpose to make proposals for the ninth edition stage classification system. This article outlines the proposed definitions for the T categories for the ninth edition TNM stage classification of thymic malignancies. METHODS: A worldwide collective database of 11,347 patients with thymic epithelial tumors was assembled. Analysis was performed on 9147 patients with available survival data. Overall survival, freedom-from-recurrence, and cumulative incidence of recurrence were used as outcome measures. Analysis was performed separately for thymomas, thymic carcinomas, and neuroendocrine thymic tumors. RESULTS: Proposals for the T categories include the following: T1 category is divided into T1a (≤5 cm) and T1b (>5 cm), irrespective of mediastinal pleura invasion; T2 includes direct invasion of the pericardium, lung, or phrenic nerve; T3 denotes direct invasion of the brachiocephalic vein, superior vena cava, chest wall, or extrapericardial pulmonary arteries and veins; and T4 category remains the same as in the eighth edition classification, involving direct invasion of the aorta and arch vessels, intrapericardial pulmonary arteries and veins, myocardium, trachea, or esophagus. CONCLUSIONS: The proposed T categories for the ninth edition of the TNM classification provide good discrimination in outcome for the T component of the TNM-based stage system of thymic epithelial tumors.

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.

Case report: Primary pleural squamous cell carcinoma in a 68-year-old male.

Introduction: Primary pleural squamous cell carcinoma (PPSCC) is a sporadic disease that is rarely reported in the literature. Due to its low incidence, the pathogenesis of PPSCC is unknown. Case summary: We report a case of a 68-year-old male with PPSCC and sizable pulmonary bullae. Two months after complete resection of both lesions, a total dose of 50 Gy radiotherapy was administered over the operative field. After more than a year of follow-up, the patient is in steady condition without any sign of recurrence. Conclusion: Since PPSCC is rarely reported, our case proposed that complete surgical resection combined with radiotherapy may be a promising therapeutic approach.