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.

So Now We Know-Reflections on the Extent of Resection for Stage I Lung Cancer

Lobectomy has been the standard treatment for stage I lung cancer in healthy patients, largely based on a randomized trial published in 1995. Nevertheless, research has continued regarding the role of sublobar resection. Three additional randomized trials addressing resection extent in healthy patients have recently been published. These 4 trials involve differences in design, eligibility, interventions, and intraoperative processes. Patients were ineligible if intraoperative assessment demonstrated stage > IA or inadequate resection margins. All trials consistently show no differences in perioperative morbidity, mortality, and postoperative changes in lung function between sublobar resection and lobectomy-consistent with other nonrandomized evidence. Long-term outcomes are generally encouraging of lesser resection, but some inconsistencies are apparent. The 2 larger recent trials demonstrated no overall survival difference while the others suggested better survival after lobectomy versus sublobar resection. Recurrence-free survival was found to be the same after lobectomy versus sublobar resection in 3 trials, despite higher locoregional recurrences after sublobar resection. The low 5-year recurrence-free survival (64%, regardless of resection extent) in 1 recent trial highlights the need for further optimization. Thus, there is high-level evidence that sublobar resection is a reasonable alternative to lobectomy in healthy patients. However, variability in long-term results suggests that aspects of patients, tumors and interventions need to be better understood. Therefore, we propose to apply sublobar resection cautiously; especially because there are no short-term benefits. Sublobar resection requires careful attention to intraoperative details (nodes, margins), and may be best suited for less aggressive (eg, ground glass, slow growing) tumors.

Postoperative Radiation Therapy for Thymic Carcinoma: An Analysis of the International Thymic Malignancy Interest Group/European Society of Thoracic Surgeons Database

INTRODUCTION

R0 resection and radiation therapy have been associated with improved overall survival (OS) in patients with thymic carcinoma (TC). Here, we analyzed which subgroups of patients derive the greatest benefit from postoperative radiation therapy (PORT).

METHODS

Clinical, pathologic, treatment, and survival information of 462 patients with TC from the International Thymic Malignancy Interest Group/European Society of Thoracic Surgeons database were analyzed. Variables included age, sex, continent of treatment, paraneoplastic syndrome, carcinoma subtype, tumor size, pathologic Masaoka stage, resection status, and use of chemotherapy. OS was the primary end point using the Kaplan-Meier method. Time to recurrence (TTR) was the secondary end point using a competing risk analysis. A 3-month landmark analysis was performed.

RESULTS

PORT was associated with a significant OS benefit (5-y OS 68% versus 53%, p = 0.002). In patients with R0 resection, PORT was associated with increased OS for advanced (stages III-IV, p = 0.04), but not early (stages I-II, p = 0.14) stage TC. In patients with an R1/2 resection of advanced-stage TC, PORT was associated with significantly longer OS (5-y OS 53% versus 38%; p < 0.001). Subset analyses did not reveal clear associations of PORT with TTR. On multivariable analysis, lower pathologic stage, PORT, and R0 resection status were associated with an OS benefit, whereas only higher age and lower pathologic stage had an association with longer TTR.

CONCLUSIONS

In the largest individual patient data set on patients with TC reported to date, PORT was associated with a meaningful OS benefit in patients with advanced-stage TC after an R0 or R1/2 resection.

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.

Impact of the COVID-19 Pandemic on Lung Cancer Screening Processes in a Northeast Tertiary Health Care Network

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic disrupted health care systems, including implementation of lung cancer screening programs. The impact and recovery from this disruption on screening processes is not well appreciated. Herein, the radiology database of a Northeast tertiary health care network was reviewed before and during the pandemic (2013-2022). In the 3 months before the pandemic, an average of 77.3 lung cancer screening with computed tomography scans (LCS-CT) were performed per month. The average dropped to 23.3 between April and June of 2020, whereas COVID-19 hospitalizations peaked at 1604. By July, average hospitalizations dropped to 50, and LCS-CTs rose to >110 per month for the remaining year. LCS-CTs did not decline during COVID-19 surges in December of 2021 and 2022. The LCS-CT performance grew by 4.5% in 2020, 69.6% in 2021, and 27.0% in 2022, exceeding projected growth by 722 examinations. This resiliency indicates a potentially smaller impact of COVID-19 on lung cancer diagnoses than initially feared.

International reproducibility study of thymic epithelial tumors staging: pT stage is an issue. proposals for improvement. A RYTHMIC/ITMIG study

INTRODUCTION

Pathologists are staging thymic epithelial tumors (TET) according to the 8th UICC/AJCC TNM system. Within the French RYTHMIC network, dedicated to TET, agreement on pathologic tumor stage (pT) among the pathology panelists was difficult. The aim of our study was to determine the interobserver reproducibility of pT at an international level, to explore the source of discrepancies and potential interventions to address these.

METHODS

An international panel of pathologists was recruited through the International Thymic Malignancy Interest Group (ITMIG). The study focused on invasion of mediastinal pleura, pericardium, and lung. From a cohort of cases identified as challenging within the RYTHMIC network, we chose a series of test and validation cases (n = 5 and 10, respectively).

RESULTS

Reproducibility of the pT stage was also challenging at an international level as none of the 15 cases was classified as the same pT stage by all ITMIG pathologists. The agreement rose from slight (κ = 0.13) to moderate (κ = 0.48) between test and validation series. Discussion among the expert pathologists pinpointed two major reasons underlying discrepancies: 1) Thymomas growing with their "capsule" and adhering to the pleurae, pericardium, or lung were often misinterpreted as invading these structures. 2) Recognition of the mediastinal pleura was identified as challenging.

CONCLUSION

Our study underlines that the evaluation of the pT stage of TET is problematic and needs to be addressed in more detail in an upcoming TNM classification. The publication of histopathologic images of landmarks, including ancillary tests could improve reproducibility for future TNM classifications.

The IASLC Lung Cancer Staging Project: Proposals for the Revision of the M Descriptors in the Forthcoming 9th edition of the TNM Classification of Lung Cancer

INTRODUCTION

This study analyzed all metastatic categories of the current tumor, node, and metastasis (TNM) classification of non-small cell lung cancer to propose modifications of the M component in the next edition (9th) of the classification.

METHODS

A database of 124,581 patients diagnosed between 2011 and 2019 was established; of these, 14,937 with NSCLC in stage IVA-IVB were available for this analysis. Overall survival was calculated using the Kaplan-Meier method, and prognosis assessed using multivariable-adjusted Cox proportional hazards regression.

RESULTS

The 8th edition M categories demonstrated good discrimination in the 9th edition dataset. Assessments demonstrated that an increasing number of metastatic lesions was associated with decreasing prognosis; because this appears 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 seen with an increasing number of organ systems involved. Multiple assessments, including after adjustment for potential confounders, demonstrated that patients with 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 8th edition M1a and M1b categories, that 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).

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.

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.

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.

Autologous humanized PDX modeling for immuno-oncology recapitulates features of the human tumor microenvironment

BACKGROUND

Interactions between immune and tumor cells are critical to determining cancer progression and response. In addition, preclinical prediction of immune-related drug efficacy is limited by interspecies differences between human and mouse, as well as inter-person germline and somatic variation. To address these gaps, we developed an autologous system that models the tumor microenvironment (TME) from individual patients with solid tumors.

METHOD

With patient-derived bone marrow hematopoietic stem and progenitor cells (HSPCs), we engrafted a patient's hematopoietic system in MISTRG6 mice, followed by transfer of patient-derived xenograft (PDX) tissue, providing a fully genetically matched model to recapitulate the individual's TME. We used this system to prospectively study tumor-immune interactions in patients with solid tumor.

RESULTS

Autologous PDX mice generated innate and adaptive immune populations; these cells populated the TME; and tumors from autologously engrafted mice grew larger than tumors from non-engrafted littermate controls. Single-cell transcriptomics revealed a prominent vascular endothelial growth factor A (VEGFA) signature in TME myeloid cells, and inhibition of human VEGF-A abrogated enhanced growth.

CONCLUSIONS

Humanization of the interleukin 6 locus in MISTRG6 mice enhances HSPC engraftment, making it feasible to model tumor-immune interactions in an autologous manner from a bedside bone marrow aspirate. The TME from these autologous tumors display hallmarks of the human TME including innate and adaptive immune activation and provide a platform for preclinical drug testing.

Abstract NG11: Autologous humanized PDX modeling for immuno-oncology recapitulates the human tumor microenvironment

The immune milieu within tumors, consisting of diverse cell types including adaptive immune cells as well as macrophages, dendritic cells, natural killer and other innate immune cells, is critical to determining cancer outcome. However, the immune tumor microenvironment (TME) has been challenging to model, owing to inherent inter-species differences. While humanized mice can support human immune cells, the hematopoietic stem and progenitor cells (HSPCs) used for transplantation have been largely limited to fetal or neonatal stem cell sources, necessitating allogeneic experiments with limited applicability. We sought to develop a method to pre-clinically model an individual adult cancer patient, capturing the unique features of an individual such as germline genetic determinants of immune function and somatic tumor heterogeneity, and creating an autologous system.

MISTRG6 may be engrafted with low numbers of HSPCs. When engrafted with equivalent numbers of CD34+ cells from human fetal liver (FL), neonatal cord blood (CB), adult mobilized peripheral blood (MPB), or adult bone marrow (BM), MISTRG6 mice harbored greatly increased human hematopoietic cells as a proportion of total hematopoietic cells in peripheral blood compared with NOD-scid-gamma (NSG) and MISTRG mice (p&lt;0.0001). We found that MISTRG6 mice could be engrafted with as few as 1,000 human HSPCs, arguably 100x more efficient than other models, and achieve robust hematopoietic transplantation after 10-12 weeks, indicating the efficiency of this strain in supporting the growth of hematopoietic cells. To better elucidate the mechanism responsible for this enhanced human engraftment, we enumerated human and mouse hematopoietic progenitors in BM of NSG, MISTRG, and MISTRG6 mice. Human progenitors, including CD34+ and CD34+CD38+ cells, were significantly increased in both frequency and absolute numbers in MISTRG and MISTRG6 mice compared with NSG mice (p&lt;0.001), and mouse hematopoietic lin(-)cKit+ (LK) and lin(-)Sca1+cKit+ (LSK) progenitor populations were significantly diminished (p&lt;0.0001), suggesting that the enhanced hematopoietic engraftment observed in MISTRG6 is, in part, a consequence of increased human progenitor frequency and reduced mouse competition.

MISTRG6 allows efficient engraftment of patient derived HSPCs. We sought to apply this improved engraftment prospectively to model individual patients’ TME through collection of BM-derived CD34+ cells from patients under active treatment along with tumor tissue from the same patient. At two cancer centers, we enrolled patients with melanoma, NSCLC, PDAC, and HNSCC to provide BM aspirate, peripheral blood, and tumor tissue. CD34+ cells were isolated from BM aspirates and tumor tissue was utilized to generate PDXs. Overall, 71 patients were enrolled, 46 melanoma, 19 NSCLC, 4 PDAC, 2 HNSCC, ages 22-85, 39% females. These yielded autologous, immune-reconstituted MISTRG6 hosts from 14 melanoma, 5 NSCLC, 2 PDAC, and 1 HNSCC patients. Autologously engrafted MISTRG6 mice displayed the gamut of human immune cells of adaptive and innate types in PB at 7 weeks of age. Notably, this included CD33+ myeloid cells such as CD14+CD16− classical, CD14+CD16+ intermediate, and CD14−CD16+ non-classical monocytes. Moreover, human dendritic cells (DCs), key innate immune cells for initiation of anti-tumor responses were readily detected by flow cytometry in spleens of autologously-engrafted mice, including cDC1, cDC2, and pDC cells.

MISTRG6 mice bearing a patient’s hematopoietic cells support autologous PDX growth. Having achieved successful engraftment of patient hematopoietic systems in MISTRG6 hosts, we next subcutaneously introduced the patient’s matched PDX tumor tissue to generate autologously engrafted PDX mice. For most patients, tumors grown in autologous HSPC-engrafted hosts were significantly larger than in non-engrafted hosts. Multicolor immunofluorescence staining of PDX tumors demonstrated that human immune cells, including CD3+ T cells, CD14+ and HLA-DR+ myeloid cells, penetrated deeply into the tumor and co-localized with tumor cells as well as with other engrafted immune cells. Indeed, HLA-DR+CD14+macrophages and HLA-DR+CD14(-) dendritic cells were present, and direct physical interaction between T cells and macrophages was evident. Using whole-exome sequencing, we found that 225 somatic changes were shared between patient Mel738’s surgical resection sample, two PDX tumors from non-engrafted mice lacking human immune cells, and two PDX tumors from mice with autologous engraftment. 5 additional changes were shared among the tumor samples and absent from the cell line, with 36 additional mutations being specific to the cell line. These data underscore the capacity of the autologous PDX method to recapitulate the somatic heterogeneity that the patient tumor possesses.

Autologous MISTRG6 mice display diverse human immune cell populations and recapitulate an immunosuppressive TME. To fully characterize the autologous MISTRG6 model and investigate mechanisms by which autologous human immune cells enhance tumor growth, we performed single cell transcriptomics on hCD45+-enriched cells from blood and tumor isolated from autologous mice. This revealed 16 distinct cell subtypes, including 3 myeloid, 2 NK cell, 2 CD8 T cell, 3 CD4 T cell, 2 cycling lymphocyte, 1 B cell, and 3 melanoma cell clusters. Subclustering of myeloid cells revealed 9 distinct clusters including 4 monocyte, 4 macrophage, and 1 DC cluster. Comparing CD8 T cells present in blood versus tumor revealed that the most differentially expressed genes (DEGs) found in blood were characteristic of naïve T cells, while genes present in the TME were consistent with activated T cell phenotypes. In addition, sub-clustering revealed 3 distinct CD8 T cell types that included two activated-like populations, with one of these populations also expressing an activated/exhausted program typified by expression of PDCD1, LAG3, and GZMA. Naïve-like T cells were most highly represented in the blood, while activated and activated/exhausted-like genes were more present in the TME.

Inhibiting the actions of human VEGF-A blocks the enhanced tumor growth in autologously engrafted mice. Notably, IPA Upstream Regulator Analysis identified VEGFA, a central player in tumor growth and vascularization, as a key upstream inducer of genes in the TME (FDR p= 5.65 × 10−13). Indeed, expression VEGFA itself was nearly absent in blood but induced in the TME, especially in macrophages and VEGFA targets were highly represented among the DEGs between tumor and blood.To test the relevance of VEGF-A in the TME, we selectively blocked human VEGF-A by treating autologous mice humanized from Mel2 with the anti-hVEGF-A antibody bevacizumab that has high affinity for human VEGF-A yet low affinity for mouse VEGF-A. PDXs grown in untreated autologously engrafted MISTRG6 mice grew significantly larger than those in non-engrafted littermate control hosts (p&lt;0.05). When treated with bevacizumab, the enhanced tumor growth was significantly abrogated, with bevacizumab-treated mice bearing significantly smaller tumors compared with controls (p&lt;0.001).

Future Directions: Thus, these in silico and in vivo results suggest that human VEGF-A production in the autologous TME enhances tumor growth in MISTRG6 PDX models and underscores the utility of the MISTRG6 system for pre-clinical testing of drugs that act on human immune components of the TME. By engrafting mice with bone marrow derived stem cells followed by implantation of tumor derived from the same donor, we have demonstrated that autologous MISTRG6 models recapitulate important features of the human TME, including sufficient immunosuppression to prevent tumor clearance, presence of activated/exhausted T cells, and innate immune cells including DCs, monocytes, NK cells, and macrophages, the latter especially relevant to the production of VEGF-A.

Citation Format: Michael Chiorazzi, Jan Martinek, Bradley Krasnick, Yunjiang Zheng, Keenan Robbins, Rihao Qu, Gabriel Kaufmann, Zachary Skidmore, Laura Henze, Frederic Brösecke, Adam Adonyi, Jun Zhao, Liang Shan, Esen Sefik, Jacqueline Mudd, Ye Bi, S Peter Goedegebuure, Malachi Griffith, Obi Griffith, Abimbola Oyedeji, Sofia Fertuzinhos, Roland Garcia-Milian, Daniel Boffa, Frank Detterbeck, Andrew Dhanasopon, Justin Blasberg, Benjamin Judson, Scott Gettinger, Katerina Politi, Yuval Kluger, A Karolina Palucka, Ryan Fields, Richard A. Flavell. Autologous humanized PDX modeling for immuno-oncology recapitulates the human tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr NG11.

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.

Pretreatment Invasive Nodal Staging in Lung Cancer: Knowledge, Attitudes, and Beliefs Among Academic and Community Physicians

BACKGROUND

Pretreatment invasive nodal staging is paramount for appropriate treatment decisions in non-small cell lung cancer. Despite guidelines recommending when to perform staging, many studies suggest that invasive nodal staging is underused. Attitudes and barriers to guideline-recommended staging are unclear. The National Lung Cancer Roundtable initiated this study to better understand the factors associated with guideline-adherent nodal staging.

RESEARCH QUESTION

What are the knowledge gaps, attitudes, and beliefs of thoracic surgeons and pulmonologists about invasive nodal staging? What are the barriers to guideline-recommended staging?

STUDY DESIGN AND METHODS

A web-based survey of a random sample of pulmonologists and thoracic surgeons identified as members of American College of Chest Physicians (CHEST) was conducted in 2019. Survey domains included knowledge of invasive nodal staging guidelines, attitudes and beliefs toward implementation, and perceived barriers to guideline adherence.

RESULTS

Among 453 responding physicians, 29% were unaware that invasive nodal staging guidelines exist. Among the 320 physicians who knew guidelines exist, attitudes toward the guidelines were favorable, with 91% agreeing guidelines are generalizable and 90% agreeing that recommendations improved their staging and treatment decisions. Approximately 80% responded that guideline recommendations are based on satisfactory levels of scientific evidence, and 50% stated a lack of evidence linking adherence to guidelines to changes in management or better patient outcomes. Nearly 9 in 10 physicians reported at least one barrier to guideline adherence. The most common barriers included patient anxiety associated with treatment delays (62%), difficulty implementing guidelines into routine practice (52%), and time delays of additional testing (51%).

INTERPRETATION

Among physicians who responded to our survey, more than one-quarter were unaware of invasive nodal staging guidelines. Attitudes toward guideline recommendations were positive, although 20% reported insufficient evidence to support staging algorithms. Most physicians reported barriers to implementing guidelines. Multilevel interventions are likely needed to increase rates of guideline-recommended invasive nodal staging.

Management of Stage III Non-Small-Cell Lung Cancer: ASCO Guideline

PURPOSE

To provide evidence-based recommendations to practicing clinicians on management of patients with stage III non-small-cell lung cancer (NSCLC).

METHODS

An Expert Panel of medical oncology, thoracic surgery, radiation oncology, pulmonary oncology, community oncology, research methodology, and advocacy experts was convened to conduct a literature search, which included systematic reviews, meta-analyses, and randomized controlled trials published from 1990 through 2021. Outcomes of interest included survival, disease-free or recurrence-free survival, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 127 relevant studies to inform the evidence base for this guideline.

RECOMMENDATIONS

Evidence-based recommendations were developed to address evaluation and staging workup of patients with suspected stage III NSCLC, surgical management, neoadjuvant and adjuvant approaches, and management of patients with unresectable stage III NSCLC.Additional information is available at www.asco.org/thoracic-cancer-guidelines.

The 2021 WHO Classification of Tumors of the Thymus and Mediastinum: What Is New in Thymic Epithelial, Germ Cell, and Mesenchymal Tumors?

This overview of the fifth edition of the WHO classification of thymic epithelial tumors (including thymomas, thymic carcinomas, and thymic neuroendocrine tumors [NETs]), mediastinal germ cell tumors, and mesenchymal neoplasms aims to (1) list established and new tumor entities and subtypes and (2) focus on diagnostic, molecular, and conceptual advances since publication of the fourth edition in 2015. Diagnostic advances are best exemplified by the immunohistochemical characterization of adenocarcinomas and the recognition of genetic translocations in metaplastic thymomas, rare B2 and B3 thymomas, and hyalinizing clear cell carcinomas. Advancements at the molecular and tumor biological levels of utmost oncological relevance are the findings that thymomas and most thymic carcinomas lack currently targetable mutations, have an extraordinarily low tumor mutational burden, but typically have a programmed death-ligand 1^high phenotype. Finally, data underpinning a conceptual advance are illustrated for the future classification of thymic NETs that may fit into the classification scheme of extrathoracic NETs. Endowed with updated clinical information and state-of-the-art positron emission tomography and computed tomography images, the fifth edition of the WHO classification of thymic epithelial tumors, germ cell tumors, and mesenchymal neoplasms with its wealth of new diagnostic and molecular insights will be a valuable source for pathologists, radiologists, surgeons, and oncologists alike. Therapeutic perspectives and research challenges will be addressed as well.

Report from the European Society of Thoracic Surgeons prospective thymic database 2017: a powerful resource for a collaborative global effort to manage thymic tumours

OBJECTIVES

We queried the European Society of Thoracic Surgeons (ESTS) prospective thymic database for descriptive analysis and for comparison with the ESTS retrospective thymic database (1990-2010).

METHODS

Data were retrieved (January 2007-November 2017) for 1122 patients from 75 ESTS institutions.

RESULTS

There were 484 (65%) thymomas, 207 (28%) thymic carcinomas and 49 (7%) neuroendocrine thymic tumours. Staging (Masaoka) included 483 (67%) stage I and II, 100 (14%) stage III and 70 (10%) stage IV tumours. The new International Association for the Study of Lung Cancer/International Thymic Malignancies Interest Group tumour, node and metastasis (TNM) classification was available for 224 patients and including 177 (85%) stage I-II, 37 (16%) stage IIIA and 10 (4%) stage IIIB tumours. Chemotherapy as induction and adjuvant treatment was used in 14% and 15% of the patients. Radiotherapy was almost exclusively used postoperatively (24%). A minimally invasive surgical approach (video-assisted thoracic surgery/robotic-assisted thoracic surgery) was used in 276 (33%) patients. The overall recurrence rate was 10.8% (N = 38). Compared to the ESTS retrospective database, the increased prevalence of thymic carcinomas (from 9% to 28%) and neuroendocrine thymic tumours (from 2% to 7%), an increase in the use of minimally invasive techniques (from 6% to 34%) and a wider use of chemotherapy as induction (from 9% to 15%) and adjuvant (from 2% to 16%) treatment were observed in the prospective database. The introduction of a set of variables considered essential for the data use ('minimum dataset') resulted in an increased average completeness rate.

CONCLUSIONS

The reported data from the ESTS prospective thymic database confirm the recent trends in the management of thymic tumours. The ESTS prospective thymic database represents a powerful resource open to all ESTS members for the global effort to manage these rare tumours.

Radiation Therapy for Small Cell Lung Cancer: An ASTRO Clinical Practice Guideline

PURPOSE

Several sentinel phase III randomized trials have recently been published challenging traditional radiation therapy (RT) practices for small cell lung cancer (SCLC). This American Society for Radiation Oncology guideline reviews the evidence for thoracic RT and prophylactic cranial irradiation (PCI) for both limited-stage (LS) and extensive-stage (ES) SCLC.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on indications, dose fractionation, techniques and timing of thoracic RT for LS-SCLC, the role of stereotactic body radiation therapy (SBRT) compared with conventional RT in stage I or II node negative SCLC, PCI for LS-SCLC and ES-SCLC, and thoracic consolidation for ES-SCLC. Recommendations were based on a systematic literature review and created using a consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

The task force strongly recommends definitive thoracic RT administered once or twice daily early in the course of treatment for LS-SCLC. Adjuvant RT is conditionally recommended in surgically resected patients with positive margins or nodal metastases. Involved field RT delivered using conformal advanced treatment modalities to postchemotherapy volumes is also strongly recommended. For patients with stage I or II node negative disease, SBRT or conventional fractionation is strongly recommended, and chemotherapy should be delivered before or after SBRT. In LS-SCLC, PCI is strongly recommended for stage II or III patients who responded to chemoradiation, conditionally not recommended for stage I patients, and should be a shared decision for patients at higher risk of neurocognitive toxicities. In ES-SCLC, radiation oncologist consultation for consideration of PCI versus magnetic resonance surveillance is strongly recommended. Lastly, the use of thoracic RT is strongly recommended in select patients with ES-SCLC after chemotherapy treatment, including a conditional recommendation in those responding to chemotherapy and immunotherapy.

CONCLUSIONS

RT plays a vital role in both LS-SCLC and ES-SCLC. These guidelines inform best clinical practices for local therapy in SCLC.