The IASLC Lung Cancer Staging Project: Proposals for the Revision of the N Descriptors in the Forthcoming Seventh Edition of the TNM Classification for Lung Cancer

Is the burden of metastatic lymph node stations a prognostic factor in patients with resected lung cancer?

OBJECTIVES

The burden of metastatic lymph node (LN) stations might reflect a distinct N subcategory with a more aggressive biology and behaviour than the traditional N classification.

METHODS

Between 2008 and 2018, we analyzed 1236 patients with pN1/2 lung cancer. Survival was analyzed based on LN station metastasis, determining the optimal threshold for the number of metastatic LN stations that provided additional prognostic information. N prognostic subgrouping was performed using thresholds for the number of metastatic LN stations with the maximum chi-square log-rank value, and validated at each pT-stage.

RESULTS

Survival showed stepwise statistical deterioration with an increase in the number of metastatic LN stations., Threshold values for the number of metastatic LN stations were determined and N prognostic subgroupswas created as sN-alpha; one LN station metastases (n = 632), sN-beta; two-three LN stations metastases (n = 505), and sN-gamma; ≥4 LN stations metastasis (n = 99). The 5-year survival rate was 57.7% for sN-alpha, 39.2% for sN-beta, and 12.7% for sN-gamma (chi-square log rank = 97.906, p < 0.001). A clear tendency of survival deterioration was observed from sN-alpha to sN-gamma in the same pT stage, except for pT4 stage. Multivariate analysis showed that age (p < 0.001), sex (p = 0.002), tumour histology (p < 0.001), IASLC-proposed N subclassification (p < 0.001), and sN prognostic subgroups (p < 0.001) were independent risk factors for survival.

CONCLUSION

The burden of metastatic LN stations is an independent prognostic factor for survival in patients with lung cancer. It could provide additional prognostic information to the N 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.

Validation Study for the N Descriptor of the Newly Proposed Ninth Edition of the TNM Staging System Proposed by the International Association for the Study of Lung Cancer

INTRODUCTION

The aim of this study was to validate the discriminatory ability and clinical utility of the N descriptor of the newly proposed ninth edition of the TNM staging system for lung cancer in a large independent cohort.

METHODS

We retrospectively analyzed patients who underwent curative surgery for NSCLC between January 2004 and December 2019. The N descriptor of patients included in this study was retrospectively reclassified based on the ninth edition of the TNM classification. Survival analysis was performed using the log-rank test and Cox proportional hazard model to compare adjacent N categories.

RESULTS

A total of 6649 patients were included in this study. The median follow-up period was 54 months. According to the newly proposed ninth edition N classification, 5573 patients (83.8%), 639 patients (9.6%), 268 patients (4.0%), and 169 patients (2.5%) were classified into the clinical N0, N1, N2a, and N2b categories and 4957 patients (74.6%), 744 patients (11.2%), 567 patients (8.5%), and 381 patients (5.7%) were classified into the pathologic N0, N1, N2a, and N2b categories, respectively. The prognostic differences between all adjacent clinical and pathologic N categories were highly significant in terms of both overall survival and recurrence-free survival.

CONCLUSIONS

We validated the clinical utility of the newly proposed ninth edition N classification for both clinical and pathologic stages in NSCLC. The new N classification revealed clear prognostic separation between all categories (N0, N1, N2a, and N2b) in terms of both overall survival and recurrence-free survival.

CT-based intratumoral and peritumoral deep transfer learning features prediction of lymph node metastasis in non-small cell lung cancer

BACKGROUND

The main metastatic route for lung cancer is lymph node metastasis, and studies have shown that non-small cell lung cancer (NSCLC) has a high risk of lymph node infiltration.

OBJECTIVE

This study aimed to compare the performance of handcrafted radiomics (HR) features and deep transfer learning (DTL) features in Computed Tomography (CT) of intratumoral and peritumoral regions in predicting the metastatic status of NSCLC lymph nodes in different machine learning classifier models.

METHODS

We retrospectively collected data of 199 patients with pathologically confirmed NSCLC. All patients were divided into training (n = 159) and validation (n = 40) cohorts, respectively. The best HR and DTL features in the intratumoral and peritumoral regions were extracted and selected, respectively. Support Vector Machine (SVM), k-Nearest Neighbors (KNN), Light Gradient Boosting Machine (Light GBM), Multilayer Perceptron (MLP), and Logistic Regression (LR) models were constructed, and the performance of the models was evaluated.

RESULTS

Among the five models in the training and validation cohorts, the LR classifier model performed best in terms of HR and DTL features. The AUCs of the training cohort were 0.841 (95% CI: 0.776-0.907) and 0.955 (95% CI: 0.926-0.983), and the AUCs of the validation cohort were 0.812 (95% CI: 0.677-0.948) and 0.893 (95% CI: 0.795-0.991), respectively. The DTL signature was superior to the handcrafted radiomics signature.

CONCLUSIONS

Compared with the radiomics signature, the DTL signature constructed based on intratumoral and peritumoral areas in CT can better predict NSCLC lymph node metastasis.

Efficacy of paclitaxel-carboplatin with bevacizumab as a late-line therapy for patients with advanced nonsquamous non-small cell lung cancer: A platinum rechallenge

BACKGROUND

There is no well-established late-line treatment for advanced nonsquamous non-small cell lung cancer (NSCLC). Therefore, we retrospectively determined the efficacy and safety of platinum rechallenge with paclitaxel-carboplatin and bevacizumab in patients with nonsquamous NSCLC as a late-line therapy in a clinical setting.

METHODS

Thirty patients with nonsquamous NSCLC who received paclitaxel-carboplatin with bevacizumab therapy as a late-line treatment at Sendai Kousei Hospital (Miyagi, Japan) between December 2011 and December 2021 were enrolled into the study. The efficacy and safety of this treatment were evaluated. The patients were further categorized into responders and nonresponders, and predictive factors of treatment response were estimated.

RESULTS

The median progression-free survival (PFS) was 6.3 (range, 4.9-6.8) months, and the median overall survival (OS) was 11.8 (range, 7.2-17.2) months. There were no significant differences in PFS and OS between patients with and those without epidermal growth factor receptor mutations. In the univariate analyses of this study, responders were younger than nonresponders (p = 0.012). No fatal adverse events were reported.

CONCLUSIONS

With the increase in the number of treatment options in recent years, the sequence of treatments and overall therapeutic strategy are becoming increasingly important. Thus, platinum rechallenge with paclitaxel-carboplatin and bevacizumab, a late-line treatment for patients with nonsquamous NSCLC, may be an effective therapeutic option.

Comparative analysis of methodologies for predicting overall survival in patients with non-small cell lung cancer based on the number and rate of resected positive lymph nodes: A study based on the SEER database for 2010 through 2019

BACKGROUND

Lymph node (LN) metastasis is crucial in non-small cell lung cancer (NSCLC) prognosis and treatment, but the TNM system lacks LN quantity consideration. Our goal is to investigate the role of positive LNs (nPLN) and positive LN rate (LNR) in overall survival (OS) and assess whether they offer higher value in prognostic assessment of NSCLC than N-stage.

METHODS

Patients were stratified into four subgroups using X-Tile software. Statistical analysis was conducted using the Kaplan-Meier method, univariate analysis, and multivariate Cox regression analysis. Model performance was evaluated using the Harrell consistency index (C-index), Akaike information criterion (AIC), and Bayesian information criterion (BIC). The prognostic performance of the nodal classification was validated using overall survival as the endpoint.

RESULTS

The survival curves demonstrate distinct disparities between each nPLN and LNR category. A pronounced trend toward deteriorating overall survival from N-PLN 1 to N-PLN 2+ was observed across all tumor size categories. However, the differences between each LNR category were only significant for tumors ≤3 cm and 5-7 cm. Notably, both nPLN and LNR classifications displayed a higher C-index, lower AIC, and lower BIC compared with the N staging. Furthermore, the LNR classification provided superior prognostic stratification when compared with the nPLN classification.

CONCLUSIONS

Our results demonstrate that nPLN and LNR classifications may offer improved prognostic performance compared with the current N classification for LN-positive NSCLC patients. Nonetheless, more studies are needed to assess the feasibility of incorporating these classifications into the next TNM staging system.

Association between number of dissected lymph nodes and survival in patients undergoing resection for clinical stage IA pure solid lung adenocarcinoma: a retrospective analysis

BACKGROUND

Lymph node dissection is essential for staging of pure solid lung adenocarcinoma and selection of treatment after surgical resection, particularly for stage I disease since the rate of lymph node metastasis can vary from 0 to 23.7%.

METHODS

We retrospectively screened all adult patients (18 years of age or older) who underwent lobectomy for pure solid cT1N0M0 lung adenocarcinoma between January 2015 and December 2017 at our center. Cox proportional hazard regression was used to assess the association between the number of dissected lymph nodes and recurrence-free survival (RFS) and to determine the optimal number of dissected lymph nodes.

RESULTS

The final analysis included 458 patients (age: 60.26 ± 8.07 years; 241 women). RFS increased linearly with an increasing number of dissected lymph nodes at a range between 0 and 9. Kaplan-Meier analysis revealed significantly longer RFS in patients with ≥ 9 vs. <9 dissected lymph nodes. In subgroup analysis, ≥ 9 dissected lymph nodes was not only associated with longer RFS in patients without lymph node metastasis (n = 332) but also in patients with metastasis (n = 126). In multivariate Cox proportional hazard regression, ≥ 9 dissected lymph nodes was independently associated with longer RFS (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.26 to 0.73; P = 0.002).

CONCLUSIONS

≥9 Dissected lymph nodes was associated with longer RFS; accordingly, we recommend dissecting 9 lymph nodes in patients undergoing lobectomy for stage IA pure solid lung adenocarcinoma.

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).

True Prevalence of Unforeseen N2 Disease in NSCLC: A Systematic Review + Meta-Analysis

Patients with unforeseen N2 (uN2) disease are traditionally considered to have an unfavorable prognosis. As preoperative and intraoperative mediastinal staging improved over time, the prevalence of uN2 changed. In this review, the current evidence on uN2 disease and its prevalence will be evaluated. A systematic literature search was performed to identify all studies or completed, published trials that included uN2 disease until 6 April 2023, without language restrictions. The Newcastle-Ottawa Scale (NOS) was used to score the included papers. A total of 512 articles were initially identified, of which a total of 22 studies met the predefined inclusion criteria. Despite adequate mediastinal staging, the pooled prevalence of true unforeseen pN2 (9387 patients) was 7.97% (95% CI 6.67-9.27%), with a pooled OS after five years (892 patients) of 44% (95% CI 31-58%). Substantial heterogeneity regarding the characteristics of uN2 disease limited our meta-analysis considerably. However, it seems patients with uN2 disease represent a subcategory with a similar prognosis to stage IIb if complete surgical resection can be achieved, and the contribution of adjuvant therapy is to be further explored.

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.

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.

[Bronchial carcinoma: metastatic pathways with involvement of hilar and mediastinal lymph nodes]

SIGNIFICANCE OF LUNG CANCER

Lung cancer has enormous socioeconomical impact on our society due to its high prevalence and mortality. About 59,700 new cases of lung cancer were forecasted for 2022.

TNM SCHEME FOR STAGING

Correct staging is the basis for therapy planning, prognosis estimation, and future analyses. Staging is performed using the TNM scheme from the Union for International Cancer Control (UICC). Involvement of lymph nodes is used to differentiate between stage IIB and IIIC.

LYMPH NODE LEVELS FOR LUNG CANCER

Knowledge of the intrathoracic lymph node levels is crucial for the exact classification and its involvement has direct implications on therapy. The International Association for the Study of Lung Cancer (IASLC) proposed a unified lymph node map with exact anatomic definitions, which is recommended by the German national lung cancer guideline. The extent of lymph node involvement is stratified into N0-N3. Different metastatic paths are known depending on the location of the primary tumor, but the burden of disease has a greater influence on survival, than the location of metastases.

ASSESSING THE SPREAD OF LUNG CANCER

Computed tomography can assess operability of the primary tumor safely in most cases. Invasive procedures to confirm the diagnosis by sampling tissue should be performed after noninvasive diagnostics.

PRACTICAL RECOMMENDATION

Systematic lymph node dissection for all patients with non-small cell lung cancer intended for curative resection is recommended in the current German national guideline for lung cancer.

[Review for N2 Sub-staging in Non-small Cell Lung Cancer]

Patients with N2 non-small cell lung cancer (NSCLC) were heterogeneous groups and required further stratification. The International Society for the Study of Lung Cancer (IASLC) divided N2 into three sub-stages: N2 at a single station without N1 involvement (N2a1), N2 at a single station with N1 involvement (N2a2), and N2 at multiple stations (N2b). These new descriptors significantly distinguished the overall survival (OS), disease-free survival (DFS), and recurrence pattern of patients with different N2 sub-stages. The OS and DFS of N2a1 were not sufficiently distinguished from N1 at multiple stations (N1b). The OS and DFS of N2a2 were intermediate between those of N2a1 and N2b. Current evidence did not support the further subdivision of the N2b. The main recurrence pattern of N2a1, N2a2 and N2b were distant metastasis, and the risks of distant metastasis increased successively. N2a1 patients were at low risk of locoregional recurrence, which could not be reduced by postoperative radiotherapy (PORT). N2a2 and N2b patients had a similar higher risk of locoregional recurrence, which could be reduced to a similar level of N2a1 patients by PORT.
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A Comprehensive Comparison of Different Nodal Subclassification Methods in Surgically Resected Non-Small-Cell Lung Cancer Patients

INTRODUCTION

The revision of the N descriptor in non-small-cell lung cancer has been widely discussed in the past few years. Many different subclassification methods based on number or location of lymph nodes have been proposed for better distinguishing different N patients. This study aimed to systematically collect them and provide a comprehensive comparison among different subclassification methods in a large cohort.

METHOD

Pathological N1 or N2 non-small-cell lung cancer patients undergoing surgical resection between 2005 and 2016 in the Western China Lung Cancer Database were retrospectively reviewed. A literature review was conducted to collect previous subclassification methods. Kaplan-Meier and multivariable Cox analyses were used to examine the prognostic performance of subclassification methods. Decision curve analysis, Akaike's information criterion, and area under the receiver operating curve concordance were also performed to evaluate the standardized net benefit of the subclassification methods.

RESULTS

A total of 1625 patients were identified in our cohort. Eight subclassification methods were collected from previous articles and further grouped into subclassification based on number categories (node number or station number), location categories (lymph node zone or chain) or combination of number and location categories. Subclassification based on combination of lymph node location and number tended to have better discrimination ability in multivariable Cox analysis. No significant superiority among the different subclassification methods was observed in the three statistical models.

CONCLUSION

Subclassification based on the combination of location and number could be used to provide a more accurate prognostic stratification in surgically resected NSCLC and is worth further validation.

Mediastinal Staging with Endobronchial Ultrasound in Early-Stage Non-Small Cell Lung Cancer: Is It Necessary?

Herein we examine the need for minimally invasive mediastinal staging for patients with early-stage non-small cell lung cancer (NSCLC) using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Early NSCLC, stages 1 and 2, has a 5-year survival rate between 53 and 92%, whereas stages 3 and 4 have a 5-year survival of 36% and below. With more favorable outcomes in earlier stages, greater emphasis has been placed on identifying lung cancer earlier in its disease process. Accurate staging is crucial as it dictates both prognosis and therapy. Inaccurate staging can adversely impact surgical candidacy (if falsely "over-staged") or lead to inadequate treatment (if "under-staged"). Clinical staging utilizes noninvasive methods to evaluate the anatomic extent of disease; however, it remains controversial whether mediastinal staging of early NSCLC with radiological exams alone is sufficient. EBUS-TBNA has altered the landscape of invasive mediastinal staging and is a crucial component to improving confidence in lung cancer staging, specifically in early NSCLC. Radiographic occult lymph node metastasis identified upon review of surgical resection specimens of early NSCLC may support the argument to perform EBUS-TBNA in all cases of early-stage disease. Other data suggest that EBUS-TBNA could be spared in cases of peripheral cT1aN0 and cT1bN0 for which surgical resection with lymph node dissection is planned. By reviewing reported EBUS-TBNA outcomes in patients with early NSCLC, we aim to emphasize the necessity of staging with EBUS in this population.

Clinical utility of EBUS-TBNA of hilar, interlobar, and lobar lymph nodes in patients with primary lung cancer

Background

Endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) is used to evaluate hilar/interlobar/lobar lymph nodes. This study aimed to assess the clinical utility of EBUS‐TBNA for station 10/11/12 lymph nodes (LNs) in patients with primary lung cancer.

Methods

This was a retrospective analysis of a prospectively collected database of patients with primary lung cancer who underwent EBUS‐TBNA for station 10/11/12 LNs from January 2015 to December 2019. Patients with benign results from EBUS‐TBNA who did not undergo surgical sampling/clinical follow‐up or who received radiotherapy/chemotherapy were excluded.

Results

The analyses were conducted on 889 LNs from 797 patients. The overall diagnostic sensitivity, specificity, accuracy, negative predictive value (NPV), and positive predictive value of EBUS‐TBNA were 95.7, 100, 97.3, 93.2, and 100%, respectively. Diagnostic sensitivity was significantly lower for LNs <10 mm than ≥10 mm in size (90.1% vs. 97.8%; p < 0.001). There was no significant difference in diagnostic performance according to the nodal station (10 vs. 11/12) and left‐ versus right‐sided LNs. The diagnostic sensitivity (100 vs. 95.5%; p = 0.221) and specificity (100 vs. 100%) of N3 LNs was not significantly different from those of N1 LNs. In this study, eight (8/91, 8.8%) patients with cN1 NSCLC received neoadjuvant treatment based on the results of EBUS‐TBNA.

Conclusion

EBUS‐TBNA accurately evaluates station 10/11/12 LNs of both N1 and N3 disease. The diagnostic performances of EBUS‐TBNA for station 10/11/12 LNs seem to be comparable to those of EBUS‐TBNA for mediastinal LNs.

Multimodality Treatment including Surgery Related to the Type of N2 Involvement in Locally Advanced Non-Small Cell Lung Cancer

Simple Summary

Multimodality therapy for locally advanced non-small cell lung cancer (NSCLC) is a complex and controversial issue, especially regarding optimal treatment regimens for patients with ipsilateral positive mediastinal nodes (N2 disease). Is the landscape in this hotly debated stage changing the role for surgery as immunotherapy and targeted therapies are being investigated and implemented? A review on multimodality therapeutic options for stage IIIA-N2 NSCLC is presented.

Abstract

For patients with locally advanced non-small cell lung cancer (NSCLC) or positive N1 nodes, multimodality treatment is indicated. However, the optimal management of patients presenting with ipsilateral positive mediastinal nodes (N2 disease) has not been determined yet. Different treatment regimens consisting of chemotherapy, radiation therapy, and surgery have been proposed and implemented previously. In more recent years, immunotherapy and targeted therapies have been added as therapeutic options. The role of surgery is currently redefined. Recent studies have shown that surgical resection after induction immunotherapy or targeted therapy is feasible and yields good short-term results. In this review, we summarize the latest data on multimodality treatment options for stage IIIA-N2 locally advanced NSCLC, depending on the extent of nodal involvement.

Survival Analysis of Surgically Resected ypN2 Lung Cancer after Neoadjuvant Therapy

INTRODUCTION

 Surgery is widely accepted today when downstaging of mediastinal lymph nodes after neoadjuvant therapy is achieved. However, the role of surgery in patients with persistent N2 disease is still controversial. This study aims to detail the diagnostic problems, prognostic features, and long-term survival of the persistent N2 non-small cell lung cancer patient group.

PATIENTS AND METHODS

 One-hundred fifty patients who received neoadjuvant therapy and subsequently underwent resection, in-between 2003 and 2015, were retrospectively analyzed. In this study, "persistent N2" group refers to patients who received neoadjuvant therapy for clinically or histologically proven N2, who underwent a surgery after having been classified as "downstaged" at restaging, but in whom ypN2 lesions were subsequently confirmed on the operative specimens. Patients with multistation N2 were included in the study. There were 119 patients who met the criteria, whereas persistent ypN2 was detected in 28.5% (n = 34) of all patients.

RESULTS

 Overall 5-year survival rate was 47.2%, while it was 23.4% for patients with persistent N2. Factors that adversely affected survival were to have nonsquamous cell histological type (p = 0.006), high ypT stage (p = 0.001), persistent N2 (p = 0.02), and recurrence during follow-up (p < 0.001). A trend toward a shorter survival was observed when the ypN2 zone was subcarinal versus other zones, but did not reach statistical significance (p = 0.08). In addition, a trend toward a shorter survival of patients with multiple N2 involvement (p = 0.412) was observed.

CONCLUSION

 In the persistent N2 group, when multiple involvement or subcarinal involvement was excluded, relatively good survival was detected.

Perioperative and long-term outcomes of spontaneous ventilation video-assisted thoracoscopic surgery for non-small cell lung cancer

Background

Spontaneous ventilation video-assisted thoracoscopic surgery (SV-VATS) exhibits dual intraoperative and postoperative advantages for patients with non-small cell lung cancer (NSCLC). However, there is a lack of data regarding its long-term survival superiority over the double-lumen intubated mechanical ventilation video-assisted thoracoscopic surgery (MV-VATS) or thoracotomy.

Methods

A retrospective study was conducted from 2011 to 2018 in the First Affiliated Hospital of Guangzhou Medical University among patients with NSCLC who underwent the SV-VATS or the MV-VATS. Patients receiving the SV-VATS were the study group, and patients receiving the MV-VATS were the control group. Propensity score matching (PSM) was performed to establish 1:1 SV-VATS versus MV-VATS group matching to balance potential baseline confounding factors. Primary endpoints were overall survival (OS) and disease-free survival (DFS). Secondary endpoints were perioperative outcomes. The baseline information of these patients was recorded. The perioperative data and survival data were collected using a combination of electronic data record system and telephone interview. A 1:1:1 SPM was also used to compare the OS in the SV-VATS, the MV-VATS and thoracotomy group by using another database, including patients undergoing thoracotomy and the MV-VATS.

Results

For the two-group comparison, after 1:1 PSM, a matched cohort with 400 (200:200) patients was generated. The median follow-up time in this cohort was 4.78 years (IQR, 3.78–6.62 years). The OS (HR =0.567, 95% CI, 0.330 to 0.974, P=0.0498) and the DFS (HR =0.546, 95% CI, 0.346 to 0.863, P=0.013) of the SV-VATS group were significantly better than the MV-VATS group. There were no statistically differences between the SV-VATS and the MV-VATS group on the operative time (158.56±40.09 vs. 172.06±61.75, P=0.200) anesthesia time (247.4±62.49 vs. 256.7±58.52, P=0.528), and intraoperative bleeding volume (78.88±80.25 vs. 109.932±180.86, P=0.092). For the three-group comparison, after 1:1:1 PSM, 582 (194:194:194) patients were included for the comparison of SV-VATS, MV-VATS and thoracotomy. The OS of the SV-VATS group was significantly better than the thoracotomy group (HR =0.379, 95% CI, 0.233 to 0.617, P<0.001).

Conclusions

Invasive NSCLC patients undergoing SV-VATS lobectomy demonstrated better long-term outcomes compared with MV-VATS.

Prognostic value of different N1 lymph node zones in pN1M0 non-small cell lung cancer: a systematic review and meta-analysis

The IASLC lymph node map grouped the lymph node stations into “zones” for prognostic analyses. In the N1 lymph nodes group, N1 nodes are divided into the Hilar/Interlobar zone (N1h) and Peripheral zone (N1p). There is no consensus on the different prognostic values of N1 lymph nodes in N1h and N1p. Therefore, we conducted a systematic review and meta-analysis to assess the survival difference between N1h and N1p in patients of pN1M0 NSCLC. Medline, the Cochrane Library, Embase, and the Web of science were systematically searched to identify relevant studies published up to April 4th, 2020. A retrospective and prospective cohort study comparing N1h versus N1p to the pN1M0 NSCLC was included. Hazard ratios (HRs) for OS were aggregated according to a fixed or random-effect model. Ten publications for 1946 patients of pN1M0 NSCLC were included for the meta-analysis.The 5-year OS was lower for patients with N1h (HR: 1.67, 95% CI 1.44–1.94; P < 0.001). The pooled 5-year OS in N1h and N1p were 40% and 56%, respectively. The patients in pN1M0 NSCLC have different survival according to different N1 lymph node zones involvement: patients with N1p metastasis have a better prognosis than those with N1h metastasis.

Clinical Significance of Regional Lymph Node Evaluation during Sublobar Resection in Lung Cancer

BACKGROUND

This study evaluated the prognostic effect of regional lymph node evaluation (LNE) in patients with non-small cell lung cancer (NSCLC) who underwent sublobar resection based on harvested node stations.

METHODS

We retrospectively reviewed the data of patients with NSCLC who underwent sublobar resection at Asan Medical Center between 2007-2016. To adjust for the differences in confounding variables between the groups, propensity score-based inverse probability of treatment weighting (IPTW) was performed.

RESULTS

In the LNE group with pathological N0 disease (n = 522), 458 (87.7%) patients underwent both N1 and N2 LNE (N1 + N2 group) and 64 (12.3%) underwent only N2 LNE (N2 alone group). The N1 + N2 group had better prognosis before (p < 0.001) and after IPTW adjustment (p = 0.019). Similar results were obtained even in patients with tumor size ≤ 2 cm (p = 0.032) or who underwent wedge resection (p = 0.041). According to IPTW-adjusted multivariable analysis, the performance of regional LNE was a significant prognostic factor for survival outcome (hazard ratio [95% confidence interval] = 0.45 [0.27-0.74], p = 0.002).

CONCLUSIONS

LNE is a critical process during sublobar resection in patients with NSCLC. Regional LNE during sublobar resection can significantly affect clinical outcomes even in patients with wedge resection or with tumor size < 2 cm.

Clinicopathological and Prognostic Significance of Inhibitor of Apoptosis Protein (IAP) Family Members in Lung Cancer: A Meta-Analysis

Lung cancer is the most common cause of cancer-related death worldwide. Approximately 85% is non-small-cell and 15% is small-cell lung cancer. The inhibitor of apoptosis proteins (IAPs) represent a heterogeneous family of anti-apoptotic proteins, some members of which have been reported to correlate with clinical outcome in lung cancer. We screened PubMed, Web of Science, and Scopus for studies that investigated the prognostic value and clinicopathological features of IAPs in lung cancer. Forty-five eligible studies with 4428 patients assessed the expression of the IAPs survivin, XIAP, livin, and BRUCE. The pooled hazard ratio (HR) of 33 studies that analyzed overall survival (OS) revealed a positive correlation between survivin expression and poor prognosis. Seven studies displayed a strong association between survivin and disease recurrence. Two studies that assessed the expression of XIAP and livin, respectively, proved a significant relationship of these IAPs with poor OS. Meta-analyses of clinicopathological variables revealed a significant association between survivin and T stage, UICC stage, the presence of lymph node metastasis, and grade of differentiation. In conclusion, high expression of distinct IAPs significantly correlates with prognosis in lung cancer. Therefore, lung cancer patients might benefit from a targeted therapy against specific IAPs.

Long-term outcomes of upfront surgery in patients with resectable pathological N2 non-small-cell lung cancer

OBJECTIVES

Although the standard treatment for pathological N2 (pN2) non-small-cell lung cancer (NSCLC) patients is definitive chemoradiation, surgery can be beneficial for resectable pN2 disease. Herein, we report the long-term clinical outcomes of upfront surgery followed by adjuvant treatment for selected patients with resectable pN2 disease.

METHODS

We performed a retrospective analysis of clinical outcomes for patients with pN2 disease who underwent surgery as the first-line therapy. Multivariable Cox regression analysis was used to identify the significant factors for overall survival (OS) and recurrence-free survival.

RESULTS

From 2004 to 2015, a total of 706 patients with pN2 NSCLC underwent complete anatomical resection at our institution. The patients' clinical N stages were cN0, 308 (43.6%); cN1, 123 (17.4%) and cN2, 275 (39.0%). Adjuvant chemotherapy, radiotherapy and chemoradiotherapy were administered to 169 (23.9%), 115 (17.4%) and 299 patients (42.4%), respectively. With a median follow-up of 40 months, the respective median time and 5-year rate of OS were 52 months and 44.7%. According to subdivided pN2 descriptors, the median OS time was 80, 53 and 37 months for patients with pN2a1, pN2a2 and pN2b, respectively. Adjuvant chemotherapy was a significant prognostic factor for both OS [hazard ratio (HR) 0.39, 95% confidence interval (CI) 0.28-0.52; P < 0.001] and recurrence-free survival (HR 0.42, 95% CI 0.30-0.58; P < 0.001).

CONCLUSIONS

Upfront surgery followed by adjuvant therapy for resectable N2 disease showed favourable outcomes compared to those reported in previous studies. Adjuvant chemotherapy is essential to improve the prognosis for patients undergoing upfront surgery for N2 disease.

The Evolving Concept of Complete Resection in Lung Cancer Surgery

Simple Summary

In the surgical treatment of lung cancer, the complete removal of the portion of the lung where the cancer is and of the involved adjacent structures is of paramount importance to achieve long-term survival. The International Association for the Study of Lung Cancer (IASLC) proposed a definition of complete resection that included a well-defined type of removal of the regional lymph nodes as a fundamental step. The lymph nodes may contain cancer cells and, if left behind, cancer will soon progress. The IASLC also defined incomplete resection when there is any evidence of persistent cancer after the operation. It also defined an intermediate condition, uncertain resection, when no evidence of residual disease can be proved, but all the conditions of complete resection are not fulfilled. Four validations of the definitions have proved their prognostic value and, therefore, the definitions should be followed when a surgical resection of lung cancer is planned.

Abstract

Different definitions of complete resection were formulated to complement the residual tumor (R) descriptor proposed by the American Joint Committee on Cancer in 1977. The definitions went beyond resection margins to include the status of the visceral pleura, the most distant nodes and the nodal capsule and the performance of a complete mediastinal lymphadenectomy. In 2005, the International Association for the Study of Lung Cancer (IASLC) proposed definitions for complete, incomplete and uncertain resections for international implementation. Central to the IASLC definition of complete resection is an adequate nodal evaluation either by systematic nodal dissection or lobe-specific systematic nodal dissection, as well as the integrity of the highest mediastinal node, the nodal capsule and the resection margins. When there is evidence of cancer remaining after treatment, the resection is incomplete, and when all margins are free of tumor, but the conditions for complete resection are not fulfilled, the resection is defined as uncertain. The prognostic relevance of the definitions has been validated by four studies. The definitions can be improved in the future by considering the cells spread through air spaces, the residual tumor cells, DNA or RNA in the blood, and the determination of the adequate margins and lymphadenectomy in sublobar resections.

Comparison of Two Proposed Changes to the Current Nodal Classification for Non-Small Cell Lung Cancer Based on the Number and Ratio of Metastatic Lymph Nodes

BACKGROUND

The current nodal classification is unsatisfactory in distinguishing the prognostically heterogeneous N1 or N2 non-small cell lung cancer (NSCLC).

RESEARCH QUESTION

Is the combination of the current N category and the number of metastatic lymph nodes (N_#number) or the combination of the current N category and the ratio of the number of positive to resected lymph nodes (N_#ratio) better than the current N category alone?

STUDY DESIGN AND METHODS

We identified 2,162 patients with N1 or N2 NSCLC from the Surveillance, Epidemiology, and End Results database (2004-2016). We classified these patients into three N_#number categories (N_#number-1, N_#number-2a, N_#number-2b) and three N_#ratio categories (N_#ratio-1, N_#ratio-2a, N_#ratio-2b). Lung cancer-specific survival (LCSS) were compared using the Kaplan-Meier method. The prognostic significance of the new nodal classifications was validated across each tumor size category (≤3 cm, 3-5 cm, 5-7cm, >7 cm). Cox proportional hazards regression was used to evaluate the association between each nodal classification and LCSS.

RESULTS

The survival curves showed clear differences between each pair of N_#number and N_#ratio categories. A significant tendency toward the deterioration of LCSS from N_#number-1 to N_#number-2b was observed in all tumor size categories. However, the differences between each pair of N_#ratio categories were significant only in tumors from 3 to 7 cm. Although all three nodal classifications were independent prognostic indicators, the N_#number classification provided more accurate prognostic stratifications compared with the N_#ratio classification and the current nodal classification.

INTERPRETATION

The N_#number classification followed by the N_#ratio classification might be better prognostic determinants than the current nodal classification in prognostically heterogeneous N1 or N2 NSCLC.

Number of metastatic lymph nodes and zones as prognostic factors in non-small-cell lung cancer

OBJECTIVES

Characterizing pathological nodes (pNs) by location alone is sometimes inadequate as patients with pN1 or pN2 non-small-cell lung cancer (NSCLC) show prognostic heterogeneity. We aimed to assess the relationship of the number of metastatic lymph nodes (LNs) and zones with prognosis in NSCLC patients.

METHODS

We analysed 1393 patients who underwent lobectomy with mediastinal LN dissection for NSCLC at the Osaka International Cancer Institute between January 2006 and December 2015. Patients were classified into 3 groups according to the number of LNs: n1-3, n4-6 and n7-. We investigated the relationship of prognosis with the number of metastatic LNs and metastatic zones.

RESULTS

In the multivariable analyses, the number of metastatic LNs and zones were not independent factors for overall survival or recurrence-free survival in patients with pN1 disease after adjustment for age, sex, tumour histology and tumour diameter. However, n4-6 (ref. n1-3) was an independent prognostic factor for overall survival [hazard ratio (HR) 4.148, P < 0.001] in those with pN2 disease. There were no significant differences in overall survival and recurrence-free survival between pN1 (HR 0.674, P = 0.175) and pN2n1-3 disease (HR 1.056, P = 0.808). Moreover, patients with pN2 disease with a higher number of metastatic zones had a poor prognosis for recurrence-free survival [3 zones (ref. 1): HR 1.774, P = 0.051, and 4 zones (ref. 1): HR 2.173, P < 0.047].

CONCLUSIONS

The number of metastatic LNs and metastatic zones were useful prognostic factors in NSCLC patients. The findings could help in establishing a new pN classification.

Future Perspectives on the TNM Staging for Lung Cancer

Since its conception by Pierre Denoix in the mid-20th century, the tumor, node, and metastasis (TNM) classification has undergone seven revisions. The North American database managed by Clifton Mountain was used to inform the 2nd to the 6th editions, and an international database collected by the International Association for the Study of Lung Cancer, promoted by Peter Goldstraw, was used to inform the 7th and the 8th editions. In these two latest editions, it was evident that the impact of tumor size was much greater than it was suggested in previous editions; that the amount of nodal disease had prognostic relevance; and that the number and location of the distant metastases had prognostic implications. However, the TNM classification is not the only prognostic factor. Data are being collected now to inform the 9th edition of the TNM classification, scheduled for publication in 2024. Patient-, environment-, and tumor-related factors, including biomarkers (genetic biomarkers, copy number alterations, and protein alterations) are being collected to combine them in prognostic groups to enhance the prognosis provided by the mere anatomic extent of the tumor, and to offer a more personalized prognosis to an individual patient. International collaboration is essential to build a large and detailed database to achieve these objectives.

The addition of radiotherapy to adjuvant chemotherapy has a combinatorial effect in pN2 non-small cell lung cancer only with extranodal invasion or multiple N2 metastasis

OBJECTIVES

The benefit of adjuvant therapy for heterogenous group of pathological N2 (pN2) non-small cell lung cancer (NSCLC) remains unclear. We evaluated the prognostic effect of adjuvant therapy after stratifying patients with pN2 according to subdivided N2 descriptors.

MATERIALS AND METHODS

We performed a retrospective analysis of clinical outcomes in patients with pN2 NSCLC who underwent upfront surgery. N2 descriptors were subdivided as single N2 metastasis without N1 involvement (pN2a1), single N2 with metastasis with N1 involvement (pN2a2), and multiple N2 metastasis (pN2b).

RESULTS

From 2005-2017, 838 patients with pN2 NSCLC underwent complete resection. There were 173 (21.0 %), 338 (40.3 %), and 324 (38.7 %) in the pN2a1, pN2a2, and pN2b groups. Patients who received chemoradiotherapy (CRTx; n = 389, 46.4 %) or chemotherapy (CTx; n = 204, 24.3 %) had similar prognoses, which were better than prognoses in patients who received with radiotherapy (RTx; n = 116, 13.8 %) or those who did not receive adjuvant therapy (n = 129, 15.4 %). According to the stratified multivariable Cox analysis, patients with pN2b stage in the CTx group had a significantly poor prognosis than those in the CRTx group (hazard ratio, 1.38; 95 % confidence interval, 1.03-1.98; p = 0.046). The difference in survival outcomes between the CRTx and CTx groups was significant in patients with extranodal invasion (ENI) (p = 0.011), but not in those without ENI (p = 0.527) CONCLUSIONS: Adjuvant CTx improves the overall and recurrence-free survival in patients with pN2 NSCLC undergoing upfront surgery with complete resection. RTx with adjuvant chemotherapy has a combinatorial effect on pN2 NSCLC only with ENI or multiple N2 metastasis.

The role of EGFR-TKIs as adjuvant therapy in EGFR mutation-positive early-stage NSCLC: A meta-analysis

BACKGROUND

The role of adjuvant epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is not clear in early-stage nonsmall-cell lung cancer (NSCLC) patients. This meta-analysis aims to compare the efficacy and safety of EGFR-TKIs as adjuvant therapy with chemotherapy or placebo in NSCLC patients harboring EGFR mutations.

PATIENTS AND METHODS

Pubmed, Embase, and Cochrane databases were searched for randomized controlled trials. The hazard ratio (HR) of disease-free survival (DFS) and overall survival (OS) as well as the risk ratio (RR) of severe adverse events were merged.

RESULTS

Seven articles from five studies from 1843 records, a total of 1227 patients, were included in the analysis. The HR for DFS was 0.38 (95% confidence interval [CI] 0.22-0.63), in favor of EGFR-TKIs. However, no significant benefit of OS was seen (HR = 0.61, 95% CI 0.31-1.22). Treatment benefit was more pronounced in patients with advanced disease stage and longer duration of medication, EGFR exon 19 deletion mutation, and treatment with third-generation EGFR-TKIs. Adjuvant targeted therapy may cause few adverse events compared with chemotherapy (RR = 0.28, 95% CI 0.09-0.94). The possibility of severe adverse events for the first-generation drugs was significantly lower than for third-generation drugs.

CONCLUSION

In EGFR mutation-positive patients with stage IB-IIIA NSCLC, compared with adjuvant chemotherapy or placebo, adjuvant EGFR-TKIs should effectively improve the patient's DFS, but not effectively improve OS. Disease stage, treatment duration, mutation types, and therapeutic drugs could affect the degree of benefit. Adjuvant EGFR-TKIs had more favorable tolerability than chemotherapy, especially with the usage of first-generation drugs.

The current treatment landscape in the UK for stage III NSCLC

For stage III non-small cell lung cancer (NSCLC), approximately a third of patients survive up to 5 years, with decreasing 5-year survival rates for stage IIIB and stage IIIC disease. Although curable, stage III NSCLC encompasses a diverse range of disease presentation, with an equally complex range of multi-modal treatment options, including systemic and local therapies for distant and local disease control, respectively. This complexity results in a number of challenges for the multi-disciplinary team (MDT) in achieving optimal treatment outcomes for patients. As multi-modality treatment is the preferred treatment strategy for all stage III disease, the focus of this article is the key surgical, chemotherapy and radiotherapy clinical trials as well as guidelines that currently outline radical therapy options for patients with both potentially resectable and unresectable stage III NSCLC.

The lymph node ratio predicts cancer-specific survival of node-positive non-small cell lung cancer patients: a population-based SEER analysis

Background

Lymph node ratio (LNR) has been suggested to be an effective prognostic tool for stratifying non-small cell lung cancer (NSCLC) cases. In this study, we sought to determine cancer-specific survival (CCS) of NSCLC cases from the SEER registry and used the X-tile method to optimize CCS-based LNR cut-off points for prognostic stratification of node-positive NSCLC.

Methods

CSS and other clinicopathologic variables were retrieved from the SEER registry. Kaplan-Meier methods were used to calculate CSS. The optimal cut-off points for LNR classification were determined by the X-tile approach. Multivariate Cox regression analysis was performed to identify independent risks of CSS.

Results

Totally 11,341 lung cancer patients were included. Their median CSS was 22 months (range 0,143). The median LNR was 0.22 (Q1,Q3: 0.11, 0.50). X-tile analysis showed that the optimal LNR cut-off points were 0.28 and 0.81, dividing the cohort into low (LNR1 ≤ 0.28; n = 6580, 58%), middle (0.28 < LNR2 < 0.81; n = 3025, 26.7%), and high (LNR3 > 0.81; n = 1736, 15.3%) subsets. Kaplan-Meier analysis showed that patients with a low LNR had a significantly higher CCS versus patients with middle or high LNR (P < 0.001). Multivariate competing risks regression analysis revealed that LNR was an independent and significant adverse predictor of CSS (LNR2 vs. LNR1: SHR: 1.56, 95%CI: 1.47,1.67, P < 0.001; LNR3 vs. LNR1: SHR: 2.54, 95%CI: 2.30,2.80, P < 0.001).

Conclusions

LNR is an independent prognostic factor of node-positive NSCLC and its optimal cut-off values established using the robust x-tile method effectively define subpopulations of node-positive NSCLC cases, which is important in guiding selection of treatment strategies clinically.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-020-01390-x.

Which N Descriptor Is More Predictive of Prognosis in Resected Non-small Cell Lung Cancer: The Number of Involved Nodal Stations or the Location-Based Pathological N Stage?

BACKGROUND

The eighth edition of nodal classification for non-small cell lung cancer (NSCLC) is defined only by the anatomical location of metastatic lymph nodes.

RESEARCH QUESTION

We sought to evaluate the prognostic significance and discriminatory capability of the number of involved nodal stations (nS) in a large Chinese cohort.

STUDY DESIGN AND METHODS

A total of 4,011 patients with NSCLC undergoing surgical resection between 2009 and 2013 were identified. The optimal cutoff values for nS classification were determined with X-tile software. Kaplan-Meier and multivariate Cox analysis were used to examine the prognostic performance of nS classification in comparison with location-based N classification. A decision curve analysis was performed to evaluate the standardized net benefit of nS classification in predicting prognosis.

RESULTS

All the patients were classified into four prognostically different subgroups according to the number of involved nodal stations: (1) nS0 (none positive), (2) nS1 (one involved station), (3) nS2 (two involved stations), and (4) nS ≥ 3 (three or more involved stations). The prognoses among all the neighboring categories of nS classification were statistically significantly different in terms of disease-free survival and overall survival. The multivariate Cox analysis demonstrated that nS was an independent prognostic factor of disease-free survival and overall survival. Patients with N1 or N2 stage disease could be divided into three prognostically different subgroups according to nS classification. However, the prognosis was similar between the N1 and N2 subgroups when patients were staged in the same nS category. The decision curve analysis showed that nS classification tended to have a higher predictive capability than location-based N classification.

INTERPRETATION

The nS classification could be used to provide a more accurate prognosis for patients with resected NSCLC. The nS is worth taking into consideration when defining nodal category in the forthcoming ninth edition of the staging system.

MITF functions as a tumor suppressor in non-small cell lung cancer beyond the canonically oncogenic role

Microphthalamia-associated transcription factor (MITF) is a critical mediator in melanocyte differentiation and exerts oncogenic functions in melanoma progression. However, the role of MITF in non-small cell lung cancer (NSCLC) is still unknown. We found that MITF is dominantly expressed in the low-invasive CL1-0 lung adenocarcinoma cells and paired adjacent normal lung tissues. MITF expression is significantly associated with better overall survival and disease-free survival in NSCLC and serves as an independent prognostic marker. Silencing MITF promotes tumor cell migration, invasion and colony formation in lung adenocarcinoma cells. In xenograft mouse model, MITF knockdown enhances metastasis and tumorigenesis, but decreases angiogenesis in the Matrigel plug assay. Whole transcriptome profiling of the landscape of MITF regulation in lung adenocarcinoma indicates that MITF is involved in cell development, cell cycle, inflammation and WNT signaling pathways. Chromatin immunoprecipitation assays revealed that MITF targets the promoters of FZD7, PTGR1 and ANXA1. Moreover, silencing FZD7 reduces the invasiveness that is promoted by silencing MITF. Strikingly, MITF has significantly inverse correlations with the expression of its downstream genes in lung adenocarcinoma. In summary, we demonstrate the suppressive role of MITF in lung cancer progression, which is opposite to the canonical oncogenic function of MITF in melanoma.

New N1/N2 classification and lobe specific lymphatic drainage: Impact on survival in patients with non-small cell lung cancer treated with surgery

OBJECTIVE

to validate the proposed N descriptor revision on a large cohort of patients and assess the impact of tumour location on the distribution pattern of lymph node metastases for patients with NSCLC.

METHODS

This is a retrospective review of a consecutive series of patients who had anatomical lung resections. Systematic lymph node dissection was done for all patients.

RESULTS

Between January 2009 and December 2019 2566 patients had surgical resection for NSCLC. 448 patients (17.5%) had histologically confirmed lymph node metastases: 257 (57.4 %) had pN1 and 191 pN2. Median age of the study population was 69.1 years. Overall survival (OS) for study population was 37.3 months with 5-year survival rate of 35.7 %. The survival analysis of the N subgroups showed the pN2 patients had a median OS of 27.9 months vs. 41.7 months for pN1 patients (p = 0.013). Analysis as per the new proposal of the N subgroups N1a vs N1b vs N2a1 vs N2a2 vs N2b showed that median survival OS was 41.7 vs. 39.2 mo vs. 33.3 mo vs. 28.9 mo vs. 24.6 mo (p = 0.099). There was statistically significant difference in survival between N2 patients with skip metastasis and N2 patients without skip metastases: OS 32.2 (95 % CI: 16.8-47.6) months vs. 24.2 months (p = 0.024). On multivariate analysis only pathological N (p = 0.011) and the new proposed N classification (p = 0.006) were independent prognostic factors for survival.

CONCLUSIONS

N1 and N2 disease are heterogeneous groups and require further stratification. The number of N2 lymph node stations involved and the presence or not of N1 disease translated to significant differences in survival and therefore have to be included in N staging.

Lung Cancer Staging

Anatomic staging is a critical step in evaluation of patients with lung cancer. Accurate identification of stage based on features of primary tumor (T), regional nodes (N), and metastatic disease (M) is fundamental to determining appropriate care. In this article, the TNM components of the anatomic staging system and a framework for description of lung cancer with multiple pulmonary sites of involvement are discussed. TNM combinations are grouped according to prognosis, with patient-level, tumor-level, and environment-level factors also influencing survival outcomes. Although the staging system does not include molecular and immunologic information, anatomic staging remains the common language for communicating extent of disease.

Advances in the Treatment of Stage III Non-Small Cell Lung Cancer

Treatment of stage III non-small cell lung cancer (NSCLC) traditionally has involved combinations of chemotherapy, radiation, and surgical resection. Although the multimodality approach remains standard, only a fraction of patients with stage III lung cancer can undergo complete resection, and long-term prognosis remains poor. The PACIFIC trial generated significant enthusiasm when it demonstrated that the programmed death ligand-1 inhibitor, durvalumab, improved survival in patients with unresectable stage III NSCLC after completion of definitive concurrent chemoradiation. This article reviews the indications for traditional therapies in stage III NSCLC and highlights ongoing advances that have led to the incorporation of novel therapeutic agents.

Alternative methods of lymph node staging in lung cancer: a narrative review

The nodal status indicator in non-small cell lung cancer is one of the most crucial prognostic factors available. However, there are still many arguments among scientists regarding whether the currently used nodal status descriptor should be changed in the forthcoming editions of the Tumor Node Metastasis classification or whether it is precise enough and should be maintained as is. We reviewed studies concerning nodal factor classifications to evaluate their accuracy in non-small cell lung cancer patients and to address the previously mentioned challenge. We reviewed the PubMed database regarding the following classifications: ongoing 8^th edition of the Tumor Node Metastasis classification, number of positive lymph nodes, number of negative lymph nodes, number of dissected lymph nodes, lymph node ratio, nodal chains, log odds of positive lymph nodes, zone-based classification and one that is based on the number of lymph node stations involved. Moreover, we analysed data regarding various combinations of these classifications. Our analysis showed that the present nodal staging may not accurately categorize every lung cancer patient. The number of positive lymph nodes and lymph node ratio or the log odds of positive lymph nodes (as the mathematical modification of lymph node ratio) are more legitimate, as they possess very robust data and should be considered initially as additional factors that can be incorporated in ongoing nodal staging systems. Forthcoming non-small cell lung cancer staging systems could benefit from the addition of quantitative-based parameters. Additionally, the minimal extent of lymphadenectomy should be established as staging benefits from it. International, prospective validation studies need to be performed to optimize the cut-off values and prognostic groups and to confirm the superiority of the newly suggested descriptors in non-small cell lung cancer nodal staging.

Lymph-node ratio predicts survival among the different stages of non-small-cell lung cancer: a multicentre analysis†

OBJECTIVES

The prognostic role of the number of resected and metastatic lymph nodes in non-small-cell lung cancer (NSCLC) is still being debated. The aim of this study was to evaluate the impact of lymphadenectomy in addition to the already validated variables in NSCLC survival.

METHODS

From January 2002 to December 2012, data on 4858 patients with NSCLC undergoing anatomical lung resection and hilomediastinal lymphadenectomy in 6 institutions were analysed retrospectively. Established prognostic factors in addition to the number of resected lymph nodes and the ratio between the number of metastatic lymph nodes and the number of resected lymph nodes (NR) were correlated to overall survival (OS) and disease-free survival (DFS) using the multivariable Cox regression model. Harrell's C-statistic with the 95% confidence interval (CI) was determined. Analysis by means of maximally selected log-rank statistics was performed to find optimal cut-off points in order to split patients into groups with different outcome probabilities.

RESULTS

The median numbers of resected lymph nodes and of metastatic lymph nodes were 17 (range 6-85) and 2 (1-36), respectively. Hilar (N1) and mediastinal (N2) metastases were identified in 21.3% and 20.0% of cases, respectively. Overall, the 5-year OS and DFS rates were 54.6% and 44.8%, respectively. At multivariable analysis, age, gender, pathological stage, R0 resection, type of surgery and NR correlated with longer OS rates; the same variables plus tumour grading were further related to DFS. C-statistics were 66.0 (95% CI 62.7-69.4) for DFS and 60.5 (95% CI 58.3-62.6) for OS. An NR <40% significantly correlated with a higher 5-year survival rate in the total sample (OS 57.6% vs 23.8%, P < 0.001; DFS 48.2% vs 11.4, P < 0.001) and in patients with N1 (OS 47.9% vs 36.1%, P = 0.03; DFS 39% vs 24.2%, P = 0.02) and N2 (OS 36.9% vs 21.8%, P < 0.001 DFS 23.9% vs 9.1%, P < 0.001).

CONCLUSIONS

Our study confirms that the number of resected lymph nodes is a strong prognostic indicator in NSCLC. In particular, an NR cut-off value of 40% may predict both OS and DFS.

Risk factors of lobar lymph node metastases in non-primary tumor-bearing lobes among the patients of non-small-cell lung cancer

Purpose

Lobar lymph node metastases in non-primary tumor-bearing lobes (NTBL) are rarely reported. This study examined the risk factors of lobar lymph node metastasis in NTBL.

Methods

We retrospectively studied 301 patients with non-small-cell lung cancer (NSCLC) who underwent surgical pulmonary resection with systematic lymph node dissection plus extended lobar lymph node dissection of NTBL. Patients were classified into positive and negative NTBL groups. Unconditional logistic regression was used to identify the risk factors for lobar lymph node metastasis in NTBL.

Results

NTBL lobar lymph nodes were identified in 38 patients (12.6%). A higher proportion of adenocarcinomas occurred in the positive NTBL group compared to the negative NTBL group (73.7% vs. 46.4%, P = 0.01). Risk of NTBL lobar lymph node metastases was significantly elevated in the lower lobe of primary site compared to the upper lobe (OR = 2.61, 95% CI = 1.26–5.75, P = 0.01), and with adenocarcinomas compared to squamous cell carcinomas (OR = 2.75, 95% CI = 1.09–7.65, P = 0.04). No differences were observed when comparing left and right lobes. NTBL lobar lymph node metastasis was most often observed among patients with larger tumor size, N1/N2 nodal involvement, with lymph vascular invasion (LVI), and visceral pleural invasion (VPI).

Conclusion

NTBL lobar lymph node metastases occurred more often in patients with a primary NSCLC tumor in the lower lobe, with adenocarcinomas, larger tumor size, N1/N2 nodal involvement, LVI or VPI. Extended lymphadenectomy including NTBL nodes may be clinically advantageous when these risk factors are present.

Video-assisted thoracoscopic lobectomy is feasible for selected patients with clinical N2 non-small cell lung cancer

Few studies have evaluated the usefulness of video-assisted thoracoscopic surgery (VATS) for advanced-stage lung cancer. We aimed to evaluate the feasibility of VATS for treating clinical N2 (cN2) lung cancer. A retrospective cohort analysis was performed with data from 268 patients who underwent lobectomy for cN2 disease from 2007 to 2016. Using propensity score-based inverse probability of treatment weighting (IPTW), perioperative and long-term survival outcomes were compared. We performed VATS and open thoracotomy on 121 and 147 patients, respectively. Overall, VATS was preferred for patients with peripherally located tumors (p < 0.001). After IPTW-adjustment, all preoperative information became similar between the groups. Compared to thoracotomy, VATS was associated with shorter hospitalization (7.7 days vs. 9.1 days, p = 0.028), despite equivalent complete resection rates (92.6% vs. 90.5%, p = 0.488) and dissected lymph nodes (mean, 31.9 vs. 29.4, p = 0.100). On IPTW-adjusted analysis, overall survival (50.5% vs. 48.4%, p = 0.127) and recurrence-free survival (60.5% vs 44.6%, p = 0.069) at 5 years were also similar between the groups. Among selected patients with resectable cN2 disease and peripherally located tumors, VATS is feasible, associated with shorter hospitalization and comparable perioperative and long-term survival outcomes, compared with open thoracotomy.

Evaluation of Postoperative Radiotherapy Effect on Survival of Resected Stage III-N2 Non-small Cell Lung Cancer Patients

Objective: The role of postoperative radiotherapy (PORT) in resected stage IIIA-N2 non-small cell lung cancer (NSCLC) patients remains controversial. This study aimed to explore the effect of PORT on survival of resected stage IIIA-N2 NSCLC patients.

Methods: Resected stage IIIA-N2 NSCLC patients aged 18 years or older were identified from the SEER (Surveillance, Epidemiology, and End Results) database from 2010 to 2015. Cox regression analysis was used to identify factors including PORT associated with survival time. A subgroup analysis of patients stratified by number of lymph node metastases was also performed. Overall survival (OS) and overall mortality were compared among the different groups.

Results: A total of 3,445 patients were included in the study. Multivariate Cox analysis showed that PORT had no significant impact on survival of patients with <6 positive lymph node [hazard ratio (HR) = 1.012, P = 0.858, 95% CI: 0.886–1.156]. Postoperative chemotherapy (POCT) (HR = 0.605, P < 0.001, 95% CI: 0.468–0.783) and PORT (HR = 0.724, P = 0.007, 95% CI: 0.574–0.914) are both favorable prognostic factors for stage IIIA-N2 patients with ≥6 positive lymph nodes. In 2,735 patients who featured <6 number of positive regional lymph nodes, patients who received PORT had better survival and lower 3-years and 5-years overall mortality rate than patients who underwent surgery only (41 vs. 28 months, P < 0.015). There was no significant difference in the survival of postoperative patients who underwent POCT in view of whether received PORT (44 vs. 53 months, P = 0.176). A total of 710 patients who featured ≥6 number of positive regional lymph node metastasis were divided into two groups by PORT. PORT did not prolong survival for postoperative patients who did not receive chemotherapy (12 vs. 15 months, P = 0.632). PORT showed a significant advantage in influencing OS in patients who received PORT combined with POCT as compared with those who received POCT only (32 vs. 25 months, P = 0.006).

Conclusions: For IIIA-N2 patients with <6 lymph node metastases, use of PORT can be encouraged to improve survival. For patients with ≥6 positive lymph nodes, PORT combined with POCT significantly improved OS and decreased overall mortality.

Surgical Results in Pathological N1 Nonsmall Cell Lung Cancer

BACKGROUND

This retrospective study investigated the prognosis of patients with pathological N1 (pN1) nonsmall cell lung cancer (NSCLC).

METHODS

We included patients with pN1 NSCLC who underwent lobectomy or pneumonectomy with mediastinal lymph node dissection and achieved complete resection (R0) between January 2000 and December 2012. Patients who received neoadjuvant therapy were excluded.

RESULTS

A total of 249 patients were included. The mean age was 63.2 years, and 172 patients were males. Of the 249 patients, 200, 20, and 29 underwent lobectomy, bilobectomy, and pneumonectomy, respectively. The median observation period was 5.5 years. The 5-year overall survival (OS) rate was 64.6% (95% confidence interval: 58.3-70.4). Five-year OS rates were 79.8% for positive lymph nodes at station 13 or 14 (n = 57), 59.6% at station 12 (n = 72), 62.7% at station 11 (n = 69), and 56.9% at station 10 (n = 51) (log-rank test; p = 0.016); furthermore, the 5-year OS rate was 75.2% for patients with positive lymph nodes at a single station (n = 160) and 45.4% for patients with positive lymph nodes at multiple stations (n = 89) (log-rank test; p < 0.001). Five-year cumulative incidences of recurrence were equivalent between patients who received adjuvant chemotherapy and patients who did not (45.9 vs. 55.1%; Gray's test; p = 0.366). Distant recurrence was the most frequent mode of recurrence in both groups (70.8 and 67.3%).

CONCLUSION

The locations and the number of stations of the positive lymph nodes were identified as prognostic factors in patients with pN1 NSCLC. The primary mode of recurrence was distant recurrence irrespective of postoperative adjuvant chemotherapy.

Prognostic impact of the number of involved lymph node stations in patients with completely resected non-small cell lung cancer: a proposal for future revisions of the N classification

OBJECTIVE

The current nodal staging for lung cancer is defined only by the anatomical site of metastasis. However, the International Association for the Study of Lung Cancer (IASLC) proposed further subdivisions of the N descriptor that considers the locations and numbers of involved lymph node stations. This study aimed to test the new IASLC categories and compare their prognostic abilities to those of our proposed model that considers only the number of involved lymph node stations instead of the sites of metastasis.

METHODS

Between September 2002 and December 2016, 1581 patients who underwent complete resection for pathologically diagnosed Tis-4N0-2M0 non-small cell lung cancer were retrospectively analyzed. We evaluated the survival rates according to the patients' N classification as recently proposed by the IASLC and by the number of involved lymph node stations, and determined the optimal N classification.

RESULTS

The 5-year survival rates for patients with IASLC stages N1a, N1b, N2a1, N2a2, and N2b were 71.5%, 49.9%, 73.7%, 62.1%, and 46.9%, respectively. These results showed relatively good categorizations; however, some prognostic overlaps existed and not all differences were significant. After redefining the number of involved stations as Nα for 1, Nβ for 2-3, and Nγ for ≥ 4 without considering the metastasis sites, the 5-year survival rates for patients in these categories were 72.1%, 58.3%, and 29.6%, respectively; the differences between them were significant.

CONCLUSION

The number of involved lymph node stations is a more accurate prognostic indicator in patients with completely resected non-small cell lung cancer.

Myeloid-derived suppressor cells infiltration in non-small-cell lung cancer tumor and MAGE-A4 and NY-ESO-1 expression

Cancer/testis antigens melanoma-associated antigen 4 (MAGE-A4) and New York esophageal squamous cell carcinoma-1 (NY-ESO-1) are of clinical interest as biomarkers and present valuable targets for immunotherapy; however, they are poor prognostic markers in non-small cell lung cancer (NSCLC). In addition, myeloid derived suppressor cells (MDSCs) are recognized as a key element in tumor escape and progression. The aim of the present study was to investigate the diagnostic and prognostic value of MAGE-A4 and NY-ESO-1, and their association with MDSCs in NSCLC samples. The expression levels of MAGE-A4 and NY-ESO-1, and the infiltration of MDSCs (CD33⁺), were analyzed by immunohistochemistry of 67 tissue samples from patients with NSCLC. Overall, 58.33% of the NSCLC squamous cell carcinoma tissues and 94.7% of adenocarcinoma tissues were positive for MAGE-A4. NY-ESO-1 expression was observed in 52.78% of the squamous cell carcinoma tissues and 80% of the adenocarcinoma tissues. In primary adenocarcinoma tumor tissues, MAGE-A4 and NY-ESO-1 demonstrated a higher intensity of expression compared with the squamous cell carcinoma tissues. A total of 33 (91.7%) squamous cell carcinoma and 19 (95.0%) adenocarcinoma specimens were positive for CD33. The expression of MAGE-A4 and NY-ESO-1 antigens and infiltration of MDSCs was associated with poor prognosis of patients with NSCLC. Further studies investigating the association between these findings and underlying molecular mechanisms are required.