Including positive lymph node count in the AJCC N staging may be a better predictor of the prognosis of NSCLC patients, especially stage III patients: a large population-based study

BACKGROUND

The study was designed to explore the value of including positive lymph node count in the TNM staging system of non-small cell lung cancer.

PATIENTS AND METHODS

The X-tile model was applied to determine the cutoff values of positive lymph node count. Survival curves were generated using the Kaplan-Meier method and differences in survival among subgroups were examined using the log-rank test. The influence of different variables on overall survival and lung cancer-specific survival was further evaluated using univariate and multivariate Cox proportional hazard models. All statistical analyses were performed using SPSS version 22.0 (SPSS, Chicago, IL, USA). All p values were 2-sided and p < 0.05 was considered statistically significant.

RESULTS

The overall survival and lung cancer-specific survival between stage IIIA and IIIB classified by the sixth edition TNM staging system show no statistically significant difference (p = 0.479 for overall survival; p = 0.081 for lung cancer specific survival). The X-tile model was used to screen three different cutoff values including nN = 0, nN1-3 and nN4-. The nN value is a significant independent prognostic factor that affects overall survival and lung cancer-specific survival of non-small cell lung cancer patients (all, p < 0.001). We obtained the hypothesized TNM sub-stages based on location and the number of PLN. There were significant differences between the hypothesized stage IIIA and IIIB regarding overall survival and lung cancer-specific survival (all, p < 0.001).

CONCLUSIONS

It needs to be considered that N stage in combination with positive lymph node count may be used to predict the prognosis of non-small cell lung cancer for stage III cases with increased accuracy than category location-based stage.

Prognostic Impact of the Number of Metastatic Lymph Nodes on the Eighth Edition of the TNM Classification of NSCLC

INTRODUCTION

Current nodal staging of NSCLC is defined only by anatomical location of lymph nodes (LNs). The aim of this study is to investigate prognostic impacts of the number of metastatic LNs by stratifying the present N classification.

METHODS

We analyzed 1989 patients with NSCLC who underwent complete resection by lobectomy or pneumonectomy involving dissection of the hilar and mediastinal LNs from 2003 to 2012. We classified patients according to the number of metastatic nodes and stations and their current category of metastatic LNs. We analyzed the overall survival in each group and assessed the survival impact of the combination of them.

RESULTS

In the multivariate analyses of all patients, pathological N1 (pN1) (reference [ref.] pN2) and single-node metastasis (ref. multiple-node) were independent prognostic factors whereas single-station metastasis (ref. multiple-station) was not. In the respective multivariate analyses of pN1 and pN2 disease, multiple-node metastasis (ref. single-node) was an independent prognostic factor in pN1 disease (hazard ratio: 1.41, p = 0.04), but not in pN2 disease. Investigation for other boundaries of a number of metastatic LNs of three or more (ref. one to two), four or more (ref. one to three), and five or more (ref. one to four) found that all of them were independent prognostic factors in both pN1 and pN2 diseases.

CONCLUSIONS

The number of metastatic LNs had a strong impact on survival in addition to the current pN classification. To clarify its prognostic impact, further study is needed in other datasets including patients treated by nonsurgical modalities.

Proposal of a new nodal classification for operable non-small cell lung cancer based on the number of negative lymph nodes and the anatomical location of metastatic lymph nodes

Lymph node metastasis is one of the most important prognostic indicators in patients with radically resected non-small cell lung cancer (NSCLC). This retrospective study aimed to compare the predictive value of metastatic lymph nodes (MNs), lymph node ratio (LNR), resected lymph nodes (RNs), and negative lymph nodes (NNs) with the currently used pathologic nodal (pN) staging category.We conducted a retrospective analysis of 1019 consecutive NSCLC patients treated with complete resection in a single institution. Prognostic values of various lymph node factors were evaluated by analysis of univariate and multivariate Cox proportional hazards model, and the results were compared with those using the location-based pN stage classification.The median follow-up duration was 47 months. During this period, 353 cases of cancer recurrence and 337 deaths were reported. Multivariate cox analysis indicated that both pN and NN categories were independent predictors of patient survival. The patients were divided into six groups on the basis of pN and NN categories. The survival rates of the groups were as follows: pN0, NN≥8, 81.4%; pN0, NN<8, 73.8%; pN1, NN≥8, 61.4%; pN1, NN<8, 54.2%; pN2, NN≥8, 48.4%; and pN2>1, NN<8, 35.0%. Comparison of the predictive values of the lymph node factors showed that the new N category was a more valuable prognostic factor in operable NSCLC.The combination of anatomically based pN stage classification and the number of MNs is an accurate prognostic determinant in patients with operable NSCLC which can be equal to 8th N category.

New revisions and current issues in the eighth edition of the TNM classification for non-small cell lung cancer

In the eighth edition of the TNM classification of lung cancer, the prognostic impact of tumor size is emphasized as a descriptor of all T categories. Especially in lung cancer where tumor size is 5 cm or less, the 1-cm cutoff point significantly differentiated the survival outcome. In addition, the new staging categories were assigned, namely, Tis (adenocarcinoma in situ) and T1mi (minimally invasive adenocarcinoma). Furthermore, the measurement of a radiological solid component size excluding the ground glass opacity component or pathological invasive size without a lepidic component was proposed for deciding the cT/pT categories for lung adenocarcinoma. The N descriptors were kept the same as in the eventh edition on the whole, however, quantification of nodal disease had a prognostic impact based on the number of nodal stations involved in the eighth edition, i.e. N1a as a single N1 station, N1b as a multiple N1 station, N2a1 as a single N2 station without N1 (skip metastasis), N2a2 as a single N2 station with N1 disease, and N2b as a multiple N2 station. In the M descriptors, subclassification was performed based on the location or numbers of distantly metastatic lesions, i.e. M1a as any intrathoracic metastases, M1b as a single distant metastatic lesion in one organ, and M1c as multiple distant metastases in either a single organ or multiple organs. Survival analysis of the eighth edition of the TNM classification clearly separated the distinct groups, however, unsolved issues still remain that should be discussed and further revised for the forthcoming TNM staging system.

Systematic and combined endosonographic staging of lung cancer (SCORE study)

Guidelines recommend endosonography for mediastinal nodal staging in patients with resectable nonsmall cell lung cancer (NSCLC). We hypothesise that a systematic endobronchial ultrasound (EBUS) evaluation combined with an oesophageal investigation using the same EBUS bronchoscope (EUS-B) improves mediastinal nodal staging versus the current practice of targeted positron emission tomography (PET)-computed tomography (CT)-guided EBUS staging alone.A prospective, multicentre, international study (NCT02014324) was conducted in consecutive patients with (suspected) resectable NSCLC. After PET-CT, patients underwent systematic EBUS and EUS-B. Node(s) suspicious on CT, PET, EBUS and/or EUS-B imaging and station 4R, 4L and 7 (short axis ≥8 mm) were sampled. For patients without N2/N3 disease determined on endosonography, surgical-pathological staging was the reference standard.229 patients were included in this study. The prevalence of N2/N3 disease was 103 out of 229 patients (45%). A PET-CT-guided targeted approach by EBUS identified 75 patients with N2/N3 disease (sensitivity 73%, 95% CI 63-81%; negative predictive value (NPV) 81%, 95% CI 74-87%). Four additional patients with N2/N3 disease were found by systematic EBUS (sensitivity 77%, 95% CI 67-84%; NPV 84%, 95% CI 76-89%) and five more by EUS-B (84 patients total; sensitivity 82%, 95% CI 72-88%; NPV 87%, 95% CI 80-91%). Additional clinical relevant staging information was obtained in 23 out of 229 patients (10%).Systematic EBUS followed by EUS-B increased sensitivity for the detection of N2/N3 disease by 9% compared to PET-CT-targeted EBUS alone.

Predicting prognosis of post-chemotherapy patients with resected IIIA non-small cell lung cancer

Background

Recently, nomogram has been widely used in cancer prognoses. However, the predicting model for post-chemotherapy patients with resected IIIA non-small cell lung cancer (NSCLC) still remains scarce. Here, we tried to develop nomograms for predicting the recurrence and survival of these patients.

Methods

We retrospectively analyzed our database from October 2007 to May 2013 at Fudan University Shanghai Cancer Center. 437 qualified patients were included. Univariable and multivariable analyses of cox regression were performed successively to select prognostic factors and nomograms for recurrence-free survival (RFS) and overall survival (OS) were developed. Concordance indexes (C-index) and calibration curves were created to measure the consistency between predicted and actual survivals. Finally, risk group stratifications according to risk scores calculated from nomograms were delineated.

Results

With a total of 437 patients, five independent prognostic factors related to RFS and two to OS were selected to develop nomograms, respectively. Both 3- and 5-year RFS and OS calibration curves indicated a moderate concordance between the predicted and actual outcomes, consisted with the C-index 0.656 (95% CI: 0.626-0.687) for RFS and 0.651 (95% CI: 0.611-0.691) for OS. Different risk groups showed significant differences in RFS and OS.

Conclusions

We developed nomograms of RFS and OS for predicting recurrence and survival of post-chemotherapy patients with resected IIIA NSCLC. These nomograms could help doctors more easily estimate the prognosis and choose optimal decisions for individual during clinical practices.

Five-year survival analysis and prognostic factors in patients operated on for non-small cell lung cancer with N2 disease

Background

The aim of the study is to analyse 5-year survival and prognostic factors in patients operated due to lung cancer with postoperatively confirmed metastases to N2 group nodes.

Methods

In the years 2007-2015, 1,148 patients with lung cancer were treated surgically. A postoperative histopathological study confirmed N2 feature in 150 patients. One hundred and ten patients, in whom a 5-year survival analysis was possible to perform, were included in such analysis. The patients underwent the following procedures: pneumonectomy, 31 patients; lobectomy, 61; bilobectomy, 10; and wedge resection, 8. All patients were subjected to supplementary treatment after the surgery.

Results

Five-year survival was achieved in 23 patients (21%). The patients' survival did not depend on the type of surgery, type of tumour, its location or presence of metastases in N1 nodes (P=0.82, P=0.51, P=0.36 and P=0.23, respectively). A statistically significant correlation was observed (P=0.01) between the 5-year survival of a patient and the occurrence of metastases only in one group of lymph nodes of the N2 feature (22 patients, 20%). Involvement of three or more mediastinal nodal groups resulted in survival shorter than 5-year.

Conclusions

(I) In patients with the N2 feature, the type of performed surgery, type of tumour and the occurrence of metastases in the lymph nodes of the lung hilum do not affect 5-year survival; (II) involvement of only one nodal group allows to achieve 5-year survival in 20% of patients; (III) involvement of three and more nodal groups with the N2 feature results in decreased 5-year survival.

Analyzing EGFR mutations and their association with clinicopathological characteristics and prognosis of patients with lung adenocarcinoma

Epidermal growth factor receptor (EGFR) is an important gene in the development of lung adenocarcinoma. However, there is controversy regarding the association between EGFR mutations and survival time of patients with lung adenocarcinoma. In the present study, tissue specimens and clinical data were collected from 219 patients with lung adenocarcinoma who had not undergone prior radiotherapy or chemotherapy. EGFR mutations were detected using a fluorescence polymerase chain reaction method, and the association between EGFR mutations and clinicopathological characteristics was analyzed. Overall survival (OS) curves were constructed using the Kaplan-Meier method and the influence of clinicopathological characteristics on OS was analyzed using the Cox regression model. The EGFR mutation rate was 50.7%, and the most common mutations were the L858R substitution mutation in exon 21 (L858R; 54.9%) and the deletion mutation in exon 19 (19-Del; 36%). The presence of EGFR mutations varied significantly with sex, smoking history, T stage, vascular invasion and adenocarcinoma subtypes (P<0.05). The survival time was significantly longer for female, young (<60 years-old), non-smokers or patients exhibiting EGFR mutations (G719X, 19-Del, L858R and L861Q). The survival time was also significantly longer for patients with a 19-Del mutation, early stage tumors, tyrosine kinase inhibitors targeted therapy-treated patients, for those not exhibiting nerve or vascular invasion, and for those without disease recurrence (P<0.05). Multivariate analysis revealed that tumor pathological Tumor-Node-Metastasis (pTNM) stage, nerve invasion, vascular invasion, EGFR mutation and the 19-Del mutation were independent predictors (P<0.05). Therefore, tumor pTNM stage, nerve invasion, vascular invasion and EGFR mutation status, particularly that of 19-Del, were independent prognostic factors for patients with lung adenocarcinoma.

Staging Lung Cancer: Regional Lymph Node Classification

This article reviews regional lymph node assessment in lung cancer. In the absence of a distant metastasis, the absence or location of lung cancer spread to a regional mediastinal lymph node affects treatment options and prognosis. Regional lymph node maps have been created to standardize assessment of the N descriptor. The International Association for the Study of Lung Cancer lymph node map is used for the standardization of N descriptor assessment. CT, PET/CT with fluorodeoxyglucose, endobronchial ultrasound-guided and/or esophageal ultrasound-guided biopsy, and mediastinoscopy are common modalities used to determine the N descriptor.

Current Controversies in Lung Cancer Staging

Lung cancer remains the leading cause of cancer-related mortality in the United States, and accurate staging of disease plays an important role in the formulation of treatment strategies and optimization of patient outcomes. The International Association for the Study of Lung Cancer has recently proposed changes to the upcoming eighth edition of the tumor, node, and metastasis (TNM-8) staging system used for lung cancer. This revised classification is based on significant differences in patient survival identified on analysis of a new large international database of lung cancer cases. Key changes include: further modifications to the T descriptors based on 1 cm increments in tumor size; grouping of tumors resulting in partial or complete lung atelectasis/pneumonitis; grouping of tumors involving a main bronchus with respect to distance from the carina; reassignment of diaphragmatic invasion; elimination of mediastinal pleural invasion as a descriptor; and further subdivision of metastatic disease into distinct descriptors based on the number of extrathoracic metastases and involved organs. Because of these changes, several new stage groups have been developed, and others have shifted. Although TNM-8 represents continued improvement upon modifications previously made to the staging system, reflecting an evolving understanding of tumor behavior and patient management, several limitations and unaddressed issues persist. Understanding the proposed revisions to TNM-8 and awareness of key limitations and potential controversial issues still unaddressed will allow radiologists to accurately stage patients with lung cancer and optimize treatment decisions.

Lymph node volume predicts survival but not nodal clearance in Stage IIIA-IIIB NSCLC

BACKGROUND

Locally advanced non-small cell lung cancer (LA-NSCLC) patients have poorer survival and local control with mediastinal node (N2) tumor involvement at resection. Earlier assessment of nodal burden could inform clinical decision-making prior to surgery. This study evaluated the association between clinical outcomes and lymph node volume before and after neoadjuvant therapy.

MATERIALS AND METHODS

CT imaging of patients with operable LA-NSCLC treated with chemoradiation and surgical resection was assessed. Clinically involved lymph node stations were identified by FDG-PET or mediastinoscopy. Locoregional recurrence (LRR), distant metastasis (DM), progression free survival (PFS) and overall survival (OS) were analyzed by the Kaplan Meier method, concordance index and Cox regression.

RESULTS

73 patients with Stage IIIA-IIIB NSCLC treated with neoadjuvant chemoradiation and surgical resection were identified. The median RT dose was 54 Gy and all patients received concurrent chemotherapy. Involved lymph node volume was significantly associated with LRR and OS but not DM on univariate analysis. Additionally, lymph node volume greater than 10.6 cm3 after the completion of preoperative chemoradiation was associated with increased LRR (p<0.001) and decreased OS (p = 0.04). There was no association between nodal volumes and nodal clearance.

CONCLUSION

For patients with LA-NSCLC, large volume nodal disease post-chemoradiation is associated with increased risk of locoregional recurrence and decreased survival. Nodal volume can thus be used to further stratify patients within the heterogeneous Stage IIIA-IIIB population and potentially guide clinical decision-making.

[The new TNM classification for lung tumors : Changes and the assessment of multiple tumor foci]

Recently a new TNM classification for tumors of the lung was published, encompassing some relevant changes, for example how to deal with multiple lung tumors. This article comprehensively describes respective changes. Furthermore, background information on how the new TNM classification was built and what should be done in the future to further improve prognosis and outcome prediction is reviewed.

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for the Revision of the N Descriptors in the Forthcoming 8th Edition of the TNM Classification for Lung Cancer

INTRODUCTION

Nodal status is considered to be one of the most reliable indicators of the prognosis in patients with lung cancer and thus is indispensable in determining the optimal therapeutic options. We sought to determine whether the current nodal (N) descriptors should be maintained or revised for the next edition (8th) of the International Lung Cancer Staging System.

METHODS

The new International Association for the Study of Lung Cancer lung cancer database was created from 94,708 patients diagnosed as having lung cancer between 1999 and 2010. Among these, 38,910 and 31,426 patients with non-small-cell lung carcinoma were available for an analysis of the clinical (c)N and pathological (p)N status, respectively. The anatomical location of lymph node involvement was defined by either the Naruke (for Japanese data) or American Thoracic Society (for non-Japanese data) nodal charts. Survival was calculated by the Kaplan-Meier method, and prognostic groups were assessed by a Cox regression analysis.

RESULTS

The current N0 to N3 descriptors for both the cN and pN status consistently separated prognostically distinct groups. The 5-year survival rates according to the cN and pN status were 60% and 75% (N0), 37% and 49% (N1), 23% and 36% (N2), and 9% and 20% (N3), respectively. The differences in survival between all neighboring nodal categories were highly significant for both the cN and pN status. With regard to pathological staging, additional analyses regarding the prognosis were performed by further dividing N1 into N1 at a single station (N1a) and N1 at multiple stations (N1b); N2 into N2 at a single station without N1 involvement ("skip" metastasis, N2a1), N2 at a single station with N1 involvement (N2a2), and N2 at multiple stations (N2b). The survival curves for N1b and N2a2 overlapped each other, and N2a1 had numerically a better prognosis than N1b, although the difference was not significant. Geographic difference in N-specific prognosis was observed for both c-settings and p-settings. This might have been because of the difference in the used nodal map, surgical technique, and pathologist's handling of the resected specimen.

CONCLUSIONS

Current N descriptors adequately predict the prognosis and therefore should be maintained in the forthcoming staging system. Furthermore, we recommend that physicians record the number of metastatic lymph nodes (or stations) and to further classify the N category using new descriptors, such as N1a, N1b, N2a, N2b, and N3, for further testing.

Survival Prediction Model Using Clinico-Pathologic Characteristics for Nonsmall Cell Lung Cancer Patients After Curative Resection

The current TNM staging system did not provide disease relapse information. The aim of study was try to establish a predictive survival model for disease and overall survival in nonsmall cell lung cancer patients who presented as resectable disease and to develop a reference for follow-up imaging tool selection.From January 2005 to December 2011, 442 patients who initially presented as resectable disease (stages I-IIIa) and received anatomic resection and mediastinal lymph node dissection were included in the study.Medical charts were thoroughly reviewed and clinico-pathologic factors were collected and analyzed.Visceral pleural invasion, tumor size >5 cm, and postoperative adjuvant therapy were identified as risk factors for poorer disease-free survival. The 5-year disease-free survival from score 0 to 3 was 68.7%, 46.6%, 31.9%, and 26.1%, respectively. The disease relapse percentage for scores 0 to 3 were 26.49%, 50.61%, 65.05%, and 73.81%, respectively. For analysis of overall survival, age >60 years, tumor size >3 cm, and total metastatic lymph node ratio >0.05 were correlated to worse overall survival. Because greater age may be correlated with poor general condition, we re-scored risk factors that correlated to disease severity that ranging from 0 to 2. The 5-year overall survival range from score 0 to 2 was 56.3%, 43.1%, and 13.1%, respectively.Poor prognostic factors correlated to disease-free survival were tumor size >5 cm, visceral pleural invasion, and patients needing to receive postoperative adjuvant therapy. Disease-free survival of resectable nonsmall cell lung cancer patients and disease relapse can be stratified by these 3 factors. Chest tomography may be recommended for patients with 1 or more poor disease-free survival risk factors.

Number of mediastinal lymph nodes as a prognostic factor in PN2 non small cell lung cancer: a single centre experience and review of the literature

Currently the most important prognostic factor in lung cancer is the stage. In the current lung TNM classification system, N category is defined exclusively by anatomic nodal location though, in other type of tumours, number of lymph nodes is confirmed to be a fundamental prognostic factor. Therefore we evaluated the number of mediastinal lymph nodes as a prognostic factor in locally advanced NSCLC after multimodality treatment, observing a significant effect of the number of lymph nodes in terms of OS (p<0.01) and DFS (p<0.001): patients with a low number of positive mediastinal nodes have a better prognosis.

Prognostic Factors for Survival After Recurrence in Patients With Completely Resected Lung Adenocarcinoma: Important Roles of Epidermal Growth Factor Receptor Mutation Status and the Current Staging System

Epidermal growth factor receptor (EGFR) status and pathological stage (p-stage) were shown to be essential prognostic factors for estimating survival after recurrence of lung adenocarcinoma. In patients with EGFR mutations, those with early p-stage tumors showed better survival after disease recurrence than those with advanced p-stage tumors. The EGFR mutation status and p-stage could also prompt the design of clinical trials on adjuvant therapy for patients after complete surgical resection.

BACKGROUND

The current staging system and epidermal growth factor receptor (EGFR) mutation status are key factors for predicting survival. However, the significance of these factors as predictors of survival after disease recurrence (PRS) has not been sufficiently elucidated. The objective of this study was to investigate the clinicopathological factors, particularly the EGFR mutation status and pathological stage (p-stage), which affect PRS in patients with completely resected lung adenocarcinoma.

PATIENTS AND METHODS

We retrospectively reviewed the data of 198 consecutive lung adenocarcinoma patients with disease recurrence who previously underwent complete surgical resection in our hospital.

RESULTS

Of the 198 patients, 117 were examined for EGFR mutations (mutants). Mutants were detected in 57 patients (28.7%). The patients with mutants had a significantly better 3-year PRS (3y-PRS) rate (68.6%) than those with an EGFR wild type (WT) status (51.7%) or an unknown (UN) status (27.0%). The 3y-PRS rates for p-stage I to II (p-I-II) and p-stage III (p-III) were 52.5% and 29.3%, respectively. Multivariate survival analysis showed that the EGFR mutation status and p-stage had significant associations with favorable PRS. The 3y-PRS rate for mutants/p-I-II (81.4%) was significantly better than that for mutants/p-III (48.0%). Conversely, there was no significant difference between mutants/p-III and WT/UN/p-I-II (3y-PRS: 40.7%) or between mutants/p-III and WT/UN/p-III (3y-PRS: 24.4%).

CONCLUSION

EGFR status and p-stage were shown to be essential prognostic factors for estimating PRS. In patients with mutants, those with early p-stage tumors showed better PRS than those with advanced p-stage tumors.

A comparison of the proposed classifications for the revision of N descriptors for non-small-cell lung cancer

OBJECTIVES

Several new classifications have been proposed for revision of the N descriptors for non-small-cell lung cancer (NSCLC), but external validation is required. The aim of this study was to validate various newly proposed nodal classifications and to compare the discrimination abilities of these classifications.

METHODS

A retrospective analysis was conducted of 1487 patients who underwent complete resection with systematic lymph node dissection for NSCLC between 2000 and 2008. Four nodal classifications based on the following categories were analysed: zone-based classification (single-zone N1, multiple-zone N1, single-zone N2 and multiple-zone N2), number-based classification (the number of metastatic lymph nodes; 1-2, 3-6 and ≥7), rate-based classification (ratio of the number of metastatic lymph nodes to the total number of resected lymph nodes; ≤15, 15-40 and >40%) and the combination of location- and number-based classification (N1: 1-3, N1: ≥4, N2: 1-3 and N2: ≥4). Concordance (C)-index and net reclassification improvement (NRI) index were used to assess the discrimination abilities of the models.

RESULTS

In multivariate analysis, all of the newly proposed classifications were independent predictors (P < 0.001) of overall survival (OS) after adjustment for significant variables (age, tumour histology and pathological T status). The C-indices of the classifications based on the nodal zone, nodal number, rate and location alongside the number of metastatic lymph nodes were 0.6179, 0.6280, 0.6203 and 0.6221, respectively; however, the differences in the C-indices were statistically insignificant. Compared with the zone-based classification, the NRI for OS of classifications based on the nodal number, rate and location with number were 0.1101, 0.0972 and 0.0416, respectively.

CONCLUSIONS

All four proposed classifications based on the nodal zone, nodal number, rate and the combination of location and number are prognostically valid and could serve as future N descriptors after complete resection of NSCLC. The discrimination ability was not significantly different among the four proposed classifications, although the number-based classification tended to have a higher predictive ability compared with the zone-based classification. Future studies with an in-depth discussion are needed to clarify optimal future N descriptors for NSCLC.