Comment on the Proposals for the Revision of the N Descriptors in the Forthcoming Eighth Edition of the TNM Classification for Lung Cancer

Assessment of textbook outcome after lobectomy for early‐stage non‐small cell lung cancer in a Korean institution: A retrospective study

Background

Textbook outcome (TO) has been introduced as a novel composite measure for lung cancer surgery. We investigated TO after lobectomy for early‐stage non‐small cell lung cancer (NSCLC) in a Korean tertiary hospital and its prognostic implications for overall survival and recurrence.

Methods

Between January 2012 and December 2017, 418 consecutive patients who underwent lobectomy for clinical stages I and II NSCLC were identified and retrospectively reviewed. TO was defined as complete resection (negative resection margins and sufficient lymph node dissection), no 30‐day or in‐hospital mortality, no reintervention within 30 days, no readmission to the intensive care unit, no prolonged hospital stay (<14 days), no hospital readmission within 30 days, and no major complications. Propensity score matching analysis was performed to investigate the association between TO, medical costs, and long‐term outcomes.

Results

Of 418 patients, 277 (66.3%) achieved TO. The most common events leading to TO failure were prolonged air leakage (n = 54, 12.9%) and prolonged hospital stay (n = 53, 12.7%). Male sex (odds ratio [OR] = 2.148, p = 0.036) and low diffusing capacity for carbon monoxide (OR = 0.986, p = 0.047) were significant risk factors for failed TO in multivariate analysis. In matched cohorts, achieving TO was associated with lower medical costs and better overall survival but not cancer recurrence.

Conclusions

TO is associated with low medical cost and favorable overall survival; thus, surgical teams and hospitals should make efforts to improve the quality of care and achieve TO.

Expression Level and Clinical Significance of AK021443 in Non-Small-Cell Lung Carcinoma

To explore the prognostic potential of AK021443 in non-small-cell lung carcinoma (NSCLC), AK021443 levels in NSCLC specimens were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between the AK021443 level and pathological factors in NSCLC patients was analyzed. Kaplan-Meier curves were plotted for assessing the prognostic value of AK021443 in NSCLC patients. Potential factors influencing NSCLC prognosis were analyzed by multivariable Cox regression test. AK021443 was upregulated in NSCLC specimens than normal ones. Its level was correlated to histological type, tumor differentiation, TNM staging, and lymphatic metastasis in NSCLC patients. AK021443 was the independent risk factor for the overall survival of NSCLC. AK021443 is highly expressed in NSCLC specimens, which is correlated to histological type, tumor differentiation, TNM staging, and lymphatic metastasis in NSCLC patients. It is the independent prognostic factor for NSCLC.

Prognostic Value of the Glasgow Prognostic Score on Overall Survival in patients with Advanced Non-Small Cell Lung Cancer

Background: Findings from previous studies regarding the association between the Glasgow Prognostic Score (GPS) and overall survival (OS) of patients with advanced non-small cell lung cancer (NSCLC) were limited. This study aimed to investigate the prognostic value of GPS in patients with advanced NSCLC after adjusting for potential confounding factors. Methods: A retrospective cohort study was conducted in 494 patients with advanced NSCLC between 2009 and 2019. Clinicopathological characteristics (including GPS) were analyzed to determine predictors of OS using univariate and multivariate Cox proportional hazards models. Survival curves were estimated using the Kaplan-Meier method. Results: Of the enrolled patients with advanced NSCLC, 66.46% were men and 53.85% were aged <60 years. The percentages of GPS scores of 0, 1, and 2 were 36.44%, 36.03%, and 27.53%, respectively. The median OS of the GPS 0, 1, and 2 groups were 23.27, 14.37, and 10.27 months, respectively (log-rank P <0.0001). A higher GPS was independently associated with an increased risk of death (P for trend = 0.0004) after full adjustment for potential confounders. The risk of death increased by 77% in the GPS 1 group (hazard ratio [HR]=1.77, 95% confidence interval [CI]=1.22-2.57, P=0.0027) and 109% in the GPS 2 group (HR=2.09, 95%CI=1.36-3.22, P=0.0008) compared with the GPS 0 group after adjustment. We did not find significant heterogeneity among the analyzed subgroups apart from sex (P interaction=0.017). Conclusion: High pretreatment GPS is independently associated with worse OS in patients with advanced NSCLC. GPS should be considered in patient counseling and decision-making and needs to be further validated by large-cohort and prospective studies.

Outcomes After Use of a Lymph Node Collection Kit for Lung Cancer Surgery: A Pragmatic, Population-Based, Multi-Institutional, Staggered Implementation Study

INTRODUCTION

Suboptimal pathologic nodal staging prevails after curative-intent resection of lung cancer. We evaluated the impact of a lymph node specimen collection kit on lung cancer surgery outcomes in a prospective, population-based, staggered implementation study.

METHODS

From January 1, 2014, to August 28, 2018, we implemented the kit in three homogeneous institutional cohorts involving 11 eligible hospitals from four contiguous hospital referral regions. Our primary outcome was pathologic nodal staging quality, defined by the following evidence-based measures: the number of lymph nodes or stations examined, proportions with poor-quality markers such as nonexamination of lymph nodes, and aggregate quality benchmarks including the National Comprehensive Cancer Network criteria. Additional outcomes included perioperative complications, health care utilization, and overall survival.

RESULTS

Of 1492 participants, 56% had resection with the kit and 44% without. Pathologic nodal staging quality was significantly higher in the kit cases: 0.2% of kit cases versus 9.8% of nonkit cases had no lymph nodes examined; 3.2% versus 25.3% had no mediastinal lymph nodes; 75% versus 26% attained the National Comprehensive Cancer Network criteria (p < 0.0001 for all comparisons). Kit cases revealed no difference in perioperative complications or health care utilization except for significantly shorter duration of surgery, lower proportions with atelectasis, and slightly higher use of blood transfusion. Resection with the kit was associated with a lower hazard of death (crude, 0.78 [95% confidence interval: 0.61-0.99]; adjusted 0.85 [0.71-1.02]).

CONCLUSIONS

Lung cancer surgery with a lymph node collection kit significantly improved pathologic nodal staging quality, with a trend toward survival improvement, without excessive perioperative morbidity or mortality.

Comparative Effectiveness of a Lymph Node Collection Kit Versus Heightened Awareness on Lung Cancer Surgery Quality and Outcomes

INTRODUCTION

The adverse prognostic impact of poor pathologic nodal staging has stimulated efforts to heighten awareness of the problem through guidelines, without guidance on processes to overcome it. We compared heightened awareness (HA) of nodal staging quality versus a lymph node collection kit.

METHODS

We categorized curative-intent lung cancer resections from 2009 to 2020 in a population-based, nonrandomized stepped-wedge implementation study of both interventions, into preintervention baseline, HA, and kit subcohorts. We used differences in proportion and hazard ratios across the subcohorts to estimate the effect of the interventions on poor quality (nonexamination of nodes [pNX] or nonexamination of mediastinal lymph nodes) and attainment of quality recommendations of the National Comprehensive Cancer Network, the Commission on Cancer, and the proposed complete resection definition of the International Association for the Study of Lung Cancer across the three cohorts.

RESULTS

Of 3734 resections, 39% were preintervention, 40% kit, and 21% HA cases. Cohort proportions were the following: pNX, 11% (baseline) versus 0% (kit) versus 9% (HA); nonexamination of mediastinal lymph nodes, 27% versus 1% versus 22%; Commission on Cancer benchmark attainment, 14% versus 77% versus 30%; International Association for the Study of Lung Cancer-defined complete resection, 11% versus 58% versus 24%; National Comprehensive Cancer Network attainment, 23% versus 79% versus 35% (p < 0.001 for all, except pNX rate baseline versus HA). Survival rate was significantly higher for both interventions compared with baseline (p < 0.0001).

CONCLUSIONS

Resections with HA or the kit significantly improved surgical quality and outcomes, but the kit was more effective. We propose to conduct a prospective, institutional cluster-randomized clinical trial comparing both interventions.

The influence of the number of lymph nodes removed on the accuracy of a newly proposed N descriptor classification in patients with surgically-treated lung cancer

INTRODUCTION

The International Association for the Study of Lung Cancer has proposed a new classification of N descriptor based on the number of metastatic lymph nodes (LNs) stations, including skip metastasis. The aim of the study was to determine the effect of removed LNs on the adequacy of this new classification.

MATERIALS AND METHODS

The material was collected retrospectively based on the database of the Polish Lung Cancer Group, including information on 8016 patients with non-small cell lung cancer operated in 23 thoracic surgery centers in Poland. The material covered the period from January 2005 to September 2015. We divided patients into two groups: ≤6LNs and >6LNs removed.

RESULTS

In the whole group, an average of 13.4 nodes and 4.54 nodal stations were removed. 5-year survivals in the >6LNs group vs ≤ 6LNs group were: 62.3% and 55.1% (N0), 44.5% and 35.9% (N1a), 34.1% and 31,7% (N1b), 37.3% and 26.3% (N2a1), 32.4% and 26.7% (N2a2), 29.4% and 29.2% (N2b1), and 22.0% and 23.0% (N2b2), respectively. Comparing these groups, we detected significant differences at N0 (p < 0.001) and N2a1 (p = 0.022). In the ≤6LNs group, the survival curves for N2a1, N2a2, N2b1, and N2b2 overlapped (p > 0.05). In the >6LNs group, the survival curves were significantly different between grades, with survival for N2a1 better than N1b (p = 0.232).

CONCLUSION

The proposed classification N descriptor is potentially better at differentiating patients into different stages. The accuracy of the classification depends on the number of lymph nodes removed. Therefore, the extent of lymphadenectomy has a significant impact on the staging of surgically-treated lung cancer.

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.

Survival After Mediastinal Node Dissection, Systematic Sampling, or Neither for Early Stage NSCLC

INTRODUCTION

The American College of Surgeons Oncology Group Z0030 found no survival difference between patients with early stage NSCLC who had mediastinal nodal dissection or systematic sampling. However, a meta-analysis of 1980 patients in five randomized controlled trials from 1989 to 2007 associated better survival with nodal dissection. We tested the survival impact of the extent of nodal dissection in curative-intent resections for early stage NSCLC in a population-based observational cohort.

METHODS

Resections for clinical T1 or T2, N0 or nonhilar N1, M0 NSCLC in four contiguous United States Hospital Referral Regions from 2009 to 2019 were categorized into mediastinal nodal dissection, systematic sampling, and "neither" on the basis of of the evaluation of lymph node stations. We compared demographic and clinical characteristics, perioperative complication rates, and survival after assessing statistical interactions and confounding.

RESULTS

Of the 1942 eligible patients, 18% had nodal dissection, 6% had systematic sampling, and 75% had an intraoperative nodal evaluation that met neither standard. In teaching hospitals, nodal dissection was associated with a lower hazard of death than "neither" resections (0.57 [95% confidence interval: 0.41-0.79]) but not systematic sampling (0.74 [0.40-1.37]) after adjusting for multiple comparisons. There was no significant difference in hazard ratios at nonteaching institutions (p > 0.3 for all comparisons). Perioperative complication rates were not significantly worse after mediastinal nodal dissection or systematic sampling, compared with "neither," (p > 0.1 for all comparisons).

CONCLUSIONS

In teaching institutions, mediastinal nodal dissection was associated with superior survival over less-comprehensive pathologic nodal staging. There was no survival difference between teaching and nonteaching institutions, a finding that warrants further investigation.

Beyond Margin Status: Population-Based Validation of the Proposed International Association for the Study of Lung Cancer Residual Tumor Classification Recategorization

INTRODUCTION

The International Association for the Study of Lung Cancer's (IASLC's) proposal to recategorize the residual tumor (R) classification for resected NSCLC needs validation.

METHODS

Using a 2009 to 2019 population-based multi-institutional NSCLC resection cohort from the United States, we classified resections by Union for International Cancer Control (UICC) and IASLC R criteria and compared the distribution of R classification variables and their survival associations.

RESULTS

Of 3361 resections, 95.3% were R0, 4.3% were R1, and 0.4% were R2 by UICC criteria; 33.3% were R0, 60.8% were R-uncertain, and 5.8% were R1/2 by IASLC criteria; 2044 patients (63.8%) migrated from UICC R0 to IASLC R-uncertain. Median survival was not reached, 69 (95% confidence interval [CI]: 64-77), and 25 (95% CI: 18-36) months, respectively, for patients with IASLC R0, R-uncertain, and R1 or R2 resections. Failure to achieve nodal dissection criteria caused 98% of migration to R-uncertainty, metastasis to the highest mediastinal node station, 5.8%. Compared with R0, R-uncertain resections with mediastinal nodes, no mediastinal nodes, and no nodes had adjusted hazard ratios of 1.28 (95% CI: 1.10-1.48), 1.47 (95% CI: 1.24-1.74), and 1.74 (95% CI: 1.37-2.21), respectively, suggesting a dose-response relationship between nodal R-uncertainty and survival. Accounting for mediastinal nodal involvement, the highest mediastinal station involvement was not independently prognostic. The incomplete resection variables were uniformly prognostic.

CONCLUSIONS

The proposed R classification recategorization variables were mostly prognostic, except the highest mediastinal nodal station involvement. Further categorization of R-uncertainty by severity of nodal quality deficit should be considered.

Association of Pathologic Nodal Staging Quality With Survival Among Patients With Non-Small Cell Lung Cancer After Resection With Curative Intent

Importance

Pathologic nodal stage is the most significant prognostic factor in resectable non-small cell lung cancer (NSCLC). The International Association for the Study of Lung Cancer NSCLC staging project revealed intercontinental differences in N category-stratified survival. These differences may indicate differences not only in cancer biology but also in the thoroughness of the nodal examination.

Objective

To determine whether survival was affected by sequentially more stringent definitions of pN staging quality in a cohort of patients with NSCLC after resection with curative intent.

Design

This observational study used the Mid-South Quality of Surgical Resection cohort, a population-based database of lung cancer resections with curative intent. A total of 2047 consecutive patients who underwent surgical resection at 11 hospitals with at least 5 annual lung cancer resections in 4 contiguous US Dartmouth hospital referral regions in northern Mississippi, eastern Arkansas, and western Tennessee (>90% of the eligible population) were included. Resections were performed from January 1, 2009, through January 25, 2016. Survival was evaluated with the Kaplan-Meier method and Cox proportional hazards models.

Exposures

Eight sequentially more stringent pN staging quality strata included the following: all patients (group 1); those with complete resections only (group 2); those with examination of at least 1 mediastinal lymph node (group 3); those with examination of at least 10 lymph nodes (group 4); those with examination of at least 3 hilar or intrapulmonary and at least 3 mediastinal lymph nodes (group 5); those with examination of at least 10 lymph nodes, including at least 1 mediastinal lymph node (group 6); those with examination of at least 1 hilar or intrapulmonary and at least 3 mediastinal nodal stations (group 7); and those with examination of at least 1 hilar or intrapulmonary lymph node, at least 10 total lymph nodes, and at least 3 mediastinal nodal stations (group 8).

Main Outcomes and Measures

N category-stratified overall survival.

Results

Of the total 2047 patients (1046 men [51.1%] and 1001 women [48.9%]; mean [SD] age, 67.0 [9.6] years) included in the analysis, the eligible analysis population ranged from 541 to 2047, depending on stringency. Sequential improvement in the N category-stratified 5-year survival of pN0 and pN1 tumors was found from the least stringent group (0.63 [95% CI, 0.59-0.66] for pN0 vs 0.46 [95% CI, 0.38-0.54] for pN1) to the most stringent group (0.71 [95% CI, 0.60-0.79] for pN0 vs 0.60 [95% CI, 0.43-0.73] for pN1). The pN1 cohorts with 3 or more mediastinal nodal stations examined had the most striking survival improvements. More stringently defined mediastinal nodal examination was associated with better separation in survival curves between patients with pN1 and pN2 tumors.

Conclusions and Relevance

The prognostic value of pN stratification depends on the thoroughness of examination. Differences in thoroughness of nodal staging may explain a large proportion of intercontinental survival differences. More thorough nodal examination practice must be disseminated to improve the prognostic value of the TNM staging system. Future updates of the TNM staging system should incorporate more quality restraints.

Recommended Change in the N Descriptor Proposed by the International Association for the Study of Lung Cancer: A Validation Study

INTRODUCTION

The International Association for the Study of Lung Cancer recently proposed a new N descriptor by combining the location of metastatic lymph nodes (LNs), nN (single-station versus multiple-station), and absence versus presence of skip metastasis as pN1a, pN1b, pN2a1, pN2a2 and pN2b. This study aimed to evaluate the discriminatory ability and prognostic performance of the proposed N descriptor in a large independent NSCLC cohort.

METHODS

We analyzed 1228 patients who underwent major pulmonary resection for pathological N1 or N2 NSCLC between 2004 and 2014. Survival analysis using the Cox proportional hazard model was performed to assess the prognostic significance of the N descriptor.

RESULTS

From 2004 to 2014, a total of 7437 patients were operated on for NSCLC. Patients pathologically confirmed as having N1 (n = 732) or N2 (n = 496) disease after surgery were included. The median total number of dissected LNs was 24 (range 10-83), and the median number of involved LNs was 2 (range 1-40). The 5-year overall survival rates were 62.6%, 57.0%, 64.7%, 48.4%, and 42.8% for stages N1a, N1b, N2a1, N2a2, and N2b, respectively. Analysis of overall and recurrence-free survival revealed that N2a1 is not sufficiently distinguished from N1a and N1b. In terms of overall survival, N1b is not sufficiently distinguished from N2a2.

CONCLUSION

On the basis of the N descriptor proposed by the International Association for the Study of Lung Cancer, some of the prognostic implications of the five groups overlapped. It would be better to classify similar prognostic groups into three or four groups to divide the group. A large-scale prospective study is needed to validate these N descriptors.

Progress in the Management of Early-Stage Non-Small Cell Lung Cancer in 2017

The landscape of care for early-stage non-small cell lung cancer continues to evolve. While some of the developments do not seem as dramatic as what has occurred in advanced disease in recent years, there is a continuous improvement in our ability to diagnose disease earlier and more accurately. We have an increased understanding of the diversity of early-stage disease and how to better tailor treatments to make them more tolerable without impacting efficacy. The International Association for the Study of Lung Cancer and the Journal of Thoracic Oncology publish this annual update to help readers keep pace with these important developments. Experts in the care of early-stage lung cancer patients have provided focused updates across multiple areas including screening, pathology, staging, surgical techniques and novel technologies, adjuvant therapy, radiotherapy, surveillance, disparities, and quality of life. The source for information includes large academic meetings, the published literature, or novel unpublished data from other international oncology assemblies.

Eighth Edition Staging of Thoracic Malignancies: Implications for the Reporting Pathologist

Context The Staging and Prognostic Factors Committee of the International Association for the Study of Lung Cancer, in conjunction with the International Mesothelioma Interest Group, the International Thymic Malignancy Interest Group, and the Worldwide Esophageal Cancer Collaboration, developed proposals for the 8th edition of their respective tumor, node, metastasis (TNM) staging classification systems. Objective To review these changes and discuss issues for the reporting pathologist. Data Sources Proposals were based on international databases of lung (N = 94 708), with an external validation using the US National Cancer Database; mesothelioma (N = 3519); thymic epithelial tumors (10 808); and epithelial cancers of the esophagus and esophagogastric junction (N = 22 654). Conclusions These proposals have been mostly accepted by the Union for International Cancer Control and the American Joint Committee on Cancer and incorporated into their respective staging manuals (2017). The Union for International Cancer Control recommended implementation beginning in January 2017; however, the American Joint Committee on Cancer has deferred deployment of the eighth TNM until January 1, 2018, to ensure appropriate infrastructure for data collection. This manuscript summarizes the updated staging of thoracic malignancies, specifically highlighting changes from the 7th edition that are relevant to pathologic staging. Histopathologists should become familiar with, and start to incorporate, the 8th edition staging in their daily reporting of thoracic cancers henceforth.

Prognostic significance of subclassification of stage IIB lung cancer: a retrospective study of 226 patients

We investigated the prognostic significance of subclassification of stage IIB lung cancer according to the eighth tumor-node-metastasis (TNM) classification. To this purpose, the prognostic outcomes of 226 stage IIB lung cancer patients who underwent surgery without adjuvant therapies between 2001 and 2010 were evaluated retrospectively based on the eighth TNM classification. Of the 226 patients, 23, 30, 118 and 55 had pT1b, pT1c, pT2a, and pT2b stage cancers, respectively. Their 5-year survival rates were 67%, 33%, 21%, and 27%, respectively. There was no significant difference in the 5-year survival between T1b and T1c, between T1c and T2a, and between T2a and T2b (p = 0.128, 0.105, and 0.403, respectively). There were significant differences in the 5-year survival between T1b and T2a, between T1b and T2b, and between T1c and T2b (p = 0.005, 0.002, and 0.042, respectively). The 5-year survival of patients with pleural invasion and vessel invasion was significantly worse than that of their counterparts (p = 0.009 and <0.001, respectively). Subclassification of stage IIB lung cancer is of prominent prognostic significance. It is recommended that the current stage be subclassified, in order to more accurately predict the prognosis of patients.