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

Comparative validation of nodal classifications in resected non-small cell lung cancer based on the anatomical location and number of involved stations

INTRODUCTION

Nodal staging of non-small cell lung cancer (NSCLC) is important for treatment decision-making. Comparative validation of various classifications based on anatomical location and station count, alone or in combination, remains lacking.

METHODS

We analyzed 1,601 patients with pathological stage I-III disease undergoing complete resection between 2002 and 2019. Nodal classifications were based on "TNM 8th," "the International Association for the Study of Lung Cancer (IASLC) exploratory proposal in TNM 8th," "TNM 9th," and "the number of involved nodal stations/zones." The ability of each classification to predict recurrence-free survival was examined using multivariate Cox regression analysis and time-dependent receiver operating characteristic (ROC) curves. Agreement between clinical and pathological nodal staging (cN and pN) was also assessed.

RESULTS

The IASLC exploratory proposal classification in TNM 8th revealed a better prognosis (P < 0.05) for single-station skip N2 within the N2 group, overlapping with N1. Other classifications stratified N descriptors into prognostically distinct subgroups, with time-dependent ROC curves showing no clinically significant differences between the classifications. However, N descriptors based on the number of involved stations/zones formed distinct prognostic subgroups when further stratified by anatomical location. cN and pN agreement was generally low for N1 (44.7 %) and very low for N1 based on the number of involved stations (in the 20 % range).

CONCLUSIONS

Future revisions of NSCLC nodal staging should integrate anatomical location and the number of involved stations, as in TNM 9th. Moreover, N1 subclassification should be avoided, given the difficulty in counting cN1 stations. From a prognostic perspective, single-station skip N2 should be integrated with N1.

Prognostic significance of different lymph node staging systems in patients with resectable, node-positive, stage III, non-small cell lung cancer: Identifying the optimal classification for enhanced prognostic stratification

PURPOSE

The traditional N staging system fails to adequately stratify the prognostic heterogeneity in patients with resectable node-positive, stage III, non-small cell lung cancer, particularly in those undergoing postoperative radiotherapy. The purpose of this study was to determine the optimal nodal status classification strategy: the traditional N classification, the positive lymph nodes-based classification, or the lymph node ratio-based classification. Furthermore, we aimed to identify the population that would benefit the most from postoperative radiotherapy using the best classification strategy.

METHODS

We analysed data from 5028 patients with resectable node-positive, stage III, non-small cell lung cancer sourced from the Surveillance, Epidemiology, and End Results (SEER) database. Various lymph node staging systems, including traditional N staging, classification based on the number of positive lymph nodes, and classification based on the lymph node ratio, were incorporated into the prognostic prediction model. Survival outcomes were evaluated using lung cancer-specific survival and Kaplan-Meier analysis.

RESULTS

The lymph node ratio classification model demonstrated the highest prognostic prediction performance, with the highest C-index, area under the curve, and the lowest Akaike information criterion, followed by the positive lymph nodes classification model and the traditional N staging model. Prognostic stratification analysis based on different lymph node staging systems indicated that a lymph node ratio greater than 0.28 and more than three positive lymph nodes were associated with a high-risk prognosis. Furthermore, postoperative radiotherapy significantly improved lung cancer-specific survival in overall resectable node-positive, stage III, non-small cell lung cancer (P<0.05). Notably, survival curve analysis revealed the most pronounced differences in lung cancer-specific survival between the groups receiving postoperative radiotherapy or not in the high-risk prognosis group, particularly among those with a lymph node ratio greater than 0.28, and more than three positive lymph nodes, and lastly the traditional N staging model.

CONCLUSION

In patients with resectable node-positive, stage III, non-small cell lung cancer, classification according to the lymph node ratio, followed by the positive lymph nodes, may offer superior prognostic prediction capabilities compared to the traditional N staging in addressing prognostic heterogeneity. Additionally, identifying a high-risk prognosis with a lymph node ratio greater than 0.28 appears to be the most effective criterion for selecting candidates who would benefit from postoperative radiotherapy.

Predictive Role of Lymph Node Germinal Centers in Postoperative Recurrence of Non-Small Cell Lung Cancer Treated With Immune Checkpoint Inhibitor Therapy

Introduction The germinal center (GC) in lymph nodes plays an important role in immune responses; however, their relevance to the effects of immune checkpoint inhibitor (ICI) remains unclear. The relationship between GC and ICI efficacy is investigated in this study. Materials and methods This investigation included 16 non-small cell lung cancer (NSCLC) patients with postoperative recurrence who were treated with immune checkpoint inhibitors (ICI) between January 2016 and April 2022. Patients were categorized into two groups based on the presence of GC in the lymph nodes. Additionally, the association between the number of lymph nodes dissected during pulmonary resection and ICI efficacy was evaluated. Results Sixteen patients were included with eight GC+ patients and eight GC- patients. The presence of GC positively influenced ICI efficacy, with the objective response rate (ORR) being significantly higher in the GC+ group (62.5%) compared to the GC- group (12.5%) (p=0.039). Disease control rate (DCR) was also more favorable in the GC+ group (100%) compared to the GC- group (50%) (p=0.021). Additionally, patients with fewer lymph nodes dissected at surgery had a better progression-free survival (median: 15.7 months) than those with more lymph nodes dissected (median: 7.4 months) (p=0.027). Conclusion GC in the lymph nodes can enhance the efficacy of ICI in treating NSCLC. Moreover, the number of dissected lymph nodes has emerged as a crucial prognostic factor that influences the effectiveness of treatment. These findings underscore the importance of considering lymph node characteristics in personalized ICI therapy for NSCLC.

Prognostic impact of the N2 subclassification and stage migration in the ninth edition of the TNM classification in surgically resected lung cancer

OBJECTIVES

In the ninth edition of the TNM classification of lung cancer, N2 is subdivided into single-station (N2a) and multiple-station involvement (N2b), and some stage changes are made to stage II-III. This study aimed to validate the new classification and determine the effect of stage migration and vice versa on the prognosis of each pathological stage due to these changes.

MATERIALS AND METHODS

A total of 1,754 patients with surgically resected lung cancer were included. Clinical characteristics of patients at each new pathological N (pN) status were compared. Overall survival (OS) was evaluated according to the new pN status and pathological stages.

RESULTS

The OS of pN2a patients tended to be superior to that of pN2b patients without significance (p = 0.083). Several patient characteristics, including clinical N status, were not significantly different between pN2a and pN2b. The OS of the downstaged patients (T1N1M0 from IIB to IIA, T1N2aM0 from IIIA to IIB, and T3N2aM0 from IIIB to IIIA) was not significantly different from that of other patients in the same stages (p = 0.376, p = 0.630, and p = 0.970, respectively). The OS of the upstaged patients (T3N2bM0 from IIIA to IIIB) was significantly better than that of other patients in the same stage (p < 0.001). The 5-year OS rates of stages IIIA and IIIB were 63.3 % and 49.4 % in the eighth edition and 58.9 % and 54.3 % in the ninth edition, respectively.

CONCLUSION

Although the N2 subclassification had some impact on survival stratification, it was difficult to predict the subdivided pN2 status, preoperatively. The OS difference in stage III was smaller in the ninth edition than in the eighth edition, due to the complex effects of stage migration and vice versa.

Real-world status of multimodal treatment of Stage IIIA-N2 non-small cell lung cancer in Japan: Results from the SOLUTION study, a non-interventional, multicenter cohort study

OBJECTIVES

There is limited consensus on resectability criteria for Stage IIIA-N2 non-small cell lung cancer (NSCLC). We examined the patient characteristics, N2 status, treatment decisions, and clinical outcomes according to the treatment modality for Stage IIIA-N2 NSCLC in Japan.

MATERIALS AND METHODS

Patients with Stage IIIA-N2 NSCLC in Japan were consecutively registered in the SOLUTION study between 2013 and 2014. Patients were divided according to treatment (chemoradiotherapy [CRT], surgery + perioperative therapy [neoadjuvant and/or adjuvant therapy], surgery alone). Demographic characteristics, N2 status (number and morphological features), pathological information, and treatments were analyzed descriptively. Overall survival (OS), progression-free survival (PFS), and disease-free survival (DFS) were estimated using the Kaplan-Meier method.

RESULTS

Of 227 patients registered, 133 underwent CRT, 56 underwent surgery + perioperative therapy, and 38 underwent surgery alone. The physicians reported the following reasons for unresectability for 116 of 133 CRT patients: large number of metastatic lymph nodes (70.7 %), extranodal infiltration (25.0 %), poor surgical tolerance (19.0 %), or other reasons (18.1 %). CRT was more frequently performed in patients whose lymph nodes had an infiltrative appearance (64.3 %) and was the predominant treatment in patients with multiple involved stations (discrete: 60.0 %; infiltrative: 80.4 %). Distant metastasis with/without local progression was found in 50.4 %, 50.0 %, and 36.8 % of patients in the CRT, surgery + perioperative therapy, and surgery alone groups, respectively. The respective 3-year OS and DFS/PFS rates (median values) were as follows: surgery + perioperative therapy-61.9 % (not reached) and 37.1 % (22.4 months; DFS); CRT group-42.2 % (31.9 months) and 26.8 % (12.0 months; PFS); surgery alone group-37.7 % (26.5 months) and 28.7 % (12.6 months; DFS).

CONCLUSION

This study has illuminated the real-world decision rules for choosing between surgical and non-surgical approaches in patients with Stage IIIA-N2 NSCLC. Our landmark data could support treatment decision making for using immune checkpoint inhibitors and targeted therapy for driver oncogenes in the perioperative therapy era.

Prognostic performance of the N category in the 9th edition of lung cancer staging

OBJECTIVES

To compare the prognostic performance of the N category of lung cancer in the 9th edition with previous editions (7th edition and 8th edition's proposal).

METHODS

Patients who underwent lobectomy or pneumonectomy for lung cancer from January 2015 to December 2021 were retrospectively analyzed. Clinical and pathologic N categories were reclassified according to the 9th edition (N0, N1, N2a, and N2b), the 8th edition's proposal (N0, N1a, N1b, N2a1, N2a2, and N2b), and the 7th edition (N0, N1, and N2). Concordance index (C-index) and calibration were assessed for each edition.

RESULTS

A total of 3864 patients were included (962 pN positive and 513 cN positive). The 9th edition demonstrated clear hazard stratification between neighboring pN categories after multivariable adjustment, whereas multiple overlaps were observed in the 8th edition's proposal. It had superior discrimination performance compared with the 7th edition in pathologic staging (all p < 0.05). Compared with the 8th edition's proposal, the 9th edition showed comparable performance in pN2 and overall patients (C-index, 0.560 vs 0.569 [p = 0.163]; 0.666 vs 0.668 [p = 0.396]), In clinical staging, there was no difference in discrimination across 7th to 9th editions (all p > 0.05). N1 dichotomization in the 8th edition's proposal showed discrimination ability (C-index, 0.539 [95% confidence interval: 0.502-0.576]) only in pathologic staging. The calibration was acceptable across the clinical 7th to 9th editions for 5-year survival.

CONCLUSION

The revision of the N category in the 9th edition appears reasonable, offering enhanced prognostic discrimination compared with the 7th edition and comparability to the 8th edition's proposal.

KEY POINTS

Question Does the revised N category in the 9th edition offer added value in discrimination over previous editions? Findings The discrimination performance of the 9th edition is comparable to that of the 8th edition's proposal, demonstrating a distinct hazard stratification between neighboring pN categories. Clinical relevance The revision of the N category in the 9th edition appears reasonable; however, survival heterogeneity within the pathologic N1 category needs to be considered in future updates.

Comprehensive analysis of surgical strategies and prognosis for non-small cell lung cancer with pleural metastasis detected intraoperatively

BACKGROUND AND OBJECTIVES

Lung cancer is one of the prevailing malignancies worldwide. Surgical interventions hold an important position in the treatment framework for lung cancer. Pleural metastasis is often assumed to be a surgical contraindication, but not all instances of pleural metastasis can be accurately identified before surgery. The question of how to address pleural metastasis detected intraoperatively is still undecided.

METHODS

This retrospective study included 187 lung cancer patients who underwent surgery from 2005 to 2017 in whom pleural metastasis was discovered incidentally during the operation. Data on demographic, surgical, pathological, postoperative treatment, and survival information were collected for further analysis.

RESULTS

For patients with intraoperatively detected pleural metastasis, two independent protective prognostic factors were receiving primary tumor resection (compared to only receiving pleural nodule biopsy, HR = 0.079, p = 0.022) and receiving postoperative adjuvant chemotherapy (HR = 0.081, p < 0.001). Simultaneously, performing systematic lymph node dissection during primary tumor resection was found to be detrimental to long-term prognosis (HR = 2.375, p = 0.044). However, the resection of pleural metastatic lesions did not significantly impact patient prognosis.

CONCLUSION

Our study supports the implementation of major tumor resection in patients with pleural metastasis detected intraoperatively but not lymph node dissection or the resection of pleural metastatic lesions. Postoperative chemotherapy is also necessary.

Number of involved nodal stations predicts survival in small cell lung cancer

BACKGROUND

In small cell lung cancer (SCLC), the pathological N category is identical to it in non-small cell lung cancer (NSCLC) and remains unchanged over a decade. Here we verified the discriminability of number of involved nodal stations (nS) in SCLC and compared its efficacy in predicting survival with currently used pathological nodal (pN) staging.

METHODS

We retrospectively analyzed the patients who received operations and were pathologically diagnosed as SCLC at Shanghai Pulmonary Hospital between 2009 and 2019. X-tile software was adopted to determine optimal cut-off values for nS groups. Kaplan-Meier method and Cox regression analysis were used to compare survival between different groups. Decision curve analysis (DCA) was employed to evaluate the standardized net benefit.

RESULTS

A total of 369 patients were included. The median number of sampled stations was 6 (range 3-11), and the median number of positive stations was 1 (range 0-7). The optimal cutoff for nS groups was: nS0 (no station involved), nS1-2 (one or two stations involved), and nS ≥ 3 (three or more stations involved). Overall survival (OS) and relapse-free survival (RFS) were statistically different among all adjacent categories within the nS classification (p < 0.001, for both OS and RFS between each two subgroups), but survival curves for subgroups in pN overlapped (OS, p = 0.067; RFS, p = 0.068, pN2 vs. pN1). After adjusting for other confounders, nS was a prognostic indicator for OS and RFS. The DCA revealed that nS had improved predictive capability than pN.

CONCLUSIONS

Our cohort study demonstrated that the nS might serve as a superior indicator to predict survival than pN in SCLC and was worth considering in the future definition of the N category.

Survival difference between patients with single versus multiple metastatic lymph nodes and the role of histology in pathological stage II-N1 non-small cell lung cancer

BACKGROUND

Previous studies investigating whether metastatic lymph node count is a relevant prognostic factor in pathological N1 non-small cell lung cancer (NSCLC), showed conflicting results. Hypothesizing that outcome may also be related to histological features, we determined the prognostic impact of single versus multiple metastatic lymph nodes in different histological subtypes for patients with stage II-N1 NSCLC.

METHODS

We performed a retrospective cohort study using data from the Netherlands Cancer Registry, including patients treated with a surgical resection for stage II-N1 NSCLC (TNM 7th edition) in 2010-2016. Overall survival (OS) was assessed for patients with single (pN1a) and multiple (pN1b) metastatic nodes. Using multivariable analysis, we compared OS between pN1a and pN1b in different histological subtypes.

RESULTS

After complete resection of histologically proven stage II-N1 NSCLC, 1309 patients were analyzed, comprising 871 patients with pN1a and 438 with pN1b. The median number of pathologically examined nodes (N1 + N2) was 9 (interquartile range 6-13). Five-year OS was 53% for pN1a versus 51% for pN1b. In multivariable analysis, OS was significantly different between pN1a and pN1b (HR 1.19, 95% CI 1.01-1.40). When stratifying for histology, the prognostic impact of pN1a/b was only observed in adenocarcinoma patients (HR 1.44, 95% CI 1.15-1.81).

CONCLUSION

Among patients with stage II-N1 adenocarcinoma, the presence of multiple metastatic nodes had a significant impact on survival, which was not observed for other histological subtypes. If further refinement as to lymph node count will be considered for incorporation into a new staging system, evaluation of the role of histology is recommended.

Association of log odds of positive lymph nodes with survival in patients with small cell lung cancer: Results from the SEER database

OBJECTIVES

The prognosis of patients with Small Cell Lung Cancer (SCLC) can be predicted by their Lymph Node (LN) status. The authors aimed to assess the correlations between SCLC survival and number of LN Ratio (LNR), positive LN (pLNs), and Logarithmic Odds of positive LN (LODDS).

METHODS

This cohort study retrospectively included 1,762 patients with SCLC from the SEER database 2004‒2015. The X-tile software was used to determine the cutoff values for pLNs, LNR, and LODDS. The correlations between pLNs, LNR, and LODDS with Overall Survival (OS) and Cancer-Specific Survival (CSS) were explored using Cox regression analysis. The study used the C-index to assess the predictive value of LNR, pLNs, and LODDS on survival.

RESULTS

Among these 1,762 patients, 121 (6.87%) were alive, 1,641 (93.13%) died, and 1,532 (86.95%) died of SCLC. In univariable COX analysis, LNR, pLNs, and LODDS all showed a correlation with CSS and OS (p < 0.05). In multivariable COX analysis, only patients with LODDS (> 0.3 vs. ≤ 0.3) were related to both worse OS (HR = 1.28, 95% CI 1.10‒1.50) and CSS (HR = 1.29, 95% CI 1.10‒1.51), but no correction was observed between LNR and pLNs and survival (p > 0.05). The C-indices for predicting OS for LODDS were 0.552 (95% CI 0.541‒0.563), for LNR 0.504 (95% CI 0.501‒0.507), and for pLNs 0.527 (95% CI 0.514‒0.540). Moreover, the association between LODDS and prognosis in SCLC patients was significant only in patients with LN stage N1 and N2, but not in stage N3.

CONCLUSION

LODDS may be better than other LN assessment tools at predicting survival in SCLC patients.

The prognostic significance of lymph nodes in patients with pT1c33N0M0 non-small cell lung cancer: a retrospective study

Objective

The objective of this study was to appraise the prognostic impact of lymph nodes in patients diagnosed with pT1c33N0M0 non-small cell lung cancer (NSCLC) and to delve into the prognostic significance of lymph nodes located at the N1 lymph node station in this patient cohort.

Methods

A retrospective analysis of clinical data was conducted for 255 patients diagnosed with pT1c33N0M0 NSCLC. Lymph nodes were tabulated and categorized into three groups (0-10 nodes, 11-16 nodes, >16 nodes). Clinical data among these three groups of pT1c33N0M0 NSCLC patients were compared. We conducted both univariate and multivariate analyses to pinpoint the factors that impact the prognosis of patients with pT1c33N0M0 non-small cell lung cancer (NSCLC). Additionally, we employed receiver operating characteristic (ROC) curve analysis to pinpoint the optimal lymph node criteria at the N1 station for prognostic prediction in pT1c33N0M0 NSCLC patients.

Results

Within the cohort of 255 individuals afflicted with pT1c33N0M0 non-small cell lung cancer (NSCLC), a comprehensive tally of 3,902 lymph nodes was diligently established, yielding an average of 15.3 nodes for each patient. Multivariate analysis demonstrated that tumor size, T stage, and lymph nodes were independent factors significantly impacting the prognosis of pT1c33N0M0 NSCLC patients (P < 0.05). ROC curve analysis revealed an area under the curve of 0.6982 for predicting prognosis using N1 station in pT1c33N0M0 NSCLC patients. The maximum Youden index was observed at an N1 station of 2.7 nodes. Patients with N1 station ≥ three nodes had significantly better prognoses compared to those with < 3 nodes (both P < 0.05).

Conclusion

Lymph nodes serve as an independent prognostic factor for pT1c33N0M0 NSCLC patients. Detecting at least three or more lymph nodes at the N1 station is associated with a more favourable prognosis in pT1c33N0M0 NSCLC patients.

The number of metastatic lymph nodes is more predictive of prognosis than location-based N stage for nonsmall cell lung cancer: a retrospective cohort study

BACKGROUND

The eighth edition of nodal classification is defined only by the anatomical location of metastatic lymph nodes and has limited prognostic discrimination power. The authors aimed to evaluate the prognostic significance and discriminatory capability of the number of metastatic lymph nodes (nN) in resected nonsmall cell lung cancer.

MATERIALS AND METHODS

Patients with stage IA to IIIB resected nonsmall cell lung cancer between 1 January 2009 and 31 December 2013 were analyzed as a Chinese cohort. The optimal thresholds for the nN classification were determined by the X-tile. The receiver operating characteristic curve, net reclassification improvement and standardized net benefit calculated by decision curve analysis was estimated to quantify the nN classification's performance in prognostic stratification. External validation in the surveillance, epidemiology, and end results database was performed to test the robustness of the nN classification.

RESULTS

Both cohorts showed a stepwise prognosis deterioration with increasing nN. One to three, four to six, and more than six were selected as optimal thresholds of nN classification in the Chinese cohort, which included 4432 patients, then validated in the SEER cohort ( n =28 022 patients). Multivariate Cox analysis showed the nN classification was an independent predictive factor for overall survival in both cohorts (Chinese cohort and SEER cohort: N 0 vs. N 1-3 , P <0.001; N 0 vs. N 3-6 , P <0.001; N 0 vs. N >6 , P <0.001). And prognostic discriminatory capability was improved in the nN classification compared with location-based N classification [5-year NRI score, 0.106 (95% CI: 0.049-0.132) and 5-year time-independent AUC, 0.593 (95% CI: 0.560-0.625) vs. 0.554 (95% CI: 0.520-0.588), P <0.001].

CONCLUSIONS

The nN classification tended to be a superior prognostic indicator than the location-based N classification. The number of metastatic lymph nodes should be considered in the future revision of the TNM system.

Non-Small Cell Lung Cancer With N1 Involvement or Skip Metastases Presents the Same Survival Outcome: Results From a Multicentric Study

BACKGROUND

The prognostic difference among patients affected by NSCLC with hilar metastases only or mediastinal nodes metastases without hilar involvement (skip metastases) is still unclear. Aim of this study is to analyse if prognostic difference are present or if the two groups present the same survival outcome.

MATERIALS AND METHODS

Data on NSCLC patients from 7 high volume centres (2004-2014) were collected and retrospectively reviewed. Histology different from adenocarcinoma(ADC) or squamous cell carcinoma(SCC), patients without data on lymphadenectomy, who underwent neoadjuvant treatment, with distant metastases or incomplete resection were excluded, selecting patients with hilar involvement or with skip metastases. Different prognostic factors such as Tstage, histology, pathological stage, nodal characteristics and adjuvant therapy administration were correlated to overall survival (OS) by the Kaplan-Meier product-limit method. The log-rank test was used to assess differences between subgroups. A multivariable Cox proportional hazard model was developed using stepwise regression to compare the prognostic power of different factors.

RESULTS

The final analysis was conducted on 480 adenocarcinoma/squamous cell carcinoma patients. Five-year OS (5YOS) resulted 53.9%. No significant differences in OS were detected comparing pN1 vs. pN2 patients or stage IIB vs. stage IIIA-B patients. Univariable confirmed as favourable prognostic factors young age (P<.001), T1-2 tumors (P=.030), number of resected nodes≥10 (P=.040), lymph node ratio (P=.026). Multivariable analysis confirmed as independent negative prognostic factors T≥3 (HR:1.385, 95%CI:1.037-1.851, P=.027) and age≥68 years (HR1.637, 95%CI:1.245-2.152).

CONCLUSION

Patients with N1 involvement or skip metastases present a similar prognosis, suggesting that N2 involvement in these cases may be related to a direct lymphatic drainage to the mediastinal stations.

Radiologic Extranodal Extension of Metastatic Lymph Nodes in Patients With Non-Small Cell Lung Cancer: Prognostic Utility and Diagnostic Performance

BACKGROUND. Pathologic extranodal extension (ENE) in metastatic lymph nodes (LNs) has been associated with unfavorable prognosis in patients with non-small cell lung cancer (NSCLC). OBJECTIVE. The purpose of this article was to evaluate the prognostic utility of radiologic ENE and its diagnostic performance in predicting pathologic ENE in patients with NSCLC. METHODS. This retrospective study included 382 patients (mean age, 67 ± 10 [SD] years; 297 men, 85 women) diagnosed with NSCLC and clinical N1 or N2 disease between January 2010 and December 2016. Two thoracic radiologists reviewed staging chest CT examinations to record subjective overall impression for radiologic ENE (no ENE, possible/probable ENE, or unambiguous ENE), reviewing 30 examinations in consensus and the remaining examinations independently. Kaplan-Meier survival analysis and multivariable Cox proportional hazards model were used to evaluate the utility of radiologic ENE in predicting overall survival (OS). Prognostic utility of radiologic ENE was also assessed in patients with clinical N2a disease. In patients who underwent surgery, sensitivity and specificity were determined of radiologic unambiguous ENE in predicting pathologic ENE. RESULTS. The 5-year OS rates for no ENE, possible/probable ENE, and unambiguous ENE were 44.4%, 39.1%, and 20.9% for reader 1 and 45.7%, 36.6%, and 25.6% for reader 2, respectively. Unambiguous ENE was an independent prognostic factor for worse OS (reader 1: adjusted HR, 1.72, p = .008; reader 2: adjusted HR, 1.56, p = .03), whereas possible/probable ENE was not (reader 1: adjusted HR, 1.18, p = .33; reader 2: adjusted HR, 1.21, p = .25). In patients with clinical N2a disease, 5-year OS rate in patients with versus without unambiguous ENE for reader 1 was 22.2% versus 40.6% (p = .59) and for reader 2 was 27.6% versus 41.0% (p = .49). In 203 patients who underwent surgery (66 with pathologic ENE), sensitivity and specificity of radiologic unambiguous ENE for predicting pathologic ENE were 11% and 93% for reader 1 and 23% and 87% for reader 2. CONCLUSION. Radiologic unambiguous ENE was an independent predictor of worse OS in patients with NSCLC. The finding had low sensitivity but high specificity for pathologic ENE. CLINICAL IMPACT. Radiologic ENE may have a role in NSCLC staging workup and treatment selection.

Occult lymph node metastasis is not a favorable factor for resected NSCLC patients

BACKGROUND

This study was to compare the clinical presentations and survivals between the non-small cell lung cancer (NSCLC) patients with occult lymph node metastasis (OLNM) and those with evident lymph node metastasis (ELNM). We also intended to analyze the predictive factors for OLNM.

METHODS

Kaplan-Meier method with log-rank test was used to compare survivals between groups. Propensity score matching (PSM) was used to reduce bias. The least absolute shrinkage and selection operator (LASSO)-penalized Cox multivariable analysis was used to identify the prognostic factors. Random forest was used to determine the predictive factors for OLNM.

RESULTS

A total of 2,067 eligible cases (N0: 1,497 cases; occult N1: 165 cases; evident N1: 54 cases; occult N2: 243 cases; evident N2: 108 cases) were included. The rate of OLNM was 21.4%. Patients with OLNM were tend to be female, non-smoker, adenocarcinoma and had smaller-sized tumors when compared with the patients with ELNM. Survival curves showed that the survivals of the patients with OLNM were similar to those of the patients with ELNM both before and after PSM. Multivariable Cox analysis suggested that positive lymph nodes (PLN) was the only prognostic factor for the patients with OLNM. Random forest showed that clinical tumor size was an important predictive factor for OLNM.

CONCLUSIONS

OLNM was not rare. OLNM was not a favorable sign for resected NSCLC patients with lymph node metastasis. PLN determined the survivals of the patients with OLNM. Clinical tumor size was a strong predictive factor for OLNM.

Number of involved nodal stations: a better lymph node classification for clinical stage IA lung adenocarcinoma

Background

With the popularization of lung cancer screening, more early-stage lung cancers are being detected. This study aims to compare three types of N classifications, including location-based N classification (pathologic nodal classification [pN]), the number of lymph node stations (nS)-based N classification (nS classification), and the combined approach proposed by the International Association for the Study of Lung Cancer (IASLC) which incorporates both pN and nS classification to determine if the nS classification is more appropriate for early-stage lung cancer.

Methods

We retrospectively reviewed the clinical data of lung cancer patients treated at the Cancer Hospital, Chinese Academy of Medical Sciences between 2005 and 2018. Inclusion criteria was clinical stage IA lung adenocarcinoma patients who underwent resection during this period. Sub-analyses were performed for the three types of N classifications. The optimal cutoff values for nS classification were determined with X-tile software. Kaplan‒Meier and multivariate Cox analyses were performed to assess the prognostic significance of the different N classifications. The prediction performance among the three types of N classifications was compared using the concordance index (C-index) and decision curve analysis (DCA).

Results

Of the 669 patients evaluated, 534 had pathological stage N0 disease (79.8%), 82 had N1 disease (12.3%) and 53 had N2 disease (7.9%). Multivariate Cox analysis indicated that all three types of N classifications were independent prognostic factors for prognosis (all P < 0.001). However, the prognosis overlaps between pN (N1 and N2, P = 0.052) and IASLC-proposed N classification (N1b and N2a1 [P = 0.407], N2a1 and N2a2 [P = 0.364], and N2a2 and N2b [P = 0.779]), except for nS classification subgroups (nS0 and nS1 [P < 0.001] and nS1 and nS >1 [P = 0.006]). There was no significant difference in the C-index values between the three N classifications (P = 0.370). The DCA results demonstrated that the nS classification provided greater clinical utility.

Conclusion

The nS classification might be a better choice for nodal classification in clinical stage IA lung adenocarcinoma.

Locally advanced non-small cell lung cancer: current issues and recent trends

The focus of this paper was to review and summarise the current issues and recent trends within the framework of locally advanced (LA) non-small cell lung cancer (NSCLC). The recently proposed 8^th tumour-node-metastases (TNM) staging system exhibited significant amendments in the distribution of the T and M descriptors. Every revision to the TNM classification should contribute to clinical improvement. This is particularly necessary regarding LA NSCLC stratification, therapy and outcomes. While several studies reported the superiority of the 8^th TNM edition in comparison to the previous 7^th TNM edition, in terms of both the discrimination ability among the various T subgroups and clinical outcomes, others argued against this interpretation. Synergistic cytotoxic chemotherapy with radiotherapy is most prevalent in treating LA NSCLC. Clinical trial experience from multiple references has reported that the risk of locoregional relapse and distant metastasis was less evident for patients treated with concomitant radiochemotherapy than radiotherapy alone. Nevertheless, concern persists as to whether major incidences of toxicity may occur due to the addition of chemotherapy. Cutting-edge technologies such as four-dimensional computed tomography (4D-CT) and volumetric modulated arc therapy (VMAT) should yield therapeutic gains due to their capability to conform radiation doses to tumours. On the basis of the preceding notion, the optimum radiotherapy technique for LA NSCLC has been a controversial and much-disputed subject within the field of radiation oncology. Notably, no single-perspective research has been undertaken to determine the optimum radiotherapy modality for LA NSCLC. The landscape of immunotherapy in lung cancer is rapidly expanding. Currently, the standard of care for patients with inoperable LA NSCLC is concurrent chemoradiotherapy followed by maintenance durvalumab according to clinical outcomes from the PACIFIC trial. An estimated 42.9% of patients randomly assigned to durvalumab remained alive at five years, and free of disease progression, thereby establishing a new benchmark for the standard of care in this setting.

Surgical Treatment Outcomes of Patients with Non-Small Cell Lung Cancer and Lymph Node Metastases

This study aimed to investigate the appropriate subgroups for surgery and adjuvant chemotherapy in patients with non-small-cell lung cancer (NSCLC) and nodal metastases. We retrospectively reviewed 210 patients with NSCLC and nodal metastases who underwent surgery and examined the risk factors for poor overall survival (OS) and recurrence-free probability (RFP) using multivariate Cox proportional hazards analysis. Pathological N1 and N2 were observed in 114 (52.4%) and 96 (47.6%) patients, respectively. A single positive node was identified in 102 patients (48.6%), and multiple nodes were identified in 108 (51.4%). Multivariate analysis revealed that vital capacity < 80% (hazard ratio [HR]: 2.678, 95% confidence interval [CI]: 1.483-4.837), radiological usual interstitial pneumonia pattern (HR: 2.321, 95% CI: 1.506-3.576), tumor size > 4.0 cm (HR: 1.534, 95% CI: 1.035-2.133), and multiple-node metastases (HR: 2.283, 95% CI: 1.517-3.955) were significant independent risk factors for poor OS. Tumor size > 4.0 cm (HR: 1.780, 95% CI: 1.237-2.562), lymphatic permeation (HR: 1.525, 95% CI: 1.053-2.207), and multiple lymph node metastases (HR: 2.858, 95% CI: 1.933-4.226) were significant independent risk factors for recurrence. In patients with squamous cell carcinoma (n = 93), there were no significant differences in OS or RFP between those who received platinum-based adjuvant chemotherapy (n = 25) and those who did not (n = 68), at p = 0.690 and p = 0.292, respectively. Multiple-node metastases were independent predictors of poor OS and recurrence. Patients with NSCLC and single-node metastases should be considered for surgery despite N2 disease. Additional treatment with platinum-based adjuvant chemotherapy may be expected, especially in patients with squamous cell carcinoma.

A multi-kernel and multi-scale learning based deep ensemble model for predicting recurrence of non-small cell lung cancer

Predicting recurrence in patients with non-small cell lung cancer (NSCLC) before treatment is vital for guiding personalized medicine. Deep learning techniques have revolutionized the application of cancer informatics, including lung cancer time-to-event prediction. Most existing convolutional neural network (CNN) models are based on a single two-dimensional (2D) computational tomography (CT) image or three-dimensional (3D) CT volume. However, studies have shown that using multi-scale input and fusing multiple networks provide promising performance. This study proposes a deep learning-based ensemble network for recurrence prediction using a dataset of 530 patients with NSCLC. This network assembles 2D CNN models of various input slices, scales, and convolutional kernels, using a deep learning-based feature fusion model as an ensemble strategy. The proposed framework is uniquely designed to benefit from (i) multiple 2D in-plane slices to provide more information than a single central slice, (ii) multi-scale networks and multi-kernel networks to capture the local and peritumoral features, (iii) ensemble design to integrate features from various inputs and model architectures for final prediction. The ensemble of five 2D-CNN models, three slices, and two multi-kernel networks, using 5 × 5 and 6 × 6 convolutional kernels, achieved the best performance with an accuracy of 69.62%, area under the curve (AUC) of 72.5%, F1 score of 70.12%, and recall of 70.81%. Furthermore, the proposed method achieved competitive results compared with the 2D and 3D-CNN models for cancer outcome prediction in the benchmark studies. Our model is also a potential adjuvant treatment tool for identifying NSCLC patients with a high risk of recurrence.

Tumour-pleura relationship on CT is a risk factor for occult lymph node metastasis in peripheral clinical stage IA solid adenocarcinoma

OBJECTIVES

To investigate whether the tumour-pleura relationship on computed tomography (CT) is a risk factor for occult lymph node metastasis (OLNM) in peripheral clinical stage IA solid adenocarcinoma.

METHODS

A total of 232 patients were included in the study. The tumour-pleura relationship was divided into four types: type 1, the tumour was unrelated to the pleura; type 2, the tumour was not in contact with the pleura, and one or more linear or striated pleural tags were visible; type 3, the tumour was not in contact with the pleura, and one or more linear or striated pleural tags with soft tissue component at the pleural end were visible; and type 4, the tumour was in contact with the pleura. Univariate and multivariate logistic regression analyses were used to identify the predictive factors, including the tumour-pleura relationship, clinical factors, conventional CT findings, and pathology-reported visceral pleural invasion, for OLNM.

RESULTS

Type 3 and 4 tumour-pleura relationships were more likely to have visceral pleural invasion than type 1 and 2 tumour-pleura relationships (p < 0.001). Univariate and multivariate logistic regression analyses revealed that the type 3 or 4 tumour-pleura relationship (OR: 3.261, p = 0.026), carcinoembryonic antigen level (OR: 3.361, p = 0.006), cytokeratin 19 fragments level (OR: 2.539, p = 0.025), and mediastinal window tumour size (OR: 1.078, p = 0.020) were predictive factors for OLNM.

CONCLUSIONS

The type 3 or 4 tumour-pleura relationship is correlated with a greater risk of OLNM in peripheral clinical stage IA solid adenocarcinoma.

KEY POINTS

• The tumour-pleura relationship on CT is a risk factor for occult lymph node metastasis in peripheral clinical stage IA solid adenocarcinoma. • Other risk factors for OLNM include CEA level, CYFRA level, and mediastinal window tumour size. • Pathology-reported visceral pleural invasion is not a risk factor for OLNM.

Fluorescence probes for lung carcinoma diagnosis and clinical application

This review provides an overview of the most recent developments in fluorescence probe technology for the accurate detection and clinical therapy of lung carcinoma.

Association of metastatic nodal size with survival in non-surgical non-small cell lung cancer patients: Recommendations for clinical N staging

Background

This study aims to analyze the prognostic significance of the metastatic lymph node (mLN) size in non-small cell lung cancer (NSCLC) patients receiving chemoradiotherapy (CRT) to provide some information for the optimization of clinical nodal (cN) staging.

Methods

A retrospective study with 325 NSCLC patients was conducted between January 2011 and December 2018 at two participating institutes. We evaluated the potential relationship between the mLN size and the survival to propose a potential revised nodal (rN) staging.

Results

Kaplan–Meier analyses showed significant differences in the overall survival (OS) based on the cN staging and the size of mLNs (N0, ≤2 cm, and >2 cm). We found that the nodal size correlated statistically with the response to CRT. The HRs of OS for patients with bulky mLNs increase significantly compared with patients in the non-bulky mLNs group in the cN2-3 group. Interestingly, the HRs of patients with bulky cN2 disease and non-bulky cN3 disease were similar to each other. We classified the patients into five subsets: N0, rN1(cN1), rN2(non-bulky cN2), rN3a(bulky cN2, and non-bulky cN3), and rN3b(bulky cN3). In our study, the rN stage showed better prognostic discrimination than the 8th IASLC cN staging and was an independent prognostic factor for survival.

Conclusions

In addition to the anatomic location, the size of mLNs correlated statistically with the response to CRT and should be incorporated into the cN staging system to predict survival more accurately.

Consistency and prognostic value of preoperative staging and postoperative pathological staging using 18F-FDG PET/MRI in patients with non-small cell lung cancer

OBJECTIVE

In recent years, positron emission tomography/magnetic resonance imaging (PET/MRI) has been clinically used as a method to diagnose non-small cell lung cancer (NSCLC). This study aimed to evaluate the concordance of staging and prognostic ability of NSCLC patients using thin-slice computed tomography (CT) and ¹⁸F-fluorodeoxyglucose (FDG) PET/MRI.

METHODS

This retrospective study was performed on consecutive NSCLC patients who underwent both diagnostic CT and ¹⁸F-FDG PET/MRI before surgery between November 2015 and May 2019. The cTNM staging yielded from PET/MRI was compared with CT and pathological staging, and concordance was investigated, defining pathological findings as reference. To assess the prognostic value of disease-free survival (DFS) and overall survival (OS), we dichotomized the typical prognostic factors and TNM classification staging (Stage I vs. Stage II or higher). Kaplan-Meier curves derived by the log-rank test were generated, and univariate and multivariate analyses were performed to identify the factors associated with DFS and OS.

RESULTS

A total of 82 subjects were included; PET/MRI staging was more consistent (59 of 82) with pathological staging than with CT staging. There was a total of 21 cases of CT and 11 cases of PET/MRI that were judged as cStage I, but were actually pStage II or pStage III. CT tended to judge pN1 or pN2 as cN0 compared to PET/MRI. There was a significant difference between NSCLC patients with Stage I and Stage II or higher by PET/MRI staging as well as prognosis prediction of DFS by pathological staging (P < 0.001). In univariate analysis, PET/MRI, CT, and pathological staging (Stage I or lower vs. Stage II or higher) all showed significant differences as prognostic factors of recurrence or metastases. In multivariate analysis, pathological staging was the only independent factor for recurrence (P = 0.009), and preoperative PET/MRI staging was a predictor of patient survival (P = 0.013).

CONCLUSIONS

In NSCLC, pathologic staging was better at predicting recurrence, and preoperative PET/MRI staging was better at predicting survival. Preoperative staging by PET/MRI was superior to CT in diagnosing hilar and mediastinal lymph-node metastases, which contributed to the high concordance with pathologic staging.

Prognostic Impact of Examined Mediastinal Lymph Node Count in Clinical N0 Non-Small Cell Lung Cancer

OBJECTIVES

The number of examined mediastinal lymph nodes (mLNs) could represent the quality of mediastinal lymphadenectomy for non-small cell lung cancer (NSCLC). This study aimed to evaluate the prognostic impact of the number of examined individual mLNs in patients with resectable NSCLC.

METHODS

We retrospectively evaluated 1,420 patients with clinical-stage IA-IIB, N0 NSCLC who underwent complete resection by lobectomy, which involved hilar and mLN dissection, between 2008 and 2016. We investigated the threshold number of examined mLNs that had prognostic significance and evaluated their effects on the risk of mLN recurrence.

RESULTS

In a respective multivariable analysis according to the number of examined mLNs, examining ≥3 mLNs (reference [ref.] mLNs ≤2) achieved statistical significance and had the best prognosis (hazard ratio [HR], 0.68; p = 0.013). In the multivariable analyses for each pathological N (pN) stage, ≥3 examined mLNs (ref. mLNs ≤2) was an independent prognostic factor in pN1 disease (HR, 0.32, p = 0.002), but not in pN0 or pN2 disease. The cumulative incidence of mLN recurrence was significantly lower in patients with ≥3 examined mLNs (ref. mLNs ≤2, HR, 0.27; p = 0.008) in pN1 disease. Patients with ≥3 examined mLNs had higher upstaging rates to pN2 than those with ≤2 examined mLNs.

CONCLUSIONS

Examining ≥3 mLNs contributed to a favorable prognosis and low mLN recurrence risk in patients with clinical stage I-II, N0 NSCLC. Our findings can serve as a benchmark for the number of required mLNs to be examined.

FDG uptake in PET is associated with the tumor microenvironment in metastatic lymph nodes and prognosis in N2 lung adenocarcinoma

Positron emission tomography is a useful technique for diagnosing lymph node (LN) metastasis. This study aimed to elucidate the association between fluorodeoxyglucose accumulation and the microenvironment in metastatic LNs in lung adenocarcinoma. We retrospectively analyzed 62 patients with surgically resected pathological N2 lung adenocarcinoma who underwent preoperative PET. The maximum standardized uptake value (SUV_max) in the metastatic LNs was measured. Lymph node specimens were immunohistochemically analyzed for CD8⁺, FoxP3⁺, and CD79a⁺ lymphocytes, CD204⁺ tumor‐associated macrophages (TAMs), and alpha‐smooth muscle actin‐positive cancer‐associated fibroblasts (αSMA⁺ CAFs). We compared the clinicopathologic and immunohistochemical characteristics between two groups with high and low LN SUV_max. Using novel 3D hybrid spheroid models, we investigated the change in invasiveness of cancer cells in the presence of CAFs. In the multivariate analyses, LN SUV_max was an independent prognostic factor. The overall survival in the LN SUV_max high group was significantly worse than in the low group (P = .034). In the LN SUV_max high group, metastatic cancer cell invasion of extranodal tissue was more frequent (P = .005) and the number of CD204⁺ TAMs and αSMA⁺ CAFs in metastatic LNs was significantly higher than in the low group (P < .001 and P = .002, respectively). Hybrid spheroid models revealed that cancer cells coexisting with CAFs were more invasive than those without CAFs. Our results indicated a strong association between LN SUV_max and poor prognosis in patients with N2 lung adenocarcinoma. Moreover, LN SUV_max was suggested to be associated with the presence of tumor‐promoting stromal cells in metastatic LNs.

The number of metastatic lymph nodes optimizes staging in patients aged 55 years or older with papillary thyroid cancer

PURPOSE

Current staging criteria for papillary thyroid cancer (PTC) do not include the number of metastatic lymph nodes (LNs), which is highly predictive of survival in multiple cancers. The LN metastasis burden is particularly relevant for older adults with thyroid cancer because of their poor prognosis. We examined a modified staging system for this population utilizing node number (Nn).

METHODS

Overall, 14,341 patients aged 55 years or older with stage I-IVB PTC were identified in the 2004-2015 Surveillance, Epidemiology and End Results database. Cox regression models were conducted to test the relationship between positive LN number and PTC-specific survival (PTCSS). Independent training/validation sets were used to derive and validate a new revised TNnM grouping. The 8th edition American Joint Committee on Cancer TNM staging system was compared with TNnM stage by calculating the 10-year PTCSS rates, Harrell's concordance index (C-index), and Akaike's information criterion (AIC).

RESULTS

An increase in number of LN metastases was identified as an independent, negative prognostic factor for PTCSS in multivariate analysis. 10-year PTCSS for stage I-IVB based on the AJCC 8th edition TNM were 98.83%, 93.49%, 71.21%, 72.95%, and 58.52%, respectively, while 10-year PTCSS for the corresponding stage in the TNnM were 98.59%, 92.2%, 83.26%, 75.24%, and 56.73%, respectively. The revised TNnM stage was superior, with a higher C-index and a lower AIC in both the training and validation cohorts.

CONCLUSION

The TNnM staging system for PTC patients ≥ 55 years could be associated with improved outcomes. External validation studies of this system are warranted.

Update on adjuvant therapy in completely resected NSCLC patients

In patients with completely resected non‐small cell lung cancer (NSCLC), postoperative adjuvant chemotherapy has been associated with improvement in survival by minimizing the risk of recurrence. For years, systemic chemotherapy including platinum based regimen has been a mainstay treatment modality of adjuvant treatment after complete resection. ADAURA study showed that among completely resected IB to IIIA NSCLC, disease‐free survival was significantly better in patients under adjuvant osimertinib than a placebo group. After the advent of a variety of new treatment regimens, such as third generation TKI and immunotherapy, the landscape of postoperative adjuvant treatment has been changing. In this review, we discuss some key issues regarding choice of adjuvant treatment after complete resection in NSCLC, and provide further updates on recent advances in treatment modalities.

Construction and Validation of Two Novel Nomograms for Predicting the Overall Survival and Cancer-Specific Survival of NSCLC Patients with Bone Metastasis

Background

Bone metastasis (BM) is the most common site of metastasis in non-small cell lung carcinoma (NSCLC). We aimed to construct and validate 2 novel nomograms predicting the 3-, 6-, and 12-months overall survival (OS) and cancer-specific survival (CSS).

Methods

The clinical data of 7480 patients between 2010 and 2016 were enrolled from the Surveillance, Epidemiology, and End Results database (SEER). The patients were allocated randomly to training and validation cohorts in a 7:3 ratio. Cox proportional hazards regression models were used to identify prognostic risk factors and establish 2 nomograms. The prediction accuracy of nomograms was assessed by C-index, the area under the ROC curve (AUC), and calibration curves.

Results

A total of 244998 NSCLC patients were identified between 2010 and 2016, with 7480 found with BM, accounting for 3.1%. Overall, 7480 patients were enrolled in the OS nomogram construction and were randomized to the training set (n = 5236) and the validation set (n = 2244). Age, sex, race, marital status, histology, grade, primary site, T stage, N stage, liver metastasis, surgery, radiotherapy, and chemotherapy were found to correlate with OS. A total of 7422 samples were included in the CSS nomogram construction, randomly grouped into training set (n = 5195) and the validation set (n = 2227). Age, sex, race, histology, grade, primary site, T stage, N stage, brain metastasis, liver metastasis, surgery, radiotherapy, and chemotherapy were associated with CSS. Two nomograms were conducted to predict the 3-, 6-, and 12-months OS and CSS. The ROC curves and exhibited good performance for predicting OS and CSS.

Conclusion

We established and validated 2 high-performance nomograms to assist clinical doctors in making personalized treatment decisions.

Prognostic characterization of immune molecular subtypes in non-small cell lung cancer to immunotherapy

Background

Non-small cell lung cancer (NSCLC) was usually associated with poor prognosis and invalid therapeutical response to immunotherapy due to biological heterogeneity. It is urgent to screen reliable biomarkers, especially immunotherapy-associated biomarkers, that can predict outcomes of these patients.

Methods

Gene expression profiles of 1026 NSCLC patients were collected from The Cancer Genome Atlas (TCGA) datasets with their corresponding clinical and somatic mutation data. Based on immune infiltration scores, molecular clustering classification was performed to identify immune subtypes in NSCLC. After the functional enrichment analysis of subtypes, hub genes were further screened using univariate Cox, Lasso, and multivariate Cox regression analysis, and the risk score was defined to construct the prognostic model. Other microarray data and corresponding clinical information of 603 NSCLC patients from the GEO datasets were applied to conduct random forest models for the prognosis of NSCLC with 100 runs of cross-validation. Finally, external datasets with immunotherapy and chemotherapy were further applied to explore the significance of risk-scores in clinical immunotherapy response for NSCLC patients.

Results

Compared with Subtype-B, the Subtype-A, associated with better outcomes, was characterized by significantly higher stromal and immune scores, T lymphocytes infiltration scores and up-regulation of immunotherapy markers. In addition, we found and validated an eleven -gene signatures for better application of distinguishing high- and low-risk NSCLC patients and predict patients’ prognosis and therapeutical response to immunotherapy. Furthermore, combined with other clinical characteristics based on multivariate Cox regression analysis, we successfully constructed and validated a nomogram to effectively predict the survival rate of NSCLC patients. External immunotherapy and chemotherapy cohorts validated the patients with higher risk-scores exhibited significant therapeutic response and clinical benefits.

Conclusion

These results demonstrated the immunological and prognostic heterogeneity within NSCLC and provided a new clinical application in predicting the prognosis and benefits of immunotherapy for the disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01765-3.

Anatomical location and number of metastatic lymph nodes for prognosis of non-small cell lung cancer

Background

The nodal classification of lung cancer is determined by the anatomical location of metastatic lymph nodes (mLNs). However, prognosis can be heterogeneous at the same nodal stage, and the current classification system requires improvement. Therefore, we investigated the correlation between the number of mLNs and prognosis in patients with non-small cell lung cancer.

Methods

Using a multicenter database in Japan, we retrospectively reviewed the records of patients who underwent complete resection for lung cancer between 2010 and 2016. Kaplan-Meier curves were used to determine recurrence-free and overall survival. Multivariate analyses were performed using the Cox proportional hazards model.

Results

We included 1,567 patients in this study. We could show a statistically significant difference in recurrence-free survival between pN2 patients with 1 mLN and pN2 patients with ≥2 mLNs (P=0.016). Patients with a combination of pN1 (≥4 mLNs) plus pN2 (1 mLN) had a poorer prognosis than pN1 patients (1-3 mLNs) (P=0.061) and a better prognosis than pN2 patients (≥2 mLNs) patients (P=0.007). Multivariate analysis showed that the number of mLNs was independently associated with cancer recurrence in patients with pN1 and pN2 disease (P=0.034 and 0.018, respectively).

Conclusions

Nodal classification that combines anatomical location and the number of mLNs may predict prognosis more accurately than the current classification system. Our study provides the concept that supports the subdivision of nodal classification in the upcoming revision of the tumor, node, and metastasis staging system.

Effects of Postoperative Radiotherapy on Survival of Patients With Stage IIIA Resected Non-Small Cell Lung Cancer: Analysis of the SEER Database

BACKGROUND

The role of postoperative radiotherapy (PORT) in patients with resected stage IIIA non-small cell lung cancer (NSCLC) remains controversial. The purpose of this study was to explore the effect of PORT on survival of these patients.

METHODS

Patients aged ≥18 years with stage IIIA NSCLC were identified in the SEER database from 2010 through 2015. Cox regression analysis was used to identify independant prognostic factors in patients with stage IIIA NSCLC. Subgroup analysis of patients stratified by N stage was also performed. Overall survival and lung cancer-related death were compared among the different groups by using Kaplan-Meier analysis and competitive risk analysis.

RESULTS

A total of 5,168 patients (1,711 of whom received PORT) were included in the study. In multivariable analysis, PORT was an independent prognostic risk factor for patients with N1 stage (hazard ratio [HR], 1.416, 95% CI, 1.144-1.753; P=.001). PORT was a favorable prognostic factor for patients with stage IIIA, N2 disease with ≥6 positive lymph nodes (HR, 0.742; 95% CI, 0.587-0.938; P=.012). Median survival time of patients with stage IIIA, N2 disease with ≥6 positive lymph nodes who received postoperative chemotherapy combined with PORT was significantly longer compared with those who received postoperative chemotherapy alone (32 vs 25 months, respectively; P=.009). The competitive risk model revealed that 3- and 5-year lung cancer-related mortality rates increased by 8.99% and 16.92%, respectively, in patients with N1 disease who were treated with PORT, whereas the 3-year mortality rate decreased by 4.67% and the 5-year mortality rate by 10.08% in patients with N2 disease and ≥6 positive lymph nodes who were treated using PORT.

CONCLUSIONS

Our results revealed that PORT significantly improved overall survival and decreased lung cancer-related mortality in patients with stage IIIA, N2 disease with ≥6 positive lymph node metastases. PORT was not recommended for patients with N0 and N1 disease.

Prognostic significance of the N1 classification pattern: a meta-analysis of different subclassification methods

OBJECTIVES

The number of positive lymph node stations has been viewed as a subclassification in the N1 category in the new revision of tumour node metastasis (TNM) staging. However, the survival curve of these patients overlapped with that of some patients in the N2 categories. Our study focused on the prognostic significance of different subclassifications for N1 patients.

METHODS

We systematically searched PubMed, Ovid, Web of Science and the Cochrane Library on the topic of N1 lymph node dissection. Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were used to assess the prognostic significance of N1 metastases. I2 statistics was used to evaluate heterogeneity among the studies: If significant heterogeneity existed (P ≤ 0.10; I2 >50%), a random effect model was adopted.

RESULTS

After a careful investigation, a total of 17 articles were included in the analysis. The results showed that patients with non-small-cell lung cancer with multistation N1 disease have worse survival compared with those with single-station N1 disease (HR 1.53, 95% CI 1.32-1.77; P < 0.001; I2 = 5.1%). No significant difference was observed between groups when we assessed the number of positive lymph nodes (single or multiple) (HR 1.25, 95% CI 0.96-1.64; P = 0.097; I2 = 72.5%). Patients with positive hilar zone lymph nodes had poorer survival than those limited to the intrapulmonary zone (HR 1.80, 95% CI 1.57-2.07; P < 0.001; I2 = 0%). A subgroup analysis conducted according to the different validated lymph node maps showed a stable result.

CONCLUSIONS

Our result confirmed the prognostic significance of the N1 subclassification based on station number. Meanwhile, location-based classifications, especially zone-based, were also identified as prognostically significant, which may need further confirmation and validation in the staged population.

External validation of the N descriptor in the proposed tumour-node-metastasis subclassification for lung cancer: the crucial role of histological type, number of resected nodes and adjuvant therapy

OBJECTIVES

Overlapping survival curves for N1b (multiple N1 stations), N2a2 (single N2 station + N1 involvement) and N2a1 (skip N2 metastasis) limit the current tumour-node-metastasis (TNM) node (N) subclassification for node involvement. We validated externally the proposed subclassification.

METHODS

Clinical records from a multicentric database comprising 1036 patients with pulmonary adenocarcinoma (ADC) or squamous cell carcinoma with N1/N2 involvement who underwent, from January 2002 to December 2014, complete lung resections were retrospectively reviewed. Patients were categorized according to the 8th TNM N subclassification proposal. Histological type, number of resected nodes (#RN) and adjuvant therapy (ADJ) were considered limiting factors.

RESULTS

No difference in the 5-year overall survival (-OS) was noted between N1b and N2a1 (49.6% vs 44.8%, P = 0.72); instead, the 5-year-OS was significantly improved in patients with squamous cell carcinoma (63% in N1b vs 30.7% in N2a1, P = 0.04). In patients with ADC, the 5-year-OS was better in those with N2a1 than with N1b (50.6% vs 37.5%, P = 0.09). When we compared N1b with N2a2, the 5-year-OS was statistically significant (49.6% vs 32.8%, P = 0.02); considering only patients with squamous cell carcinoma (63% vs 25.8%, P = 0.003), #RN >10 (63.2% vs 35.3%, P = 0.05) and without ADJ (56.4% vs 24.5%, P = 0.02), the 5-year-OS was significantly different. Differences were not significant for ADC, #RN <10 and ADJ. Finally, the 5-year-OS was statistically significant when we compared N2a1 with N2a2 of the total cohort (44.8% vs 32.8%, P = 0.04), in ADC (5-year-OS 50.6% vs 36.5%, P = 0.04) and #RN >10 (5-year-OS 49.8% vs 32.1%, P = 0.03) without ADJ.

CONCLUSIONS

Histological type, ADJ and #RN are relevant prognostic factors in N + non-small-cell lung cancer. Considering these results, we may better interpret the prognosis prediction limits of the proposed 8th TNM subclassification for the N descriptor.

Prognostic Value of Combing Primary Tumor and Nodal Glycolytic-Volumetric Parameters of 18F-FDG PET in Patients with Non-Small Cell Lung Cancer and Regional Lymph Node Metastasis

We investigated whether the combination of primary tumor and nodal ¹⁸F-FDG PET parameters predict survival outcomes in patients with nodal metastatic non-small cell lung cancer (NSCLC) without distant metastasis. We retrospectively extracted pre-treatment ¹⁸F-FDG PET parameters from 89 nodal-positive NSCLC patients (stage IIB–IIIC). The Cox proportional hazard model was used to identify independent prognosticators of overall survival (OS) and progression-free survival (PFS). We devised survival stratification models based on the independent prognosticators and compared the model to the American Joint Committee on Cancer (AJCC) staging system using Harrell’s concordance index (c-index). Our results demonstrated that total TLG (the combination of primary tumor and nodal total lesion glycolysis) and age were independent risk factors for unfavorable OS (p < 0.001 and p = 0.001) and PFS (both p < 0.001), while the Eastern Cooperative Oncology Group scale independently predicted poor OS (p = 0.022). Our models based on the independent prognosticators outperformed the AJCC staging system (c-index = 0.732 versus 0.544 for OS and c-index = 0.672 versus 0.521 for PFS, both p < 0.001). Our results indicate that incorporating total TLG with clinical factors may refine risk stratification in nodal metastatic NSCLC patients and may facilitate tailored therapeutic strategies in this patient group.

Application of N Descriptors Proposed by the International Association for the Study of Lung Cancer in Clinical Staging

Background Patients with N1 or N2 non-small cell lung cancer exhibit prognostic heterogeneity. To refine the current N staging system, new N stages were proposed by the International Association for the Study of Lung Cancer. However, those proposed new N stages have not been validated. Purpose To evaluate the prognostic performance of the proposed N descriptors for clinical staging. Materials and Methods Participants with non-small cell lung cancer without distant metastasis from January 2010 to December 2014 were retrospectively included. Each patient's clinical N (cN) stage was assigned to one of seven categories (cN0, cN1a, cN1b, cN2a1, cN2a2, cN2b, cN3). The 5-year overall survival rates were estimated with the Kaplan-Meier method. The adjusted hazard ratios (HRs) and their 95% CIs were estimated by using a multivariable Cox proportional hazard model. Ad hoc analyses according to lymph node (LN) size were performed. Results A total of 1271 patients (median age, 66 years; interquartile range, 59-73 years; 812 men) were included. The 5-year overall survival rates were 77.3%, 53.7%, 36.0%, 29.2%, 34.4%, 18.0%, and 12.4% for stages cN0, cN1a, cN1b, cN2a1, cN2a2, cN2b, and cN3, respectively. Patients with cN2b disease had a worse prognosis than patients with cN2a disease (HR, 1.53; 95% CI: 1.06, 2.22; P = .02). There was no prognostic difference between cN1b and cN1a (HR, 1.13; 95% CI: 0.61, 2.09; P = .71); however, there was a difference between cN1 subgroups when stratified by LN size (≥2 cm; HR, 2.26; 95% CI: 1.16, 4.44; P = .02). Within cN2a disease, there were no differences between cN2a1 and cN2a2 (HR, 0.98; 95% CI: 0.61, 1.56; P = .93) or between subgroups according to LN size (HR, 0.74; 95% CI: 0.40, 1.37; P = .34). Conclusion A survival difference was observed between single- and multistation involvement among cN2 disease. The number of involved lymph node stations in patients with cN1 disease and the presence of skip metastasis in patients with cN2 disease were not associated with survival differences. © RSNA, 2021 Online supplemental material is available for this article.

Mediastinal lymph node dissection for the elderly with clinical stage I non-small cell lung cancer

OBJECTIVES

We aimed to compare the differences in prognosis and perioperative complications between patients with and without mediastinal lymph node dissection (MLND) among elderly patients with clinical stage I non-small cell lung cancer (NSCLC).

METHODS

We analysed 439 patients ≥ 75 years of age with NSCLC classified as clinical stage I who underwent complete resection with lobectomy. We divided the patients into two groups. Those with MLND were included in the MLND group (n = 365), and those without MLND or adequate systematic mediastinal lymph node sampling were included in the non-MLND group (n = 74). To reduce selection bias, a propensity score matching method (3:1) was implemented. We compared survival and the incidence of perioperative complications.

RESULTS

After matching, we compared 171 patients in the MLND group to 57 patients in the non-MLND group. There were no significant differences in clinicopathological characteristics between the groups. The non-MLND group did not show a significantly better prognosis than the MLND group in overall survival and cancer-specific survival (p = 0.246 and 0.150, respectively). The cumulative incidence of recurrence was similar in the two groups. MLND did not affect chest drain duration or hospitalization. The numbers of patients with perioperative complications ≥ grade 2 or ≥ grade 3 did not differ between the groups (p = 0.312 and > 0.999, respectively).

CONCLUSIONS

Anatomical pulmonary resection without MLND might be a treatment option for elderly patients with clinical stage I NSCLC. Further investigation is needed to clarify the value of MLND, especially for vulnerable elderly individuals.

Development and Validation of a Combined Model for Preoperative Prediction of Lymph Node Metastasis in Peripheral Lung Adenocarcinoma

Background

Based on the “seed and soil” theory proposed by previous studies, we aimed to develop and validate a combined model of machine learning for predicting lymph node metastasis (LNM) in patients with peripheral lung adenocarcinoma (PLADC).

Methods

Radiomics models were developed in a primary cohort of 390 patients (training cohort) with pathologically confirmed PLADC from January 2016 to August 2018. The patients were divided into the LNM (−) and LNM (+) groups. Thereafter, the patients were subdivided according to TNM stages N0, N1, N2, and N3. Radiomic features from unenhanced computed tomography (CT) were extracted. Radiomic signatures of the primary tumor (R1) and adjacent pleura (R2) were built as predictors of LNM. CT morphological features and clinical characteristics were compared between both groups. A combined model incorporating R1, R2, and CT morphological features, and clinical risk factors was developed by multivariate analysis. The combined model’s performance was assessed by receiver operating characteristic (ROC) curve. An internal validation cohort containing 166 consecutive patients from September 2018 to November 2019 was also assessed.

Results

Thirty-one radiomic features of R1 and R2 were significant predictors of LNM (all P < 0.05). Sex, smoking history, tumor size, density, air bronchogram, spiculation, lobulation, necrosis, pleural effusion, and pleural involvement also differed significantly between the groups (all P < 0.05). R1, R2, tumor size, and spiculation in the combined model were independent risk factors for predicting LNM in patients with PLADC, with area under the ROC curves (AUCs) of 0.897 and 0.883 in the training and validation cohorts, respectively. The combined model identified N0, N1, N2, and N3, with AUCs ranging from 0.691–0.927 in the training cohort and 0.700–0.951 in the validation cohort, respectively, thereby indicating good performance.

Conclusion

CT phenotypes of the primary tumor and adjacent pleura were significantly associated with LNM. A combined model incorporating radiomic signatures, CT morphological features, and clinical risk factors can assess LNM of patients with PLADC accurately and non-invasively.

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.

Survival Rates of Patients with Non-Small Cell Lung Cancer Depending on Lymph Node Metastasis: A Focus on Saliva

The aim of this study was to compare overall survival (OS) rates at different pN stages of NSCLC depending on tumor characteristics and to assess the applicability of saliva biochemical markers as prognostic signs. The study included 239 patients with NSCLC (pN₀-120, pN₁-51, pN₂-68). Saliva was analyzed for 34 biochemical indicators before the start of treatment. For pN₀, the tumor size does not have a prognostic effect, but the histological type should be taken into account. For pN₁ and pN₂, long-term results are significantly worse in squamous cell cancer with a large tumor size. A larger volume of surgical treatment reduces the differences between OS. The statistically significant factors of an unfavorable prognosis at pN₀ are the lactate dehydrogenase activity <1294 U/L and the level of diene conjugates >3.97 c.u. (HR = 3.48, 95% CI 1.21-9.85, p = 0.01541); at pN₁, the content of imidazole compounds >0.296 mmol/L (HR = 6.75, 95% CI 1.28-34.57, p = 0.00822); at pN₂ levels of protein <0.583 g/L and Schiff bases >0.602 c.u., as well as protein >0.583 g/L and Schiff bases <0.602 c.u. (HR = 2.07, 95% CI 1.47-8.93, p = 0.04351). Using salivary biochemical indicators, it is possible to carry out stratification into prognostic groups depending on the lymph node metastasis.

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.

Prognostic impact of extranodal extension in patients with pN1-N2 lung adenocarcinoma

PURPOSE

Lymph node involvement is one of the important prognostic factors of patients with lung adenocarcinoma. In the tumor, node, and metastasis classification, lymph node involvement is categorized only according to the anatomical station and not the involvement pattern. The aim of this study was to investigate which morphological pattern of lymph node involvement affects the prognosis of patients with surgically resected lung adenocarcinoma.

METHODS

We retrospectively reviewed 168 consecutive patients who underwent surgical resection for primary lung adenocarcinoma with lymph node involvement. The morphological patterns of lymph node involvement (tumor area, number of metastatic lymph nodes, presence of necrosis, and extranodal extension) were histologically examined. The relationships between the patterns of lymph node involvement, clinicopathological features, and survival of patients were analyzed.

RESULTS

Eighty patients had N1 disease, and 88 patients had N2 disease. Univariate analysis revealed that invasive size, history of adjuvant chemotherapy, and presence of extranodal extension were significant prognostic factors in N1 patients, and vascular invasion, pleural invasion, presence of epidermal growth factor receptor mutation, history of adjuvant chemotherapy, and presence of extranodal extension were significant prognostic factors in N2 patients. In a bivariate analysis including other clinicopathological factors and patterns of lymph node involvement, the presence of extranodal extension was significantly associated with poor 3-year overall and recurrence-free survival of both N1 and N2 patients.

CONCLUSIONS

In patients who underwent surgical resection for lung adenocarcinoma with lymph node involvement, the extranodal extension was the most important prognostic factor among morphological lymph node involvement patterns.

Pathological features and prognostic implications of ground-glass opacity components on computed tomography for clinical stage I lung adenocarcinoma

PURPOSE

To investigate the prognostic implications and pathological features of clinical stage I lung adenocarcinoma with ground-glass opacity (GGO) on computed tomography (CT).

METHODS

The subjects of this retrospective study were 1228 patients with lung adenocarcinoma classified as clinical stage I, who underwent complete resection by lobectomy. The patients were divided into four groups based on the presence and proportion of GGO according to the consolidation-to-tumor ratio (CTR); A, CTR ≤ 0.5; B, 0.5 < CTR ≤ 0.75; C, 0.75 < CTR ≤ 1.0 with GGO; D, without GGO (pure-solid). We compared overall survival, pathological findings (N/ly/v/STAS), and histological subtypes within each clinical stage among the four groups.

RESULTS

We found no significant differences among tumors with GGO (groups A, B and C) for prognosis or pathological findings in all the clinical stages. The prognoses of groups A, B and C were significantly better than that of group D for patients with clinical stages IA2-IB disease. Tumors without GGO on CT had a significantly larger number of positive N, ly, v and STAS in almost all stages than tumors with GGO on CT. Tumors without GGO on CT had significantly more solid predominant and less lepidic predominant adenocarcinoma.

CONCLUSION

Not the proportion of GGO, but its presence on CT, as well as the size of the solid component, were correlated significantly with pathological characteristics and survival.

Survival Analysis in Single N2 Station Lung Adenocarcinoma: The Prognostic Role of Involved Lymph Nodes and Adjuvant Therapy

BACKGROUND

Prognostic factors in patients with single mediastinal station (sN2) involvement continues to be a debated issue.

METHODS

Data on 213 adenocarcinoma patients with sN2 involvement and who had undergone complete anatomical lung resection and lymphadenectomy, were retrospectively reviewed. Clinical and pathological characteristics together with adjuvant therapy (AD) and node (N) status classifications (number of resected nodes (#RN), number of metastatic nodes (#MN), and node ratio (#MN/#RN = NR) were analyzed.

RESULTS

Univariable analysis confirmed that age (0.009), #MN (0.009), NR (0.003), #N1 involved stations (p = 0.003), and skip metastases (p = 0.005) were related to overall survival (OS). Multivariable analysis confirmed, as independent prognostic factors, age <66 years and NR with a three-year OS (3YOS) of 78.7% in NR < 10% vs. 46.6% in NR > 10%. In skip metastases, NR (HR 2.734, 95% CI 1.417-5.277, p = 0.003) and pT stage (HR2.136, 95% CI 1.001-4.557, p = 0.050) were confirmed as independent prognostic factors. AD did not influence the OS of patients with singular positive lymph nodes (p = 0.41), while in patients with multiple lymph nodes and AD, a significantly better 3YOS was demonstrated, i.e., 49.1% vs. 30% (p = 0.004). In patients with N2 + N1 involvement, age (p = 0.002) and AD (p = 0.022) were favorable prognostic factors.

CONCLUSIONS

Adenocarcinoma patients with single N2 station involvement had a favorable outcome in the case of skip metastases and low NR. Adjuvant therapy improves survival with multiple nodal involvement, while its role in single node involvement should be clarified.

Comparison of Treatment Strategies for Patients With Clinical Stage T1-3/N2 Lung Cancer

BACKGROUND

The therapeutic strategies for clinical stage T1-3N2 (cT1-3N2) lung cancer are controversial. For operable tumors, treatment can vary by center, region, and continent. This study aimed to identify the optimal therapeutic method and type of surgical strategy for cT1-3N2 lung cancer.

METHODS

This retrospective evaluation analyzed the records of 17,954 patients with cT1-3N2 lung cancer treated in 2010 through 2015 from the SEER database. The effects of different therapeutic methods and types of surgical strategies on overall survival (OS) were assessed. Univariate and multivariate analyses were performed using a Cox proportional hazards model.

RESULTS

The 5-year OS rates were 27.7% for patients with T1N2 disease, 21.8% for those with T2N2 disease, and 19.9% for T3N2 disease. Neoadjuvant therapy plus operation (OP) plus adjuvant therapy, and OP plus adjuvant therapy, provided better 5-year OS rates than OP alone or concurrent chemoradiotherapy (34.1%, 37.7%, 29.3%, and 16.1%, respectively). In the T1N2, T2N2, and T3N2 groups, lobectomy provided better 5-year OS than pneumonectomy, sublobectomy, and no surgery. Both univariate and multivariate analyses showed that young age, female sex, well-differentiated histologic grade, adenocarcinoma cell type, neoadjuvant and adjuvant therapy, lobectomy, and T1 stage were statistically associated with better 5-year OS rates.

CONCLUSIONS

In cT1-3N2 lung cancer, multimodal treatments tended to provide better 5-year OS than OP alone or concurrent chemoradiotherapy. In addition, lobectomy was associated with better survival than other operative methods.

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.

Characterization of Extracapsular Lymph Node Involvement and Its Clinicopathological Characteristics in Stage II-IIIA Lung Adenocarcinoma

BACKGROUND

The prognostic impact and clinicopathological characteristics of extracapsular lymph node involvement (ECLNI) in patients with surgically resected lung adenocarcinoma (LUAD) remain unknown in the context of the eighth edition N classification.

PATIENTS AND METHODS

We retrospectively reviewed 279 patients with stage II-IIIA LUAD who underwent lobectomy and lymphadenectomy. The correlations of ECLNI presence and clinicopathological profiles were analyzed. We also assessed the impact of ECLNI on the postoperative survival of pN1 and pN2 LUAD patients.

RESULTS

ECLNI-positive status was more common in patients with high lymph node yield and in patients with multiple stations involved. The logistic regression model identified tumor spread through air spaces, micropapillary component, cribriform component, and nodal stage as predictive factors for ECLNI presence. LUAD patients with ECLNI presence had an increased risk of locoregional recurrence compared with those without (p < 0.001). Presence of ECLNI was confirmed as an independent risk factor for worse recurrence-free survival (RFS) (p < 0.001) and overall survival (OS) (p < 0.001) in the entire cohort. Among the 61 patients with ECLNI(+)pN2 disease, our analysis revealed that adjuvant radiation was a significant predictor of improved RFS and OS. In addition, ECLNI status provides additional precision in stratifying pN1 and pN2 patients with significantly different RFS and OS.

CONCLUSIONS

Our data suggest that ECLNI remains a strong prognosticator of unfavorable OS and RFS for LUADs in the context of the eighth edition N classification. Adjuvant radiation should be actively considered for pN1b and pN2 LUAD patients with ECLNI presence.

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.

The Prognostic Value Of Lymph Node Ratio In Patients With N2 Stage Lung Squamous Cell Carcinoma: A Nomogram And Heat Map Approach

Background

Lymph node ratio (LNR), defined as the ratio of the number of positive lymph nodes to the total of all resected nodes, has been reported to be a predictor of survival of patients with several types of cancer. However, the prognostic value of LNR and other factors in patients with resected N2 stage lung squamous cell carcinoma has never been considered.

Methods

Data from 1778 patients with resected N2 stage lung squamous cell carcinoma were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. The optimal cutoff value of LNR was identified by X-tile. A multivariable Cox model and corresponding nomogram were constructed to predict overall survival (OS) and cancer-specific survival (CSS). Both the cutoff value of LNR and the model were further validated in 146 similar patients treated in Zhongshan Hospital. Heat maps were created to visualize the distribution of LNR and the number of positive lymph nodes with the predicted survival probabilities.

Results

The optimal cutoff value for LNR was identified as 0.42. Multivariable analysis showed that age, sex, tumor laterality, type of surgery, T stage, chemotherapy and LNR were independently correlated with OS. Harrell’s C-index of the nomogram (0.64) was significantly higher than the index of the T stage-based model (0.54). Calibration curves showed good agreement between predicted and observed survival probabilities. The robustness of the model was also demonstrated by external validation.

Conclusion

LNR less than 0.42 was associated with improved OS and CSS for patients with resected N2 stage lung squamous cell carcinoma.

New perspective to evaluate N1 staging: The peripheral lymph node metastasis status of non-small cell lung cancer

Background

Lymph node (LN) metastasis status is the decision‐making basis for the surgical procedure and adjuvant therapy modalities. Fewer studies have previously focused on LN metastasis in N1 station, especially on peripheral lymph node (PLN) metastasis in N1 station. This study aimed to reveal the metastasis status of PLN of non‐small cell lung cancer (NSCLC), and investigate its effects on N staging.

Methods

We retrospectively evaluated a consecutive series of patients who underwent curative resection for histologically confirmed N1 NSCLC. Propensity score matching (PSM) was used to analyze the effects of PLN on N staging.

Results

A total of 105 patients with confirmed pathological N1 (pN1) stage NSCLC with solitary nodule and without neoadjuvant therapy were enrolled into the study: 55 patients had intraperipheral LN metastasis (IPLNM), and 50 patients had extra‐peripheral LN metastasis (EPLNM). Before PSM analysis, type of location (P = 0.002), surgical procedure (P = 0.008), number of positive LNs (P = 0.029), number of LNs removed (P = 0.010), lobe of lung cancer (P = 0.031), and vascular invasion (P = 0.049) showed significant differences between the two groups. After PSM analysis, statistically there were differences in type of location (P = 0.034), number of positive LNs (P = 0.008) and vascular invasion (P = 0.049) between them.

Conclusion

PLN metastasis was a quite common pattern of LN metastasis in N1 station of NSCLC. IPLNM occurred more frequently in central NSCLC and NSCLC with vascular invasion, and thoracotomy was likely to secure more accurate PLN staging. Clinicians should pay great attention to PLN dissection. Follow‐up data will be needed in order to detect the prognosis of IPLNM patients.