Is the lymphatic drainage of lung cancer lobe-specific? A surgical appraisal

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for Revision of the Classification of Residual Tumor After Resection for the Forthcoming (Ninth) Edition of the TNM Classification of Lung Cancer

INTRODUCTION

The goal of surgical resection is to completely remove a cancer; it is useful to have a system to describe how well this was accomplished. This is captured by the residual tumor (R) classification, which is separate from the TNM classification that describes the anatomic extent of a cancer independent of treatment. The traditional R-classification designates as R0 a complete resection, as R1 a macroscopically complete resection but with microscopic tumor at the surgical margin, and as R2 a resection that leaves gross tumor behind. For lung cancer, an additional category encompasses situations in which the presence of residual tumor is uncertain.

METHODS

This paper represents a comprehensive review of evidence regarding these R categories and the descriptors thereof, focusing on studies published after the year 2000 and with adjustment for potential confounders.

RESULTS

Consistent discrimination between complete, uncertain, and incomplete resection is revealed with respect to overall survival. Evidence regarding specific descriptors is generally somewhat limited and only partially consistent; nevertheless, the data suggest retaining all descriptors but with clarifications to address ambiguities.

CONCLUSION

On the basis of this review, the R-classification for the ninth edition of stage classification of lung cancer is proposed to retain the same overall framework and descriptors, with more precise definitions of descriptors. These refinements should facilitate application and further research.

Investigation of mediastinal lymph node dissection in clinical stage IA pure-solid non-small cell lung cancer patients

OBJECTIVE

To explore the independent predictors of pathological mediastinal lymph node (pN2) metastasis in clinical stage IA (cIA) pure-solid non-small cell lung cancer (NSCLC) patients, and to find an appropriate method of mediastinal lymph node dissection.

METHODS

This study retrospectively evaluated 533 cIA pure-solid NSCLC patients who underwent radical resection of lung cancer (lobectomy combined with systematic lymph node dissection) from January 2014 to December 2016. The relationship between clinicopathological characteristics and pN2 metastasis was analyzed, and the independent predictors of pN2 metastasis were determined by univariate and multivariate logistic regression analysis. We defined the new factor Y as composed of preoperative cT, CEA, and NSE.

RESULTS

There were 72 cases (13.5%) of pN2 metastasis in cIA pure-solid NSCLC patients. Preoperative clinical tumor diameter (cT), serum CEA level, serum NSE level, and pathological status of station 10 lymph nodes were independent predictors of pN2 metastasis. Patients with cT ≤ 21.5 mm, CEA ≤ 3.85 ng/mL, NSE ≤ 13.40 ng/mL and negative station 10 lymph node group showed lower rates of pN2 metastasis. The new factor Y was an independent predictor of pN2 metastasis. Only 3 (2.1%) of 143 patients in the Y low-risk group showed pN2 metastasis.

CONCLUSION

For patients with low risk of pN2 metastasis, it might be feasible to take lobe-specific lymph node sampling or systematic lymph node sampling. As for those with high risk of pN2 metastasis, systematic lymph node dissection would be recommended.

Role of invasive mediastinal nodal staging in survival outcomes of patients with non-small cell lung cancer and without radiologic lymph node metastasis: a retrospective cohort study

Background

Lung cancer diagnostic guidelines advocate for invasive mediastinal nodal staging (IMNS), but the survival benefits of this approach in patients with non-small cell lung cancer (NSCLC) without radiologic evidence of lymph node metastasis (rN0) remain uncertain. We aimed to investigate the impact of IMNS in patients with rN0 NSCLC by comparing the long-term survival between patients who underwent IMNS and those who did not (non-IMNS).

Methods

In this retrospective cohort study, we included patients with NSCLC but without radiologic evidence of lymph node metastasis from the Registry for Thoracic Cancer Surgery and the clinical data warehouse at the Samsung Medical Centre, Republic of Korea between January 2, 2008 and December 31, 2016. We compared the 5-year overall survival (OS) rate as the primary outcome after propensity score matching between the IMNS and non-IMNS groups. The age, sex, performance statue, tumor size, centrality, solidity, lung function, FDG uptake in PET-CT, and histological examination of the tumor before surgery were matched.

Findings

A total of 4545 patients (887 in the IMNS group and 3658 in the non-IMNS group) who received curative treatment for NSCLC were included in this study. By the mediastinal node dissection, the overall incidence of unforeseen mediastinal node metastasis (N2) was 7.2% (317/4378 patients). Despite the IMNS, 67% of pathological N2 was missed (61/91 patients with unforeseen N2). Based on propensity score matching, 866 patients each for the IMNS and non-IMNS groups were assigned. There was no significant difference in 5-year OS and recurrence-free survival (RFS) between two groups: 5-year OS was 73.9% (95% confidence interval, CI: 71%-77%) for IMNS and 71.7% (95% CI: 68.6%-74.9%; p = 0.23), for non-IMNS (hazard ratio, HR 0.90, 95% CI: 0.77-1.07), while 5-year RFS was 64.7% (95% CI: 61.5%-68.2%) and 67.5% (95% CI: 64.3%-70.9%; p = 0.35 (HR 1.08, 95% CI: 0.92-1.27), respectively. Moreover, the timing and locations of recurrence were similar in both groups.

Interpretation

IMNS might not be required before surgery for patients with NSCLC without LN suspicious of metastasis. Further randomised trials are required to validate the findings of the present study.

Funding

None.

Video-assisted mediastinoscopic lymphadenectomy (VAMLA): Mature results for staging non-small cell lung cancer with normal mediastinum

OBJECTIVES

The aim of this study is to analyze the accuracy of video-assisted mediastinoscopic lymphadenectomy (VAMLA) and the unsuspected (u) N2/3 rates in patients with non-small cell lung cancer (NSCLC) and normal mediastinum by integrated positron emission tomography-computed tomography.

METHODS

Prospective observational single-center study of 603 consecutive VAMLAs from 2010 to 2022.

EXCLUSION CRITERIA

other indications (n = 32), tumors different from NSCLC (n = 91), and clinical (c) N2/3 tumors by positron emission tomography-computed tomography (n = 46). Systematic nodal dissection was the gold standard to validate negative VAMLAs. Those patients with negative VAMLA and missing reference standard test were excluded. uN2/3 rates were analyzed in the global series and in the subgroups of tumors according to their clinical nodal and tumor categories. Pathologic findings were reviewed, and staging values were calculated.

RESULTS

Three hundred eighty-three patients with cN0/1 NSCLC underwent VAMLA. Staging values of VAMLA were: sensitivity, 0.98 (95% CI, 0.92-0.99); negative predictive value, 0.99 (95% CI, 0.98-1); and diagnostic accuracy, 0.99 (95% CI, 0.98-1). The uN2/3 rate for the whole series (N = 383) was 18.8%. The uN2/3 rates according to presurgical nodal and tumor categories determined by positron emission tomography computed tomography were: 3.6% (4 out of 111) in cT1N0; 16.3% (18 out of 110) in cT2N0; 10.25% (4 out of 39) in cT3N0; and 32% (7 out of 22) in cT4N0. Forty-two percent (39 out of 93) in cN1; complication rate was 7%.

CONCLUSIONS

This series of NSCLC with normal mediastinum staged by VAMLA demonstrates a high accuracy of this technique and a high rate of uN2/3 disease (specially in cN1 and cT4N0). VAMLA could be considered the reference staging procedure for staging cN0/1 NSCLC.

Comparison of the Outcomes between Systematic Lymph Node Dissection and Lobe-Specific Lymph Node Dissection for Stage I Non-small Cell Lung Cancer

BACKGROUND

This study compares the surgical and long-term outcomes, including disease-free survival (DFS), overall survival (OS), and cancer-specific survival (CSS), between lobe-specific lymph node dissection (L-SND) and systematic lymph node dissection (SND) among patients with stage I non-small cell lung cancer (NSCLC).

METHODS

In this retrospective study, 107 patients diagnosed with clinical stage I NSCLC undergoing video-assisted thoracic surgery lobectomy (exclusion of the right middle lobe) from January 2011 to December 2018 were enrolled. The patients were assigned to the L-SND (n = 28) and SND (n = 79) groups according to the procedure performed on them. Demographics, perioperative data, and surgical and long-term oncological outcomes were collected and compared between the L-SND and SND groups.

RESULTS

The mean follow-duration was 60.6 months. The demographic data and surgical outcomes and long-term oncological outcomes were not significantly different between the two groups. The 5-year OS of the L-SND and SND groups was 82% and 84%, respectively. The 5-year DFS of the L-SND and SND groups was 70% and 65%, respectively. The 5-year CSS of the L-SND and SND groups was 80% and 86%, respectively. All the surgical and long-term outcomes were not statistically different between the two groups.

CONCLUSION

L-SND showed comparable surgical and oncologic outcomes with SND for clinical stage I NSCLC. L-SND could be a treatment choice for stage I NSCLC.

Lobe-Specific Lymph Node Dissection May be Feasible for Clinical N0 Solid-Predominant Part-Solid Lung Adenocarcinoma With Solid Component Diameter ≤ 2 cm

BACKGROUND

Lymph node (LN) involvement was not rare in patients with radiological solid-predominant part-solid nodules (PSNs). The lymph node dissection (LND) strategy remained unclear.

MATERIALS AND METHODS

Six hundred seventy-two patients with clinical N0 solid-predominant PSNs (0.5 < consolidation-to-tumor ratio < 1) receiving systematic LND (development cohort, n = 598) or limited LND (validation cohort A, n = 74) at 2 Chinese institutions from 2008 to 2016 were collected. The development cohort was utilized to investigate the incidence and pattern of LN metastasis. Lobe-specific LN metastasis pattern was defined as superior mediastinal LN involvement from upper-lobe tumor or inferior mediastinal LN involvement from lower-lobe tumor. To further validate the LN metastasis pattern observed in the development cohort, validation cohort B consisting of 7273 patients with primary lung adenocarcinomas who received surgery from 2016 to 2021 was identified. The clinical outcomes between the development cohort and validation cohort A were compared in order to assess the feasibility of limited LND.

RESULTS

LN involvement rate for solid-predominant PSNs was 10.0%. Larger solid component diameter (P = .005) was independently associated with increased risk of LN involvement. In upper/lower lobes solid-predominant PSNs with solid component diameter ≤ 2 cm, a lobe-specific LN involvement pattern was identified. Further validation indicated that the observed mediastinal LN involvement pattern was generalizable, and the oncologic outcomes did not vary by the extent of LND in solid-predominant PSNs with solid component diameter ≤ 2 cm.

CONCLUSION

Lobe-specific LND might be feasible for solid-predominant PSNs with solid component diameter ≤ 2 cm. For other solid-predominant PSNs, systematic LND should be recommended.

Prognostic impact of lymph node spreading pattern in N2 NSCLC patients

BACKGROUND

One-third of non-small cell lung cancer (NSCLC) patients are diagnosed with locally advanced disease. Long-term survival in stage IIIA/B-N2 remains poor; this may also be due to lymph node spreading pattern. Therefore, we compared the overall survival of stage IIIA/B-N2 patients with superior mediastinal lymph nodes (SML) with infracarinal- or inferior mediastinal lymph nodes (IML) and with multilevel disease (MLD).

RESEARCH DESIGN AND METHODS

One-, three-and five-year survival rates were measured. Kaplan-Meier curves and Cox proportional hazards model assessed survival and were used to identify prognostic factors.

RESULTS

We reviewed data of stage IIIA/B-N2 patients (n = 129) who underwent surgery for NSCLC between 2012 and 2020. Patients with SML (n = 62) were compared to ILM (n = 37) and MLD (n = 30). SML patients showed significantly better one- (SML: 95.2% vs. IML: 78.6% vs. MLD: 69.4%, p = 0.03), three- (78.8% vs. 27.7 vs. 13.3%; p = <0.001) and five-year (61.1% vs. 17.1 vs. 3%; p < 0.001) survival rates, than IML and MLD patients. Kaplan-Meier curves showed prolonged overall survival for SML patients (log-rank SML, ILM, MLD p < 0.0001).

CONCLUSIONS

This study showed significantly better long-term survival of SML patients than IML and MLD patients. The long-term survival of ILM and MLD patients was equally poor.

Regional lymph node recurrence after stereotactic body radiation therapy for lung cancer: Patterns of recurrence, treatment approaches, and clinical outcomes (KROG 21-09)

PURPOSE

To present the multi-institutional data on patterns of recurrence, treatment approaches, and clinical outcomes for regional lymph node (LN) recurrence after stereotactic body radiation therapy (SBRT) for primary lung cancer.

MATERIALS AND METHODS

The medical records of 114 patients who experienced regional LN recurrence as the first recurrence after lung SBRT were retrospectively reviewed. Patterns of recurrence were classified as local recurrence, regional recurrence, and distant metastasis. Clinical outcomes including progression-free survival (PFS) and overall survival (OS) were analyzed.

RESULTS

Half of the patients had regional LN recurrence only. The most common simultaneous recurrence was distant metastasis (38.6 %). Common sites of regional recurrence were ipsilateral hilar (47.2 %), ipsilateral upper mediastinal (40.6 %), and subcarinal (42.5 %) LN stations. 24 (21.1 %) patients underwent salvage radiation therapy (RT), and 44 (38.6 %) patients underwent palliative treatment. Better OS was observed in the salvage RT group (p = 0.025). The 1-year PFS and OS rates were 27.7 % and 55.2 %, respectively, with salvage RT, 14.0 % and 39.9 %, respectively, with palliative treatment, and 22.8 % and 26.8 %, respectively, with no additional treatment. Multivariate analysis showed that salvage RT (PFS, HR 0.463, p = 0.050; OS, HR 0.312, p = 0.002), palliative treatment (PFS, HR 0.436, p = 0.013; OS, HR 0.553, p = 0.050), and simultaneous distant metastasis (PFS, HR 2.335, p = 0.005; OS, HR 1.726, p = 0.054) affected clinical outcomes.

CONCLUSION

Many cases of regional LN recurrence are confined to the locoregional area of patients, and appropriate treatment can improve the prognosis of these patients.

Lobe-specific lymph node dissection in early-stage non-small-cell lung cancer: An overview

Lymph node dissection is a vital part of surgical treatment for early-stage non-small cell lung cancer (NSCLC). Lobectomy with systematic lymph node dissection (SLND) still remains the gold standard surgical treatment for early-stage NSCLC patients. However, an increasing number of studies have demonstrated that lobe-specific lymph node dissection (L-SLND) can be used as an alternative therapy for SLND in carefully selected patients with early-stage NSCLC. However, there are no currently available evidences of review summarizing the role of L-SLDN in treating early-stage NSCLC. Therefore, we performed this literature review by summarizing the existing literatures on the lymph node drainage pattern, definition, scope and role of L-SLND in patients with early-stage NSCLC, aiming to provide evidence for the application of L-SLND in patients with early-stage NSCLC.

Persistent N2 After Induction Is Not a Contraindication to Surgery for Lung Cancer

BACKGROUND

Surgical management for potentially resectable stage IIIA-N2 non-small cell lung cancer (NSCLC) is controversial. For some, persistent N2 disease after induction therapy is a contraindication to resection. We examined outcomes of a well-selected surgical cohort of postinduction IIIA-N2 NSCLC patients with persistent N2 disease.

METHODS

We retrospectively reviewed all resected clinical IIIA-N2 NSCLC patients from 2001 to 2018. Thorough preoperative staging, including invasive mediastinal staging, was performed. Those with nonbulky N2 disease, appropriate restaging, and potential for a margin-negative resection were included. After resection, patients were classified as having persistent N2 disease or mediastinal downstaging (N2 to >N0/N1). Persistent N2 patients were further classified as uncertain resection (R[un]) or complete resection (R0) according to the International Association for the Study of Lung Cancer definition. Kaplan-Meier survival analysis was used.

RESULTS

Fifty-four patients met inclusion criteria. After induction, 31 patients (57%) demonstrated persistent N2 disease, and 23 patients (43%) had mediastinal downstaging. Preinduction invasive mediastinal staging was performed in 98.1%. Most had clinical single-station N2 disease (75.9%). Margin-negative resections were performed in 100%. Eight patients were reclassified as R(un) due to positive highest sampled mediastinal station. The median overall survival for persistent N2 was 26 months for R(un) and 69 months for R0. Overall survival for the downstaged group was 67 months (P = .31).

CONCLUSIONS

Overall survival for patients with non-R(un) or persistent N2 (true R0) was similar to those with mediastinal downstaging. Well-selected patients with persistent N2 disease experience reasonable survival after resection and should have surgery considered as part of their multimodality treatment. This study underscores the importance of classifying the extent of mediastinal involvement for persistent N2 patients, supporting the proposed International Association for the Study of Lung Cancer R(un) classification.

Station 3A lymph node dissection does not improve long-term survival in right-side operable non-small-cell lung cancer patients: A propensity score matching study

Background

To investigate the impact of station 3A lymph node dissection (LND) on overall survival (OS) and disease‐free survival (DFS) in completely resected right‐side non‐small‐cell lung cancer (NSCLC) patients.

Methods

A total of 1661 cases with completely resected right‐side NSCLC were included. Propensity score matching (PSM) was performed to minimize selection bias, and a logistic regression model was conducted to investigate the risk factors associated with station 3A lymph node metastasis (LNM). The Kaplan–Meier method and Cox proportional hazards model were used to evaluate the impact of station 3A LND on survival.

Results

For the entire cohort, 503 patients (30.3%) underwent station 3A LND. Of those, 11.3% (57/503) presented station 3A LNM. Univariate and multivariate logistic analyses showed that station 10 LNM, tumor location, and the number of resected lymph nodes were independent risk factors associated with station 3A LNM. Before PSM, patients with station 3A LND had worse 5‐year OS (p = 0.002) and DFS (p = 0.011), and more drainage on postoperative day 1 (p = 0.041) than those without. After PSM, however, station 3A LND was not associated with the 5‐year OS (65.7% vs. 63.6%, p = 0.432) or DFS (57.4% vs. 56.0%, p = 0.437). The multivariate analysis further confirmed that station 3A LND was not a prognostic factor (OS, p = 0.361; DFS, p = 0.447).

Conclusions

Station 3A LND could not improve long‐term outcomes and it was unnecessary to dissect station 3A lymph nodes during surgery of right‐side NSCLC.

Lung Cancer Treatment: From Tradition to Innovation

Lung cancer (LC) is the second most commonly diagnosed cancer and the primary cause of cancer death worldwide in 2020. LC treatment is associated with huge costs for patients and society; consequently, there is an increasing interest in the prevention, early detection with screening, and development of new treatments. Its surgical management accounts for at least 90% of the activity of thoracic surgery departments. Surgery is the treatment of choice for early-stage non-small cell LC. In this article, we discuss the state of the art of thoracic surgery for surgical management of LC. We start by describing the milestones of LC treatment, which are lobectomy and an adequate lymphadenectomy, and then we focus on the traditional and innovative minimally invasive surgical approaches available: video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracoscopic surgery (RATS). A brief overview of the innovation and future perspective in thoracic surgery will close this mini-review.

The Prognostic Impact of Lymph Node Dissection on Primary Tumor Resection for Stage IV Non-Small Cell Lung Cancer: A Population-Based Study

Objective

Selected patients with stage IV non–small cell lung cancer (NSCLC) who underwent primary tumor resection have witnessed a survival benefit. Whether additional lymph node dissection (LND) would result in a better effect remain unknown. We investigated the prognostic impact of LND on patients with stage IV NSCLC who received primary tumor resection (PTR).

Methods

Patients with stage IV NSCLC who underwent PTR were identified from the Surveillance, Epidemiology, and End Results database from 2004 to 2016. Propensity-score matching was performed to minimize the confounding effect, and lung cancer-specific survival (CSS) and overall survival (OS) were compared after matching. Multivariable Cox regression was used to identify prognostic factors and to adjust for covariates in subgroup analysis. The effect of the number of lymph nodes examined on the CSS was evaluated by repeating the Cox analysis in a binary method.

Results

A total of 4,114 patients with stage IV NSCLC who receive surgery met our criteria, of which 2,622 (63.73%) underwent LND and 628 patients were identified 1:1 in LND and non-LND groups after matching. Compared with the non-LND group, the LND group had a longer CSS (median: 23 vs. 16 months, p < 0.001) and OS (median: 21 vs. 15 months, p < 0.001). Multivariable regression showed that LND was independently associated with favorable CCS [hazard ratio (HR) = 0.78, 95% confidence interval (CI) 0.69–0.89, P < 0.001] and OS (HR = 0.79, 95% CI 0.70–0.89, P < 0.001). Subgroup analysis suggested that LND is an independent favorable predictor to survival in the surgical patients who were older age (>60 years old), female, T3-4, N0, and M1a stage and those who underwent sublobar resection. In addition, a statistically significant CCS benefit was associated with an increasing number of lymph nodes examined through 25 lymph nodes.

Conclusions

LND with a certain range of lymph nodes number examined was associated with improved survival for patients with stage IV NSCLC who received primary tumor resection. The results may have implications for guidelines on lymph nodes management in selective advanced NSCLC for surgery.

Comparison of Silicosis and Tuberculosis Involving Mediastinal Lymph Nodes Based on Contrast-Enhanced Multidetector-Row Computed Tomography

PURPOSE

To investigate the different imaging features of contrast-enhanced multidetector-row-computed tomography (MDCT) for distinguishing between silicosis and tuberculosis involving the mediastinal lymph nodes.

METHODS

86 silicosis patients and 61 tuberculosis patients with mediastinal lymphadenopathy based on contrast-enhanced MDCT were included. The enhanced patterns, anatomical distribution and calcification features of the enlarged lymph nodes were retrospectively compared between the groups using the Pearson chi-square test or Fisher's exact test.

RESULTS

Homogeneous enhancement of the mediastinal lymph nodes was more commonly observed in silicosis (94.2%, 81/86) than in tuberculosis (19.7%, 12/61). Peripheral enhancement was more frequent in tuberculosis (n = 44, 72.1%) than in silicosis involving the mediastinal lymph nodes (n = 1, 1.2%), and multilocular appearance was more frequent in TB than in silicosis. Tuberculosis was more likely to affect regions 1R, 2R, 2L, 3A, 5 and 6 than silicosis (all p < 0.05), especially region 2R. Calcification of the lymph nodes was more common in the silicosis group than in tuberculosis group. The sensitivity, specificity, and accuracy of silicosis with lymphadenopathy with homogeneous enhanced pattern were 94.2%, 80.3% and 88.4%, respectively. The sensitivity, specificity, and accuracy of tuberculosis lymphadenopathy with peripheral enhanced pattern were 72.1%, 98.8%, and 87.7%, respectively.

CONCLUSION

The predominant enhanced patterns, anatomical distribution, and calcification features of mediastinal lymph nodes were different between tuberculosis and silicosis. These radiographic features might help differentiate tuberculosis from silicosis, which provides imaging information for the differential diagnosis of the two diseases in a clinical setting.

Thoracic lymphadenopathies in diffuse systemic sclerosis: an observational study on 48 patients using computed tomography

Background

Thoracic multidetector computed tomography (MDCT) is essential for the detection of interstitial lung disease (ILD) in patients with systemic sclerosis (SSc). Thoracic MDCT assessment can reveal the presence of thoracic lymphadenopathies (LAP) whose signification remains uncertain. The purpose of the study was to describe the characteristics and to assess the significance of thoracic LAP in patients with diffuse SSc.

Methods

We conducted a monocentric observational study on adult patients with diffuse SSc, and collected general patient and first thoracic MDCT characteristics, PET-CT and outcome data. Comparisons were made between patients with and without thoracic LAP.

Results

Forty-eight patients were included. There were 30 patients (62.5%) with an ILD and 23 (48%) with at least one thoracic LAP on the first MDCT assessment. Median number per patient of thoracic LAP was 3 [1–8], with a mean size of 11.7 ± 1.7 mm, mainly located in right para-tracheal area (22.8% of the total number of LAP), right hilar area (20.3%), left hilar area (6.5%), and sub-carinal area (15.2%). PET-CT showed lymph node hypermetabolism in 11/15 patients (73.3%) with mean SUVmax at 4 ± 1.3. There were significantly more males (p = 0.002) and more patients exposed to silica (p = 0.001) in patients with thoracic LAP. ILD was significantly more extended according to Goh score (p = 0.03), and using semi-quantitative score for mixed ground-glass reticulation (p = 0.01) and global abnormalities (p = 0.03) in patients with thoracic LAP and ILD. Thirteen patients (27.1%) died during follow-up without significant difference according to the presence or not of thoracic LAP (p = 0.15). There was also no significant difference concerning immunosuppressive treatment initiation (p = 0.17).

Conclusions

Thoracic LAP are common in diffuse SSc and are generally multiple, not bulky, moderately hypermetabolic, and located at the base of the mediastinum lymph node chains. Their presence correlates with the extent of ILD. In absence of ILD, thoracic LAP presence seems to be often explained by silica exposure.

Trial Registration: NA.

The Impact of Skip vs. Non-Skip N2 Lymph Node Metastasis on the Prognosis of Non-Small-Cell Lung Cancer: A Systematic Review and Meta-Analysis

Objective: The skip N2 metastases were frequent in non-small-cell lung cancer (NSCLC) and the better prognosis of NSCLC with a skip over non-skip N2 lymph node metastases is controversial. The primary aim of this study is to investigate the prognosis effect of skip N2 lymph node metastases on the survival of NSCLC.

Setting: A literature search was conducted in PubMed, EMBASE, and Cochrane Library with the term of “N2” or “mediastinal lymph node” or “mediastinal nodal metastases”, and “lung cancer” and “skip” or “skipping” in the title/abstract field. The primary outcomes of interests are 3- and 5-year survival in NSCLC.

Participants: Patients who underwent complete resection by lobectomy, bilobectomy, or pneumonectomy with systemic ipsilateral lymphadenectomy and were staged as pathologically N2 were included.

Primary and Secondary Outcome Measures: The 3- and 5-year survival of NSCLC was analyzed. The impact of publication year, number of patients, baseline mean age, gender, histology, adjuvant therapy, number of skip N2 stations, and survival analysis methods on the primary outcome were also analyzed.

Results: A total of 21 of 409 studies with 6,806 patients met the inclusion criteria and were finally included for the analysis. The skip N2 lymph node metastases NSCLC had a significantly better overall survival (OS) than the non-skip N2 NSCLC [hazard ratio (HR), 0.71; 95% CI, 0.62–0.82; P < 0.001; I² = 40.4%]. The skip N2 lymph node metastases NSCLC had significantly higher 3- and 5-year survival rates than the non-skip N2 lymph node metastases NSCLC (OR, 0.75; 95% CI, 0.66–0.84; P < 0.001; I² = 60%; and OR, 0.78; 95% CI, 0.71–0.86; P < 0.001; I² = 67.1%, respectively).

Conclusion: This meta-analysis suggests that the prognosis of skip N2 lymph node metastases NSCLC is better than that of a non-skip N2 lymph node.

Patterns of nodal spread in stage III NSCLC: importance of EBUS-TBNA and 18F-FDG PET/CT for radiotherapy target volume definition

Purpose

The aim of this study was to compare the pattern of intra-patient spread of lymph-node (LN)-metastases within the mediastinum as assessed by ¹⁸F-FDG PET/CT and systematic endobronchial ultrasound-guided transbronchial-needle aspiration (EBUS-TBNA) for precise target volume definition in stage III NSCLC.

Methods

This is a single-center study based on our preceding investigation, including all consecutive patients with initial diagnosis of stage IIIA-C NSCLC, receiving concurrent radiochemotherapy (12/2011–06/2018). Inclusion criteria were curative treatment intent, ¹⁸F-FDG PET/CT and EBUS-TBNA prior to start of treatment. The lymphatic drainage was classified into echelon-1 (ipsilateral hilum), echelon-2 (ipsilateral LN-stations 4 and 7) and echelon-3 (rest of the mediastinum, contralateral hilum). The pattern of spread was classified according to all permutations of echelon-1, echelon-2, and echelon-3 EBUS-TBNA findings.

Results

In total, 180 patients were enrolled. Various patterns of LN-spread could be identified. Skip lesions with an involved echelon distal from an uninvolved one were detected in less than 10% of patients by both EBUS-TBNA and PET. The pattern with largest asymmetry was detected in cases with EBUS-TBNA- or PET-positivity at all three echelons (p < 0.0001, exact symmetry test). In a multivariable logistic model for EBUS-positivity at echelon-3, prognostic factors were PET-positivity at echelon-3 (Hazard ratio (HR) = 12.1; 95%-CI: 3.2–46.5), EBUS-TBNA positivity at echelon-2 (HR = 6.7; 95%-CI: 1.31–31.2) and left-sided tumor location (HR = 4.0; 95%-CI: 1.24–13.2). There were significantly less combined ipsilateral upper (LN-stations 2 and 4) and lower (LN-station 7) mediastinal involvements (16.8% of patients) with EBUS-TBNA than with PET (38.9%, p < 0.0001, exact symmetry test). EBUS-TBNA detected a lobe specific heterogeneity between the odds ratios of LN-positivity in the upper versus lower mediastinum (p = 0.0021, Breslow-Day test), while PET did not (p = 0.19).

Conclusion

Frequent patterns of LN-metastatic spread could be defined by EBUS-TBNA and PET and discrepancies in the pattern were seen between both methods. EBUS-TBNA showed more lobe and tumor laterality specific patterns of LN-metastases than PET and skipped lymph node stations were rare. These systematic relations offer the opportunity to further refine multi-parameter risk of LN-involvement models for target volume delineation based on pattern of spread by EBUS-TBNA and PET.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01904-4.

Dissection of 4L lymph node for left-sided non-small cell lung cancer: a meta-analysis

BACKGROUND

Whether dissection of left lower paratracheal (4L) lymph node has any impact on survival of patients with left-sided non-small cell lung cancer (NSCLC) remains unclear. We conducted the first meta-analysis to compare the survival of patients treated with 4L lymph node dissection (LND) and those without for left-sided NSCLC.

METHODS

We systematically searched relevant studies from PubMed, Embase, and Web of Science on February 6, 2020. Data for analysis included 5-year overall survival (OS) and disease-free survival (DFS) rates, OS, and DFS. We calculated risk ratio (RR) for pooling 5-year OS and DFS rates and extracted hazard ratio (HR) from multivariate analysis for pooling OS and DFS.

RESULTS

We finally included three retrospective cohort studies with propensity score-matched analysis consisting of 2103 patients. Meta-analysis showed that patients treated with 4L LND yielded significantly higher 5-year OS (67.7% vs. 54.6%; fixed effects models: RR = 0.75; 95% confidence interval [CI] = [0.67, 0.84]; p < 0.001; I²  = 0%) and DFS (53.3% vs. 44.8%; fixed effects models: RR = 0.85; 95% CI = [0.76, 0.95]; p = 0.003; I²  = 41.7%) rates than patients without 4L LNDS. Moreover, dissection of 4L lymph node was significantly associated with better OS (fixed effects model: HR = 0.66; 95% CI = [0.57, 0.76]; p < 0.001; I²  = 45.7%) and DFS (fixed effects model: HR = 0.67; 95% CI = [0.52, 0.87]; p = 0.003; I²  = 0%). No significant heterogeneities were observed.

CONCLUSIONS

Dissection of 4L lymph node could significantly improve both 5-year OS and DFS rates and 4L LND was a favorable prognostic factor for patients with left-sided NSCLC.

Lobe-specific lymph node dissection in stage IA non-small-cell lung cancer: a retrospective cohort study

OBJECTIVES

To investigate lymph node (LN) metastasis according to tumour location and assess the impact of lobe-specific LN dissection on survival in stage IA non-small-cell lung cancer (NSCLC).

METHODS

We retrospectively analysed the data of patients with clinical stage IA NSCLC treated with lobectomy and systematic LN dissection at Asan Medical Center (Seoul, Korea) between June 2005 and April 2017. Patients who received neoadjuvant therapy had multiple primary tumours or missed the follow-up during the first postoperative year were excluded. The patients were divided into five groups according to involved lung lobes: right upper lobe (RUL), right middle lobe (RML), right lower lobe (RLL), left upper lobe (LUL) and left lower lobe (LLL), which were further divided into subgroups according to LN station metastasis. Overall survival (OS) and the incidence of metastasis were calculated for each subgroup. Efficacy indices (EIs) were calculated to determine the correlation between each lung lobe and LN station, and the impact of the dissection of these stations on survival.

RESULTS

A total of 1202 patients were analysed. The 5-year OS in the RUL, RML, RLL, LUL and LLL groups was 74%, 88%, 78%, 80% and 75%, respectively. The incidence of single LN station metastasis was 11%, 10%, 10%, 16% and 14%, respectively. The lobe-specific LNs for RUL, RML, RLL, LUL and LLL were stations 2/3/4, 4/7, 2/4/7, 4/5/6 and 6/7/9, respectively. Moreover, the LN stations with high EIs for RUL, RML, RLL, LUL and LLL were 4, 7, 7, 5 and 7, respectively. In the RUL group, the incidence of metastasis to stations 2, 3 and 4 was 2.3%, 0.5% and 7.6%, and the EI was 0.8, 0.3 and 4.3, respectively. In RML, the incidence of metastasis to stations 4 and 7 was 4% and 6%, and the EI was 1.3 and 2.4, respectively. In RLL, the incidence of metastasis to stations 2, 4 and 7 was 4.4%, 5.6% and 8.3%, and the EI was 1.3, 1.4 and 3.3, respectively. In LUL, the incidence of metastasis to stations 4, 5 and 6 was 1.4%, 11.8% and 2.5%, and the EI was 0.4, 7.1 and 0.5, respectively. In LLL, the incidence of metastasis to stations 6, 7 and 9 was 1.1%, 5.7% and 1.7%, and the EI was 0.6, 2.3 and 0.5, respectively. Furthermore, the OS of patients with lobe-specific LN metastasis was statistically significantly different from that of the non-lobe-specific LN metastasis group with P-values of <0.001 for RUL, 0.002 for RML, 0.002 for RLL, 0.001 for LUL and 0.003 for LLL.

CONCLUSIONS

Our findings support the use of lobe-specific LN dissection in stage IA NSCLC. When LN stations with high EI were negative, LN metastasis in other stations was unlikely. The incidence of LN metastasis beyond lobe-specific LN stations was ∼1% in all subgroups. Dissection of non-lobe-specific LNs may not improve the OS; however, prospective randomized controlled trials are needed to modify the standard approach.

Correlation between tumor location and survival in stage I lung adenocarcinoma and squamous cell carcinoma: a SEER-based study

Background: Whether location mattered remained controversial in early-stage non-small cell lung cancer.

Methods: We conducted a retrospective study with the Surveillance, Epidemiology, and End Results (SEER) database. Overall survival (OS) and lung cancer-specific survival (LCSS) with landmark analysis and restricted mean survival time (RMST) were compared between patients with a tumor in upper lobe and non-upper lobe. The multivariable Cox analysis was applied to evaluate multiple prognostic factors.

Results: Tumor in non-upper lobe had worse OS (hazard ratio [HR]: 1.354, p < 0.001) and LCSS (HR: 1.476, p = 0.005) than the upper lobe in stage IB adenocarcinoma in 32-month landmark and IA3 (OS, HR: 1.300, p < 0.001; LCSS, HR: 1.413, p = 0.004) adenocarcinoma in 48-month landmark, but not in stage IA1 and IA2 adenocarcinoma. The results remained positive in subgroups of < 4, ≥ 4 and ≥ 11 LN examined in stage IB tumor and ≥ 4 LN examined in stage IA3 tumor. For SCC, non-upper lobar tumor had similar OS and LCSS with upper lobar tumor in all stages. The multivariate Cox analysis confirmed that the non-upper lobe was an independent risk factor in stage IA3-IB adenocarcinoma, but not in SCC. Adjuvant chemotherapy (ACT) could improve OS in stage IB adenocarcinoma (HR: 0.586, p < 0.001) and SCC (HR: 0.708, p = 0.030) located in non-upper lobe.

Conclusions: Non-upper lobar adenocarcinoma in stage IA3-IB was associated with worse prognosis. ACT may improve prognosis in stage IB tumor located in non-upper lobe.

Prognostic score for survival with pulmonary carcinoids: the importance of associating clinical with pathological characteristics

OBJECTIVES

Lung carcinoids (LCs) are staged using the non-small-cell lung cancer tumour/node/metastasis staging system; the possibility of an LC-specific staging system is still being debated. The goal of our study was to construct a composite prognostic score for LC.

METHODS

From January 2002 to December 2014, data from 293 patients who underwent surgical treatment for LC in 7 research institutes were retrospectively analysed. A panel of established prognostic factors in addition to lymph node metastasis patterns (single/multiple N1-N2 station, skip metastasis, lobe specific), numbers of lymph nodes resected and the ratio between the numbers of metastatic lymph nodes and the numbers of lymph nodes resected (node ratio) were correlated to overall survival (OS) and disease-free survival (DFS). The log-hazard ratio (HR), obtained from the Cox model, was used to derive weighting factors for a continuous prognostic index, designed to identify differential outcome risks. The score was dichotomized according to maximally selected log-rank statistics.

RESULTS

Pathological analysis showed typical carcinoids in 223 (76.1%) and atypical carcinoids in 70 (23.9%) patients; the tumour/node/metastasis pattern was stage I in 72.4%, stage II in 18.1%, stage III in 9.5% and stage IV in 0.03% cases. The median numbers of lymph nodes resected was 12 (range 0-53); hilar and mediastinal node metastases were identified in 14% and 6.8% of cases, respectively. Overall, the 5-year OS and 5-year DFS rates were 90.6% and 76.7%, respectively. At multivariable analysis, sex, age, pathological T stage and node ratio were significantly related to a better OS; age, histological type, pathological T stage and node ratio were related to DFS. These factors were used to generate the prognostic score, which showed statistically significant differences between the high-risk and low-risk groups: 5-year OS = 96.6% if score <3.1 vs 63.5% if score ≥3.1 [P < 0.0001; HR 17.56, 95% confidence interval (CI) 5.45-56.53]; 5-year DFS 92.3% if score <1.5 vs 52.5% if score ≥ 1.5 (P < 0.0001; HR 7.95, 95% CI 3.48-18.16).

CONCLUSIONS

The proposed prognostic scores seem to be effective in predicting outcomes for patients with LCs.

Surgical Consideration Based on Lymph Nodes Spread Patterns in Patients with Peripheral Right Middle Non-small Cell Lung Cancer 3 cm or Less

BACKGROUND

The optimal extent of lung resection and lymph nodes dissection for peripheral early-stage right middle non-small cell lung cancer (NSCLC) still remains controversial. In this study, we analyzed the patterns of lymph nodes metastasis (LNM) of patients with peripheral right middle NSCLC ≤ 3 cm, aiming to provide evidences for surgical choice for early-stage peripheral right middle lobe NSCLC.

METHODS

We retrospectively investigated the clinical and pathological data of patients diagnosed with peripheral right middle lobe NSCLC ≤ 3 cm between January 2015 and December 2019. The LNM patterns were analyzed by tumor size.

RESULTS

A total of 60 patients were included for analysis. The tumor size was preoperatively divided as follows: ≤ 1 cm (13 patients); > 1 cm but ≤ 2 cm (36 patients); > 2 cm but ≤ 3 cm (11 patients). Fifty-four patients were categorized as N0 group, 1 patient as N1 group, and 5 patients as N2 group. In the upper zone, 3 patients were found to have LNM. In the subcarinal zone, another 3 patients had LNM. But the lymph nodes of all these patients were negative in the lower zone. In station 10, 1 patient (1.67%) was found to have LNM, while in station 11-13, 2 patients (3.33%) were found to have LNM.

CONCLUSION

For the right middle lobe peripheral NSCLC ≤ 1 cm, sublobar resection with lymph node sampling may be a feasible treatment. For cancers > 1 cm but ≤ 2 cm, lobectomy with lobe-specific lymph node dissection (especially station 2R and 4R) may be a preferred choice. For tumors > 2 cm but ≤ 3 cm, lobectomy with systematic lymph node dissection may still be the standard of care.

Primary pulmonary lymphoepithelioma-like carcinoma with positive expression of Epstein-Barr virus and PD-L1: A case report

•

Pulmonary lymphoepithelioma-like carcinoma (LELC) is extremely rare in Japan.

•

None of the studies regarding LELC in Japan described an association with PD-L1.

•

This is the first case of LELC in Japan with both expression of EBER-ISH and PD-L1.

•

An investigation of PD-L1 would be useful considering the PD-1/PD-L1 blockade.

•

Thus, PD-L1 expression should be examined in patients with pulmonary LELC.

Introduction and importance

Pulmonary lymphoepithelioma-like carcinoma (LELC) is a rare type of non-small cell lung cancer (NSCLC) that is classified as a subtype of unclassified carcinoma by the WHO. LELC is usually associated with Epstein-Barr virus (EBV) infection. LELC has often been observed in Southeast Asia; however, it is extremely rare in Japan.

Case presentation

A 60-year-old Japanese woman presented with an abnormal shadow in the left lung on chest radiography. Chest computed tomography showed a nodule located between the lingular and basal anteromedial segments. A blood test suggested an existing EBV infection, and LELC was suspected preoperatively in the transbronchial lung biopsy. She underwent a lingular and basal bi-segmentectomy. The EBV-encoded small ribonucleic acid in-situ hybridization (EBER-ISH) was positive, and she was diagnosed with LELC. Moreover, programmed death-ligand 1 (PD-L1) expression was moderately positive. No recurrence was observed for 30 months.

Clinical discussion

Although LELC has been reported as a low-grade malignancy with a good prognosis, the frequency of PD-L1 expression in LELC seems to be higher than that in other NSCLCs. Moreover, it has been reported that LELC patients with high PD-L1 expression are likely to have early recurrence/metastasis and poor prognosis.

Conclusion

An investigation of PD-L1 expression for LELC would be useful considering the benefit of PD-1/PD-L1 blockade in patients with pulmonary LELC with high PD-L1 expression. The present case is the first report of LELC with positive expression of EBER-ISH and PD-L1 in Japan.

[Clinicopathological characteristics and risk factors of station 4L lymph node metastasis of left non-small cell lung cancer]

OBJECTIVE

To analyze the clinicopathological characteristics and risk factors of 4L lymph node metastasis in left non-small cell lung cancer.

METHODS

We retrospectively analyzed the data of 134 patients undergoing surgical resection of left non-small cell lung cancer and 4L lymph node dissection, including 60 patients with squamous cell carcinoma (SCC) and 74 with lung adenocarcinoma (ADC). The clinicopathological characteristics of the patients were analyzed, and logistic regression analysis was used to identify the predictors of station 4L metastasis.

RESULTS

Of these patients, 16.4% (22/134) presented with station 4L metastasis. The patients with SCC and ADC showed significant differences in age, gender, smoking history, neoadjuvant chemotherapy, tumor size, tumor location and type, visceral pleural invasion, Ki-67 index, 4L metastasis and pathological TNM stage (stage Ⅱ). The rate of station 4L metastasis was significantly lower in SCC group than in ADC group. Univariate analysis revealed that pathological types (SCC or ADC), visceral pleural invasion, lymphovascular invasion, tumor markerabnormality, and station 5 to 10 metastasis were all high-risk factors for station 4L metastasis. Multivariate analysis suggested that the pathological type (OR=0.120, P=0.025), station 5 metastasis (OR=18.784, P=0.007) and station 10 metastasis (OR=5.233, P=0.044) were independent risk factors for 4L metastasis in patients with left non-small cell lung cancer.

CONCLUSIONS

In patients with left non-small cell lung cancer, station 4L metastasis is not rare and is more likely to occur in patients with lung adenocarcinoma. Dissection of the 4L lymph nodes should be performed in cases with low risk of damages of the adjacent tissues and high risk of station 4L metastasis.

Machine learning-based diagnostic method of pre-therapeutic 18F-FDG PET/CT for evaluating mediastinal lymph nodes in non-small cell lung cancer

OBJECTIVES

We aimed to find the best machine learning (ML) model using ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for evaluating metastatic mediastinal lymph nodes (MedLNs) in non-small cell lung cancer, and compare the diagnostic results with those of nuclear medicine physicians.

METHODS

A total of 1329 MedLNs were reviewed. Boosted decision tree, logistic regression, support vector machine, neural network, and decision forest models were compared. The diagnostic performance of the best ML model was compared with that of physicians. The ML method was divided into ML with quantitative variables only (MLq) and adding clinical information (MLc). We performed an analysis based on the ¹⁸F-FDG-avidity of the MedLNs.

RESULTS

The boosted decision tree model obtained higher sensitivity and negative predictive values but lower specificity and positive predictive values than the physicians. There was no significant difference between the accuracy of the physicians and MLq (79.8% vs. 76.8%, p = 0.067). The accuracy of MLc was significantly higher than that of the physicians (81.0% vs. 76.8%, p = 0.009). In MedLNs with low ¹⁸F-FDG-avidity, ML had significantly higher accuracy than the physicians (70.0% vs. 63.3%, p = 0.018).

CONCLUSION

Although there was no significant difference in accuracy between the MLq and physicians, the diagnostic performance of MLc was better than that of MLq or of the physicians. The ML method appeared to be useful for evaluating low metabolic MedLNs. Therefore, adding clinical information to the quantitative variables from ¹⁸F-FDG PET/CT can improve the diagnostic results of ML.

KEY POINTS

• Machine learning using two-class boosted decision tree model revealed the highest value of area under curve, and it showed higher sensitivity and negative predictive values but lower specificity and positive predictive values than nuclear medicine physicians. • The diagnostic results from machine learning method after adding clinical information to the quantitative variables improved accuracy significantly than nuclear medicine physicians. • Machine learning could improve the diagnostic significance of metastatic mediastinal lymph nodes, especially in mediastinal lymph nodes with low 18F-FDG-avidity.

Long-term outcomes of sentinel node identification using indocyanine green in patients with lung cancer

BACKGROUND

Sentinel node (SN) biopsy is used in the management of numerous cancers to avoid unnecessary lymphadenectomy. This was a clinical exploration/feasibility study of a novel identification technique for SN biopsy using indocyanine green (ICG) fluorescence imaging during lung cancer surgery.

METHODS

SN biopsy using ICG was performed on 22 patients who had cT1 or T2N0M0 lung cancer. ICG was injected just around the primary tumor. The fluorescence imaging system enabled visualization of the lymphatic vessels draining from the primary tumor toward the lymph nodes. Fluorescently labeled nodes were dissected, and patients were followed-up for prognosis and recurrence to confirm the pattern of lymph node metastasis after surgery.

RESULTS

SNs were successfully identified in 16 (72.7%) of 22 patients. A total of 13 of 16 patients had pathological N0 and three had SN metastasis. The median follow-up time was 92.7 months. Only one patient had no SN metastasis at the postoperative pathological examination and lymph node metastasis during the follow-up period. The accuracy rate was 93.8% (15/16) and the false-negative rate was 7.7% (1/13).

CONCLUSIONS

SNs were identified by ICG fluorescence imaging, and this technique during lung cancer surgery had good identification and accuracy rates throughout the follow-up period.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: We attempted to identify sentinel lymph nodes by indocyanine green in lung cancer surgery. The identification rate was 72.7%. The accuracy rate was 100% immediately after surgery, and 93.8% after follow-up.

WHAT THIS STUDY ADDS

Sentinel node biopsy by indocyanine green may be useful for lymph node dissection during lung cancer surgery to avoid unnecessary lymphadenectomy.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Numbers and Stations: Impact of Examined Lymph Node on Precise Staging and Survival of Radiologically Pure-Solid NSCLC: A Multi-Institutional Study

Objectives

To determine the optimal number of examined lymph nodes (ELNs) and examined node stations (ENSs) in patients with radiologically pure-solid NSCLC and to investigate the impact of ELNs and ENSs on accurate staging and long-term survival.

Methods

Data from six institutions in the People’s Republic of China on resected c-stage Ⅰ to Ⅱ NSCLCs presenting as pure-solid tumors were analyzed for the impact of ELNs and ENSs on nodal upstaging, stage migration, recurrence-free survival, and overall survival by using multivariate models. The correlations between different end points and ELNs or ENSs were fitted with a smoother (using Locally Weighted Scatterplot Smoothing tool), and the structural break points were determined by the Chow test.

Results

Both ELNs and ENSs were identified as prognostic factors for overall survival (ENS: hazard ratio [HR], 0.697; 95% confidence interval [CI]: 0.590–0.824; p < 0.001; ELN: HR, 0.945; 95% CI: 0.909–0.983; p = 0.005) and recurrence-free survival (ENS: HR, 0.863; 95% CI: 0.791–0.941; p = 0.001; ELN: HR, 0.960; 95% CI: 0.938–0.981; p < 0.001). Intraoperative ELNs and ENSs were found to be associated with postoperative nodal upstaging. Cut point analysis revealed an optimal cutoff of 16 LNs and five node stations for patients with c-stage Ⅰ to Ⅱ pure-solid NSCLCs, which were examined in our multi-institutional cohort.

Conclusions

Both ELNs and ENSs are associated with more accurate node staging and better long-term survival. We recommend 16 LNs and five stations as the cut point for evaluating the quality of LN examination for c-stage Ⅰ to Ⅱ patients with radiologically pure-solid NSCLCs.

Mediastinal Up-Staging During Surgery in Non-Small-Cell Lung Cancer: Which Mediastinal Lymph Node Metastasis Patterns Better Predict The Outcome? A Multicenter Analysis

BACKGROUND

Unexpected N2 involvement occurs in approximately 10% to 20% of patients with non-small-cell lung cancer (NSCLC) and patients' prognostic factors remain unclear. The aim of this study was to evaluate prognostic factors in these patients.

METHODS

From January 2002 to December 2012, we retrospectively analyzed data of 550 patients with NSCLC with preoperative negative, but pathologic positive N2 involvement, who underwent anatomical lung resection and hilo-mediastinal lymphadenectomy, obtained from 6 institutions. An established prognostic factor panel and N2-type involvement were correlated to overall (OS), cancer-specific (CSS), and disease-free survival (DFS) using multivariate Cox Regression model. The following lymph node patterns were analyzed: number of resected nodes (#RNs), metastatic nodes (#MNs), ratio between #MNs and #RNs (NR), N2 subgroups proposed for the eighth TNM edition, and lobe-specific versus nonspecific metastasis.

RESULTS

Regarding our cohort, 419 patients were staged IIIA (T1-2N2), 131 IIIB (T3-4 N2), 113 pT1, 306 pT2, 94 pT3, and 37 pT4; 5-year OS, DFS, and CSS were 34.1%, 20.1%, and 64.6%, respectively. Independent prognostic factor for OS, in the multivariable analysis, were as follows: NR <17% (P = .009), proposed N2 classification subgroups (P = .014), age <66 (P < .001), and pT (P = .005); for DFS: NR <17% (P = .003), adjuvant treatment (P = .026), and pT (P = .026); and for CSS: NR <17% (P = .008), grading (P = .001), and adjuvant treatment (P < .001).

CONCLUSION

Our study confirms that adjuvant therapy is fundamental and NR, in patients with unexpected N2 involvement, has a strong prognostic factor. In particular, a NR cutoff value of 17% could predict OS, DFS, and CSS in patients with NSCLC.

Is lobe specific lymph node dissection adequate for cN0-1 non-small cell lung cancer?

Purpose

This study aims to explore whether lobe specific lymph node dissection (LND) is adequate for cN0–1 non-small cell lung cancer (NSCLC) or not.

Methods

Among 5613 cN0–1 NSCLC patients, 394 cases (7.0%) with pN2 were enrolled and the distribution of mediastinal lymph node metastasis was analyzed. The included patients were divided into the non-lobe specific lymph node metastasis (NLSLNM) group and the lobe specific lymph node metastasis (LSLNM) group. The clinicopathological characteristics were compared between two groups and multivariable analysis was performed to find independent factors predicting NLSLNM.

Results

The incidence of pN2 cases deserved serious attention. The proportion of upper zone lymph node metastases was not rare in right (55.0%) and left (35.7%) lower lobe tumors. The proportion of subcarinal zone lymph node involvement was also high in right (21.8%) and left (25.8%) upper lobe tumors. Multivariable analysis showed that elevated carcinoembryonic antigen (CEA) level (P = 0.034), right lower lobe (RLL) tumors (P = 0.022) and station 11 involvement (P = 0.030) were independent risk factors for NLSLNM.

Conclusion

Systematic LND seems to be superior to lobe specific LND in the assessment of lymph node status and high CEA level, RLL tumors and station 11 involvement are predictors for NLSLNM.

[Analysis of lymphatic drainage pathways using infrared fluorescence in patients with lung cancer]

OBJECTIVE

To develop a method for analysis of lymphatic drainage pathways from the lobe of the lung affected by non-small cell lung cancer (NSCLC) using infrared fluorescence.

MATERIAL AND METHODS

A study enrolled patients with NSCLC who underwent anatomic resection of the lung with systematic lymph node dissection and preliminary intraoperative peritumoral injection of indocyanine green conjugate with human albumin. Registration of fluorescence in regional lymph nodes (LN) was carried out immediately after excision of specimen using the FLUM-808 instrumental system.

RESULTS

Infrared fluorescence was observed in 117 hilar and mediastinal lymph nodes from 43 patients (2.7 nodes per a patient). Comparison of localization of fluorescent LN with localization of tumor in various lobes established significant variability of lymphatic drainage pathways.

CONCLUSION

The developed method of infrared fluorescent evaluation of lymphatic drainage in patients with NSCLC confirms the necessity of systematic lymph node dissection for adequate staging.

Minimizing residual occult nodal metastasis in NSCLC: recent advances, current status and controversies

Introduction: Nodal involvement in lung cancer is a significant determinant of prognosis and treatment management. New evidence exists regarding the management of occult lymph node metastasis and residual disease in the fields of imaging, mediastinal staging, and operative management.Areas covered: This review summarizes the latest body of knowledge on the identification and management of occult lymph node metastasis in NSCLC. We focus on tumor-specific characteristics; imaging modalities; invasive mediastinal staging; and operative management including, technique, degree of resection, and lymph node examination.Expert opinion: Newly identified risk-factors associated with nodal metastasis including tumor histology, location, radiologic features, and metabolic activity are not included in professional societal guidelines due to the heterogeneity of their reporting and uncertainty on how to adopt them into practice. Imaging as a sole diagnostic method is limited. We recommend confirmation with invasive mediastinal staging. EBUS-FNA is the best initial method, but adoption has not been uniform. The diagnostic algorithm is less certain for re-staging of mediastinal nodes after neoadjuvant therapy. Mediastinal node sampling during lobectomy remains the gold-standard, but evidence supports the use of minimally invasive techniques. More study is warranted regarding sublobar resection. No consensus exists regarding lymph node examination, but new evidence supports reexamination of current quality metrics.

Segment Location and Ground Glass Opacity Ratio Reliably Predict Node-Negative Status in Lung Cancer

BACKGROUND

Although selective mediastinal lymph node dissection based on lobe-specific nodal metastasis has been proposed for non-small cell lung cancer, controversy remains over its validity. We hypothesized that different segments within the same lobe might have different patterns of lymph node metastasis.

METHODS

Data on 2749 invasive non-small cell lung cancer patients who underwent pulmonary resection with systematic lymph node dissection from April 2008 to December 2015 were retrospectively analyzed. The segment location and consolidation tumor ratio were identified using preoperative computed tomography scans.

RESULTS

None of the 151 tumors with consolidation tumor ratio ≤ 0.5 had lymph node involvement. None of the 333 tumors located in apical segments had inferior mediastinal lymph node metastasis. When the analysis was limited to patients without hilar nodes involvement, only 7 out of 740 (0.9%) peripheral upper lobe tumors had inferior mediastinal lymph node metastasis. Interestingly, all these 7 tumors showed visceral pleural invasion. If hilar nodes were negative, superior mediastinal lymph node metastasis was not present for lower lobe ground glass opacity lesions. Among patients with left lower lobe tumors, if hilar nodes were negative, station 4L lymph node metastasis was not found in superior-segment or basal-segment tumors, and station 5/6 lymph node involvement was always absent in basal-segment tumors.

CONCLUSIONS

Segment location, ground glass opacity proportion, and absence of hilar lymph nodes involvement are reliable predictors of node-negative status in specific mediastinal regions. Based on these findings, we propose a new selective mediastinal lymph node dissection strategy for non-small cell lung cancer.

Clinicopathologic predictors of metastasis of different regional lymph nodes in patients intraoperatively diagnosed with stage-I non-small cell lung cancer

Background

Selection of the best lymph node for dissection is a controversial topic in clinical stage-I non-small cell lung cancer (NSCLC). Here, we sought to identify the clinicopathologic predictors of regional lymph node metastasis in patients intraoperatively diagnosed with stage-I NSCLC.

Methods

A retrospective review of 595 patients intraoperatively diagnosed as stage I non-small-cell lung cancer who underwent lobectomy with complete lymph node dissection was performed. Univariate and multivariable logistic regression analysis was performed to determine the independent predictors of regional lymph node metastasis.

Results

Univariate logistic regression and multivariable analysis revealed three independent predictors of the presence of metastatic hilar lymph nodes, five independent predictors for lobe specific mediastinal lymph nodes, two independent predictors for lobe nonspecific mediastinal lymph nodes and two independent predictors for skipping mediastinal lymph nodes.

Conclusions

A complete mediastinal lymph node dissection may be considered for patients suspected of nerve invasion and albumin (> 43.1 g/L) or nerve and vascular invasions. Lobe-specific lymph node dissection should probably be performed for patients suspected of pulmonary membrane invasion, vascular invasion, CEA (> 2.21 ng/mL), and tumor (> 1.6 cm) in the right lower lobe or mixed lobes. Hilar lymph node dissection should probably be performed for patients suspected of having bronchial mucosa and cartilage invasion, vascular invasion, and CEA (> 2.21 ng/mL).

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5632-2) contains supplementary material, which is available to authorized users.

Lymph node metastasis outside of a tumor-bearing lobe in primary lung cancer and the status of interlobar fissures: The necessity for removing lymph nodes from an adjacent lobe

The new Tumor Node Metastasis staging system does not recognize fissure status with respect to adjacent lobe invasion (ALI) in lung cancer. Furthermore, no specific surgical strategies have been recommended for lymph node dissections around adjacent nontumor-bearing lobes (NTBLs) according to fissure status. Therefore, this study was undertaken to investigate the necessity of removing additional adjacent lobe lymph nodes in patients with nonsmall cell lung cancer (NSCLC) for lesions limited to in the vicinity of the interlobar fissure.From August 2013 to March 2015, the records of 332 patients, who underwent systematic mediastinal lymph node dissection, were reviewed in this retrospective study. The bronchial lymph nodes had been subjected to pathological examination, and the status of the fissures was also recorded. A statistical analysis was performed to identify the significant predictors of lymph node metastasis.The patients were divided into a nonadjacent lobe invasion (NALI) group (n = 295) and an ALI group (n = 37). There was a significant difference in tumors with pN2 disease between the ALI and NALI groups (37.8% vs 8.8%, P = .001). ALI tumors had significantly more frequent pleural involvement than NALI tumors (62.2% vs 43.1%, P = .035). The frequency of N2 involvement among tumors invading across the complete fissure was higher than that of the tumors invading across the incomplete fissure (44.4% vs 14.3%, P = .015). However, the frequency of N1 involvement among tumors invading across the incomplete fissure was not statistically different than that of tumors not invading across incomplete fissure (32.1% vs 24.2%, P = .357). Regarding lymph node metastasis in NTBL, 15 (12.7%) patients had lymph node metastases in NTBLs. Pleural involvement was an independent predictor of lymph node metastasis in an NTBL.A greater frequency of N2 lymph nodes existed in NSCLC with invading adjacent lobe across complete fissure, extensive lymphatic resection within the hilum, and NTBL in tumors with pleural involvement are justifiable and necessary.

Novel perspective to evaluate the safety of segmentectomy: clinical significance of lobar and segmental lymph node metastasis in cT1N0M0 lung adenocarcinoma

OBJECTIVES

The regularity of intrapulmonary lobar and segmental lymph node (LSN) metastasis in cT1N0M0 stage lung adenocarcinoma remains unclear. Thus, segmentectomy with uncertain LSN metastatic status remains a potential oncological risk. We aimed to facilitate more accurate determination of N staging and filter more suitable cases for segmentectomy.

METHODS

A prospective study was performed from March 2014 to September 2016. A total of 196 patients diagnosed with cT1N0M0 stage lung adenocarcinoma were enrolled and received lobectomy together with mediastinal lymph node dissection. The intrapulmonary LSNs were dissected and classified as adjacent LSN or isolated LSN. The metastatic status of the LSNs together with the TNM staging were analysed. A comparison of the metastatic probability of isolated LSN was carried out considering the metastatic status of adjacent LSN, imaging features, smoking history, pathological subtypes, size of the lesions and serum level of tumour markers (carcinoembryonic antigen and Cyfra21-1).

RESULTS

Among the 196 cases enrolled, 152 were confirmed as pN0, 36 as pN1, 6 as pN1 + N2 and 2 as skip pN2. When the LSNs had not been dissected, the false-negative rate for N staging was 9.0% (15 of 167). Patients with adjacent LSN metastasis (P < 0.001), solid nodule (P = 0.001), non-lepidic predominant invasive adenocarcinoma (P < 0.001), nodules with maximum diameter larger than 2 cm (P < 0.001) and those with elevated serum carcinoembryonic antigen level (>5 ng/ml) (P = 0.005) had a higher isolated LSN metastasis rate. No significant difference in isolated LSN metastasis rate was found between groups with or without smoking history (P = 0.90) and with different serum Cyfra21-1 levels (P = 0.14).

CONCLUSIONS

Dissection of intrapulmonary LSNs reduces the false-negative rate of lymph node metastasis. Solid nodule, non-lepidic predominant invasive adenocarcinoma, lung adenocarcinoma larger than 2 cm in maximum diameter or with elevated serum carcinoembryonic antigen level (>5 ng/ml) might not be suitable for segmentectomy. The lymph node sampling area during segmentectomy should include adjacent LSNs of the target segment. When metastasis to the adjacent LSNs is confirmed by fast-frozen pathology, segmentectomy would not be suitable.

Lung cancer staging: a concise update

Diagnosis and clinical staging of lung cancer are fundamental to planning therapy. The techniques for clinical staging, i.e anatomic and metabolic imaging, endoscopies and minimally invasive surgical procedures, should be performed sequentially and with an increasing degree of invasiveness. Intraoperative staging, assessing the magnitude of the primary tumour, the involved structures, and the loco-regional lymphatic spread by means of systematic nodal dissection, is essential in order to achieve a complete resection. In resected tumours, pathological staging, with the systematic study of the resected specimens, is the strongest prognostic indicator and is essential to make further decisions on therapy. In the present decade, the guidelines on lung cancer staging of the American College of Chest Physicians and the European Society of Thoracic Surgeons are based on the best available evidence and are widely followed. Recent advances in the classification of the adenocarcinoma of the lung, with the definition of adenocarcinoma in situ, minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma, and the publication of the eighth edition of the tumour, node and metastasis classification of lung cancer, have to be integrated into the staging process. The present review complements the latest guidelines on lung cancer staging by providing an update of all these issues.

Incidence of occult pN2 disease following resection and mediastinal lymph node dissection in clinical stage I lung cancer patients

Objectives

Early clinical stage (T1 and T2) non-small cell lung cancer (NSCLC) is commonly treated with anatomic lung resection and lymph node sampling or dissection. The aims of this study were to evaluate the incidence and the distribution of occult N2 disease according to tumour location and the short- and long-term outcomes.

Methods

We performed a retrospective review of patients with clinical stage I NSCLC who underwent anatomic lung resection and lymphadenectomy. Mediastinal lymphadenectomy (ML) was defined as resection of at least 2 mediastinal stations, always including station 7 lymph nodes. Patients who had a lobe-specific lymphadenectomy were excluded.

Results

One thousand six hundred and sixty-seven consecutive patients met inclusion criteria and were included. Overall, 9% (146/1667) of the patients had occult pN2 disease. At multivariable analysis, adenocarcinoma histology and vascular invasion were independently associated with greater risk of occult pN2 disease. In left and right upper lobe tumours, station 7 nodes were involved in 5 and 13% of pN2 positive cases, respectively. Station 5 and station 2/4 nodes were involved in 29 and 18% of left and right lower lobe pN2 tumours, respectively. There was no postoperative mortality, and postoperative morbidity was 28%. The median overall survival was 77.4 months. N0 patients had a median overall survival of 83.7 months vs 48.0 months and 37.9 months in N1 and N2 populations, respectively ( P  < 0.001).

Conclusions

Sixteen percent of pN2 patients had mediastinal lymph node metastasis beyond the lobe-specific lymphatic drainage. We recommend a complete lymphadenectomy be performed, even in clinical stage I NSCLC.