Tumor histology predicts mediastinal nodal status and may be used to guide limited lymphadenectomy in patients with clinical stage I non-small cell lung cancer

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.

Intratumoural and peritumoural CT-based radiomics for diagnosing lepidic-predominant adenocarcinoma in patients with pure ground-glass nodules: a machine learning approach

AIM

To develop and validate a diagnostic model utilising machine-learning algorithms that differentiates lepidic predominant adenocarcinoma (LPA) from other pathological subtypes in patients with pure ground-glass nodules (pGGNs).

MATERIALS AND METHODS

This bicentric study was conducted across two medical centres and included 151 patients diagnosed with lung adenocarcinoma based on histopathological confirmation of pGGNs. The training cohort consisted of 99 patients from Institution 1, while the test cohort included 52 patients from Institution 2. Radiomics features were extracted from both tumours and the 2 mm peritumoural parenchyma. The tumoural and peritumoural radiomics were designated as Modeltumoural and Modelperitumoural, respectively. The diagnostic efficacy of various models was evaluated through the receiver operating characteristic (ROC) curve analysis. Subsequently, a machine-learning-based prediction model that combined Modeltumoural, Modelperitumoural, and Modelclinical-radiological was developed to differentiate LPA from other pathological subtypes in patients with pGGNs.

RESULTS

Modeltumoural achieved area under the curve (AUC) values of 0.762 and 0.783 in the training and validation sets, respectively. Modelperitumoural attained AUCs of 0.742 and 0.667, and Modelclinical-radiological generated an AUC of 0.727 and 0.739 in the training and validation sets, respectively. Among the machine-learning models evaluated, gradient boosting machines demonstrated the best diagnostic efficacy, with accuracy, AUC, F1 score, and log loss values of 0.885, 0.956, 0.943, and 0.260, respectively.

CONCLUSION

The combined model based on machine learning that incorporated tumour and peritumoural parenchyma, as well as clinical and imaging characteristics, may offer benefits in assessing the pathological subtype of pGGNs.

Sublobar resection is associated with less lymph nodes examined and lower delivery of adjuvant therapy in patients with 1.5- to 2.0-cm clinical IA2 non-small-cell lung cancer: a retrospective cohort study

OBJECTIVES

CALGB140503, in which nodal sampling was mandated, reported non-inferior disease-free survival for patients undergoing sublobar resection (SLR) compared to lobectomy (L). Outside of trial settings, the adequacy of lymphadenectomy during SLR has been questioned. We sought to evaluate whether SLR is associated with suboptimal lymphadenectomy, differences in pathologic upstaging and survival in patients with 1.5- to 2.0-cm tumours using real-world data.

MATERIALS AND METHODS

Using the National Cancer Database(2018-2019), we evaluated patients with 1.5- to 2.0-cm non-small-cell lung cancer who underwent resection (sublobar versus lobectomy). We studied factors associated with nodal upstaging (logistic regression) and survival (Cox regression and Kaplan-Meier method) after propensity matching to adjust for differences among groups.

RESULTS

Among 3196 patients included, SLR was performed in 839 (26.3%) (of which 588 were wedge resections) and L was performed in 2357 (73.7%) patients. More patients undergoing SLR (21.7%) compared to L (2.1%) had no lymph nodes sampled (P < 0.001). Those undergoing SLR had fewer total lymph nodes examined (4 vs 11, P < 0.001) and were less likely to have pathologic nodal metastases (4.7% vs 9%, P < 0.001) compared to L. Multivariable analysis identified L [adjusted odds ratio (aOR) 2.21, 95% confidence interval, 1.47-3.35] to be independently associated with pathologic N+ disease. Overall survival was not associated with the type of procedure but was significantly decreased in those with N+ disease.

CONCLUSIONS

Despite comparable overall survival to L, SLR is associated with suboptimal lymphadenectomy in patients with 1.5-2.0 cm non-small-cell lung cancer. Surgeons should be careful to perform adequate lymphadenectomy when performing SLR to mitigate nodal under-staging and to identify appropriate patients for systemic therapy.

A Shift in Paradigm: Selective Lymph Node Dissection for Minimizing Oversurgery in Early Stage Lung Cancer

Systematic lymph node dissection has been widely accepted and turned into a standard procedure for lung cancer surgery. In recent years, the concept of "minimal invasive surgery (MIS)" has greatly changed the surgical paradigm of lung cancer. Previous studies revealed that excessive dissection of lymph nodes without metastases had uncertain clinical benefit. Meanwhile, it leads to the elevated risk of postoperative complications including chylothorax and laryngeal nerve injury. In addition, dissection of nonmetastatic lymph nodes may disturb systematic immunity, resulting in the secondary effect on primary tumor or latent metastases. The past decades have witnessed the innovative strategies such as lobe-specific lymph node dissection and selective lymph node dissection. On the basis of evolution of lymph node dissection strategy, we discuss the negative effects of excessive nonmetastatic lymph node dissection and summarize the recent advances in the optimized dissection strategies, hoping to provide unique perspectives on the future directions.

Selective Mediastinal Lymph Node Dissection Strategy for Clinical T1N0 Invasive Lung Cancer: A Prospective, Multicenter, Clinical Trial

INTRODUCTION

We aimed to prospectively evaluate our previously proposed selective mediastinal lymph node (LN) dissection strategy for peripheral clinical T1N0 invasive NSCLC.

METHODS

This is a multicenter, prospective clinical trial in China. We set six criteria for predicting negative LN stations and finally guiding selective LN dissection. Consolidation tumor ratio less than or equal to 0.5, segment location, lepidic-predominant adenocarcinoma (LPA), negative hilar nodes (stations 10-12), and negative visceral pleural invasion (VPI) were used separately or in combination as predictors of negative LN status in the whole, superior, or inferior mediastinal zone. LPA, hilar node involvement, and VPI were diagnosed intraoperatively. All patients actually underwent systematic mediastinal LN dissection. The primary end point was the accuracy of the strategy in predicting LN involvement. If LN metastasis occurred in certain mediastinal zone that was predicted to be negative, it was considered as an "inaccurate" case.

RESULTS

A total of 720 patients were enrolled. The median number of LN dissected was 15 (interquartile range: 11-20). All negative node status in certain mediastinal zone was correctly predicted by the strategy. Compared with final pathologic findings, the accuracy of frozen section to diagnose LPA, VPI, and hilar node metastasis was 94.0%, 98.9%, and 99.6%, respectively. Inaccurate intraoperative diagnosis of LPA, VPI, or hilar node metastasis did not lead to inaccurate prediction of node-negative status.

CONCLUSIONS

This is the first prospective trial validating the specific mediastinal LN metastasis pattern in cT1N0 invasive NSCLC, which provides important evidence for clinical applications of selective LN dissection strategy.

Histology of the Primary Tumor Correlates with False Positivity of Integrated 18F-FDG-PET/CT Lymph Node Staging in Resectable Lung Cancer Patients

This study aimed to evaluate the diagnostic accuracy and false positivity rate of lymph node (LN) staging assessed by integrated 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG-PET/CT) in patients with operable lung cancer to the tumor histology. In total, 129 consecutive patients with non-small-cell lung cancer (NSCLC) undergoing anatomical lung resections were included. Preoperative LN staging was evaluated in the relationship to the histology of the resected specimens (group 1: lung adenocarcinoma/LUAD; group 2: squamous cell carcinoma/SQCA). Statistical analysis was performed by the Mann-Whitney U-test, the chi² test, and binary logistic regression analysis. To establish an easy-to-use algorithm for the identification of LN false positivity, a decision tree including clinically meaningful parameters was generated. In total, 77 (59.7%) and 52 (40.3%) patients were included in the LUAD and SQCA groups, respectively. SQCA histology, non-G1 tumors, and tumor SUVmax > 12.65 were identified as independent predictors of LN false positivity in the preoperative staging. The corresponding ORs and their 95% CIs were 3.35 [1.10-10.22], p = 0.0339; 4.60 [1.06-19.94], p = 0.0412; and 2.76 [1.01-7.55], and p = 0.0483. The preoperative identification of false-positive LNs is an important aspect of the treatment regimen for patients with operable lung cancer; thus, these preliminary findings should be further evaluated in larger patient cohorts.

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.

The role of ipsilateral mediastinal lymph node dissection in treatment of patients with non-small-cell lung cancer

Background. Lung cancer occupies the leading place in the structure of cancer incidence and death rate. Treatment results are still not satisfactory. Five-year postsurgical survival rate is 24–30%. Patients die in different periods of time from local recurrences and distant metastases. To this day, there is no unambiguous attitude towards ipsilateral mediastinal lymph node dissection in surgical treatment of patients with lung cancer. Despite the oncologic relevance of the abovementioned lymph node dissection, there are still concerns on worsening of recovery conditions of bronchial stump, increase in the amount of lymphorrhea and additional injury rate of the surgery. There is also an opinion that the risk of development of postsurgical complications, and, as a result, the increase in lethality rate, outweigh the positive impact of ipsilateral mediastinal lymph node dissection on radicality and long-term treatment results. Purpose – to study the impact of ipsilateral mediastinal lymph node dissection on the course of postsurgical period in patients with lung cancer, clarifying diagnostics of spread of tumor process and survival rate of the patients. Materials and methods. Treatment results of 187 patients with non-small-cell lung cancer with different clinical stages from T1-3N0 M0 to T1-2N1 M0 were analyzed. The patients were divided into two groups: the first group (comparison group) consisted of 72 patients, who underwent radical operations with selective lymph node dissection. The patients of the second group, the study group (115 patients), obligatorily underwent ipsilateral mediastinal lymph node dissection. The number of removed lymph nodes in one patient ranged from 5 to 10 in the first group and from 18 to 25 in the second one. In the cases when no cancer cells were found in lymph nodes, they were managed with monoclonal antibodies to cytokeratins, expressed with cancer cells, with further microscopic evaluation. During the postsurgical period the following values were studied: duration of the surgery, the volume of intraoperative blood loss, the amount and duration of exudation, frequency and character of postsurgical complications. Comparison of survival rates of the patients was performed with the test of statistical significance of differences by χ2 criterion. Methods of non-parametric statistical estimate were used for statistical analysis of the results by the means of Statistica 6.0, SPSS 17.0 software. Results. Adding ipsilateral mediastinal lymph node dissection to surgical interference increased its duration by 30 minutes on average. An increase in the volume of exudate by 136,2 ± 18,4 ml was observed in early postsurgical period. Structure and frequency of postsurgical complications in both groups was similar. In most cases heart rhythm disorder, namely ciliary arrhythmia, was observed in the first days after the surgery. Postsurgical lethality rate in both groups was caused by various factors and equaled 1,4% in the first, and 0,8% in the second one. Additional usage of immunohistochemicalanalysis of lymph nodes with monoclonal antibodies to tumoral cytokeratins in patients after performing ipsilateral mediastinal lymph node dissection led to their lesion being found more frequently. Indeed, metastases were detected in 21% of 19 patients, in which N0 status was previously established in light microscopy. Also, a significant increase in three-year survival rate by 15,3% (p=0,042) was observed in patients with lung cancer, who underwent ipsilateral mediastinal lymph node dissection and had no signs of mediastinal lymph nodes lesion, and 23,2% (p=0,014) in patients with the signs of the lesion. Conclusions. Performing ipsilateral mediastinal lymph node dissection in patients with lung cancer during surgical interference does not have an impact on postsurgical lethality rate and frequency and structure of complications. During the study of lymph nodes, which, according to light microscopy, were considered unaffected by cancer, additional lymphogland metastases were found in 20,7% of the patients by the means of monoclonal antibodies to cytokeratins. It allows the stage of the disease to be more accurately determined and optimal type of adjuvant therapy to be chosen. Detection rate of metastases in regional lymph nodes significantly increases from 51,4% to 67,8% in patients with lung cancer after radical operations with additional ipsilateral mediastinal lymph node dissection. Obligatory ipsilateral mediastinal lymph node dissection in surgeries for lung cancer increases overall three-year survival rate, especially in patients with affected lymph nodes by 16,3%.

The IASLC Proposed Grading System Accurately Predicts Prognosis and Mediastinal Nodal Metastasis in Patients With Clinical Stage I Lung Adenocarcinoma

The International Association for the Study of Lung Cancer (IASLC) recently proposed a new grading system for lung adenocarcinoma (LUAD). We aimed to validate the prognostic performance of the grading system and explore its role in guiding the strategy of lymph node (LN) dissection. We retrospectively reviewed 1029 patients with clinical stage I LUAD who underwent surgery between 2011 and 2013. The association between mediastinal nodal metastasis and grading system was evaluated. To investigate the value of the grading system in guiding LN dissection strategies, 3 pathologists evaluated the feasibility of identifying the grading system using frozen section (FS). The differences in prognosis between all neighboring grades were highly significant based on the grading system ( P <0.001). Notably, almost no grade 1 LUAD (1.4%) had pN2 disease, whereas higher rates were found in grade 2 LUAD (9.6%) and grade 3 LUAD (18.3%) ( P <0.001). Multivariate logistic regression analysis revealed that higher tumor grade was an independent predictor of mediastinal nodal metastasis ( P =0.002). Moreover, limited mediastinal LN dissection had equivalent prognosis in grade 1 LUAD, but significantly worse prognosis in grade 2 and grade 3 LUAD than systematic mediastinal LN dissection. The overall accuracy of using intraoperative FS to identify the IASLC grading system was 85.4% (κ=0.765) with substantial agreement. The IASLC grading system could accurately stratify prognosis and predict mediastinal nodal metastasis in patients with clinical stage I LUAD. FS was feasible for identifying the IASLC grading system.

Reclassifying the International Association for the Study of Lung Cancer Residual Tumor Classification According to the Extent of Nodal Dissection for NSCLC: One Size Does Not Fit All

INTRODUCTION

The extent of nodal assessment may require risk-based adjustments in NSCLC. We reclassified the International Association for the Study of Lung Cancer Residual tumor classification according to the extent of nodal dissection and evaluated its long-term prognosis by tumor stage and histologic subtype.

METHODS

We reclassified 5117 patients who underwent resection for clinical stages I to III NSCLC and had complete or uncertain resection by International Association for the Study of Lung Cancer classification into the following 3 groups according to compliance with three components (N1, N2, and subcarinal node) of systematic nodal dissection criteria: fully compliant group (FCG), partially compliant group (PCG), and noncompliant group (NCG). Recurrence-free survival (RFS) and overall survival (OS) were compared.

RESULTS

Of the 5117 patients, 2806 (55%), 1959 (38%), and 359 (7%) were FCG, PCG, and NCG, respectively. PCG and NCG were more likely to be of lower clinical stage and adenocarcinoma with lepidic component than FCG. The 5-year RFS and OS were significantly better in NCG than in FCG or PCG (RFS, 86% versus 70% or 74%, p < 0.001; OS, 90% versus 80% or 83%, p < 0.001). In particular, NCG had better RFS and OS than FCG or PCG in clinical stage I and in lepidic-type adenocarcinoma.

CONCLUSIONS

In early stage NSCLC with low-risk histologic subtype, a less rigorous nodal assessment was not associated with a worse prognosis. Although surgeons should continue to aim for complete resection and thorough nodal assessment, a uniform approach to the extent and invasiveness of nodal assessment may need to be reconsidered.

[Chinese Experts Consensus on Artificial Intelligence Assisted Management for Pulmonary Nodule (2022 Version)]

Low-dose computed tomography (CT) for lung cancer screening has been proven to reduce lung cancer deaths in the screening group compared with the control group. The increasing number of pulmonary nodules being detected by CT scans significantly increase the workload of the radiologists for scan interpretation. Artificial intelligence (AI) has the potential to increase the efficiency of pulmonary nodule discrimination and has been tested in preliminary studies for nodule management. As more and more artificial AI products are commercialized, the consensus statement has been organized in a collaborative effort by Thoracic Surgery Committee, Department of Simulated Medicine, Wu Jieping Medical Foundation to aid clinicians in the application of AI-assisted management for pulmonary nodules.
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Complete Lymphadenectomy for Clinical Stage I Lepidic Adenocarcinoma of the Lung: Is it justified?

The role of a systematic lymphadenectomy in patients undergoing surgery for clinical stage I lung lepidic adenocarcinoma is still unclear. In the last years, some authors have advocated the possibility to avoid a complete lymph-node dissection in this setting. Results of patients who received systematic hilar-mediastinal nodal dissection for this oncologic condition are here reported. Between 2012 and March 2019, 135 consecutive patients underwent lung resection for clinical stage I lepidic adenocarcinoma, at our institution. Only patients (n=98) undergoing lobectomy or sublobar resection associated with systematic hilar-mediastinal nodal dissection were retrospectively enrolled in the study. Patients' mean age was 67.8±8.7 years (range 37-84). Three were 52 females and 46 males. Resection was lobectomy in 77.6% (n=76) and sublobar in 22.4% (n=22). All the resections were complete (R0). Histology was lepidic predominant adenocarcinoma in 85 cases and minimally invasive adenocarcinoma in 13 cases. At pathologic examination, N0 was confirmed in 78 patients (79.6%), while N+ was found in 20 cases (20.4%), (N1 in 12, 12.2% and N2 in 8, 8.2%). No mortality occurred. Complication rate was 8.2%. At a median follow-up of 45.5 months, recurrence rate was 26.5%. Disease-free 5-year survival was 98.6% for stage I, 75% for stage II and 45% for stage III, p<0.001. A complete nodal dissection can reveal occult nodal metastases in lepidic adenocarcinoma patients and can increase the accuracy of pathologic staging. N1/N2 disease is a negative prognostic factor for this histology. A systematic lymph-node dissection should be considered even in this setting.

Consolidation Tumor Ratio Combined With Pathological Features Could Predict Status of Lymph Nodes of Early-Stage Lung Adenocarcinoma

INTRODUCTION

Stage IA lung adenocarcinoma manifested as part-solid nodules (PSNs), has attracted immense attention owing to its unique characteristics and the definition of its invasiveness remains unclear. We sought to develop a nomogram for predicting the status of lymph nodes of this kind of nodules.

METHODS

A total of 2,504 patients between September 2018 to October 2020 with part-solid nodules in our center were reviewed. Their histopathological features were extracted from paraffin sections, whereas frozen sections were reviewed to confirm the consistency of frozen sections and paraffin sections. Univariate and multivariate logistic regression analyses and Akaike information criterion (AIC) variable selection were performed to assess the risk factors of lymph node metastasis and construct the nomogram. The nomogram was subjected to bootstrap internal validation and external validation. The concordance index (C-index) was applied to evaluate the predictive accuracy and discriminative ability.

RESULTS

We enrolled 215 and 161 eligible patients in the training cohort and validation cohort, respectively. The sensitivity between frozen and paraffin sections on the presence of micropapillary/solid subtype was 78.4%. Multivariable analysis demonstrated that MVI, the presence of micropapillary/solid subtype, and CTR >0.61 were independently associated with lymph node metastasis (p < 0.01). Five risk factors were integrated into the nomogram. The nomogram demonstrated good accuracy in estimating the risk of lymph node metastasis, with a C-index of 0.945 (95% CI: 0.916-0.974) in the training cohort and a C-index of 0.975 (95% CI: 0.954-0.995) in the validation cohort. The model's calibration was excellent in both cohorts.

CONCLUSION

The nomogram established showed excellent discrimination and calibration and could predict the status of lymph nodes for patients with ≤3 cm PSNs. Also, this prediction model has the prediction potential before the end of surgery.

Predicting lung adenocarcinoma invasiveness by measurement of pure ground-glass nodule roundness by using multiplanar reformation: a retrospective analysis

AIM

To explore the value of roundness measurement based on thin-section axial, coronal, and sagittal section computed tomography (CT) images for predicting pure ground-glass nodule (pGGN) invasiveness.

MATERIALS AND METHODS

A total of 168 pGGNs in 155 patients (44 male, 111 females; mean age, 55.74 ± 10.57 years), and confirmed by surgery and histopathology, were analysed retrospectively and divided into pre-invasive (n=72) and invasive (n=96) groups. Photoshop (CS6) software was used to measure pGGN roundness based on conventional axial section, as well as coronal and sagittal sections generated by multiplanar reformation, from thin-section (1-mm-thick) CT lung images.

RESULTS

pGGN roundness values, measured in axial, coronal, and sagittal thin-section CT sections from the pre-invasive group were 0.8 ± 0.049, 0.816 ± 0.05, and 0.818 ± 0.043, respectively, while those in the invasive group were 0.745 ± 0.077, 0.684 ± 0.106, and 0.678 ± 0.106; differences between the two groups were significant (all p<0.001). Binary logistic regression analysis showed that roundness values based on coronal and sagittal sections (p<0.001) were better than those from axial sections (p>0.05) in predicting pGGN invasiveness, with odds ratio (OR) values of 14.858 and 23.315, respectively. ROC analysis showed that evaluation of roundness measured in sagittal sections was better at predicting pGGN invasiveness than when coronal sections were used (AUC 0.870 versus 0.832).

CONCLUSION

Roundness is useful for predicting pGGN invasiveness, with measurements from coronal and sagittal sections better than those from conventional axial sections, with sagittal section images having the best predictive value.

HRCT features between lepidic-predominant type and other pathological subtypes in early-stage invasive pulmonary adenocarcinoma appearing as a ground-glass nodule

Background

Different pathological subtypes of invasive pulmonary adenocarcinoma (IPA) have different surgical methods and heterogeneous prognosis. It is essential to clarify IPA subtypes before operation and high-resolution computed tomography (HRCT) plays a very important role in this regard. We aimed to investigate the HRCT features of lepidic-predominant type and other pathological subtypes of early-stage (T1N0M0) IPA appearing as a ground-glass nodule (GGN).

Methods

We performed a retrospective analysis on clinical data and HRCT features of 630 lesions in 589 patients with pathologically confirmed IPA (invasive foci > 5 mm) appearing as pure GGN (pGGN) and mixed GGN (mGGN) with consolidation-to-tumor ratio (CTR) ≤0.5 from January to December 2019. All GGNs were classified as lepidic-predominant adenocarcinoma (LPA) and nonlepidic-predominant adenocarcinoma (n-LPA) groups. Univariate analysis was performed to analyze the differences of clinical data and HRCT features between the LPA and n-LPA groups. Multivariate analysis was conducted to determine the variables to distinguish the LPA from n-LPA group independently. The diagnostic performance of different parameters was compared using receiver operating characteristic curves.

Results

In total, 367 GGNs in the LPA group and 263 GGNs in the n-LPA group were identified. In the univariate analysis, the CTR, mean CT values, and mean diameters as well as mixed GGN, deep lobulation, spiculation, vascular change, bronchial change, and tumor–lung interface were smaller in the LPA group than in the n-LPA group (P <  0.05). Logistic regression model was reconstructed including the mean CT value, CTR, deep lobulation, spiculation, vascular change, and bronchial change (P <  0.05). Area under the curve of the logistic regression model for differentiating LPA and n-LPA was 0.840 (76.4% sensitivity, 78.7% specificity), which was significantly higher than that of the mean CT value or CTR.

Conclusions

Deep lobulation, spiculation, vascular change, and bronchial change, CT value > − 472.5 HU and CTR > 27.4% may indicate nonlepidic predominant invasive pulmonary adenocarcinoma in GGNs.

Targeted Sequencing Analysis of Predominant Histological Subtypes in Resected Stage I Invasive Lung Adenocarcinoma

Objective: Lung adenocarcinoma (LADC) is classified into five main histological subtypes with distinct clinicopathologic characteristics: lepidic-predominant adenocarcinoma (LPA), acinar-predominant adenocarcinoma (APA), papillary-predominant adenocarcinoma (PPA), micropapillary-predominant adenocarcinoma (MPA) and solid-predominant adenocarcinoma (SPA). However, the mutational profiles of predominant histological subtypes have not been well defined. In this study, we aimed to reveal the genomic landscape of 5 main histological subtypes. Patients and Methods: We performed next-generation sequencing (NGS) in a cohort of 86 stage I invasive adenocarcinoma (IAC) patients, using a customized panel including 168 cancer-associated genes. Results: Our analysis identified a total of 302 genomic alterations. Five subtypes showed different mutation profiles with LPA, APA, PPA, MPA and SPA had an average mutation rate of 1.95 (range: 0-5), 2.56 (range: 1-6), 3.5 (range: 1-7), 3.75 (range: 1-8) and 6.05 (range: 2-12), respectively (p=4.17e-06). Driver mutations occurred in 96.55% (83/86) of all patients. EGFR (73.3%), KRAS (9.3%), ALK (4.7%) and MET (4.7%) are the most commonly mutated lung cancer driver genes, TP53 is the top mutated tumor suppressor gene. SPA patients harbored more driver mutations and higher frequency of TP53 than LPA patients. Interestingly, LRP1B mutations, which has been reported to be associated with high tumor mutation burden and better response to immunotherapy, were only detected from 5 SPA patients (p=0.001). No patients from other four cohorts harbored LRP1B mutations. Conclusions: We revealed distinctive mutation landscape of the 5 major histological subtypes of LADC, evident by distinctive average mutation rate with SPA and LPA having the highest and lowest average mutation rate, respectively. SPA patients showed higher mutation rate of LRP1B and higher rates for PD-L1 positivity, indicating that SPA patients may have better response to immunotherapy.

Clock dial integrated positioning combined with single utility port video-assisted thoracoscopic surgery: a new localization method for lung tumors

Background

Preoperative localization of lung tumor mainly consisted of two methods: CT-guided percutaneous localization and electromagnetic navigation bronchoscopy-guided localization. However, these invasive methods could result in serious complications. In order to avoid the adverse effects of preoperative invasive localization, we propose a method of intraoperative noninvasive localization for lung tumors: clock dial integrated positioning (CDIP).

Methods

To retrospectively analyze the clinic data about the application of CDIP for 127 lung tumour patients in single utility port video-assisted thoracoscopic surgery (SUPVATS) between June 2017 and October 2017.

Results

One hundred and twenty-four cases (97.64%) underwent thoracoscopic surgery, which including 14 lobectomy, 107 partial resection, 2 lobectomy plus partial resection and 1 left pneumonectomy. Three cases (2.36%) underwent thoracoscopic biopsy. The mean operation time and intraoperative bleeding were 47.9±22.1 min and 70.1±40.3 mL, respectively. The mean postoperative hospital stay and chest drain duration were 3.9±2.2 and 3.6±1.8 days, respectively. There were 118 cases of malignant tumors, including adenocarcinoma (n=101), squamous cell carcinoma (n=9), large cell carcinoma (n=2), small cell lung carcinoma (n=3), and metastatic lung carcinoma (n=3). The remaining nine cases were benign tumors, including granuloma (n=3), intrapulmonary lymph node (n=2), sclerosing hemangioma (n=2), and hamartoma (n=2). The incidence of postoperative complications was 10.2%. There was no mortality, secondary operation, or conversion to open procedure due to massive intraoperative bleeding.

Conclusions

CDIP combined with SUPVATS is a safe, feasible, and effective method for the localization of lung tumors. This novel method can provide a reliable alternative technique when the marker is dislocated.

The feasibility of non-contrast enhanced plus contrast-enhanced computed tomography in discriminating invasive pure ground-glass opacity from pre-invasive pure ground-glass opacity

BACKGROUND

Invasive pure ground-glass opacity and pre-invasive pure ground-glass opacity have different 5-year overall survival rate and risk of lymph node metastasis and the extent of resection. It is difficult to discriminate these nodules since they share similar CT features and may occur concurrently. The objectives of this study were to investigate the feasibility of non-contrast enhanced plus contrast-enhanced computed tomography in discriminating invasive pure ground-glass opacity from pre-invasive pure ground-glass opacity.

METHODS

We retrospectively examined 90 patients with pure ground-glass opacity who underwent non-contrast enhanced and contrast-enhanced CT according to a simplified protocol (one non-contrast enhanced measurement and two contrast-enhanced measurements at 30 s and 60 s after contrast injection) from 2015 to 2019. All imaging examinations were analyzed using three-dimensional computer-aided volume. Two independent samples t tests, one-way analysis of variance, chi-square test and logistic regression were used for analysis. A receiver operating characteristic curve was used to determine the optimal cut-off value of mean CT attenuation for differentiation of groups and to obtain diagnostic value.

RESULTS

(1) The CT values of one non-contrast-enhanced, two contrast-enhanced and volume measurements between two groups had statistically significant differences (P < 0.001). (2) At the 30-s scan, there were more nodules in the pre-invasive group with no enhancement than in the pre-invasive group, which was statistically significant. (3) The CT value of 60-s scan was independent predictor of invasive adenocarcinoma (P = 0.019).

CONCLUSIONS

Non-contrast enhanced plus two contrast-enhanced CT based on volume measurements can differentiate invasive pGGO from pre-invasive pGGO.

Management of Ground-Glass Opacities in the Lung Cancer Spectrum

BACKGROUND

Along with the popularity of low-dose computed tomography lung cancer screening, an increasing number of lung ground-glass opacity (GGO) lesions are detected. This review focuses on lung adenocarcinoma manifesting as GGO.

METHODS

We performed a literature search of the PubMed/MEDLINE database to identify articles reporting GGO. The following terms were used: GGO, ground-glass opacity, GGN, ground-glass nodule, part-solid nodule, and subsolid nodule.

RESULTS

GGO is a nonspecific radiologic finding showing a hazy opacity without blocking underlying pulmonary vessels or bronchial structures. The pathology of GGO can be benign, preinvasive, or invasive adenocarcinoma. Although radiographic features may indicate malignancy, a short period of follow-up is the optimal method to distinguish between benign and malignant GGO lesions. Pathologically, not only lepidic, but also nonlepidic growth patterns can present as GGO. Lung adenocarcinoma with a GGO component is associated with excellent survival compared with solid lesions. Moreover, there are distinct prognostic factors in patients with lung adenocarcinoma manifesting as GGO or solid lesions. For selected GGO-featured lung adenocarcinoma, sublobar resection with selective or no mediastinal lymph node dissection may be sufficient. Intraoperative frozen section is an effective method to guide resection strategy. A less intensive postoperative surveillance strategy may be more appropriate given the excellent survival. Management of multiple GGO lesions requires comprehensive considerations of GGO characteristics and patient conditions.

CONCLUSIONS

Lung adenocarcinoma manifesting as GGO defines a special clinical subtype with excellent prognosis. The management of GGO-featured lung adenocarcinoma should be distinct from that of solid lesions.

Clinicopathological features, survival outcomes, and appropriate surgical approaches for stage I acinar and papillary predominant lung adenocarcinoma

Background

Whether prognosis differs between lung acinar predominant adenocarcinoma (ACN) and papillary predominant adenocarcinoma (PAP) patients remains controversial. Furthermore, the appropriate surgical plan for each subtype is undetermined.

Methods

Data of stage I ACN or PAP patients from 2004 to 2015 were retrospectively reviewed by SEER*Stat 8.3.5. The primary outcome was overall survival (OS) and lung cancer specific survival (LCSS).

Results

1531 patients (PAP, 484; ACN, 1047) were included. ACN patients had better OS (P = .001) and LCSS (P = .003) than PAP patients. Among stage I ACN patients, lobectomy with mediastinal lymph node dissection (Lob) (P = .001) or segmentectomy (Seg) (P = .003) provided a better OS than wedge resection (Wed). And ACN patients who received Lob had a equivalent LCSS, compared to those who received Seg (P = .895). For patients with PAP in stage I, those who received Lob tended to have a better prognosis than that received Seg (HR of OS, 0.605, 95% CI: 0.263‐1.393; HR of LCSS, 0.541, 95% CI: 0.194‐1.504) or Wed (HR of OS, 0.735, 95% CI: 0.481‐1.123; HR of LCSS, 0.688, 95% CI: 0.402‐1.180).

Conclusions

Among patients with lung adenocarcinoma in stage I, those with ACN have a better OS and LCSS than that with PAP. For patients with stage I ACN, Seg and Lob, rather than Wed, seem to be an equivalent treatment choice; however, Seg is the prior option because it could preserve more lung function than Lob. For patients with PAP, Lob tends to be a better choice than Wed and Seg, although the prognostic difference between them is nonsignificant.

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.

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.

Comprehensive circular RNA profiling identifies CircFAM120A as a new biomarker of hypoxic lung adenocarcinoma

Background

Hypoxia is crucial in the initiation and progression of tumor metastasis. Circular RNAs (CircRNAs) comprise a novel group of non-coding, RNase R resistant and regulatory RNAs which are generated by 'back-splicing' processes. However, the characterization and function of circRNAs in hypoxic cancer cells remain unknown.

Methods

High throughput RNA-seq assay was performed in lung adenocarcinoma cells (A549) under either normoxic or hypoxic conditions. Bioinformatic analysis of differentially expressed circRNAs was conducted and their target genes were predicted and partially confirmed.

Results

Hypoxia increased the expression of hypoxia-inducible factor 1 alpha (HIF-1α) and its downstream genes in A549 cells and enhanced cell migration ability. Comprehensive analysis of global circRNAs expression profiles of A549 identified a total of 558 circRNAs candidates, among which 65 circRNAs were differentially expressed (35 upregulated and 30 downregulated) in hypoxic cancer cells. The difference in their circRNA expressions were compared by computational analysis and circRNA-miRNA networks were constructed. We further characterized one circRNA (hsa_circ_0008193) derived from the FAM120A gene and renamed it as circFAM120A. The expression of circFAM120A, as validated by reverse transcription polymerase chain reaction, was significantly downregulated in both hypoxic A549 and lung cancer tissue from patients with lymph node metastasis. Gene ontology (GO) enrichment analysis and KEGG pathway analysis revealed that circFAM120A may participate in lung cancer development.

Conclusions

CircRNAs profiles were altered in lung adenocarcinoma under hypoxia and circFAM120A may have the potential to be a new biomarker of lung adenocarcinoma hypoxia.

Factors associated with nodal metastasis in 2-centimeter or less non-small cell lung cancer

OBJECTIVE

Lymph node involvement is an important determinant of treatment and prognosis in non-small cell lung cancer (NSCLC) and must be determined via surgical lymph node (LN) evaluation. However, lymphadenectomy is associated with multiple significant morbidities. Recent studies have suggested LN evaluation can be foregone in some or all patients with NSCLC ≤2.0 cm. Our objective was to identify whether these patients may be safely spared the morbidity of lymphadenectomy.

METHODS

We undertook a retrospective study of patients treated for NSCLC ≤2.0 cm at a single institution from 2005 to 2017. We examined patient, demographic, and tumor variables for associations with LN metastases via univariable and multivariable analyses.

RESULTS

In total, 555 patients met our inclusion criteria. Our primary independent variables included tumor size, histology, and histologic subtype. Although tumors ≤1 cm were less likely to have LN metastases than 1.1- to 2-cm tumors (6.8% vs 13.3%), there was no statistically significant difference. Histologic type was not associated with LN status. In an adenocarcinoma subgroup analysis, micropapillary predominant tumors were more likely to have LN metastases. All invasive mucinous adenocarcinomas and minimally invasive adenocarcinomas were N0.

CONCLUSIONS

LN evaluation may be unnecessary in patients with minimally invasive adenocarcinoma or invasive mucinous adenocarcinomas ≤2.0 cm. However, this information is rarely available pre- or intraoperatively. Thus, we recommend LN evaluation always be performed when possible, even for subcentimeter NSCLC, unless the histology is absolutely certain. To our knowledge, this is the largest dataset published to study patients with NSCLC ≤2.0 cm.

The incidence of lymph node metastasis in patients with different oncogenic driver mutations among T1 non-small-cell lung cancer

OBJECTIVE

To investigate the incidence and distribution of lymph node metastasis in patients with different gene mutations among pathological T1 non-small-cell lung cancers (NSCLC).

METHODS

NSCLC cases resected in our institution between 2016 and 2018 were included. Driver mutation testing was performed in all resected tumor tissues. These patients were grouped by the type of gene mutations. On the basis of protein that mutant-genes encoded involved in the molecular pathway, the genotypes were further classified into four distinct groups: upstream receptor mutant protein (EGFR, HER2 and MET); downstream regulator mutant protein (KRAS and BRAF); fusion mutant protein (ROS1, ALK and RET) and the wild type group. The incidence of lymph node metastasis was compared among different groups.

RESULTS

Of the 1052 patients enrolled, the frequency of positive mutations was 68.0%. The incidence of lymph node metastasis were as follows: wild type (19.3%), ROS1 (72.8%), BRAF (55.5%), ALK (44.7%), HER2 (40%), RET (23.1%), KRAS (15.3%), EGFR (15.3%) and MET mutation (0%) (P < 0.001). The incidence of lymph node metastasis was significantly higher in fusion mutant protein group (45.1%) compared with others (wild type 19.3%, downstream regulator mutant protein 19.1%, upstream receptor mutant protein 15.3%, all P < 0.001). Patients with fusion genes also showed higher proportion of vascular invasion and positive lymph node ratio of greater than 0.33 compared to others.

CONCLUSION

Different genotypes of NSCLC have different propensity to develop lymph node metastasis. Cases of fusion gene mutations had a higher risk and burden of lymph node metastasis than other genotypes, which may indicate that more intensive treatment or surveillance strategies should be applied for these patients.