Mediastinal lymph node dissection versus mediastinal lymph node sampling for early stage non-small cell lung cancer: a systematic review and meta-analysis

Protocol for a systematic review and meta-analysis of recurrence and metastasis of different surgical techniques for non-small cell lung cancer

INTRODUCTION

Lung cancer remains the primary cause of cancer-related deaths on a global scale. Surgery is the main therapeutic option for non-small cell lung cancer (NSCLC). However, the optimal surgical approach for lymph node assessment in NSCLC resection remains controversial, and it is still uncertain whether lymph node dissection (LND) is more effective in reducing recurrence and metastasis rates in NSCLC compared with lymph node sampling (LNS). Therefore, we will conduct a meta-analysis to evaluate the recurrence and metastasis of LND versus LNS in patients with NSCLC.

METHODS AND ANALYSIS

This systematic review and meta-analysis will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analysis: The PRISMA Statement. According to the predefined inclusion criteria, we will conduct a comprehensive search for randomised controlled trials and non-randomised studies examining the recurrence and metastasis of LND compared with LNS in patients with NSCLC. A literature search from inception in PubMed, EMBASE, the Cochrane Library, CNKI, Wanfang, SINOMED, VIP and Web of Science will be done. There will be no limitations on language, and the search will be undertaken on 30 August 2024, with regular search for new studies. Additionally, relevant literature references will be retrieved and hand-searching of pertinent journals will be conducted. The main outcomes include overall recurrence rate, local recurrence rate and distant metastasis rate. The supplementary outcomes encompass the rates of regional recurrence and lymph node metastasis. Two independent reviewers will perform screening, data extraction and quality assessment. Our reviewers will perform subgroup analysis, sensitivity analysis and publication bias analysis to evaluate the heterogeneity and robustness. Review Manager 5.4 will be applied in analysing and synthesising. The Grading of Recommendations Assessment, Development and Evaluation will be used to assess the quality of evidence for the whole study.

ETHICS AND DISSEMINATION

Ethical approval is dispensable for this study since no private information of the participants will be involved. The findings of the present study will be disseminated through a peer-reviewed journal or conference presentation.

STUDY REGISTRATION

The protocol of the systematic review has been registered on Open Science Framework, with a registration doi: https://doi.org/10.17605/OSF.IO/S2FT5.

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.

A comparison of machine learning methods for radiomics modeling in prediction of occult lymph node metastasis in clinical stage IA lung adenocarcinoma patients

Background

Accurate prediction of occult lymph node metastasis (ONM) is an important basis for determining whether lymph node (LN) dissection is necessary in clinical stage IA lung adenocarcinoma patients. The aim of this study is to determine the best machine learning algorithm for radiomics modeling and to compare the performances of the radiomics model, the clinical-radilogical model and the combined model incorporate both radiomics features and clinical-radilogical features in preoperatively predicting ONM in clinical stage IA lung adenocarcinoma patients.

Methods

Patients with clinical stage IA lung adenocarcinoma undergoing curative surgery from one institution were retrospectively recruited and assigned to training and test cohorts. Radiomics features were extracted from the preoperative computed tomography (CT) images of the primary tumor. Seven machine learning algorithms were used to construct radiomics models, and the model with the best performance, evaluated using the area under the curve (AUC), was selected. Univariate and multivariate logistic regression analyses were performed on the clinical-radiological features to identify statistically significant features and to develop a clinical model. The optimal radiomics and clinical models were integrated to build a combined model, and its predictive performance was assessed using receiver operating characteristic curves, Brier score, and decision curve analysis (DCA).

Results

This study included 258 patients who underwent resection (training cohort, n=182; test cohort, n=76). Six radiomics features were identified. Among the seven machine learning algorithms, extreme gradient boosting (XGB) demonstrated the highest performance for radiomics modeling, with an AUC of 0.917. The combined model improved the AUC to 0.933 and achieved a Brier score of 0.092. DCA revealed that the combined model had optimal clinical efficacy.

Conclusions

The superior performance of the combined model, based on XGB algorithm in predicting ONM in patients with clinical stage IA lung adenocarcinoma, might aid surgeons in deciding whether to conduct mediastinal LN dissection and contribute to improve patients' prognosis.

Survival outcomes following complete mediastinal lymphadenectomy or selective mediastinal lymphadenectomy in patients with stage I-IIIA non-small cell lung cancer: protocol for a systematic review and meta-analysis

INTRODUCTION

Lung cancer remains the largest cause of cancer-related deaths worldwide. Surgical removal of non-small cell lung cancer (NSCLC) has the potential to achieve a cure, although there is ongoing debate regarding the significance of removing mediastinal nodes and the optimal extent of lymph node excision. The purpose of this research is to assess the survival outcomes in patients diagnosed with stage I-IIIA NSCLC who received either complete mediastinal lymphadenectomy (CML) or selective mediastinal lymphadenectomy (SML).

METHODS AND ANALYSIS

The protocol follows the guidelines recommended in Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, and this meta-analysis will be conducted in accordance with the standard methodology recommended by the Cochrane Collaboration and reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidance. We will conduct a comprehensive search for randomised controlled trials and non-randomised studies examining the effectiveness of CML compared with SML in patients with stage I-IIIA NSCLC. Two authors will perform a comprehensive search of the MEDLINE/PubMed, Embase, the Cochrane Library, CNKI, WanFang, Sinomed, VIP and Web of Science databases. There will be no restrictions on language or publication date, and the search will be conducted on 10 April 2024, with ongoing searches for new research. Reference lists will also be checked and pertinent journals will be hand searched. The primary outcomes include overall survival (OS) and disease-free survival (DFS), while the secondary outcomes consist of 1-year, 3-year and 5-year OS rates and 1-year, 3-year and 5-year DFS rates. Two independent reviewers will screen, extract data, assess quality and evaluate the potential for bias in the selected research, with a third acting as arbitrator. Subgroup analyses and sensitivity analyses are planned. The quality of the evidence will be evaluated using Grading of Recommendations Assessment, Development and Evaluation. Review Manager V.5.4 will be used for the analysis and synthesis process.

ETHICS AND DISSEMINATION

Ethical review and approval are not necessary for this study because it is based on a secondary analysis of the literature. The results will be submitted for reporting in a peer-reviewed publication.

STUDY REGISTRATION

Open Science Framework (https://doi.org/10.17605/OSF.IO/PN7UQ).

Influencing Factors on the Quality of Lymph Node Dissection for Stage IA Non-Small Cell Lung Cancer: A Retrospective Nationwide Cohort Study

Lymphadenectomy is an essential part of complete surgical operation for non-small cell lung cancer (NSCLC). This retrospective, multicenter cohort study aimed to identify factors that influence the lymphadenectomy quality. Data were obtained from the Polish Lung Cancer Study Group Database. The primary endpoint was lobe-specific mediastinal lymph node dissection (L-SMLND). The study included 4271 patients who underwent VATS lobectomy for stage IA NSCLC, operated between 2007 and 2022. L-SMLND was performed in 1190 patients (27.9%). The remaining 3081 patients (72.1%) did not meet the L-SMLND criteria. Multivariate logistic regression analysis showed that patients with PET-CT (OR 3.238, 95% CI: 2.315 to 4.529; p < 0.001), with larger tumors (pT1a vs. pT1b vs. pT1c) (OR 1.292; 95% CI: 1.009 to 1.653; p = 0.042), and those operated on by experienced surgeons (OR 1.959, 95% CI: 1.432 to 2.679; p < 0.001) had a higher probability of undergoing L-SMLND. The quality of lymphadenectomy decreased over time (OR 0.647, 95% CI: 0.474 to 0.884; p = 0.006). An analysis of propensity-matched groups showed that more extensive lymph node dissection was not related to in-hospital mortality, complication rates, and hospitalization duration. Actions are needed to improve the quality of lymphadenectomy for NSCLC.

Comparison of lobectomy and sublobar resection for stage I non-small cell lung cancer: a meta-analysis based on randomized controlled trials

Background

This meta-analysis aimed to compare the prognostic between lobectomy and sublobar resection in patients with stage I non-small cell lung cancer (NSCLC).

Methods

We conducted a detailed search in PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials (RCTs) comparing the prognosis of lobectomy and sublobar resection for stage I NSCLC, with the primary outcomes being overall survival (OS) and disease-free survival (DFS).

Results

A total of 2222 patients were included in the 5 RCTs. The results showed no statistical difference in OS (HR=0.87, p=0.445) and DFS (HR=0.99, p=0.918) between patients who underwent lobectomy and sublobar resection during the total follow-up period. In terms of dichotomous variables, there were no statistical differences in OS (relative ratio [RR]=1.05, p=0.848) and DFS (RR=1.21, p=0.075) between the two groups during the total follow-up period, as well as 5-year OS (RR=0.96, p=0.409) and 5-year DFS (RR=0.95, p=0.270). In addition, subgroup analysis showed a better prognosis for non-adenocarcinoma patients with sublobar resection than lobectomy (HR=0.53, p=0.037), but also an increased cause of cancer death (not limited to lung cancer) (RR=1.56, p=0.004).

Conclusion

Our results showed that for stage I NSCLC, lobectomy is usually not a justified operation.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023407301, identifier CRD42023407301.

The Role of Lymphadenectomy in Early-Stage NSCLC

Lung cancer remains the leading cause of cancer-related death worldwide. The involvement of lymph nodes by the tumor has a strong impact on survival of patients. For this reason, lymphadenectomy plays a crucial role in the staging and prognosis of NSCLC, to define the most appropriate therapeutic strategies concerning the stage of the disease. To date, the benefit, in terms of survival, of the different extents of lymphadenectomy remains controversial in the scientific community. It is recognized that metastatic involvement of mediastinal lymph nodes in lung cancer is one of the most significant prognostic factors, in terms of survival, and it is therefore mandatory to identify patients with lymph node metastases who may benefit from adjuvant therapies, to prevent distant disease and local recurrences. The purpose of this review is to evaluate the role of lymphadenectomy in early-stage NSCLC in terms of efficacy and accuracy, comparing systematic, sampling, and lobe-specific lymph node dissection and analyzing the existing critical issue, through a search of the most relevant articles published in the last decades.

Horizontal Transfer of Malignant Traits and the Involvement of Extracellular Vesicles in Metastasis

Metastases are responsible for the vast majority of cancer deaths, yet most therapeutic efforts have focused on targeting and interrupting tumor growth rather than impairing the metastatic process. Traditionally, cancer metastasis is attributed to the dissemination of neoplastic cells from the primary tumor to distant organs through blood and lymphatic circulation. A thorough understanding of the metastatic process is essential to develop new therapeutic strategies that improve cancer survival. Since Paget's original description of the "Seed and Soil" hypothesis over a hundred years ago, alternative theories and new players have been proposed. In particular, the role of extracellular vesicles (EVs) released by cancer cells and their uptake by neighboring cells or at distinct anatomical sites has been explored. Here, we will outline and discuss these alternative theories and emphasize the horizontal transfer of EV-associated biomolecules as a possibly major event leading to cell transformation and the induction of metastases. We will also highlight the recently discovered intracellular pathway used by EVs to deliver their cargoes into the nucleus of recipient cells, which is a potential target for novel anti-metastatic strategies.

Evaluation of the significance of subcarinal lymph node dissection in stage IB non‑small cell lung cancer

Lymph node dissection is used to treat early-stage lung cancer. The present study aimed to investigate if resecting the subcarinal lymph nodes affects prognosis of patients with stage IB non-small cell lung cancer (NSCLC). A total of 597 patients with stage IB NSCLC who underwent lung cancer surgery at Sun Yat-Sen University Cancer Center from January 1999 to December 2009 were included in the present study. The potential prognostic factors were evaluated using the Cox proportional hazard regression model. A total of 252 cases were obtained following propensity score matching (PSM). To compare overall survival (OS) and recurrence-free survival (RFS), Kaplan-Meier method and log-rank test were used. Among the 597 cases included, 185 did not undergo subcarinal lymph node resection, whereas 412 did. There were statistically significant differences between the two groups in terms of bronchial invasion, number of resected lymph node stations and resected lymph node numbers (P<0.05). Age, family history of cancer and the number of resected lymph nodes were prognostic factors for OS, whereas age and the number of resected lymph nodes were prognostic factors for RFS (P<0.05). Resection of subcarinal lymph nodes was not associated with OS and RFS. After PSM, survival analysis was recalculated using the Kaplan-Meier method and log-rank test; subcarinal lymph node resection was not statistically associated with OS and RFS. (P>0.05). For stage IB NSCLC, there was no statistically significant association between subcarinal lymph node resection and OS and RFS. Subcarinal lymph node resection in surgery of stage IB NSCLC may be considered optional.

Evaluation of the necessity of Pulmonary Ligament Lymph Node Dissection for Upper Lobe Stage IB NSCLC: A Propensity Score-matched Study

Objective: The purpose of this study was to explore whether the resection of pulmonary ligament lymph nodes would affect the prognosis of patients with stage IB non-small cell lung cancer (NSCLC). Methods: We retrospectively analyzed 341 patients with upper lobe stage IB NSCLC who underwent radical surgery for lung cancer at Sun Yat-Sen University Cancer Center from 1999 to 2009. The Cox proportional hazard regression model was used to analyze the prognostic factors. After propensity score matching (PSM), 204 cases were selected. The Kaplan-Meier method and log-rank test were applied to compare overall survival (OS) and recurrence-free survival (RFS). Results: Among the 341 cases included in the study, 217 had no pulmonary ligament lymph nodes resected, and 124 had pulmonary ligament lymph nodes resected. They were divided into two groups according to whether the pulmonary ligament lymph nodes were resected; there were significant differences between the two groups in laterality, resected lymph node stations, and resected lymph node numbers (P<0.05). Univariate and multivariate analyses by the Cox proportional hazards model showed that age and family history of malignant tumors were prognostic factors for OS, and no variables were prognostic factors for RFS (P<0.05). Resection of the pulmonary ligament lymph node was not associated with OS or RFS. After propensity score matching (PSM), survival analysis was performed again using the Kaplan-Meier method and log-rank test; the results suggested that resection of the pulmonary ligament lymph node is not statistically associated with OS and RFS (P>0.05). Conclusions: For stage IB NSCLC, resection of the pulmonary ligament lymph nodes was not statistically associated with OS or RFS. Pulmonary ligament lymph node resection is not necessary for early-stage NSCLC.

Mediastinal lymph node evaluation, especially at station 4L, in left upper lobe lung cancer

Background

Mediastinal lymph node (LN) dissection during lung resection is essential for accurate staging. Station 4L dissection is anatomically difficult. Therefore, care should be taken to avoid complications. We investigated the importance of mediastinal LN dissection in left upper lobe lung cancer and evaluated intraoperative videos to identify relevant steps during dissection.

Methods

We retrospectively reviewed 151 consecutive patients with left upper lobe lung cancer. Finally, 139 patients were enrolled to examine the survival effects of clinical factors of metastatic LN stations. The association between risk factors or surgical procedures and recurrent laryngeal nerve palsy was analyzed.

Results

LN dissection of the left upper lobe revealed station 4L LN metastasis in nine patients, three of whom were node-negative on mediastinoscopy. Station 4L LN status was confirmed intraoperatively in 12 of 33 patients. Twenty patients had recurrent laryngeal nerve palsy, four of whom were complicated with aspiration pneumonia. Station 4L LN dissection was an independent risk factor for recurrent laryngeal nerve palsy (P=0.03). The use of an energy device near the recurrent laryngeal nerve was a significant risk factor for recurrent laryngeal nerve palsy. Incidentally, pathological N stage ≥2 was an independent prognostic factor for disease-free survival (DFS) (P=0.005) herein.

Conclusions

In patients with left upper lobe lung cancer, pathological N2 disease is an important predictor of recurrence. Therefore, accurate mediastinal LN dissection, including at station 4L, should be performed. We propose to standardize the dissection procedure at each institution to avoid complications, such as recurrent laryngeal nerve palsy.

Preoperative risk factors of lymph node metastasis in clinical N0 lung adenocarcinoma of 3 cm or less in diameter

BACKGROUND

Lung adenocarcinoma is the most common subtype of non-small cell lung cancer. The surgical strategy of lymph node dissection is controversial because many more patients are diagnosed at an early stage in clinical practice.

METHODS

We retrospectively reviewed 622 clinical N0 lung adenocarcinoma patients with 3 cm or less in tumor size who underwent lobectomy or segmentectomy combined with lymph node dissection in our hospital from January 2017 to December 2019. We performed univariate and multivariate analyses to identify preoperative risk factors of lymph node metastasis.

RESULTS

Lymph node metastasis was found in 60 out of 622 patients. On univariate analysis, lymph node metastasis was linked to smoking history, preoperative CEA level, tumor size, tumor location (peripheral or central), consolidation/tumor ratio, pleural invasion, and pathologic type. However, only the preoperative CEA level, tumor size, and consolidation/tumor ratio were independent risk factors in multivariate analysis. The ROC curve showed that the cutoff value of tumor size was 1.7 cm. There was no lymph node metastasis in patients without risk factors.

CONCLUSIONS

The preoperative CEA level, tumor size, and consolidation/tumor ratio were independent risk factors of lymph node metastasis in clinical N0 lung adenocarcinoma with tumor size ≤ 3 cm. The lymph node metastasis rate was extremely low in clinical N0 lung adenocarcinoma patients without risk factors and lymph node dissection should be avoided in these patients to reduce surgical trauma.

A modified approach of portaccess lymphadectomy for locally advanced nonsmall cell lung cancer: A single center experience

OBJECTIVES

Systematic nodal dissection (SND) is an important component of locally advanced non-small cell lung cancer (NSCLC), but modification of this procedure is rarely reported. In this paper, we reported a modified technique of systematic mediastinal lymph node dissection (MLND) of operable lung cancer by video-assisted thoracic surgery (VATS). Parallel upward dissection (the PUD technique) was named due to this modification and the efficacy of the PUD technique was evaluated as well.

METHODS

We summarized the tips of the PUD technique and its version was updated in surgical aspect. The design and procedure sequence of the PUD technique were introduced in detail as well as its pros and cons. A retrospective study was performed on 998 cases of locally advanced NSCLC which accepted the PUD procedure in Department of Thoracic Surgery, Second Xiangya Hospital, Central South University, from 2012 to 2020. The perioperative mortality and the incidence of general and serious complications (such as recurrent laryngeal nerve injury, bronchopleural fistula) were analyzed.

RESULTS

All the 998 cases were operated successfully with the PUD technique and few post-operation complications were found. There was no perioperative mortality and severe complication such as recurrent laryngeal nerve injury and bronchopleural fistula.

CONCLUSIONS

The PUD technique is safe and convenient and it can be a good supplement to the existing surgical techniques for locally advanced lung cancer.

What Should Thoracic Surgeons Consider during Surgery for Ground-Glass Nodules?: Lymph Node Dissection

Thoracic surgeons need to be aware of several important points regarding intraoperative lymph node dissection during surgery for non-small cell lung cancer with ground-glass opacities. The first point relates to the need for lymph node dissection during sublobar resection. Since even patients undergoing sublobar resection may benefit from lymph node dissection, it should be selectively performed according to adequate indications, which require further study. Second, there seems to be no difference in postoperative morbidity between systematic sampling and systematic dissection, but the survival benefit from systematic dissection remains unclear. The results of randomized controlled trials on this topic are conflicting, and their evidence is jeopardized by a high risk of bias in terms of the study design. Therefore, further randomized controlled trials with a sound design should investigate this issue. Third, more favorable survival outcomes tend to be positively associated with the number of examined lymph nodes. Minimum requirements for the number of examined lymph nodes in non-small cell lung cancer should be defined in the future. Finally, lobe-specific lymph node dissection does not have a negative prognostic impact. It should not be routinely performed, but it can be recommended in selected patients with smaller, less invasive tumors. Results from an ongoing randomized controlled trial on this topic should be awaited.

The impact of left lower paratracheal (4L) lymph node dissection on survival in patients with surgically treated left-sided NSCLC

OBJECTIVES

We aimed to investigate the clinical significance of left lower paratracheal nodes (#4L) and their impact on survival in patients with left-sided lung cancer.

METHODS

This was a retrospective analysis of prospective data. The study included 5369 patients who underwent surgery between 2005 and 2015. Six hundred fifty-nine patients underwent #4L dissection (4LND+), and 4710 did not (4LND-). Propensity score matching was used to minimize analytic error (659 vs 659).

RESULTS

The percentage of #4L metastasis increased with tumour size. Between pT2a and pT2b, it nearly doubled from 8% to 14%. The mean percentage of #4L metastasis in the pN2 group was 46, which was higher in left upper lobectomy compared to left lower lobectomy (63% vs 43%, respectively, P < 0.001). In univariable analysis, no differences in 5-year survival were observed between 4LND+ and 4LND- (48% vs 50%, respectively, P = 0.65). However, we detected a significant difference among non-metastatic 4LND+, 4LND- and metastatic 4LND+ (P < 0.0001). After propensity score matching, there were no significant differences in survival among the pN2 subgroups (pN2a1, pN2a2, pN2b1, pN2b2). Multivariable analysis after propensity score matching for each pN2 subgroup did not confirm the effect of #4L metastasis as an independent prognostic factor.

CONCLUSIONS

Despite #4L nodes not being an independent prognostic factor in lung cancer, the percentage of nodal metastases notably increases above pT2a grade and is comparable to the percentage of #5 and #7 metastasis. Therefore, lymphadenectomy in advanced stages of cancer could benefit from resections of the #4L nodes.

Tumor-to-liver standard uptake ratio using fluorine-18 fluorodeoxyglucose positron emission tomography computed tomography effectively predict occult lymph node metastasis of non-small cell lung cancer patients

OBJECTIVES

We aimed to investigate predictive factors of occult lymph node metastasis and to explore the diagnostic value of various standardized uptake value (SUV) parameters using fluorine-18 fluorodeoxyglucose (F-FDG) positron emission tomography computed tomography (PET/CT) in predicting occult lymph node metastasis of clinical N0 non-small cell lung cancer patients.

METHODS

We retrospectively analyzed PET/computed tomography parameters of tumor and clinical data of 124 clinical N0 non-small cell lung cancer patients who underwent both preoperative F-FDG PET/computed tomography and anatomical pulmonary resection with systematic lymph node dissections. The SUVmax, SUVmean, metabolic total volume, and total lesion glycolysis of the primary tumor was automatically measured on the PET/computed tomography workstation. Standardized uptake ratio (SUR) were derived from tumor standardized uptake value divided by blood SUVmean (B-SUR) or liver SUVmean (L-SUR), respectively.

RESULTS

According to postoperative pathology, 19 (15%) were diagnosed as occult lymph node metastasis among 124 clinical N0 non-small cell lung cancer patients. On univariate analysis, carcinoembryonic antigen, cytokeratin 19 fragment, lobulation, and all PET parameters were associated with occult lymph node metastasis. The area under the receiver operating characteristic curve, sensitivity, and negative predictive value of L-SURmax were the highest among all PET parameters (0.778, 94.7%, and 98.4%, respectively). On multivariate analysis, carcinoembryonic antigen, cytokeratin 19 fragment, and L-SURmax were independent risk factors for predicting occult lymph node metastasis. Compared to L-SURmax alone and the combination of carcinoembryonic antigen and cytokeratin 19 fragment, the model consisting of three independent risk factors achieved a greater area under the receiver operating characteristic curve (0.901 vs. 0.778 vs. 0.780, P = 0.021 and 0.0141).

CONCLUSIONS

L-SURmax showed the most powerful predictive performance than the other PET parameters in predicting occult lymph node metastasis. The combination of three independent risk factors (carcinoembryonic antigen, cytokeratin 19 fragment, and L-SURmax) can effectively predict occult lymph node metastasis in clinical N0 non-small cell lung cancer patients.

Video-assisted versus open thoracotomy lobectomy: comparison on lymphadenectomy and survival in early stage of lung cancer

Background

Video-assisted thoracic surgery (VATS) is increasingly used in the surgical treatment of early lung cancer, but the oncological benefits are still controversial. We aimed to compare video-assisted lobectomy and open thoracotomy lobectomy in terms of lymphadenectomy and long-term survival depending on the location of lobectomy.

Methods

A retrospective, multicenter study was based on the Polish Lung Cancer Study Group and included patients with stage I lung cancer who were surgically treated between 2007 and 2015. We included 1410 patients after video-assisted lobectomy and 4,855 after open thoracotomy.

Results

The average number of lymph nodes removed in video-assisted lobectomy was 10.9 and in open thoracotomy lobectomy was 12.9 (P<0.001). The 5-year survival was better in the video-assisted lobectomy group (78.6%) compared to open thoracotomy (73.8%) (P=0.002). Significant differences were found in the case of left lower lobe and left upper lobe lobectomies. Multivariable analysis showed that the prognostic factors for open thoracotomy relative to video-assisted lobectomy are: age over 60 [HR (95% CI): 1.55 (1.17-2.05), P=0.002], female [HR (95% CI): 1.57 (1.07-2.29), P=0.02], squamous cell carcinoma [HR (95% CI): 1.63 (1.12-2.37), P=0.011], left lower lobe [HR (95% CI): 2.69 (1.37-5.27), P=0.004] and left upper lobe [HR (95% CI): 1.53 (1.01-2.33), P=0.047].

Conclusions

The study showed that the number of lymph nodes removed during video-assisted lobectomy is significantly lower than in the open thoracotomy group. The long-term video-assisted lobectomy results were significantly better compared to open thoracotomy. Better long-term results were achieved on the left side of lobectomy.

Feasibility of limited resection for peripheral small-sized non-small cell lung cancer: a retrospective single-center-based study

PURPOSE

This study aimed to establish new criteria for limited resection of non-small cell lung cancer (NSCLC) based on computed tomography findings and maximum standardized uptake value (SUVmax).

METHODS

Between December 2007 and December 2015, 611 patients underwent lung cancer surgery; of these, 70 with cT1aN0M0 who underwent limited resection were enrolled. Criteria for undergoing intentional limited resection (ILR) were (1) tumor ground-glass opacity (GGO) ratio of ≥ 0.75 and (2) tumor SUVmax ≤ 1.5. Patients who met criteria (1) and (2) underwent partial resection, and those who only met criteria (2) underwent segmentectomy as ILR. The control group was subjected to limited surgery without meeting the criteria.

RESULTS

Overall, 45 and 25 patients who met the criteria were included in the ILR and control groups, respectively. In the ILR group, 13 patients underwent partial resection, and 32 underwent segmentectomy; in the control group, 18 patients underwent partial resection and 7 underwent segmentectomy. According to our criteria, no relapsed cases occurred in the ILR group, although six patients showed recurrence of lung cancer in the control group. The 5-year overall survival (OS) rates in the ILR and control groups were 100% and 67.7%, respectively, and the relapse-free survival (RFS) rates were 100% and 61.6%, respectively. The log-rank test showed that this difference was statistically significant (OS: P < 0.0001, RFS: P < 0.0001).

CONCLUSIONS

SUVmax may serve as a predictive marker of recurrence to determine the treatment strategy for patients with NSCLC. Patients with low GGO ratio and low SUVmax may be cured by limited resection.

[Comparison of the Clinical Effect of Uniportal Video-assisted Thoracoscopic Lobectomy and Biportal Video-assisted Thoracoscopic Lobectomy in the Treatment of Lung Cancer]

背景与目的

近年来单孔胸腔镜肺癌根治术逐渐兴起，作为一种新的手术方式，其可行性及安全性尚未得到普遍认可。本研究拟探讨单孔胸腔镜肺癌根治术在治疗Ⅰ期至部分Ⅲa期肺癌病例中的可行性及安全性。

方法

回顾性分析苏州大学附属第一医院胸外科同一治疗组在2018年5月-2019年3月连续进行的胸腔镜肺癌根治术患者的临床资料。排除部分不符合要求的病例后，根据手术方式分为单孔组（55例）和单操作孔组（87例），共142例。分析两组患者的临床数据，进行统计学分析。

结果

142例患者均行肺叶切除+淋巴结清扫术，术后顺利出院，未有围手术期死亡。单孔组和单操作孔组比较，年龄、肿瘤位置、术后病理类型、肿瘤大小、肿瘤的病理性原发灶-淋巴结-转移（pathological tumor-node-metastasis, pTNM）分期的差异均无统计学意义（P > 0.05）。单孔组手术时间更短[(167.65±43.85) min vs (181.71±51.28) min]，术中出血量更少[(57.45±50.19) mL vs (87.47±132.54) mL]，术后引流管留置时间[(4.82±2.82) d vs (5.84±3.43) d]及术后住院天数[(6.91±3.88) d vs (7.74±3.87) d]更短，但差异无统计学意义（P > 0.05）。单孔组的术后总引流量显著低于单操作孔组[(1, 064.82±776.38) mL vs (1, 658.71±1, 722.38) mL]，术后24 h及72 h视觉疼痛评分明显更低[（4.73±0.73）分vs（5.25±0.74）分；（2.16±0.71）分vs（2.55±0.86）分]，差异有统计学意义（P < 0.05）。

结论

在Ⅰ期至部分Ⅲa期肺癌病例中，单孔胸腔镜肺癌根治术安全可行。

Mediastinal staging: when and how?

Mediastinal staging for lung cancer includes both the assessment of mediastinal lymph nodes status before treatment and the postoperative pathological staging obtained by lymph-node removal performed during surgery. In patients with early stage NSCLC, the aim is to exclude with the highest certainty and the lowest morbidity the presence of mediastinal node involvement. Before treatment, mediastinal staging is based on imaging techniques, endoscopic techniques, and surgical procedures. Final pathological staging is based on lymph-node removal performed with lung resection according with different modalities (sampling, systematic dissection, etc.) and various approaches (thoracotomy, VATS, robotic). Data and indications from literature evidences are reported and discussed.

Propensity-Matched Analysis Comparing Survival After Sublobar Resection and Lobectomy for cT1N0 Lung Adenocarcinoma

BACKGROUND

The optimal surgical method for cT1N0 lung adenocarcinoma remains controversial.

OBJECTIVE

The aim of this study was to evaluate the differences in clinical outcomes of sublobar resection and lobectomy for cT1N0 lung adenocarcinoma patients.

METHODS

We included 1035 consecutive patients with cT1N0 lung adenocarcinoma who underwent surgery at our institute from January 2011 to December 2016. The surgical approach, either sublobar resection or lobectomy, was determined at the discretion of each surgeon. A propensity-matched analysis incorporating total tumor diameter, solid component diameter, consolidation-to-tumor (C/T) ratio, and performance status was used to compare the clinical outcomes of the sublobar resection and lobectomy groups.

RESULTS

Sublobar resection and lobectomy were performed for 604 (58.4%; wedge resection/segmentectomy: 470/134) and 431 (41.6%) patients, respectively. Patients in the sublobar resection group had smaller total tumor diameters, smaller solid component diameters, lower C/T ratios, and better performance status. More lymph nodes were dissected in the lobectomy group. Patients in the sublobar resection group had better perioperative outcomes. A multivariable analysis revealed that the solid component diameter and serum carcinoembryonic antigen level are independent risk factors for tumor recurrence. After propensity matching, 284 paired patients in each group were included. No differences in overall survival (OS; p = 0.424) or disease-free survival (DFS; p = 0.296) were noted between the two matched groups.

CONCLUSIONS

Sublobar resection is not inferior to lobectomy regarding both DFS and OS for cT1N0 lung adenocarcinoma patients. Sublobar resection may be a feasible surgical method for cT1N0 lung adenocarcinoma.

[Rationale of thoracic lymph node dissection in pulmonary metastasectomy]

The goal of metastasectomy is a R0 resection. Depending of the tumor entity the prevalence of lymph node metastases in pulmonary metastasectomy can be up to 45%; however, systematic lymph node dissection is not yet established as a fixed component of metastasectomy. Although there is a high prevalence of lymph node metastases and the increase in the prevalence with a higher number of lung metastases, it remains unclear if a systematic lymph node dissection should be part of pulmonary metastasectomy. For this reason, the goal of this review was to evaluate the rationale of systematic lymph node dissection in pulmonary metastasectomy based on the currently available literature. Furthermore, it was investigated whether patients with additional thoracic lymph node metastases should be excluded per se from pulmonary metastasectomy, even though positive lymph node metastases might be associated with a lower but nevertheless good long-term survival after resection.

The role of the ground-glass opacity ratio in resected lung adenocarcinoma

OBJECTIVES

The goal of this study was to investigate the role of the ground-glass opacity (GGO) ratio in lung adenocarcinoma in predicting surgical outcomes.

METHODS

Patients who underwent surgical resection for pulmonary adenocarcinoma between January 2004 and December 2013 were reviewed. The clinical data, imaging characteristics of nodules, surgical approaches and outcomes were analysed with a mean follow-up of 87 months.

RESULTS

Of 789 enrolled patients, 267 cases were categorized as having a GGO ratio ≥0.75; 522 cases were categorized as having a GGO ratio <0.75. The gender, tumour differentiation, epidermal growth factor receptor mutation, smoking habits, lymphovascular space invasion, tumour size, maximum standard uptake value and carcinoembryonic antigen levels were significantly different in the 2 groups. In the group with a GGO ratio ≥0.75, 63.3% of the patients underwent sublobar resection (18.8% with a GGO ratio < 0.75, P <0.001). These patients had fewer relapses (2.2% for GGO ratio ≥0.75, 26.8% for GGO ratio <0.75, P < 0.001) and a better 5-year survival rate (95.5% for GGO ratio ≥0.75, 77.4% for GGO ratio <0.75, P < 0.001). None of the patients with a GGO ratio ≥0.75 had lymph node involvement. The multivariable Cox regression analysis revealed that a GGO ratio <0.75 was an independent factor for postoperative relapse with a hazard ratio of 3.96.

CONCLUSIONS

A GGO ratio ≥0.75 provided a favourable prognostic prediction in patients with resected lung adenocarcinoma. Sublobar resection and lymph node sampling revealed a fair outcome regardless of tumour size. However, anatomical resection is still the standard approach for patients with tumours with a GGO ratio <0.75, size >2 cm.

Robotic lobectomy for lung cancer: initial experience of a single institution in Korea

Background

Robotic surgery is known to have several advantages including magnified three-dimensional vision and angulation of the surgical instruments. To evaluate the feasibility and efficiency of robotic lobectomy in the treatment of lung cancer, we analyzed the outcomes of our initial experiences with robotic lobectomy at a single institution in Korea.

Methods

Eighty-seven patients with lung cancer underwent robotic lobectomy (robotic group: 34 patients) and video-assisted thoracic surgery (VATS) lobectomy (VATS group: 53 patients) between 2011 and 2016 at our hospital. The medical records of these patients were retrospectively analyzed.

Results

The operation times of the two groups were significantly different (robotic group, 293±74 min; VATS group, 201±62 min; P<0.01). Intraoperative blood loss occurred more in the robotic group than in the VATS group (robotic group, 403±197 mL; VATS group, 298±188 mL; P=0.018). The numbers of lymph nodes dissected in the two groups were significantly different (robotic group, 22±12; VATS group, 14±7; P<0.01). There was no intraoperative mortality in both groups.

Conclusions

Despite the initial difficulties, robotic lobectomy for lung cancer was a safe and feasible procedure with no operative mortality. If operation time and intraoperative blood loss improve as the learning curve progresses, robotic surgery may overcome the limitations of VATS in lung cancer surgery.

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.

Tailored management of stage IIIa non-small-cell lung cancer in the era of the 8th edition of the TNM classification for lung cancer

Stage IIIA is a very heterogeneous group encompassing locally advanced disease with T3 and T4 tumors without any nodal involvement and very small T1a primary tumors with unilateral mediastinal lymphatic disease. Tailored management defines interdisciplinary management requiring board decisions, which can sometimes be difficult particularly in stage IIIa non-small-cell lung cancer (NSCLC). Lobectomy still is standard of care even for stage I NSCLC, which increasingly is implemented using minimally invasive surgical technique. On the other hand even locally extended tumors are today safely resected with low morbidity and mortality. According to the 2015 guidelines of the European Society of Thoracic Surgeons any kind of anatomical lung resection for lung cancer with curative intent has to be accompanied by formal mediastinal lymph node dissection. The transcervical route for complete bilateral mediastinal lymphadenectomy offers improved completeness of resection without the need for single lung ventilation and ideally supports the concept of minimally invasive surgery.

[The Argument and Consensus of Lymphadenectomy on Lung Cancer Surgery]

淋巴结转移是肺癌的重要转移途径，淋巴结清扫术已成为肺癌的标准术式，同时也决定着肺癌的分期、预后及治疗策略。在临床实践中肺癌淋巴结的清扫方式各有不同，从选择性的淋巴结采样到扩大的淋巴结清扫，目前各种清扫方式存在着很大的争议，本文就目前的纵隔淋巴结清扫方式的共识及争议进行综述，为今后开展多中心临床研究提供参考。

Systematic lymphadenectomy versus sampling of ipsilateral mediastinal lymph-nodes during lobectomy for non-small-cell lung cancer: a systematic review of randomized trials and a meta-analysis

OBJECTIVES

To re-examine the evidence for recommendations for complete dissection versus sampling of ipsilateral mediastinal lymph nodes during lobectomy for cancer.

METHODS

We searched for randomized trials of systematic mediastinal lymphadenectomy versus mediastinal sampling. We performed a textual analysis of the authors' own starting assumptions and conclusion. We analysed the trial designs and risk of bias. We extracted data on early mortality, perioperative complications, overall survival, local recurrence and distant recurrence for meta-analysis.

RESULTS

We found five randomized controlled trials recruiting 1980 patients spanning 1989-2007. The expressed starting position in 3/5 studies was a conviction that systematic dissection was effective. Long-term survival was better with lymphadenectomy compared with sampling (Hazard Ratio 0.78; 95% CI 0.69-0.89) as was perioperative survival (Odds Ratio 0.59; 95% CI 0.25-1.36, non-significant). But there was an overall high risk of bias and a lack of intention to treat analysis. There were higher rates (non-significant) of perioperative complications including bleeding, chylothorax and recurrent nerve palsy with lymphadenectomy.

CONCLUSIONS

The high risk of bias in these trials makes the overall conclusion insecure. The finding of clinically important surgically related morbidities but lower perioperative mortality with lymphadenectomy seems inconsistent. The multiple variables in patients, cancers and available treatments suggest that large pragmatic multicentre trials, testing currently available strategies, are the best way to find out which are more effective. The number of patients affected with lung cancer makes trials feasible.

New horizons in surgical treatment of ground-glass nodules of the lung: experience and controversies

Ground-glass nodule (GGN) is defined as a nodular shadow with ground-glass opacity that is generally associated with the early-stage lung adenocarcinoma. Nowadays, GGNs of the lung are increasingly detected with thin-section computed tomography scan. GGNs are categorized as pure GGNs and mixed GGNs according to the images from a high-resolution computed tomography. Meanwhile, it is routine to divide GGNs into different categories according to the number, solitary, or multiple, the management of which there is very different. A great number of studies have been conducted to analyze the different characteristics of GGNs in various aspects ranging from radiology, pathology, and surgery to molecular biology. However, plenty of problems still remain unsolved, ranging from the preoperative localization to intraoperative surgical resection procedure, the lymphadenectomy, and sampling of lymph nodes, as well as the accuracy of frozen sections. There has been a large volume of updated published information summarizing recently emerging and rapidly progressing aspects of surgical treatment of solitary and multiple GGNs with the unsolved problems mentioned above. However, there have been few specific reviews of surgical treatment of GGNs so far. This review presents a timely outline of advances in relevant experience and controversies of GGNs for a better understanding of this kind of lesion.

Lymph node dissection and survival in patients with early stage nonsmall cell lung cancer: A 10-year cohort study

It is still debatable whether complete mediastinal lymph node dissection (MLND) is associated with better survival than mediastinal lymph node sampling (MLNS) in surgical treatment of nonsmall cell lung cancer (NSCLC). We aimed to assess the impact of lymph node dissection on long-term survival among stage I NSCLC patients.In this cohort study, 317 stage I NSCLC Chinese patients in Shanghai Chest Hospital were followed up for at least 10 years to evaluate the impact of different lymph node dissection modes on their survival. Among them, 161 patients were in the MLND group and 156 in the MLNS group. Overall survival and median survival times were calculated for the 2 groups. The association between lymph node dissection and the survival of NSCLC patients was assessed using Cox proportional-hazard models.Patients in the MLND group presented better survival (median survival time = 154.67 months) than those in the MLNS group (median survival time = 124.67 months). The MLNS had higher mortality than the MLND group, with the crude hazard ratio of the MLNS group relative to the MLND group as 1.32 (95% confidence interval [CI] 0.97, 1.78). After adjusting for age and sex, the association between lymph node dissection and mortality (hazard ratio 1.36, 95% CI 1.00, 1.84) was statistically significant (P = .047). Further adjusting for baseline clinical characteristics, the association (hazard ratio 1.40, 95% CI 1.02, 1.92) remained statistically significant (P = .036). The association between lymph node dissection mode and mortality was strong among patients with tumor size between 2.0 and 3.0 cm (hazard ratio 2.79, 95% CI 1.45, 5.37).We found that the MLND was associated with better survival for patients with early-stage NSCLC, compared with the MLNS. The effects of MLND on survival may depend on tumor size. Our findings have important implications in the treatment of early-stage NSCLC. Further prospective studies with a large sample size are needed to confirm our findings.

Transfer of malignant traits as opposed to migration of cells: A novel concept to explain metastatic disease

Metastatic disease is believed to develop following dissemination of cells to target organs. Inability of this theory to effectively explain certain phenomena such as patterns of metastatic spread, late metastasis formation, different gene patterns between primary cancer and metastasis have brought forward the need for alternative models. Recent discoveries have strengthened the validity of theories supporting a humoral transfer of malignant traits as opposed to migration of malignant cells to explain metastatic disease in cancer patients. In light of this new evidence, we would like to highlight a model that offers a new perspective to explain cancer metastasis. In the system that we theorize, genetic material released by cancer cells would travel, either free or packed in exosomes, through the blood. Target cells located in organs deriving from the same embryological layer might uptake this genetic material due to expression of specific receptors. Interplay with the immune system would determine the fate of these oncofactors and would regulate their ability to circulate in the blood, integrate in the genome and be transcribed. We also hypothesize that the expression of cell membrane receptors such as integrins, to which cancer exosomes ligate might be mediated by inherited or acquired oncosuppressor mutations.

Lymph node dissection after pulmonary resection for lung cancer: a mini review

An accurate staging of a malignant disease is imperative in order to plan pre- and post-operative therapy, define prognosis and compare studies. According to the European Society of Thoracic Surgeons (ESTS) guidelines a systematic lymph node (LN) dissection is recommended in all cases of pulmonary resection for non-small cell lung cancer (NSCLC). The current lung cancer staging system considers the lymphatic stations involved but not the number of LNs. Up to date, published scientific studies on hilar and mediastinal lymphadenectomy mainly have been regarded the type of LN dissection procedure after pulmonary resection (selected LN biopsy, LN sampling, systematic nodal dissection, lobe specific nodal dissection and extended LN dissection) focusing particularly on the comparison between mediastinal LN dissection (MLND) and mediastinal LN sampling (MLNS). Recently, further investigations have been concentrated on surgical approach (videothoracoscopic vs. thoracotomic approach) used to perform pulmonary resection and following LN dissection in order to achieve a complete mediastinal lymphadenectomy. This short synthesis aims to present the current experiences in this setting.

The effectiveness of mediastinal lymph node evaluation in a patient with ground glass opacity tumor

BACKGROUND

The prognosis of non-small cell lung cancer (NSCLC) presenting as a ground glass opacity (GGO) nodule is better than other types of lung cancer. The purpose of this study was to evaluate the necessity of mediastinal lymph node evaluation (MLE) in clinical N0 GGO-predominant NSCLC.

METHODS

We conducted a retrospective chart review of 358 patients treated for clinical N0 NSCLC that was found by curative resection to be 3 cm or smaller in size. We analyzed clinicopathological findings and survival among three groups with either GGO-predominant or solid-predominant tumor: no mediastinal lymph node evaluation (NoMLE) group, mediastinal lymph node sampling (MLS) group, and mediastinal lymph node dissection (MLND) group.

RESULTS

Except for sex, there were no differences in clinicopathological characteristics among the three groups with GGO-predominant tumor or solid-predominant tumor. There was no difference in the 5-year recurrence-free survival (RFS) rate among three groups in the GGO-predominant patients (100%, 92.9%, 93.8%, respectively; P=0.889). However, in the solid-predominant tumor group, the 5-year recurrence free survival of the NoMLE group was lower than in the MLND group (48.6% vs. 73.1%, P=0.007). MLE was not a significant risk factor for recurrence in GGO-predominant tumor [hazard ratio (HR) =1.021; P=0.987]. GGO-predominant tumor [odds ratio (OR) =0.063; P=0.008] was identified as the sole parameter that significantly impacted nodal upstaging.

CONCLUSIONS

MLE is not an essential procedure for clinical N0 NSCLC presenting as a 3 cm or smaller GGO-predominant nodule.

[Progress of Postoperative Adjuvant Chemotherapy in Stage I Non-small Cell Lung Cancer]

The morbidity and mortality of lung cancer rank the first place among all the malignant tumor. According to the histopathological characteristics, lung cancer is divided into non-small cell lung cancer (NSCLC) and small cell lung cancer. Only 20% patients diagnosed with NSCLC have the chance for surgery while their 5-yr overall survival is about 30%-60%. The therapeutic outcome of surgery alone is not satisfying. Adjuvant chemotherapy after surgical resection in stage II-IIIa lung cancer showed efficacy in many randomized clinical trials, but its role in stage I disease remains controversial. The choice of appropriate chemotherapy candidates, the selection of chemotherapy regimens and the research progress on biomarker are mainly discussed in this review.