Radical systematic mediastinal lymphadenectomy in non-small cell lung cancer: a randomized controlled trial

A vision transformer-based deep transfer learning nomogram for predicting lymph node metastasis in lung adenocarcinoma

BACKGROUND

Lymph node metastasis (LNM) plays a crucial role in the management of lung cancer; however, the ability of chest computed tomography (CT) imaging to detect LNM status is limited.

PURPOSE

This study aimed to develop and validate a vision transformer-based deep transfer learning nomogram for predicting LNM in lung adenocarcinoma patients using preoperative unenhanced chest CT imaging.

METHODS

This study included 528 patients with lung adenocarcinoma who were randomly divided into training and validation cohorts at a 7:3 ratio. The pretrained vision transformer (ViT) was utilized to extract deep transfer learning (DTL) feature, and logistic regression was employed to construct a ViT-based DTL model. Subsequently, the model was compared with six classical convolutional neural network (CNN) models. Finally, the ViT-based DTL signature was combined with independent clinical predictors to construct a ViT-based deep transfer learning nomogram (DTLN).

RESULTS

The ViT-based DTL model showed good performance, with an area under the curve (AUC) of 0.821 (95% CI, 0.775-0.867) in the training cohort and 0.825 (95% CI, 0.758-0.891) in the validation cohort. The ViT-based DTL model demonstrated comparable performance to classical CNN models in predicting LNM, and the ViT-based DTL signature was then used to construct ViT-based DTLN with independent clinical predictors such as tumor maximum diameter, location, and density. The DTLN achieved the best predictive performance, with AUCs of 0.865 (95% CI, 0.827-0.903) and 0.894 (95% CI, 0845-0942), respectively, surpassing both the clinical factor model and the ViT-based DTL model (p < 0.001).

CONCLUSION

This study developed a new DTL model based on ViT to predict LNM status in lung adenocarcinoma patients and revealed that the performance of the ViT-based DTL model was comparable to that of classical CNN models, confirming that ViT was viable for deep learning tasks involving medical images. The ViT-based DTLN performed exceptionally well and can assist clinicians and radiologists in making accurate judgments and formulating appropriate treatment plans.

[Prevention, Diagnosis, Therapy, and Follow-up of Lung Cancer - Interdisciplinary Guideline of the German Respiratory Society and the German Cancer Society - Abridged Version]

The current S3 Lung Cancer Guidelines are edited with fundamental changes to the previous edition based on the dynamic influx of information to this field:The recommendations include de novo a mandatory case presentation for all patients with lung cancer in a multidisciplinary tumor board before initiation of treatment, furthermore CT-Screening for asymptomatic patients at risk (after federal approval), recommendations for incidental lung nodule management , molecular testing of all NSCLC independent of subtypes, EGFR-mutations in resectable early stage lung cancer in relapsed or recurrent disease, adjuvant TKI-therapy in the presence of common EGFR-mutations, adjuvant consolidation treatment with checkpoint inhibitors in resected lung cancer with PD-L1 ≥ 50%, obligatory evaluation of PD-L1-status, consolidation treatment with checkpoint inhibition after radiochemotherapy in patients with PD-L1-pos. tumor, adjuvant consolidation treatment with checkpoint inhibition in patients withPD-L1 ≥ 50% stage IIIA and treatment options in PD-L1 ≥ 50% tumors independent of PD-L1status and targeted therapy and treatment option immune chemotherapy in first line SCLC patients.Based on the current dynamic status of information in this field and the turnaround time required to implement new options, a transformation to a "living guideline" was proposed.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

[Bronchial carcinoma: metastatic pathways with involvement of hilar and mediastinal lymph nodes]

SIGNIFICANCE OF LUNG CANCER

Lung cancer has enormous socioeconomical impact on our society due to its high prevalence and mortality. About 59,700 new cases of lung cancer were forecasted for 2022.

TNM SCHEME FOR STAGING

Correct staging is the basis for therapy planning, prognosis estimation, and future analyses. Staging is performed using the TNM scheme from the Union for International Cancer Control (UICC). Involvement of lymph nodes is used to differentiate between stage IIB and IIIC.

LYMPH NODE LEVELS FOR LUNG CANCER

Knowledge of the intrathoracic lymph node levels is crucial for the exact classification and its involvement has direct implications on therapy. The International Association for the Study of Lung Cancer (IASLC) proposed a unified lymph node map with exact anatomic definitions, which is recommended by the German national lung cancer guideline. The extent of lymph node involvement is stratified into N0-N3. Different metastatic paths are known depending on the location of the primary tumor, but the burden of disease has a greater influence on survival, than the location of metastases.

ASSESSING THE SPREAD OF LUNG CANCER

Computed tomography can assess operability of the primary tumor safely in most cases. Invasive procedures to confirm the diagnosis by sampling tissue should be performed after noninvasive diagnostics.

PRACTICAL RECOMMENDATION

Systematic lymph node dissection for all patients with non-small cell lung cancer intended for curative resection is recommended in the current German national guideline for lung cancer.

Radicality of lymphadenectomy in lung cancer resections by thoracotomy and video-assisted thoracoscopic approach: A prospective, multicentre and propensity-score adjusted study

OBJECTIVE

To analyse differences in intraoperative nodal assessment in patients undergoing lung cancer resection by thoracotomy and video-assisted thoracoscopy (VATS) in the Spanish Video-Assisted Thoracic Surgery Group (GEVATS).

METHODS

Prospective multicentre cohort study of anatomic pulmonary resections (n = 3533) performed from December 2016 to March 2018. Main surgical, clinical and oncological variables related with lymphadenectomy were compared according to surgical approach. Corresponding tests for homogeneity were performed. Multiple logistic regression analyses were used to determine the odds ratio (OR) and 95% confidence interval (95%CI). Covariate adjustment using the propensity score (PS) was performed to reduce confounding effects.

RESULTS

After exclusions, 2532 patients were analysed. Systematic nodal dissection (SND) was performed in 65%, with a median of resected/sampled lymph nodes (LN) of 7 (IQR 4-12) and pathologic (p) N2 and uncertain (u) pNu rates of 9.4% and 28.9%, respectively. At multivariate analysis, the following were associated with thoracotomy (OR; 95%CI): SND (1.4; 1.08-1.96; p = 0.014), staging mediastinoscopy (2.6; 1.59-4.25; p < 0.001), tumor > 3 cm (2.1; 1.66-2.78; p < 0.001), central tumor (2.5; 1.90-3.24; p < 0.001); pN1 (1.8; 1.25-2.67; p < 0.002), pN2 (1.8; 1.18-2.76; p = 0.006), lower FEV1 (0.9; 0.98-0.99; p < 0.001), squamous cell carcinoma (1.5; 1.16-1.98; p = 0.002) and inexperienced surgeons in VATS (compared with > 100 VATS experience) (37.6; 13.55-104.6; p < 0.001). After PS adjustment, SND maintained the OR, but in the limit of signification (1.4; 1-1.98; p = 0.05). Nodal upstaging was significantly higher in the thoracotomy group. Complication rates of SND and no SND were similar.

CONCLUSIONS

Thoracotomy was associated with a more thorough lymphadenectomy in GEVATS. Therefore, intraoperative lymph node evaluation performed at VATS should be improved to have better prognostic information and more solid grounds to indicate adjuvant therapy.

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.

Safety and efficacy of lobectomy combined with off-pump coronary artery bypass grafting for lung cancer

Background

This study sought to assess the safety and efficacy of a lobectomy combined with off-pump coronary artery bypass grafting (OPCABG) among patients with lung cancer.

Methods

Patients who underwent a simultaneous pulmonary lobectomy combined with OPCABG at Tianjin Chest Hospital from December 2010 to June 2019 and patients who underwent pulmonary lobectomy during the same period were selected at a ratio of 1:2 using a multi-factor propensity score for this study. The clinical data of each group during the operation and perioperative period were analyzed and compared, and the survival curves were drawn using the Kaplan-Meier method to compare the long-term survival of the patients.

Results

In the simultaneous-surgery group, no patients required a secondary thoracotomy for hemostasis and there were no perioperative deaths; however, 2 patients underwent a second intubation, 2 patients underwent a second debridement and suturing due to wound infection, 28 patients (76.3%) had pulmonary complications, and 10 patients (26.3%) had circulatory complications. The operation time, intraoperative blood loss, postoperative drainage volume, postoperative hospital stay, and complication rate were all higher in the simultaneous-surgery group than the lobectomy group. No significant difference was observed in the long-term survival rates between the 2 groups.

Conclusions

The simultaneous surgery was safe and effective. Some differences existed in the data between the 2 groups during the perioperative period; however, the risk of complications after surgery was controllable.

Evaluation of treatment options for postoperative and spontaneous chylothorax in adults

 

OBJECTIVES

Both postoperative and spontaneous chylothorax remain therapeutic challenges without recommendations for a standardized treatment approach. Regardless of its aetiology, patients with chylothorax experience prolonged hospitalization and suffer from the associated complications or the invasive therapy administered.

METHODS

We conducted a retrospective, observational review of adult patients with chylothorax treated between January 2010 and September 2019. The primary end point was successful management with sustained cessation and/or controlled chylous output. Therapy duration, inpatient stay and the incidence of complications were evaluated as secondary end points.

RESULTS

Of the 36 patients included (22 men; median age 63 years), 24 patients (67%) suffered from a postoperative accumulation of chylous fluid in the pleural space; in the remaining 12 (33%) patients, chylothoraces occurred spontaneously. Initial conservative treatment was successful in 42% (n = 15); in the other 20 cases (56%) additional invasive therapeutic strategies were followed. A complicated course requiring more than 1 treatment was seen in 54% (n = 13) of the postoperative and in 58% (n = 7) of the spontaneous cases. The median length of hospitalization was significantly longer in the postoperative group (37.5 vs 15.5 days; P = 0.016). Serious complications were observed only in the postoperative group (P = 0.28). There were no in-hospital deaths.

CONCLUSIONS

Basic treatment of both postoperative and spontaneous chylothorax should include dietary measures in all patients. Additional sclerosing radiotherapy and interventional or surgical therapy are often necessary. The choice of therapeutic approach should be indicated, depending on the aetiology and development of the chylothorax. Early, multimodal treatment is recommended.

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.

The impact on mediastinal recurrence based on the number of harvested mediastinal lymph nodes and assessed N2 Stations in patients with stage I invasive lung adenocarcinoma

Background

To determine the impact of the number of harvested mediastinal lymph nodes (MLNs) and assessed N2 stations on the mediastinal recurrence for pathologic stage I invasive lung adenocarcinoma (IADC).

Methods

A total of 2,048 patients with stage I IADC undergoing surgical resection were enrolled at Shanghai Chest Hospital from 2009 to 2013. Survival analysis was performed by Kaplan-Meier method along with univariable and multivariable cox regression analysis.

Results

For patients with ≥5 MLNs, mediastinum-specific relapse-free survival (MS-RFS) rates were 98.3% and 96.6% for 3- and 5-year, respectively, which significantly demonstrated better survival outcomes against those with <5 MLNs (96.3% and 92.8%, respectively, log-rank P=0.018). Additionally, the 3- and 5-year RFS of patients with assessed N2 stations ≥3 (98.2% and 95.8%) were exceptionally better when compared with those with N2 stations <3 (95.5%, 90.3%, log-rank P<0.001). In the univariable and multivariable cox analyses, we found that the number of assessed N2 stations was an independent predictor to MS-RFS (HR =0.468; 95% CI, 0.312-0.867; P=0.020) as opposed to the number of harvested MLNs (HR =0.856; 95% CI, 0.423-1.489; P=0.543) which was not a predictor.

Conclusions

Based on our results, we recommend, for a better MS-RFS among patients with pathological stage I IADC, that the cutoff values for harvested MLNs and assessed N2 stations be 5 and 3, respectively. In addition, the number of assessed N2 stations was still an independent predictor to MS-RFS.

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.

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.

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

OBJECTIVE

Methods to minimize surgical trauma from mediastinal lymphadenectomy in patients with early-stage lung cancer are still immature. This study aimed to identify predictors of negative pathologic N2, which may be used to select patients for limited mediastinal lymphadenectomy.

METHODS

Clinicopathologic features of 1430 patients with resected clinical stage I non-small cell lung cancer and complete mediastinal lymphadenectomy were retrospectively analyzed for variables associated with negative N2 nodal metastasis (2008-2015). Overall and recurrence-free survival in patients after complete or limited mediastinal lymphadenectomy were assessed via Kaplan-Meier survival analysis and log-rank testing. The accuracy of frozen section diagnosis for predicting final pathology was retrospectively assessed in 126 randomly selected patients after the surgery.

RESULTS

Multivariable analysis revealed that tumor size ≤2 cm, negative pN1, lymphovascular invasion, and lepidic adenocarcinoma were associated with negative mediastinal nodal metastasis. Notably, none of the patients with histology of adenocarcinoma in situ, minimally invasive adenocarcinoma, or lepidic pattern-predominant adenocarcinoma on final pathology had pN2 disease, and the 5-year overall and recurrence free-survival of these patients (99.3% and 99.3%, respectively) was not different from those after limited mediastinal lymphadenectomy (98.7% and 100%, P = .582 and .511, respectively). If these subtypes were classified together as the low-risk group, the concordance rate between frozen section and final pathology diagnosis was 88.9% in the retrospective test cohort.

CONCLUSIONS

Tumor histology may predict negative mediastinal metastasis in patients with early-stage lung cancer. Future prospective studies are merited to validate the feasibility of using frozen section to select patients for limited mediastinal lymphadenectomy.

Computed Tomography Screening for Lung Cancer: Mediastinal Lymph Node Resection in Stage IA Nonsmall Cell Lung Cancer Manifesting as Subsolid and Solid Nodules

OBJECTIVE

To compare long-term survival rates of patients with first, primary, clinical stage IA nonsmall cell lung cancer from a large cohort undergoing computed tomography screening with and without mediastinal lymph node resection (MLNR) under an Institutional Review Board-approved common protocol from 1992 to 2014.

BACKGROUND

Assessing survival differences of patients with and without MLNR manifesting as solid and subsolid nodules.

METHODS

Long-term Kaplan-Meier (K-M) survival rates for those with and without MLNR were compared and Cox regression analyses were used to adjust for demographic, computed tomography, and surgical covariates.

RESULTS

The long-term K-M rates for 462 with and 145 without MLNR was 92% versus 96% (P = 0.19), respectively. For 203 patients with a subsolid nodule, 151 with and 52 without MLNR, the rate was 100%. For the 404 patients with a solid nodule, 311 with and 93 without MLNR, the rate was 87% versus 94% (P = 0.24) and Cox regression showed no statistically significant difference (P = 0.28) when adjusted for all covariates. Risk of dying increased significantly with increasing decades of age (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.4-3.8), centrally located tumor (HR 2.5, 95% CI 1.2-5.2), tumor size 21 to 30 mm (HR 2.7, 95% CI 1.2-6.0), and invasion beyond the lung stroma (HR 3.0, 95% CI 1.4-6.1). For the 346 patients with MLNR, tumor size was 20 mm or less; K-M rates for the 269 patients with and 169 patients without MLNR were also not significantly different (HR 2.1, P = 0.24).

CONCLUSIONS

It is not mandatory to perform MLNR when screen-diagnosed nonsmall cell lung cancer manifests as a subsolid nodule.

Rethinking N2 disease in the era of uniportal video-assisted thoracic surgery

Third Mediterranean Symposium on Thoracic Surgical Oncology, Catania, Italy, 21–22 April 2016

The primary justification for mediastinal lymphadenectomy is that it provides more complete nodal staging to help select best adjuvant treatments. There is a secondary argument that dissection of nodes might remove otherwise unrecognized nodal disease to increase the chance of cure. They have to be thought through again as patients look for less invasive treatments for their cancers such as videothoracoscopy and stereotactic radiotherapy. Evidence from analysis of Surveillance, Epidemiology and End Results data indicated that sampling or dissection can be performed adequately by surgeons using videothoracoscopy but stereotactic radiotherapy of its nature precludes intraoperative lymph node dissection and yet is being promoted as equivalent treatment. Consideration of these issues requires re-examination of the evidence that lymphadenectomy influences survival.

Peri- and postoperative management of stage I-III Non Small Cell Lung Cancer: Which quality of care indicators are evidence-based?

Quality of care (QoC) has a central role in our health care system. The aim of this review is to present a set of evidence-based quality indicators for the surgical treatment and postoperative management of lung cancer. A search was performed through PubMed, Embase and the Cochrane library database, including English literature, published between 1980 and 2012. Search terms regarding 'lung neoplasms', 'surgical treatment' and 'quality of care' were used. Potential QoC indicators were divided into structure, process or outcome measures and a final selection was made based upon the level of evidence. High hospital volume and surgery performed by a thoracic surgeon, were identified as important structure indicators. Sleeve resection instead of pneumonectomy and the importance of treatment within a clinical care path setting were identified as evidence-based process indicators. A symptom-based follow-up regime was identified as a new QoC indicator. These indicators can be used for registration, benchmarking and ultimately quality improvement in lung cancer surgery.

State of the art in surgery for early stage NSCLC-does the number of resected lymph nodes matter?

Surgery is the treatment of choice in patients with early stage NSCLC. However, the results remain poor in these patients. Lymph node involvement is the main prognostic factor in patients with NSCLC, but there is still no clear definition of the number of nodes required to consider a lymphadenectomy as complete. Although there is no defined minimum number of lymph nodes required for a complete lymphadenectomy, there are some recommendations to perform this procedure, published by different scientific societies. Current practice in thoracic surgery regarding lymphadenectomy, differs on some points from the guidelines recommendations, with data regarding patients with no mediastinal assessment between 30-45% according to some of the published data. Different studies have probed the fact that the probability of finding a positive node increases with the number of lymph nodes analyzed. Therefore, a complete lymphadenectomy provides proper staging, which helps to identify the patient's real prognosis. Several nonrandomized studies and retrospective series have shown that survival increases in the group of patients with a higher number of lymph nodes removed. There is no contraindication to performing a complete lymphadenectomy. The increase in survival in patients with a complete lymphadenectomy may be due to more accurate staging. Therefore, complete lymphadenectomy should be mandatory even in early stage patients.

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

Objective

This systematic review and meta-analysis aimed to evaluate the overall survival, local recurrence, distant metastasis, and complications of mediastinal lymph node dissection (MLND) versus mediastinal lymph node sampling (MLNS) in stage I–IIIA non-small cell lung cancer (NSCLC) patients.

Methods

A systematic search of published literature was conducted using the main databases (MEDLINE, PubMed, EMBASE, and Cochrane databases) to identify relevant randomized controlled trials that compared MLND vs. MLNS in NSCLC patients. Methodological quality of included randomized controlled trials was assessed according to the criteria from the Cochrane Handbook for Systematic Review of Interventions (Version 5.1.0). Meta-analysis was performed using The Cochrane Collaboration’s Review Manager 5.3. The results of the meta-analysis were expressed as hazard ratio (HR) or risk ratio (RR), with their corresponding 95% confidence interval (CI).

Results

We included results reported from six randomized controlled trials, with a total of 1,791 patients included in the primary meta-analysis. Compared to MLNS in NSCLC patients, there was no statistically significant difference in MLND on overall survival (HR = 0.77, 95% CI 0.55 to 1.08; P = 0.13). In addition, the results indicated that local recurrence rate (RR = 0.93, 95% CI 0.68 to 1.28; P = 0.67), distant metastasis rate (RR = 0.88, 95% CI 0.74 to 1.04; P = 0.15), and total complications rate (RR = 1.10, 95% CI 0.67 to 1.79; P = 0.72) were similar, no significant difference found between the two groups.

Conclusions

Results for overall survival, local recurrence rate, and distant metastasis rate were similar between MLND and MLNS in early stage NSCLC patients. There was no evidence that MLND increased complications compared with MLNS. Whether or not MLND is superior to MLNS for stage II–IIIA remains to be determined.

Predictive value of 18F-fluorodeoxyglucose positron emission tomography - computed tomography compared to postoperative pathological findings for patients with non-small-cell lung cancer

This study was conducted to investigate the predictive value of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) in patients with non-small-cell lung cancer (NSCLC), compared to that of postoperative pathological findings, for T and N staging and the associations of the metabolic parameters of the primary tumor with histological type and differentiation. The preoperative contrast-enhanced CT and ¹⁸F-FDG PET-CT and postoperative pathological findings of 112 NSCLC patients treated with lobectomy or pneumonectomy combined with systematic mediastinal lymphadenectomy were retrospectively reviewed. Compared to the postoperative pathological findings, the effect of contrast-enhanced CT and ¹⁸F-FDG PET-CT on T and N staging were evaluated. The metabolic tumor volume (MTV) and maximum standardized uptake value (SUVmax) of the primary tumor were measured. The associations between these metabolic parameters and histological type and differentiation were also evaluated. The differences in the accuracy in overall staging and T staging between PET-CT and contrast-enhanced CT were significant (91.1 vs. 69.6%, P=0.000; and 92.9 vs. 76.8%, P=0.000, respectively). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of regional lymph node metastasis detection were 91.7, 93.0, 86.5, 95.8 and 92.6%, respectively, with PET-CT; and 71.3, 77.2, 60.6, 84.5 and 75.2%, respectively, with contrast-enhanced CT. The SUVmax (7.29±1.83 vs. 5.91±1.65, t=4.15, P=0.000) and MTV (48.20±22.47 vs. 30.21±19.72 cm³, t=4.48, P=0.000) were significantly higher for squamous cell carcinoma (SCC) compared to those for adenocarcinoma (AC). There was a positive correlation between the MTV and SUVmax of the primary tumor (Pearson's r=0.838, P=0.000). Significant differences were observed among differentiation subgroups in the SUVmax and MTV of the primary tumor for both SCC and AC. In conclusion, compared to the postoperative pathological findings, the predictive value of ¹⁸F-FDG PET-CT for T and N staging in NSCLC was higher compared to that of contrast-enhanced CT. The FDG uptake of the primary tumor was associated with histological type and differentiation and the difference was statistically significant. Therefore, the SUVmax and MTV of the primary tumor may be valuable indices to partly predict the histological type and grade of differentiation of NSCLC.

Lobe-specific mediastinal nodal dissection is sufficient during lobectomy by video-assisted thoracic surgery or thoracotomy for early-stage lung cancer

BACKGROUND

Lobectomy with complete mediastinal lymphadenectomy is considered standard for patients with early-stage non-small cell lung cancer (NSCLC). However, the benefits of complete lymphadenectomy are unproven. There is evidence suggesting a predictable pattern of mediastinal nodal drainage. This study analyzed the frequency and pattern of mediastinal nodal disease and its impact on outcome in patients with early-stage NSCLC.

METHODS

Patients with clinical N0/N1 NSCLC staged with CT scans and PET scans were identified. Disease involvement of resected nodal stations was recorded. Patterns of recurrence in patients who underwent lobectomy with complete mediastinal systematic lymph node sampling (SLNS) were compared with those who underwent lobe-specific mediastinal SLNS.

RESULTS

From July 2004 to April 2011, 370 patients were identified. Complete SLNS was performed in 282 patients. Fifteen patients (5.3%) in the group with complete SLNS were found to have N2 disease after pathologic evaluation. Patients with left-sided tumors were more likely to have pathologic N2 disease than were patients with right-sided tumors (P = .03). Only one patient (0.36%) had positive N2 disease in the distal mediastinum while skipping lobe-specific mediastinal nodes. In addition, patients with complete SLNS had a rate of recurrence similar to that of the group that had lobe-specific mediastinal evaluation (20.6% vs 18.2%, P = .68).

CONCLUSIONS

Mediastinal N2 metastases follow predictable lobe-specific patterns in patients with negative preoperative CT scans and PET scans. Lobe-specific N2 nodal evaluation results in a recurrence rate similar to that of complete mediastinal evaluation. Lobe-specific mediastinal nodal evaluation appears acceptable in patients with early-stage NSCLC.

Treatment of stage III non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

OBJECTIVES

Stage III non-small cell lung cancer (NSCLC) describes a heterogeneous population with disease presentation ranging from apparently resectable tumors with occult microscopic nodal metastases to unresectable, bulky nodal disease. This review updates the published clinical trials since the last American College of Chest Physicians guidelines to make treatment recommendations for this controversial subset of patients.

METHODS

Systematic searches were conducted through MEDLINE, Embase, and the Cochrane Database for Systematic Review up to December 2011, focusing primarily on randomized trials, selected meta-analyses, practice guidelines, and reviews.

RESULTS

For individuals with stage IIIA or IIIB disease, good performance scores, and minimal weight loss, treatment with combined chemoradiotherapy results in better survival than radiotherapy alone. Consolidation chemotherapy or targeted therapy following definitive chemoradiation for stage IIIA is not supported. Neoadjuvant therapy followed by surgery is neither clearly better nor clearly worse than definitive chemoradiation. Most of the arguments made regarding patient selection for neoadjuvant therapy and surgical resection provide evidence for better prognosis but not for a beneficial impact of this treatment strategy; however, weak comparative data suggest a possible role if only lobectomy is needed in a center with a low perioperative mortality rate. The evidence supports routine platinum-based adjuvant chemotherapy following complete resection of stage IIIA lung cancer encountered unexpectedly at surgery. Postoperative radiotherapy improves local control without improving survival.

CONCLUSIONS

Multimodality therapy is preferable in most subsets of patients with stage III lung cancer. Variability in the patients included in randomized trials limits the ability to combine results across studies and thus limits the strength of recommendations in many scenarios. Future trials are needed to investigate the roles of individualized chemotherapy, surgery in particular cohorts or settings, prophylactic cranial radiation, and adaptive radiation.

Retrospective analysis of nodal spread patterns according to tumor location in pathological N2 non-small cell lung cancer

BACKGROUND

The purpose of the present study was to determine the nodal spread patterns of pN2 non-small cell lung cancer (NSCLC) according to tumor location, and to attempt to evaluate the possible indications of selective lymph node dissection (SLND).

METHODS

We retrospectively analyzed nodal spread patterns in 207 patients with NSCLC of less than 5 cm with N2 involvement.

RESULTS

The tumor location was right upper lobe (RUL) in 79, middle lobe in 12, right lower lobe (RLL) in 40, left upper division (LUD) in 41, lingular division in 11, and left lower lobe (LLL) in 24. Both RUL and LUD tumors showed a higher incidence of upper mediastinal (UM) involvement (96 and 100%, respectively) and a lower incidence of subcarinal involvement (15 and 10%, respectively) than lower lobe tumors (UM; RLL 60%, LLL 42%; subcarinal: RLL 60%, LLL 46%, respectively). Among the patients with 24 right UM-positive RLL and 10 left UM-positive LLL tumors, 2 showed negative hilar, subcarinal, and lower mediastinal involvement, and cT1, suggesting that UM dissection may be unnecessary in lower lobe tumors with no metastasis to hilar, subcarinal, and lower mediastinal nodes on frozen sections according to the preoperative T status. Among the patients with 12 subcarinal-positive RUL and 4 subcarinal-positive LUD tumors, one showed negative hilar or UM involvement, suggesting that subcarinal dissection may be unnecessary in RUL or LUD tumors with no metastasis to hilar and UM nodes on frozen sections.

CONCLUSIONS

The present study appears to provide one of the supportive results regarding the treatment strategies for tumor location-specific SLND.

Determination of standard number, size and weight of mediastinal lymph nodes in postmortem examinations: reflection on lung cancer surgery

Background

Mediastinal lymph node dissection is an essential component of lung cancer surgery. Literature lacks established information regarding the number and size of the healthy lymph nodes. In this postmortem autopsy study, we aim to define the number, size and weight of the lymph nodes in each mediastinal lymph node station. To implement the data for the clinical practice, we analyzed the possible number of nodes to be dissected in a systematic mediastinal lymph node dissection from the right and left sides during lung cancer surgery.

Methods

Sixty-two samples obtained from cadavers who did not die from chest malignancies, extrathoracic malignancies, any kind of infections or previous hospitalization before the death were included to the study. The locations of the nodes were recorded according to the American Thoracic Society Mediastinal Lymph Node Map. The number, size and weight of the nodes were determined at each station.

Results

Median age of the cadavers was 39 years. Primary causes of death were asphyxia in 10 (16.1%) subjects, trauma in 29 (46.8%) subjects, cardiovascular problems in 10 (16.1%) subjects, and undetermined in 13 (21%) subjects. The median number of lymph nodes resected from each patient was 23 (range: 11–54). The right sided paratracheal lymph nodes (Station 2R and 4R) were more frequent, heavier and longer than left sided lymph nodes (Station 2L and 4L) at the paratrecheal region. Right sided inferior mediastinal lymph nodes were heavier and longer than the left ones; however, their availability was more often on the left.

Conclusions

The properties of mediastinal lymph nodes at particular stations are different for number, size and weight. Station 4R and 7 have the highest number of nodes followed by stations 5 and 6. We recommend removing the lymph nodes of these stations completely in lung cancer patients to rule out the possibility of micrometastatic disease. Diameter of normal lymph node may be 1 cm for the stations other than 4R and 7, but the definition of normal diameter of a lymph node at the stations 4R and 7 may be changed as 1,5 cm and 2,0 cm, respectively. Weight of the nodes may be a new subject to study and may be defined as a new modality to define a staging to be more accurate and the issue needs further investigations.

Radiotherapy in the treatment of postoperative chylothorax

Background

Chylothorax is characterized by the presence of chyle in the pleural cavity. The healing rate of non-operative treatment varies enormously; the maximum success rate in series is 70%. We investigate the efficacy and outcomes of radiotherapy for postoperative chylothorax.

Methods

Chylothorax was identified based on the quantity and quality of the drainage fluid. Radiation was indicated if the daily chyle flow exceeded 450 ml after complete cessation of oral intake. Radiotherapy consisted of opposed isocentric portals to the mediastinum using 15 MV photon beams from a linear accelerator, a single dose of 1–1.5 Gy, and a maximum of five fractions per week. The radiation target area was the anatomical region between TH3 and TH10 depending on the localization of the resected lobe. The mean doses of the ionizing energy was 8.5 Gy ± 3.5 Gy.

Results

The median start date of the radiation was the fourth day after chylothorax diagnosis. The patients’ mediastinum was radiated an average of six times. Radiotherapy, in combination with dietary restrictions, was successful in all patients. The median time between the end of the radiation and the removal of the chest tube was one day. One patient underwent wound healing by secondary intention. The median time between the end of radiation and discharge was three days, and the overall hospital stay between the chylothorax diagnosis and discharge was 18 days (range: 11–30 days). After a follow-up of six months, no patient experienced chylothorax recurrence.

Conclusions

Our results suggest that radiotherapy in combination with dietary restriction in the treatment of postoperative chylothorax is very safe, rapid and successful. This novel interventional procedure can obviate repeat major thoracic surgery and shorten hospital stays and could be the first choice in the treatment of postthoracotomy chylothorax.

Thoracoscopic mediastinal lymph node dissection for lung cancer

Mediastinal lymph node staging is an important component of the assessment and management of patients with operable non-small cell lung cancer and is necessary to achieve complete resection. During minimally invasive surgery, performance of an equivalent oncologic resection, including adequate lymph node dissection similar in extent to open thoracotomy, is absolutely necessary. We describe our techniques for video-assisted thoracic surgery (VATS) and Robot-assisted VATS (R-VATS) mediastinal lymph node dissection when performing thoracoscopic lobectomy for lung cancer. Between 2008 and 2011, 200 consecutive patients who underwent VATS or R-VATS lobectomies for early stage lung cancer were analyzed. In our series, we removed about 25 lymph nodes per case in both complete VATS and R-VATS. A thorough lymph node dissection in lung cancer is possible with either VATS or R-VATS technique without oncological compromise.

Impact of the 7th TNM staging lung cancer in surgery

Accurate staging of lung cancer is very critical to determine the proper management approach of each patient and to address prognosis issues. In this manuscript, we will discuss the impact of the most recent staging categories (7th TNM staging) on the management of non-small cell lung cancer.

Mediastinal lymph nodes: ignore? sample? dissect? The role of mediastinal node dissection in the surgical management of primary lung cancer

The role of mediastinal lymph node dissection (MLND) during the resection of non-small-cell lung cancer is still unclear although most surgeons agree that a minimum of hilar and mediastinal nodes must be examined for appropriate pathological staging. Current surgical practices vary from visual inspection of the mediastinum with biopsy of only abnormal looking nodes to systematic mediastinal node sampling which is to the biopsy of lymph nodes from multiple levels whether they appear abnormal or not to MLND which involves the systematic removal of all lymph node bearing tissue from multiple sites unilaterally or bilaterally within the mediastinum. This review article looks at the evidence and arguments in favour of lymphadenectomy, including improved pathological staging, better locoregional control, and ultimately longer disease-free survival and those against which are longer operating time, increased operative morbidity, and lack of evidence for survival benefit.

The impact of complete lymph node dissection for lung cancer on the postoperative course

The role of lymph node dissection (LND) for non-small cell lung cancers (NSCLCs) remains controversial. LND adds little morbidity to a pulmonary resection for NSCLC, although it requires an additional 15 to 20 minutes of operative time. Four prospective randomized trials have been performed to compare lymph node sampling and LND; 3 trials showed no difference in survival and 1 showed survival benefit of LND. It is recommended that all patients with resectable NSCLC undergo LND because the procedure provides patients with the most accurate staging and the opportunity for effective adjuvant therapy.

Extent of lymph node resection does not increase perioperative morbidity and mortality after surgery for stage I lung cancer in the elderly

BACKGROUND & OBJECTIVES

Pathologic evaluation of > 10 lymph nodes (LNs) is considered necessary for accurate lung cancer staging. However, physicians have concerns about increased risk in perioperative mortality (POM) and morbidity with more extensive LN sampling, particularly in the elderly. In this study, we compared the outcomes in elderly patients with stage I non-small cell lung cancer (NSCLC) undergoing extensive (> 10 nodes) and limited (≤ 10 nodes) LN resections.

METHODS

Using data from the Surveillance, Epidemiology and End Results registry linked to Medicare records, we identified 4975 patients ≥ 65 years of age with stage I NSCLC who underwent a lobectomy between 1992 and 2002. Risk of perioperative morbidity and POM after the evaluation of ≤ 10 vs. >10 LNs was compared among patients after adjusting for propensity scores.

RESULTS

Multiple regression analysis showed similar POM between the two groups (OR, 1,01; 95% CI, 0,71-1,44). Other postoperative complications were similar across groups except for thromboembolic events, which were more common among patients undergoing resection of > 10 LNs (OR, 1,72; 95% CI, 1,12-2,63).

CONCLUSIONS

These data suggest that evaluation of > 10 LNs, which allows for more accurate staging, appears to be safe in the elderly patients undergoing lobectomy for stage I NSCLC without compromising postoperative recovery.

Does anatomical segmentectomy allow an adequate lymph node staging for cT1a non-small cell lung cancer?

INTRODUCTION

Anatomical segmentectomy is again under evaluation for the cure of T1a N0 non-small cell lung cancer and carcinoid tumors. Whether anatomical segmentectomy does permit or not, an adequate resection of nodal stations for staging or cure is still pending.

METHODS

A case-matched study was ruled on patients with peripheral cT1a N0 M0 tumors that underwent anatomical segmentectomy or lobectomy. Dissection of lymph node stations 4, 5, 6, and 7 was identical in anatomical segmentectomy and lobectomy; stations 10, 11, 12, and 13 were also dissected carefully during anatomical segmentectomy.

RESULTS

We individually matched 46 (69% men) anatomical segmentectomy with 46 (71% men) lobectomy for age, anatomical segment, and size of the tumor. The median (interquartile range) size of the resected lesions was 1.7 cm (1.35-1.95 cm) in anatomical segmentectomy and 1.6 cm (1.3-1.9 cm) (p = 0.96) in lobectomy. The anatomical segmentectomy and lobectomy resection margins were free of cancer. The median number (interquartile range) of total dissected lymph nodes was 12 (8-5-14) in anatomical segmentectomy compared with 13 (12-14.5) in lobectomy (p = 0.68), with a number of N1 nodes being 6 (4-7.5) and 7 (4.5-9.5) (p = 0.43), respectively, and N2 nodes 5.5 (4-7.7) and 5 (4-6.5) (p = 0.88). Only 1 patient of 46 (2%) anatomical segmentectomy was N1, whereas in lobectomy, 4% had N1 (2 patients). Freedom from recurrence at 36 months was 100% for anatomical segmentectomy and 93.5% for lobectomy (p = 0.33).

CONCLUSIONS

Anatomical segmentectomy for cT1a tumors compared with lobectomy procures an adequate number of N1 and N2 nodes for pathological examination. Cancer-specific survival was equivalent at 36 months.

Do all roads lead to Rome? Routes to metastasis development

Metastasis, the life-threatening aspect of cancer, is a systemic disease process. Considerable progress has been made in recent years regarding how tumor cells circulating in the blood and lymphatic systems interact with and extravasate into secondary sites, and what determines whether these disseminated tumors cells survive, remain dormant or go on to form macrometastases. New insights into the routes that tumor cells take once leaving the primary tumor have emerged. Novel concepts regarding early seeding of metastases coupled to parallel progression, self-seeding of primary tumors by circulating tumor cells and the induction of premetastatic niches in distant organs by primary tumors have come to the fore. The perceived role of the lymphatic system in determining patterns of metastasis formation in distant organs has been reassessed. Together these new insights have the potential to offer new therapeutic options. In particular, the regulation of tumor cell dormancy emerges as a key event in metastasis formation, and therapeutic control of dormancy holds the promise of rendering cancer a chronic rather than life-threatening disease.

Locoregional control of thoracoscopic lobectomy with selective lymphadenectomy for lung cancer

BACKGROUND

In this retrospective study, we review our experience with video-assisted thoracic surgery (VATS) lobectomy with selective lymphadenectomy for clinical stage I lung cancer and report the long-term results.

METHODS

From April 1999 to December 2006, 355 patients with clinical stage I lung cancer underwent a VATS lobectomy. The perioperative data, morbidity, mortality, and long-term survival of each patient were reviewed.

RESULTS

A thoracoscopic lobectomy was performed successfully in 348 patients (T1 N0, 237 patients; T2 N0, 111 patients), and a selective lymphadenectomy was performed in 268. Seven procedures (2.0%) were uneventfully converted to a thoracotomy and were excluded. The median operation time was 192 minutes, and the median blood loss was 100 mL. The median postoperative stay was 6 days. There were no intraoperative deaths; 2 patients died within 30 days of operation (mortality; 0.6%); 1 died of bacterial pneumonia and the other of postoperative interstitial pneumonia exacerbation. Postoperative complications occurred in 54 patients (16% morbidity). Major complications included prolonged air leak (3.7%), bacterial pneumonia (3.4%), and mild arrhythmia (3.4%). Pathologic upstaging was noted in 67 patients (19%). At a median follow-up of 43 months, total recurrence occurred in 66 cases (26 locoregional and 40 distant). The locoregional recurrence rate was 0.021 per person per year. The overall and 5-year locoregional recurrence-free survival rates were 78.5% and 76.6%, respectively.

CONCLUSIONS

Our findings suggest that performing VATS lobectomy with selective lymphadenectomy for clinical stage I lung cancer is safe and results in acceptable locoregional control.

Subcarinal lymph node in upper lobe non-small cell lung cancer patients: is selective lymph node dissection valid?

Little is known about selective lymph node dissection in non-small cell lung cancer (NSCLC) patients. We sought to gain insight into subcarinal node involvement for its frequency and impact on outcome to evaluate whether it is valid to omit subcarinal lymph node dissection in upper lobe NSCLC patients. We reviewed node metastases distribution according to node region, tumor location, and histology among 1099 patients with upper lobe NSCLC. We paid special attention to subcarinal metastases patients without superior mediastinal node metastases, because their pathological stages would have been underdiagnosed if subcarinal node dissection had been omitted. We also assessed the outcome and the pattern of failure among subcarinal metastases patients. To identify subcarinal node involvement predictors, we analyzed 7 clinical factors. Subcarinal node metastases were found in 20 patients and were least frequent among squamous cell carcinoma patients (0.5%). Two of them were free from superior mediastinal metastases but died of the disease at 1 month and due to an unknown cause at 18 months, respectively. Seventeen of the 20 patients developed multi-site recurrence within 37 months. The 5-year survival rate of the 20 patients with subcarinal metastases was 9.0%, which was significantly lower than 32.0% of patients with only superior mediastinal metastases. Clinical diagnosis of node metastases was significantly predictive of subcarinal metastases. Subcarinal node metastases from upper lobe NSCLC were rare and predicted an extremely poor outcome. It appears valid to omit subcarinal node dissection in upper lobe NSCLC patients, especially in clinical N0 squamous cell carcinoma patients.

Effect of selective lymph node dissection based on patterns of lobe-specific lymph node metastases on patient outcome in patients with resectable non-small cell lung cancer: a large-scale retrospective cohort study applying a propensity score

OBJECTIVE

Lobectomy with systematic complete mediastinal lymph node dissection is standard surgical treatment for localized non-small cell lung cancer. However, selective mediastinal lymph node dissection based on lobe-specific metastases (selective dissection) has often been performed. This study was designed to evaluate the validity of the selective lymph node dissection.

METHODS

From 1995 through 2003, 625 patients in our hospital had surgery for complete mediastinal lymph node dissection and 147 for selective dissection. We evaluated whether selective dissection adversely affected overall survival. To minimize possible biases due to confounding by treatment indication, we performed a retrospective cohort analysis by applying a propensity score. The propensity score was calculated by logistic regression based on 15 factors available that were potentially associated with treatment indication. Patients were divided into 4 groups according to quartile, and comparison between selective dissection and complete mediastinal lymph node dissection was made using propensity score quartile-stratified Cox proportional hazard models.

RESULTS

Comparison of baseline characteristics between patients having selective dissection and patients having complete mediastinal lymph node dissection according to propensity score quartile supported comparability of the 2 groups. The 5-year overall survival rates were 76.0% for selective dissection versus 71.9% for complete mediastinal lymph node dissection. The 5-year survival probabilities stratified by propensity score quartile consistently showed no marked difference. In multivariate models, there was no significant difference between the 2 groups (hazard ratio = 1.17, P = .500) as also seen in the analysis without propensity score (hazard ratio = 1.06; 95% confidence interval, 0.68-1.64; P = .810). Therefore, selective dissection showed no significant impact on poor survival compared with complete mediastinal lymph node dissection.

CONCLUSIONS

Selective lymph node dissection did not worsen the survival of patients with non-small cell lung cancer.

The IASLC lung cancer staging project: a proposal for a new international lymph node map in the forthcoming seventh edition of the TNM classification for lung cancer

The accurate assessment of lymph node involvement is an important part of the management of lung cancer. Lymph node "maps" have been used to describe the location of nodal metastases. However, discrepancies in nomenclature among maps used by Asian and Western countries hinder analyses of lung cancer treatment outcome. To achieve uniformity and to promote future analyses of a planned prospective international database, the International Association for the Study of Lung Cancer proposes a new lymph node map which reconciles differences among currently used maps, and provides precise anatomic definitions for all lymph node stations. A method of grouping lymph node stations together into "zones" is also proposed for the purposes of future survival analyses.