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.

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.

A Comparison of Total Thoracoscopic and Robotic Surgery for Lung Cancer Lymphadenectomy

BACKGROUND

Robotic-assisted thoracic surgery (RATS) is used increasingly frequently in major lung resection for early stage non-small-cell lung cancer (NSCLC) but has not yet been fully evaluated. The aim of this study was to compare the surgical outcomes of lymph node dissection (LND) performed via RATS with those from totally thoracoscopic (TT) four-port videothoracoscopy.

METHODS

Clinical and pathological data were collected retrospectively from patients with clinical stage N0 NSCLC who underwent pulmonary resection in the form of lobectomy or segmental resection between June 2010 and November 2022. The assessment criteria were number of mediastinal lymph nodes and number of mediastinal stations dissected via the RATS approach compared with the four-port TT approach.

RESULTS

A total of 246 pulmonary resections with LND for clinical stages I-II NSCLC were performed: 85 via TT and 161 via RATS. The clinical characteristics of the patients were similar in both groups. The number of mediastinal nodes dissected and mediastinal stations dissected was significantly higher in the RATS group (TT: mean ± SD, 10.72 ± 3.7; RATS, 14.74 ± 6.3 [p < 0.001]), except in the inferior mediastinal stations. There was no difference in terms of postoperative complications.

CONCLUSIONS

In patients with early stage NSCLC undergoing major lung resection, the quality of hilomediastinal LND performed using RATS was superior to that performed using TT.

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.

The comparison of Lobe-Specific or Systematic Mediastinal Lymph Node Dissection for Early-Stage Lung Adenocarcinoma With Consolidation Tumor Ratio Over 0.5

INTRODUCTION

Surgery is the most effective treatment for early-stage lung cancer. This study will propose a personalized plan for mediastinal lymph node dissection in early-stage lung adenocarcinoma to reduce the risk of surgery and improve the quality of life.

METHODS

This study retrospectively analyzed the patients underwent lobectomy and lymph node dissection in the Department of Thoracic Surgery, Zhongshan Hospital, Fudan University. Clinical stage I lung adenocarcinoma patients with solid component ratio (CTR) between 0.5 and 1 were included. Patients were divided into systematic (S-MLND) and lobe-specific (L-MLND) mediastinal lymph node dissection groups. The days of hospitalization, the presence or absence of complications, the recurrence-free survival rate, and the overall survival rate were calculated to evaluate the postoperative quality and operation risk of the patients.

RESULTS

210 patients (138 L-MLND and 72 S-MLND) were included. 2 lymph node metastases appeared in the S-MLND group while none in the L-MLND group (P = .049). No differences were shown in age, tumor site, size, solid component, degree of tumor invasion, and stage. The proportion of patients with severe postoperative cough and the length of hospital stay in the L-MLND group decreased. The 5-year OS of the entire cohort was 98.1%, 98.6% in L-MLND, compared with 97.2% in S-MLND; RFS was 94.8%, 95.7% in L-MLND, compared with 93.0% in S-MLND.

CONCLUSION

For cIA lung adenocarcinoma, according to the Thin-slice CT within 1 month before the operation, if the main lesion was less than 3 cm and CTR over 0.5, L-MLND is as effective as S-MLND.

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

Objective

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

Methods

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

Results

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

Conclusions

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

Prediction of lymph node metastasis of clinical stage IA non-small cell lung cancer based on the tumor volume doubling time

PURPOSE

To investigate whether the volume doubling time is a preoperative predictor of lymph node metastasis of clinical stage IA non-small cell lung cancer (NSCLC).

METHODS

The subjects of this retrospective study were 204 patients who underwent lobectomy and mediastinal lymph node dissection for clinical stage IA NSCLC. We analyzed the relationship between lymph node metastasis and clinicopathological factors, including the volume doubling time.

RESULTS

Lymph node metastasis developed in 24 (11.8%) patients. Multivariable analysis identified consolidation diameter (Odds ratio = 1.407; 95% confidence interval, 1.007-1.966, p = 0.046) and the solid-part tumor volume doubling time (Odds ratio = 0.982; 95% confidence interval, 0.973-0.991, p < 0.001) as independent predictors of lymph node metastasis. The combination of a larger consolidation diameter (> 1.9 cm) and a shorter solid-part tumor volume doubling time (< 132 days) had sensitivity, specificity, and accuracy of 79.2%, 94.4%, and 92.6%, respectively.

CONCLUSIONS

The consolidation diameter and solid-part tumor volume doubling time can be useful preoperative predictors of lymph node metastasis of clinical stage IA NSCLC.

Selective Mediastinal Lymphadenectomy or Complete Mediastinal Lymphadenectomy for Clinical Stage I Non-Small Cell Lung Cancer: A Meta-Analysis

INTRODUCTION

Selective mediastinal lymphadenectomy (SML) and complete mediastinal lymphadenectomy (CML) are two main types of surgery conducted for the treatment of non-small cell lung cancer (NSCLC) plus lobectomy or segmentectomy. It is not known whether stage I NSCLC can benefit from CML. Using the meta-analytical method, our research aimed to find out the worth of SML and CML for the therapy of clinical stage I NSCLC.

METHODS

We searched PubMed, Ovid, MEDLINE, Cochrane Controlled Trial Register (CENTRAL), Embase, and Google Scholar for literature published up to June 2021 to evaluate the comparative research and to assess the post-operative complications, overall survival rate, disease-free survival rate, and local and distant recurrence. This meta-analysis was conducted by combining the results of the reported incidences of post-operative complications, local and distant recurrence, and short- and long-term mortality. The pooled odds ratios (OR) and the 95% confidence intervals were calculated by random or fixed effects models to compare the effectiveness between these two methods.

RESULTS

Five retrospective studies and one randomized controlled trial study were included in our research. The six studies included a total of 5713 patients, of whom 1480 were assigned to the SML group and 4233 were assigned to the CML group. No statistically significant differences were found in the 1- and 5-year overall survival rates or the 1-, 3-, and 5-year disease-free survival rates between the two groups. However, the 3-year overall survival favored the SML group (P < 0.05). There were also no statistically significant differences between the local and distant metastasis. Among the postoperative complications, pneumonia, atelectasis, and prolonged air leak were more common in the CML group (P < 0.05). There were no differences in the prevalence of dysrhythmia, chylothorax, acute respiratory distress syndrome, or recurrent laryngeal nerve injury between the two groups, which may be due to the limited sample size.

CONCLUSION

Considering the comparable survival rates, disease control, and fewer postoperative complications in the evaluated participants, SML is the preferred treatment with less invasiveness for clinical stage I NSCLC.

Comparison between robot-assisted thoracoscopic surgery and video-assisted thoracoscopic surgery for mediastinal and hilar lymph node dissection in lung cancer surgery

OBJECTIVES

Lymph node dissection (LND) with robot-assisted thoracoscopic surgery (RATS) in lung cancer surgery has not been fully evaluated. The aim of this study was to compare LND surgical results between video-assisted thoracoscopic surgery (VATS) and RATS.

METHODS

We retrospectively compared perioperative parameters, including the incidence of LND-associated complications (chylothorax, recurrent and/or phrenic nerve paralysis and bronchopleural fistula), lymph node (LN) counts and postoperative locoregional recurrence, among 390 patients with primary lung cancer who underwent lobectomy and mediastinal LND by RATS (n = 104) or VATS (n = 286) at our institution.

RESULTS

The median total dissected LN numbers significantly differed between the RATS and the VATS groups (RATS: 18, VATS: 15; P < 0.001). They also significantly differed in right upper zone and hilar (#2R + #4R + #10L) (RATS: 12, VATS: 10; P = 0.002), left lower paratracheal and hilar (#4L + #10L) (RATS: 4, VATS: 3; P = 0.019), aortopulmonary zone (#5 + #6) (RATS: 3, VATS: 2; P = 0.001) and interlobar and lobar (#11 + #12) LNs (RATS: 7, VATS: 6; P = 0.041). The groups did not significantly differ in overall nodal upstaging (P = 0.64), total blood loss (P = 0.69) or incidence of LND-associated complications (P = 0.77).

CONCLUSIONS

In this comparison, it was suggested that more LNs could be dissected using RATS than VATS, especially in bilateral superior mediastinum and hilar regions. Accumulation of more cases and longer observation periods are needed to verify whether RATS can provide the acceptable quality of LND and local control of lung cancer.

The Role of Surgery in Lung Cancer Treatment: Present Indications and Future Perspectives-State of the Art

Non-small cell lung cancers (NSCLC) are different today, due to the increased use of screening programs and of innovative systemic therapies, leading to the diagnosis of earlier and pre-invasive tumors, and of more advanced and controlled metastatic tumors. Surgery for NSCLC remains the cornerstone treatment when it can be performed. The role of surgery and surgeons has also evolved because surgeons not only perform the initial curative lung cancer resection but they also accompany and follow-up patients from pre-operative rehabilitation, to treatment for recurrences. Surgery is personalized, according to cancer characteristics, including cancer extensions, from pre-invasive and local tumors to locally advanced, metastatic disease, or residual disease after medical treatment, anticipating recurrences, and patients' characteristics. Surgical management is constantly evolving to offer the best oncologic resection adapted to each NSCLC stage. Today, NSCLC can be considered as a chronic disease and surgery is a valuable tool for the diagnosis and treatment of recurrences, and in palliative conditions to relieve dyspnea and improve patients' comfort.

Surgical resection of primary tumors improved the prognosis of patients with bone metastasis of non-small cell lung cancer: a population-based and propensity score-matched study

Background

Most patients with lung cancer are in an advanced stage at the time of diagnosis due to occult onset. Bone is one of the most common sites of hematogenous metastasis of lung cancer. This study aimed to evaluate the impact of surgical resection of primary tumors on the prognosis of patients with bone metastasis of non-small cell lung cancer, using the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

A total of 9,804 patients with only bone metastasis were identified from the SEER database. Propensity score matching was used to reduce the selection bias. Cancer-specific survival (CSS) and overall survival (OS) were compared between patients with or without primary tumor resection. The Cox regression model was applied to evaluate multiple prognostic factors.

Results

After propensity score matching, 424 patients were selected for survival analysis. No statistically significant differences were found in age, sex, race, tumor location, histology, T stage, and N stage between patients with or without surgical resection of primary tumors. The prognosis of patients who underwent surgical resection of primary tumors was significantly better than that of patients who had not undergone surgery. The surgical resection of primary tumors was an independent prognostic factor. The prognosis of patients who underwent lobectomy/bilobectomy was significantly better compared to other surgical types. Regional lymph node resection during surgery also significantly improved the prognosis of the patients.

Conclusions

For patients with only bone metastasis, surgical resection of primary tumors could significantly improve prognosis. Lobectomy/bilobectomy with regional lymph node resection was the best surgical strategy.

Lobe-Specific Node Dissection Can Be a Suitable Alternative to Systematic Lymph Node Dissection in Highly Selective Early-Stage Non-Small-Cell Lung Cancer Patients: A Meta-Analysis

Purpose: Whether the lobe-specific lymph node dissection is an alternative to systematic lymph node dissection for early-stage non-small-cell lung cancer remains controversial. An elaborate meta-analysis was conducted to evaluate the effects of lobe-specific lymph node dissection in early-stage patients.

Methods: A systematic literature search was conducted up to February 19, 2020 in PubMed, Ovid, Web of Science, and China National Knowledge Infrastructure databases. The outcomes including overall survival (OS), complications, and recurrence rate were extracted and analyzed.

Results: Nine studies including one randomized controlled trial (RCT) and eight retrospective cohort studies with 8499 non-small-cell lung cancer patients were included. The results indicated that lobe-specific lymph node had a lower rate of postoperative complication (relative risk [RR]: 0.83, 95% confidence interval [CI]: 0.72–0.95, P = 0.006). No significant difference was observed between lobe-specific lymph node and systematic lymph node dissection in OS (hazard rate = 1.12, 95% CI: 0.81–1.54, P = 0.501) with high heterogeneity (I² = 71.9%).

Conclusion: Lobe-specific lymph node can reach a comparable long-term prognosis in some highly selected patients. However, these results should be viewed cautiously with the existence of high heterogeneity. Due to the high heterogeneity, a strict patient selection process by experienced thoracic surgeons was recommended before validating lobe-specific lymph node.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

WHAT THIS STUDY ADDS

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

Lymph node assessment in early stage non-small cell lung cancer lymph node dissection or sampling?

Lymph node assessment is an essential component of the treatment of lung cancer. Identification of the correct "N" stage is important for staging which in turn determines treatment. Assessment of lymph nodes may be accomplished using imaging with CT scan and PET-CT, invasive techniques such as mediastinoscopy, endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) or endoscopic ultrasound fine needle aspiration (EUS-FNA). Ultimately, regardless of any pre-resection assessment, lymph nodes must be assessed at the time of resection. The question to be addressed in this report is the role of mediastinal lymph node dissection versus lymph node sampling. However, the issues surrounding lymph node assessment in NSCLC are complex, depending on clinical stage, imaging and histology.

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

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

Prognostic relevance of regional lymph-node distribution in patients with N1-positive non-small cell lung cancer: A retrospective single-center analysis

OBJECTIVE

Lymph node (LN) metastases predict survival in patients with non-small cell lung cancer (NSCLC) treated with curative surgery. Nevertheless, prognostic differences within the same nodal (N) status have been reported. Consequently, the International Association for the Study of Lung Cancer (IASLC) proposed to stratify patients with limited nodal disease (pN1) from low (pN1a) to high (pN1b) nodal tumor burden. This study aimed to validate the IASLC proposal in a large single-center surgical cohort of patients with pN1 NSCLC.

MATERIAL AND METHODS

Data from 317 patients with pN1 NSCLC treated between January 2012 and December 2016, were retrospectively analyzed. Associations between distribution of LN metastases and survival were analyzed for different classification models-toward nodal extension (pN1a: one station involved; pN1b: multiple stations involved) and toward location (pN1 in the hilar [LN#10/11] or peripheral zone [LN#12-14]).

RESULTS

Tumor-specific survival (TSS) in the entire pN1 cohort was 67.1% at five years. Five-year TSS rates for pN1a and pN1b patients were comparable (67.6% vs. 66.5%, p = 0.623). Significant survival differences from pN1a to pN1b were observed only in patients with adenocarcinoma histology and completed adjuvant chemotherapy (5-year TSS: pN1a, 80.4% vs. pN1b, 49.6%; p = 0.005). TSS for LN metastases in the hilar zone/peripheral zone or in both zones was 68.2% and 59.9%, respectively (p = 0.068). In multivariate analysis, adjuvant chemotherapy, squamous cell histology, and nodal disease limited to one zone nodal disease were identified as independent beneficial prognostic factors (p < 0.05).

CONCLUSION

pN1 in only one region (hilar or lobar) was associated with better outcome than metastatic affection of both regions after surgery and adjuvant therapy. A stratification towards single (pN1a) and multiple (pN1b) N1-metastases was found of prognostic relevance only in adenocarcinoma. Prospective multicenter analysis of prognostic subgroups in N1 NSCLC is required to evaluate its clinical impact for consideration in future TNM classification.

Impact of Different Types of Lymphadenectomy Combined With Different Extents of Tumor Resection on Survival Outcomes of Stage I Non-small-cell Lung Cancer: A Large-Cohort Real-World Study

Background: To investigate the prognostic impact of different types of lymphadenectomy with different extents of tumor resection on the outcomes of stage I non-small-cell lung cancer (NSCLC).

Methods: Patients were classified into lobectomy and sublobectomy groups, and then each group was subdivided according to the types of lymphadenectomy. The end points of the study were overall survival (OS) and disease-free survival (DFS). Propensity score matched (PSM) comparative analysis and univariate and multivariate Cox regression analyses were performed.

Result: A total of 1,336 patients were included in the current study. Lobectomy was associated with better OS and DFS. In the lobectomy group, lobectomy with bilateral mediastinal lymphadenectomy (BML) was associated with better OS than lobectomy with systematic nodal dissection (SND) or lobe-specific systematic node dissection (L-SND). Lobectomy with SND or L-SND was associated with better OS than lobectomy with systematic nodal sampling (SNS) or selected lymph node biopsy (SLNB). Additionally, lobectomy with BML or SND was associated with better DFS than lobectomy with L-SND or SNS or SLNB. After PSM, compared with lobectomy with SNS or SLNB, lobectomy with SND resulted in more favorable OS and DFS. There was no survival difference between different types of lymphadenectomy for patients who underwent sublobectomy. A multivariable analysis revealed independent associations of lobectomy with BML or SND with better OS and DFS compared with those of lobectomy with SNS or SLNB.

Conclusion: This study reveals an association of lobectomy with more systematic and complete lymph node dissection, such as BML or SND, with better prognosis in stage I NSCLC patients.

[Research Progress of Lymph Node Micrometastasis in Non-small Cell Lung Cancer]

The incidence and mortality of lung cancer rank top in China. One important factor is the occurrence of metastasis. With the development of science technology, the effect of surgical treatment on lung cancer is improved. Moreover, the use of targeted therapy has achieved a new height for the treatment of lung cancer. However, the recurrence rate remains high even the tumor was completely resected at early stage. The occurrence of lymph node micrometastasis is considered as one of the plausible explanations. The difficulty indetecting micrometastasis has been greatly reduced. Although studies dig deeper into the lymph node micrometastasis, there are still some controversies including the selection of surgical procedures, the pathological staging and prognosis about patients with lymph node micrometastasis. This review manages to generalize the latest research progress of lymph node micrometastasis.
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Selective versus systematic lymph node dissection (other than sampling) for clinical N2-negative non-small cell lung cancer: a meta-analysis of observational studies

Background

The proper extent of lymph node dissection is still controversial. Hence, we compared the clinical efficacy between two strategies of lymph node dissection [selective lymph node dissection (SLND) and systematic lymph node dissection (LND)] for clinical N2-negative non-small cell lung cancer (NSCLC) patients.

Methods

After searching five databases, six cohort studies were eligible for this meta-analysis and the primary endpoint was overall survival (OS). In order to provide a comprehensive perspective, we estimated some perioperative outcomes as well. Either fixed effect or random effects model were properly selected to evaluate the data according to the heterogeneity of included studies.

Results

A total of 7,333 patients with clinical N2-negative NSCLC patients were analyzed for OS. The pooled results demonstrated that LND did not improve survival in OS [hazard ratio (HR) =1.05, 95% confidence interval (CI): 0.82-1.34, P=0.69] compared with SLND. In accordance with OS, there is no significant difference in DFS between LND and SLND (HR =0.98, 95% CI: 0.78-1.23, P=0.87). Moreover, SLND could significantly reduce the operative time [mean difference (MD) =-21.45, 95% CI: -29.53 to -13.36, P<0.001] and blood loss (MD =-28.88, 95% CI: -44.38 to -13.39, P<0.001). Both postoperative morbidity and recurrence showed no significant between two groups.

Conclusions

SLND is an alternative to LND for clinical N2-negative NSCLC patients, which may even provide clinical benefits. However, more randomized controlled trials (RCTs) are expected to determine whether SLND is valid and practical to become a standard procedure of surgical treatment for early-stage NSCLC patients.

Can lobe-specific lymph node dissection be an alternative to systematic lymph node dissection in treating early-stage non-small cell lung cancer: a comprehensive systematic review and meta-analysis?

Background

Whether lobe-specific lymph node dissection (L-SLND) could serve as an alternative to systematic lymph node dissection (SLND) in treating early-stage non-small cell lung cancer (NSCLC) remains unclear. Therefore, we conducted this comprehensive meta-analysis to compare the effect of L-SLND with that of SLND in treating early-stage NSCLC.

Methods

A systematic literature search in PubMed and Embase was conducted to identify relevant studies up to 30 November 2017. Data including 5-year overall survival (OS) and disease-free survival (DFS) rates, recurrence rates, and morbidity rate were extracted and analysed.

Results

A total of six studies [one randomized controlled trial (RCT) and five retrospective cohort studies] consisting of 2,037 patients with early-stage NSCLC were included for analysis. Meta-analysis showed that there was no significant difference of 5-year OS [81.7% and 79.5%, respectively; risk ratio (RR) =1.021; 95% confidence interval (CI), 0.977-1.068; P=0.352] and DFS (76.4% and 69.9%, respectively; RR =1.061; 95% CI, 0.999-1.128; P=0.054) between patients treated with L-SLND and those with SLND. Moreover, there was also no significant difference of total recurrence rates (24.3% and 25.8%, respectively; RR =0.892; 95% CI, 0.759-1.048; P=0.166) and loco-regional recurrence rates (7.9% and 9.3%, respectively; RR =0.851; 95% CI, 0.623-1.162; P=0.310) between patients treated with L-SLND and those with SLND. However, patients treated with L-SLND yielded a significant lower morbidity rate than those treated with SLND (10.2% and 13.5%, respectively; RR =0.681; 95% CI, =0.521-0.888; P=0.005).

Conclusions

L-SLND yielded a significantly lower risk of morbidity compared to SLND without compromising long-term oncologic outcomes based on available studies with relatively poor quality. L-SLND may serve as an alternative to SLND in treating early-stage NSCLC. Further well-conducted RCTs, however, are badly needed to confirm and update our conclusions.

[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.

Impact of lymph node management on resectable non-small cell lung cancer patients

BACKGROUND

A surgical lung resection with systematic mediastinal lymph node (LN) dissection is recommended by the National Comprehensive Cancer Network guideline. However, the effective number of dissected LNs, stations and positivity is still controversial. The aim of this study is to identify the impact of total numbers, LN stations and positivity of dissected LNs on tumor recurrence and overall death in resectable non-small cell lung cancer (NSCLC).

METHODS

This prognostic study used a retrospective data collection design. Adult patients with clinical resectable NSCLC who underwent pulmonary resection and mediastinal lymphadenectomy at Chiang Mai University between June 2000 and June 2012 were enrolled in this study. A multilevel mixed-effects parametric survival model was used to identify the effect of numbers, LN stations and positivity of dissected LNs to tumor recurrence and mortality.

RESULTS

The average number of dissected LNs was 22.7±12.8. Tumor recurrence was found in 51.3% and overall mortality was 43.3%. The number of dissected LNs was a prognostic factor for tumor recurrence [HR 0.98, 95% confidence interval (CI): 0.96-0.99]. There was a significant difference at the cut-pointed value of 11 dissected LNs for tumor recurrence (HR 2.22, 95% CI: 1.26-3.92). Dissection less than 11 nodes and less than 5 stations indicated a poor prognostic factor for tumor recurrence: for 3-4 stations (HR 3.01, 95% CI: 1.22-7.42) and for 1-2 stations (HR 1.96, 95% CI: 1.04-3.72). The positivity of dissected LNs was also a prognostic factor for tumor recurrence and overall mortality (HR 1.01, 95% CI: 1.01-1.02 and HR 1.01, 95% CI: 1.01-1.03, respectively).

CONCLUSIONS

Eleven or more LN dissection with at least 5 stations influenced recurrent-free survival. Systematic LN dissection (SLND) should be performed not only to identify the positivity of dissected LNs but also to determine an accurate tumor nodal stage. A larger cohort should be further conducted to support these findings.

Radiation Therapy is Independently Associated with Worse Survival After R0-Resection for Stage I-II Non-small Cell Lung Cancer: An Analysis of the National Cancer Data Base

BACKGROUND

The 1998 post-operative radiotherapy meta-analysis for lung cancer showed a survival detriment associated with radiation for stage I-II resected non-small cell lung cancer (NSCLC), but has been criticized for including antiquated radiation techniques. We analyzed the National Cancer Database (NCDB) to determine the impact of radiation after margin-negative (R0) resection for stage I-II NSCLC on survival.

METHODS

Adult patients from 2004 to 2014 were analyzed from the NCDB with respect to receiving radiation as part of their first course of treatment for resected stage I-II NSCLC; the primary outcome measure was overall survival.

RESULTS

A total of 197,969 patients underwent R0 resection for stage I-II NSCLC, and 4613 received radiation. Median radiation dose was 55 Gy with a 50-60 Gy interquartile range. On adjusted analysis, treatment at a community cancer program, sublobectomy, tumor size (3-7 cm), and pN1/Nx were associated with receiving radiation (odds ratio > 1, p < 0.05). The irradiated group had shorter median survival (45.8 vs. 77.5 months, p < 0.001), and radiation was independently associated with worse overall survival (hazard ratio (HR) 1.339, 95% confidence interval (CI) 1.282-1.399). After propensity score matching, radiation remained associated with worse overall survival (HR 1.313, 95% CI 1.237-1.394, p < 0.001).

CONCLUSIONS

Radiotherapy was independently associated with worse survival after R0 resection of stage I-II NSCLC in the NCDB and was more likely to be delivered in community cancer programs.