The prognostic value of 4L lymph node dissection in left-side operable non-small-cell lung cancer: a meta-analysis

The prognostic value of 4L lymph node dissection (4L-LND) continues to be controversial. We conducted this systematic review and meta-analysis to evaluate the prognosis of 4L-LND in operable non-small-cell lung cancer (NSCLC) patients. We systematically searched studies from PubMed, Embase, and the Cochrane Library up to May 1, 2023. Studies investigating the prognostic value of 4L-LND and non-4L-LND in NSCLC survival were included. Data for analysis mainly comprised postoperative complications, overall survival (OS), and disease-free survival (DFS). The Q-test and I2-test were used to assess heterogeneity. The stability of pooled hazard ratios (HRs) was examined by sensitivity analysis. Six retrospective studies with a total of 4565 NSCLC patients who received 4L-LND or did not receive 4L-LND were considered. The 4L-LND group had significantly better OS (HR = 0.75, 95% CI 0.61-0.91, P = 0.004) and DFS (HR = 0.76, 95% CI 0.66-0.88, P = 0.0002) than the non-4L-LND group, especially in the subgroup analysis of propensity score matching studies. Although no significant difference in the rate of chest tube drainage for more than 7 days (risk ratio (RR) = 0.98, 95% CI 0.31-3.08, P = 0.97), hoarseness rate (RR = 1.60, 95% CI 0.53-4.87, P = 0.51), and chylothorax rate (RR = 1.28, 95% CI 0.58-2.84, P = 0.54) was observed, those who received 4L-LND had a higher total postoperative complication rate than those who did not (RR = 1.35, 95% CI 1.09-1.67, P = 0.006). No significant heterogeneity existed during our analysis, and no potential publication bias was observed among these studies. Our meta-analysis showed that the 4L-LND group was significantly associated with both survival outcomes and postoperative complications compared with the non-4L-LND group in treating NSCLC patients. However, further prospective clinical trials should be designed to evaluate our conclusion owing to the lack of guideline support.

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

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

Complete dissection of right paratracheal lymph nodes (stations 2R and 4R) is critical to improve the prognosis of lung cancer patients: A retrospective cohort study

BACKGROUND

The optimal extent of mediastinal lymph node dissection is still under debate. This study aimed to investigate the prognostic impact of complete dissection of right paratracheal lymph nodes (LNs) in right-sided non-small cell lung cancer (NSCLC) and evaluate the potential patient population who will particularly benefit from right paratracheal node dissection (RPND).

METHODS

Between January 2009 and December 2019, we retrospectively reviewed 2650 patients with primary right-sided NSCLC who underwent pulmonary surgery with lymphadenectomy in the Western China Lung Cancer Database. A total of 2447 patients received both 2R and 4R LNs dissection (complete RPND group), 162 patients received only 2R or 4R LNs dissection (incomplete RPND group), and 41 patients received neither 2R nor 4R LNs dissection (no RPND group). Overall survival (OS) was analyzed.

RESULTS

The metastasis rates in stations 2R and 4R were 6.5% and 8.0%, respectively. In stage N2 patients, the frequency of involvement of stations 2R/4R was 74.8%. The complete RPND group had a significantly better survival than the incomplete and no RPND group (5-year OS, 79.5% vs. 72.7% vs. 65.5%; p < 0.001). In the multivariate analysis, status of RPND (incomplete RPND vs. complete RPND: HR 1.45, 95% CI: 1.10-1.90; p = 0.009; no RPND vs. complete RPND: HR 2.25, 95% CI: 1.37 to 3.69; p = 0.001), age, gender, tumor size, histological type, pTNM stage, pT stage, pN stage, and adjuvant treatment were independent factors for OS.

CONCLUSIONS

Complete RPND brings survival benefits to patients with right-sided NSCLC. We suggest complete RPND as a standard procedure for patients with right-sided NSCLC.

Clinicopathological and survival outcomes of 4L lymph node dissection in left lung adenocarcinoma and squamous cell carcinoma

Background

Whether 4L lymph node dissection (LND) should be performed remains unclear and controversial. Prior studies have found that station 4L metastasis was not rare and that 4L LND may provide survival benefits. The objective of this study was to analyze the clinicopathological and survival outcomes of 4L LND from the perspective of histology.

Methods

This retrospective study included 74 patients with squamous cell carcinoma (SCC) and 84 patients diagnosed with lung adenocarcinoma (ADC) between January 2008 and October 2020. All patients underwent pulmonary resection with station 4L LND and were staged as T1-4N0-2M0. Clinicopathological features and survival outcomes were investigated based on histology. The study endpoints were disease-free survival (DFS) and overall survival (OS).

Results

The incidence rate of station 4L metastasis was 17.1% (27/158) in the entire cohort, with 8.1% in the SCC group, and 25.0% in the ADC group. No statistical differences in the 5-year DFS rates (67.1% vs. 61.7%, P=0.812) and 5-year OS rates (68.6% vs. 59.3%, P=0.100) were observed between the ADC group and the SCC group. Multivariate logistic analysis revealed that histology (SCC vs. ADC: OR, 0.185; 95% CI, 0.049-0.706; P=0.013) was independently associated with 4L metastasis. Multivariate survival analysis showed that the status of 4L metastasis was an independent factor for DFS (HR, 2.563; 95% CI, 1.282-5.123; P=0.008) but not for OS (HR, 1.597; 95% CI, 0.749-3.402; P=0.225).

Conclusion

Station 4L metastasis is not rare in left lung cancer. Patients with ADC have a greater predilection for station 4L metastasis and may benefit more from performing 4L LND.

Continuous vagal intraoperative neuromonitoring during video-assisted thoracoscopic surgery for left lung cancer: its efficacy in preventing permanent vocal cord paralysis

OBJECTIVES

We investigated the safety and efficacy of continuous intraoperative neuromonitoring (CIONM) during video-assisted thoracoscopic lobectomy for left lung cancer in preventing recurrent laryngeal nerve injury.

METHODS

From August 2015 to March 2020, 22 patients with left lung cancer without CIONM (unmonitored) and 20 patients with left lung cancer with CIONM underwent thoracoscopic lobectomy with complete mediastinal lymph node dissection including 4L dissection. Clinical outcomes from these 2 groups were compared.

RESULTS

The incidence of 4L metastasis was 7.14% (3 patients). There was no significant difference in the total number of dissected 4L lymph nodes between the 2 groups (3.23 ± 2.2 in the unmonitored group, 3.95 ± 2.0 in the CIONM group). CIONM was successful in all of the cases. There was no significant difference in the incidence of postoperative vocal cord palsy (22.7% in the unmonitored group, 20% in the CIONM group, P = 1.000). All of the 5 patients (100%) had permanent vocal cord palsy in the unmonitored group. Although statistically insignificant, 75% (3 patients) had total recovery of the vocal cord function, with only 1 patient remaining in permanent vocal cord palsy in the CIONM group.

CONCLUSIONS

CIONM was safe and efficient. CIONM might be helpful to avoid permanent vocal cord palsy by immediately warning the surgeon about impending nerve injury, so the surgeon can stop delivering further injury to the recurrent laryngeal nerve.

The impact of station 4L lymph node dissection on short-term and long-term outcomes in non-small cell lung cancer

OBJECTIVE

The optimal extent of lymph node dissection (LND) remains controversial. We aimed to investigate whether the addition of station 4L lymph node dissection (S4L-LND) was beneficial for non-small cell lung cancer (NSCLC).

METHODS

Data on 1040 left-sided NSCLC patients undergoing rigorous systematic LND were retrospectively reviewed. Multivariate logistic regression analysis determined risk factors of station 4L (S4L) nodal involvement to facilitate risk stratified analysis of the significance of S4L-LND. Propensity score matching (PSM) was conducted to reduce disparities of baseline characteristics between S4L-LND group and no-S4L-LND group. Recurrence-free survival (RFS), overall survival (OS), and postoperative complications were compared.

RESULTS

S4L-LND was performed in 586 (56.3%) patients. The S4L nodal involvement rate was 15.5% (91/586). Aortopulmonary zone nodes involvement (P < 0.001), N1 nodes involvement (P < 0.001), and advanced T stage (P = 0.015) were independent risk factors of S4L nodal involvement. Patients with ≥ 2 risk factors of S4L nodal involvement were classified as high risk group, and the others were classified as low risk group. Among patients with negative aortopulmonary zone nodes and inferior mediastinal nodes (n = 425), only 28 (6.6%) patients had S4L involvement. After PSM, a total of 416 pairs were well matched. There was no significant survival difference between S4L-LND group and no-S4L-LND group (OS, P = 0.247; RFS, P = 0.569). When stratified by risk subgroup, S4L-LND group did not demonstrate superior survival than no-S4L-LND group in the high risk group (OS, P = 0.273; RFS, P = 0.754) or the low risk group (OS, P = 0.558; RFS, P = 0.319). S4L-LND group demonstrated significantly greater risk of postoperative complications than no-S4L-LND group (9.6% vs. 5.8%; P = 0.037).

CONCLUSIONS

S4L involvement was not rare and usually occurred with multiple nodal stations involvement. Routine dissection of aortopulmonary zone and inferior mediastinal nodes was sufficient to ensure staging accuracy. The addition of S4L-LND did not improve survival, but might increase the risk of postoperative complications.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Nerve at risk: anatomical variations of the left recurrent laryngeal nerve and implications for thoracic surgeons

OBJECTIVES

Recurrent laryngeal nerve (RLN) injury during thoracic surgery may result in life-threatening postoperative complications including recurrent aspiration and pneumonia. Anatomical details of the intrathoracic course are scarce. However, only an in-depth understanding of the anatomy will help reduce nerve injury. The aim of this study was to assess the anatomic variations of the intrathoracic left RLN.

METHODS

Left-sided vagal nerves and RLN were dissected in 100 consecutive Caucasian cadavers during routine autopsy. Anatomical details were documented. Available demographic data were assessed for possible correlations.

RESULTS

All nerves were identified during dissection. Variant courses were classified in 3 different groups according to the level at which the RLN separated from the vagal nerve: above the aortic arch, level with the aortic arch and below the aortic arch. We found 11% of RLN separating above the aortic arch and crossing the aortic arch at a considerable distance to the vagal nerve. In 48% of the RLN, the nerve split off when it was level with the aortic arch, and 41% of the RLN leave the vagal nerve in a perpendicular direction below the aortic arch. All nerves crossed the ligamentum arteriosum on the posterior side. No gender-specific differences were observed.

CONCLUSIONS

Mediastinal lymph node dissection in left-sided lung cancer patients puts the RLN at risk. With more detailed anatomical knowledge about its course, it is possible to avoid risking the nerve. Visualization will help protect the nerve.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical Significance of Station 3A Lymph Node Dissection in Patients with Right-Side Non-Small-Cell Lung Cancer: A Retrospective Propensity-Matched Analysis

PURPOSE

To investigate the prognostic impact of station 3A lymph node (LN) dissection in patients with right-side non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

We retrospectively reviewed data of 1906 patients with primary right-side NSCLC who underwent lobectomy between January 2005 and December 2017 (570 patients underwent station 3A LN dissection and 1336 patients did not). Propensity score matching was conducted to minimize the effects of potential confounding factors. Disease-free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

The metastasis rate of station 3A LN was 15.3% (87/570), which was second only to station 4 (17.3%). Only stations 10 and 11 LN metastases were found to be independent risk factors for station 3A LN metastasis (odds ratio = 19.43, 95% CI 1.21-311.12; P = 0.036 and odds ratio = 53.28, 95% CI 2.02-1404.90; P = 0.016, respectively). After propensity score matching, patients with dissection of station 3A LNs showed higher DFS (5-year DFS, 52.4% vs. 37.1%; P = 0.001) and OS (5-year OS, 58.8% vs. 48.7%; P = 0.007) than those without dissection. Subgroup analysis indicated that station 3A LN dissection was associated with significantly higher DFS and OS in patients with stage II and III disease. In multivariate survival analysis, dissection of 3A LNs retained its independent favorable effect on both DFS (hazard ratio = 0.76, 95% CI 0.64-0.90; P = 0.001) and OS (hazard ratio = 0.73, 95% CI 0.60-0.88; P = 0.001).

CONCLUSION

Station 3A LN involvement was not rare and station 3A LN dissection was associated with a more favorable prognosis in patients with right-side NSCLC.