Is routine dissection of the station 9 lymph nodes really necessary for primary lung cancer?

Distinct impacts of radiological appearance on lymph node metastasis and prognosis based on solid size in clinical T1 non-small cell lung cancer

BACKGROUND

Solid nodules (SN) had more aggressive features and a poorer prognosis than part-solid nodules (PSN). This study aimed to evaluate the specific impacts of nodule radiological appearance (SN vs. PSN) on lymph node metastasis and prognosis based on solid size in cT1 non-small cell lung cancer (NSCLC).

METHODS

Patients with cT1 NSCLC who underwent anatomical resection between 2010 and 2019 were retrospectively screened. Univariable and multivariable logistic regression analyses were adopted to evaluate the associations between nodule radiological appearance and lymph node metastasis. The log-rank test and Cox regression analyses were applied for prognostic evaluation. The cumulative recurrence risk was evaluated by the competing risk model.

RESULTS

There were 958 and 665 NSCLC patients with PSN and SN. Compared to the PSN group, the SN arm had a higher overall lymph node metastasis rate (21.7% vs. 2.7%, P < 0.001), including nodal metastasis at N1 stations (17.7% vs. 2.1%), N2 stations (14.0% vs. 1.6%), and skip nodal metastasis (3.9% vs. 0.6%). However, for cT1a NSCLC, no significant difference existed between SN and PSN (0 vs. 0.4%, P = 1). In addition, the impacts of nodule radiological appearance on lymph node metastasis varied between nodal stations. Solid NSCLC had an inferior prognosis than part-solid patients (5-year disease-free survival: 79.3% vs. 96.2%, P < 0.001). The survival inferiority only existed for cT1b and cT1c NSCLC, but not for cT1a. Strikingly, even for patients with nodal involvement, SN still had a poorer disease-free survival (P = 0.048) and a higher cumulative incidence of recurrence (P < 0.001) than PSN. Specifically, SN had a higher recurrence risk than PSN at each site. Nevertheless, the distribution of recurrences between SN and PSN was similar, except that N2 lymph node recurrences were more frequent in solid NSCLC (28.21% vs. 7.69%, P = 0.041).

CONCLUSION

SN had higher risks of lymph node metastasis and poorer prognosis than PSN for cT1b and cT1c NSCLC, but not for cT1a. SN exhibited a greater proportion of N2 lymph node recurrence than PSN. SN and PSN needed distinct strategies for nodal evaluation and postoperative follow-up.

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.

The impact of dissection of station 9 on survival and the necessity of pulmonary ligament division during upper lobectomy for lung cancer

BACKGROUND

We conducted this study to investigate the need for dissection of station 9 lymph nodes during upper lobectomy for non-small-cell lung cancer (NSCLC) and to find out the operative results of inferior pulmonary ligament division.

METHODS

A total of 840 patients who underwent upper lobectomy for NSCLC between January 2007 and June 2020 were evaluated retrospectively. The patients were separated into two groups - those having undergone lymph node dissection of station 9 and inferior pulmonary ligament dissection (Group I) and those who did not (Group II). In these groups, the prognostic value of station 9 lymph nodes and postoperative effects (drainage time, prolonged air leak, dead space and length of hospital stay) of ligament division or preservation were analyzed.

RESULTS

The number of patients with station 9 lymph node metastasis was only one (0.1%) and that was multi-station pN2 disease. Station 9 lymph nodes were found in 675 (80.4%) patients, while 22 (2.6%) patients had no lymph nodes in the dissected material. In the other 143 (17%) patients, the inferior pulmonary ligament and station 9 were not dissected. While 5-year survival was 64.9% in 697 patients of Group I, it was 61.3% in 143 patients of Group II (p = 0.56). There was no statistically significant difference between the groups in postoperative effects of ligament division or preservation.

CONCLUSIONS

In upper lobectomies, status of station 9 does not have a significant impact on patients' survival and lymph node staging. Additionally, preservation or division of the inferior pulmonary ligament has no significant advantage or disadvantage.

Lymph node sampling-what are the numbers?

Lung cancer is a deadly disease. Lymph node staging is the most important prognostic factor, and lymphatic drainage of the lung is complex. Major advances have been made in this field over the last several decades, but there is much left to understand and improve upon. Herein, we review the history of the lymphatic system and the creation of lymph node maps, the evolution of tumor, node, and metastasis lung cancer classification, the importance of lung cancer staging, techniques for lymph node dissection, and our recommendations regarding a minimum number of nodes to sample during pulmonary resection.

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.

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

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

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.

[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.