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

Prognostic Implications of Selective Dissection of Left Lower Paratracheal Lymph Nodes in Patients with Left-Sided Non-Small Cell Lung Cancer

Background

This study aimed to examine the clinical implications of selective station 4L lymph node dissection (S4L-LND) on survival in non-small cell lung cancer (NSCLC) and to evaluate its potential advantages.

Methods

We enrolled patients with primary left-sided NSCLC who underwent upfront video-assisted thoracoscopic surgery with R0 resection including lobectomy and segmentectomy, with or without S4L-LND, at our institution between January 2007 and December 2021. Following 1:1 propensity score matching (PSM), we compared overall survival (OS) and recurrence-free survival (RFS) between patients with and without S4L-LND.

Results

The study included 2,601 patients, of whom 1,126 underwent S4L-LND and 1,475 did not. PSM yielded 1,036 patient pairs. Among those who underwent S4L-LND, 87 (7.7%) exhibited S4L-LN involvement. Neither OS (p=0.12) nor RFS (p=0.24) differed significantly between matched patients with and without S4L-LND. In patients with S4L-LN involvement, metastases were more common in the left upper lobe (LUL) than in the left lower lobe (LLL) (3.6% vs. 2.0%, p=0.061). Metastasis became significantly more frequent with more advanced clinical N (cN) stage (cN0, 2.3%; cN1, 5.8%; cN2, 32.6%; p<0.001). Multivariate logistic regression analysis revealed that cN stage and tumor location were independently associated with S4L-LN involvement (p<0.001 for both).

Conclusion

OS and RFS did not differ significantly between matched patients with and without S4L-LND. Among participants with S4L-LN involvement, metastases occurred more frequently in the LUL than the LLL, and their incidence increased significantly with more advanced cN stage. Thus, patients with LUL or advanced cN lung cancers may benefit from S4L-LND.

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.

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.

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.