Lymphatic drainage of the middle lobe of the adult lung

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.

Survival rates after lobectomy versus sublobar resection for early-stage right middle lobe non-small cell lung cancer

Background

Lung cancer in the right middle lobe has a poorer prognosis than tumors located in other lobes. The optimal surgical procedure for early‐stage non‐small cell lung cancer (NSCLC) in the right middle lobe has not yet been elucidated. The aim of this study was to compare survival rates after lobectomy and sublobar resection for early‐stage right middle lobe NSCLC.

Methods

Patients who underwent lobectomy or sublobar resection for stage IA right middle lobe NSCLC tumors ≤ 2 cm between 2004 and 2014 were identified from the Surveillance, Epidemiology and End Results database of 18 registries. Cox regression model analysis was used to evaluate the prognostic factors. The lung cancer‐specific survival (LCSS) and overall survival (OS) rates between the two groups were compared.

Results

A total of 861 patients met our criteria, including 662 (76.9%) patients who underwent lobectomy and 199 (23.1%) patients who underwent sublobar resection. No statistical differences in LCSS and OS rates were identified between the groups of patients with stage IA right middle lobe NSCLC ≤ 1 cm. For tumors > 1–2 cm, lobectomy was associated with more favorable LCSS and OS rates compared to sublobar resection.

Conclusion

Lobectomy and sublobar resection deliver a comparable prognosis for patients with stage IA right middle lobe NSCLC ≤ 1 cm. For tumors > 1–2 cm, lobectomy showed better survival rates than sublobar resection.

[Advances in Lymph Node Metastasis and the Modes of Lymph Node Dissection in Early Stage Non-small Cell Lung Caner]

目前，肺癌已是全球范围内发病率及死亡率最高的恶性肿瘤，非小细胞肺癌（non-small cell lung cancer, NSCLC）约占肺癌80%。手术治疗在早期NSCLC治疗中占主导地位，而淋巴结分期及手术中清扫程度直接影响着患者术后生活质量及患者的预后。解剖性肺叶切除加系统性淋巴结清扫一直以来被认为是NSCLC的标准手术方式，但对早期NSCLC患者纵隔淋巴结清扫程度问题上一直存在较大争议，精确评估区域淋巴结的转移及淋巴结清扫的程度是影响患者围手术期并发症和预后的重要因素。对于早期肺癌行肺叶特异性或选择性淋巴结清扫已逐渐为国内外学者接受，并可能成为临床Ⅰ期NSCLC患者标准淋巴结清扫方式。

Therapeutic value of lymph node dissection for right middle lobe non-small-cell lung cancer

BACKGROUND

Superior mediastinal and #11i lymph node (LN) metastases are adverse prognostic factors in patients with middle lobe lung cancer. We aimed to clarify the benefit of thorough lymphadenectomy by LN station or zone in middle lobe non-small-cell lung cancer (NSCLC).

METHODS

Among 295 patients who underwent pulmonary resection and thorough lymphadenectomy for primary right middle lobe (RML) NSCLC at two institutions, we enrolled 68 patients (33 men, 35 women) and retrospectively studied their data. We divided each N1 location (i.e., #10, #11s and #11i) into N1(-)N2(+) and N1(+)N2(+) and divided the #12m location into N1(+)N2(-), N1(-)N2(+) and N1(+)N2(+).

RESULTS

Interlobar node involvement was rare in pN1 NSCLC when compared with that in other N1 nodes. Lymph node dissection (LND) was beneficial when the hilar zone (HZ)/interlobar zone (IZ) LNs were located at the intermediate point of the upper zones (UZs) and subcarinal zones (SCZs), with the therapeutic benefit at the SCZ being 2.8-fold higher than that at the UZ and 9.7-fold higher than that at the lower zone (LZ). Furthermore, LND evidently had greater therapeutic value for the SCZ than the UZ, which was compatible with skip N2 metastases.

CONCLUSIONS

For middle lobe NSCLC, mediastinal LND should be considered a priority in the SCZ than in the UZ. Moreover, the HZ/IZ is central to unfavourable prognoses in patients with pN2 middle lobe NSCLC.

Pulmonary middle lobectomy for non-small-cell lung cancer: effectiveness and prognostic implications

OBJECTIVES

The therapeutic value of pulmonary middle lobectomy (PML) has been questioned. PML is currently regarded as a standard form of lobectomy, even so it shares some surgical features with segmentectomies (SEG) more than with lobectomies. The present study's aim was to assess the therapeutic value of PML with respect to other lobectomies (LOBs) and SEGs.

METHODS

A total of 902 consecutive patients who underwent lobectomy or SEG with mediastinal lymph node dissection for Stage I-IIIa non-small-cell lung cancer were analysed. Patients with pT4 tumours and/or pathologically incomplete resection were excluded.

RESULTS

PML was performed in 50 patients, SEG in 44 and LOBs were performed in 808. The three study groups were homogeneous, except for gender, pT and grade: females, pT1 and G1 tumours were more frequent in the PML and SEG groups. The lymph node dissection yield was poorer in PML (P < 0.007) and SEG (P < 0.001) groups when compared with LOB group. Five-year overall survival (OS) was 45.3% for PML, 54.0% for SEG and 60.2% for LOB (P = 0.793). When limiting the analysis to G2-3 right-sided tumours, 5-year survival was lower in the PML group than in the LOB group: 41.3 vs 59.0% (P = 0.057). Similar results were found when analysing pT2-3 right-sided tumours: 27.3 vs 57.3% (P = 0.049). Multivariable analysis showed four independent prognostic factors: age (P = 0.001), pathological stage (P < 0.001), gender (P = 0.005) and the type of surgical resection (P = 0.029). PML (hazard ratio, HR = 1.63) and SEG (HR = 1.64) were detrimental in comparison with LOB. After adjusting for baseline differences between groups (propensity score), a trend towards a worse OS in PML group when compared with LOB group was observed (HR = 1.38, P = 0.150).

CONCLUSIONS

Both the lymphadenectomy yield and prognosis make PML more similar to SEG than lobectomy, especially for pT2-3 or G2-3 tumours.

[Advances of mediastinal lymph node metastasis and the extent of lymph node dissection in patients with stage T1 non-small cell lung cancer]

肺癌是我国发病率和死亡率最高的恶性肿瘤。非小细胞肺癌（non-small cell lung cancer, NSCLC）约占肺癌80%。临床上，早期NSCLC以手术治疗为主要治疗方式，淋巴结分期及手术中清扫程度直接影响着患者的预后。不同肺叶原发NSCLC的淋巴结转移区域存在一定规律。解剖性肺叶切除加系统性淋巴结清扫一直以来被认为是NSCLC的标准手术方式，但近年来T1期NSCLC手术中纵隔淋巴结清扫的程度存在较大争议，选择性淋巴结清扫已逐渐被大多数学者所重视。

Is the rate of pneumonectomy higher in right middle lobe lung cancer than in other right-sided locations?

BACKGROUND

Historically, right middle lobe (RML) non-small cell lung cancer (NSCLC) has been reported to be associated with a higher rate of pneumonectomy than other right-sided locations. Because this would discourage minimally invasive approaches in RML-NSCLC, we sought to update this assertion through the study of a large surgical series.

METHODS

Clinical records of patients who underwent operations for right-sided NSCLC in 2 French surgical centers were prospectively entered and retrospectively reviewed. Demographic and pathologic characteristics of RML NSCLC were compared with other right-sided NSCLC.

RESULTS

This study included 3,234 right-sided and 211 RML (6.5%) NSCLC patients. After exclusion of 14 patients who underwent exploratory thoracotomy, patients were a mean age of 61.5 years, most RML resections occurred in men (134 [72.8%]), and most were lobectomies (wedge, n=4; lobectomy, n=102; bilobectomy, n=22; pneumonectomy, n=56). Pathologic analysis revealed adenocarcinoma in 88 patients (47.8%) and squamous cell carcinoma in 80 (43.5%). pStaging was stage I in 86 patients (46.7%), II in 42 (22.8%), III in 47 (25.5%), and IV in 9 (4.9%). Superior and inferior mediastinal N2 were found in 45.4% and 54.6% of patients, respectively, when 1 station was involved. When compared with other right-sided NSCLC, RML was characterized by higher T status and higher rates of bilobectomy (10.9% vs 5.6%, p=0.0017) and pneumonectomy (30.3% vs 22.3%, p=0.0071) but similar 5-year survival (47.4%).

CONCLUSIONS

Compared with other right-sided NSCLC, RML location is associated with a higher albeit limited rate of pneumonectomy.

Some variations in lymphatic drainage of selected bronchopulmonary segments in human lungs

Interest in the role of the pulmonary lymphatic system in the pathophysiology of pulmonary and systemic diseases induced us to carry out anatomical research on the lung lymphatic system in the Polish population. The aim of the study was to evaluate whether lymphatic vessels respect bronchopulmonary segment borders and to determine how often lymphatic vessels run to nodes of another lymphatic region. A block of organs comprising the lungs with the trachea, larynx and tongue, the heart and esophagus was removed from the cadavers at autopsy. The research involved 96 lungs (48 left and 48 right), which were taken from 31 male and 17 female cadavers. The lymphatic vessels were visualized at the mediastinal and interlobar surface of the lung by visual inspection. These vessels were then cannulated and injected with drawing ink. Next, the course of a lymphatic vessel was checked to see whether it was compatible with the bronchopulmonary segments or lobar borders. The first lymph node to become ink-colored via injection was dissected and histologically examined. A total of 135 images of lymphatic vessels (63 in the left lungs and 72 in the right lung) running on the mediastinal or interlobar surface of the lung were evaluated. In all, 12 out of 135 vessels (8.9%) were observed to cross the border of the segment (6/12 vessels) or the border of the lobe (6/12 vessels). We found 10/135 vessels (7.4%) running to the lymph nodes of another lymphatic region.

Mediastinal lymphatic drainage from pulmonary lobe based on CT observations of histoplasmosis: implications for minimal N2 disease of non-small-cell lung cancer

PURPOSE

The aim of this study was to assess mediastinal lymphatic drainage patterns from each pulmonary lobe using computed tomographic (CT) observations of calcified primary complex pulmonary histoplasmosis.

MATERIALS AND METHODS

We assessed 400 CT studies of patients with primary complex histoplasmosis consisting of a single lobe pulmonary lesion and mediastinal nodal disease. We assessed the distribution of mediastinal nodal involvement depending on pulmonary lobes for the total number of involved nodes, the number with single-station involvement (which suggests the initial site of involvement), and the number with skip involvement which suggests direct drainage to the mediastinum.

RESULTS

The most commonly involved mediastinal nodal stations from the right upper lobe, left upper lobe, and left lower lobe were the right lower paratracheal node (97%, 74/76), the subaortic node (72%, 49/68), and the left pulmonary ligament node (61%, 66/108), respectively. These nodes were the most common site of skip involvement in each lobe. In the right lower lobe and middle lobe, the subcarinal node was most commonly involved: 62% (65/105) and 81% (35/43), respectively. By contrast, skip involvement was uncommon in the drainage to this node.

CONCLUSION

Our data show a predictable pattern of lobar lymphatic drainage to the mediastinum. This may have implications on the minimal N2 disease of non-small-cell lung cancer.