The problem of direct lymph drainage of the bronchopulmonary segments into the mediastinal and hilar lymph nodes

The association of visceral pleural invasion with skip N2 metastasis on clinical stage IA NSCLC

BACKGROUND

Lung lymphatic drainage occurs mainly through a peribronchial path, but it is hypothesized that visceral pleural invasion could alter this path. This study aims to investigate the association between visceral pleural invasion, node upstaging, and N2 skip metastasis and the impact on survival in a population of patients with non-small cell lung cancer of 3 cm or smaller.

METHODS

We retrospectively queried our institutional database of lung cancer resection for all patients with clinical stage IA NSCLC between June 2009 and June 2022. We collected baseline characteristics and clinical and pathological staging data. Patients were classified into two groups: The non-VPI group with negative visceral pleural invasion and the VPI group with positive. The primary results analyzed were the occurrence of nodal upstaging, skip N2 metastasis and recurrence.

RESULTS

There were 320 patients analyzed. 61.3 % were women; the median age was 65.4 years. The pleural invasion occurred in 44 patients (13.7 %). VPI group had larger nodules (2.3 vs. 1.7 cm; p < 0.0001), higher 18F-FDG uptake (7.4 vs. 3.4; p < 0.0001), and lymph-vascular invasion (35.7 % vs. 13.5 %, p = 0.001). Also, the VPI group had more nodal disease (25.6 % vs. 8.7 %; p = 0.001) and skip N2 metastasis (9.3 % vs. 1.8 %; p = 0.006). VPI was a statistically independent factor for skip N2 metastasis. Recurrence occurred in 17.2 % of the population. 5-year disease-free and overall survival were worse in the VPI group.

CONCLUSIONS

The visceral pleural invasion was an independent factor associated with N2 skip metastasis and had worse disease-free and overall survival.

Regeneration of emphysematous lungs using gelatin sheets that release basic fibroblast growth factor

PURPOSE

Basic fibroblast growth factor (bFGF) induces regeneration and neovascularization of the lungs. We conducted this study to demonstrate the regeneration of emphysematous lungs achieved by gelatin sheets that slowly release bFGF into the visceral pleura in a canine model.

METHODS

Porcine pancreatic elastase was used to induce bilateral lower lobe pulmonary emphysema in dogs. Slow-release bFGF gelatin sheets were attached to the visceral pleura of the left lower lobe via thoracotomy. The subjects were divided into two groups: one treated with gelatin sheets containing slow-release bFGF (bFGF⁺ group, n = 5), and the other, treated with only gelatin sheets (bFGF^- group, n = 5). The subjects were euthanized after 28 days and histologic lung assessment was performed. The results were evaluated in terms of the mean linear intercept (MLI) and microvessel count.

RESULTS

The MLI was significantly shorter in the bFGF⁺ group than in the bFGF^- group; (110.0 ± 24.38 vs. 208.9 ± 33.08 μm; P = 0.0006). The microvessel count was not significantly different between the bFGF⁺ and bFGF^- groups (12.20 ± 3.007 vs. 5.35 ± 2.3425; P = 0.075); however, it was significantly higher in the bFGF-attached lungs than in the emphysema group (12.20 ± 3.007 vs. 4.57 ± 0.8896; P = 0.012).

CONCLUSIONS

Attaching gelatin sheets with slow-release bFGF to the visceral pleura induced lung regeneration and vascularization in a canine pulmonary emphysema model.

Patterns of nodal spread in stage III NSCLC: importance of EBUS-TBNA and 18F-FDG PET/CT for radiotherapy target volume definition

Purpose

The aim of this study was to compare the pattern of intra-patient spread of lymph-node (LN)-metastases within the mediastinum as assessed by ¹⁸F-FDG PET/CT and systematic endobronchial ultrasound-guided transbronchial-needle aspiration (EBUS-TBNA) for precise target volume definition in stage III NSCLC.

Methods

This is a single-center study based on our preceding investigation, including all consecutive patients with initial diagnosis of stage IIIA-C NSCLC, receiving concurrent radiochemotherapy (12/2011–06/2018). Inclusion criteria were curative treatment intent, ¹⁸F-FDG PET/CT and EBUS-TBNA prior to start of treatment. The lymphatic drainage was classified into echelon-1 (ipsilateral hilum), echelon-2 (ipsilateral LN-stations 4 and 7) and echelon-3 (rest of the mediastinum, contralateral hilum). The pattern of spread was classified according to all permutations of echelon-1, echelon-2, and echelon-3 EBUS-TBNA findings.

Results

In total, 180 patients were enrolled. Various patterns of LN-spread could be identified. Skip lesions with an involved echelon distal from an uninvolved one were detected in less than 10% of patients by both EBUS-TBNA and PET. The pattern with largest asymmetry was detected in cases with EBUS-TBNA- or PET-positivity at all three echelons (p < 0.0001, exact symmetry test). In a multivariable logistic model for EBUS-positivity at echelon-3, prognostic factors were PET-positivity at echelon-3 (Hazard ratio (HR) = 12.1; 95%-CI: 3.2–46.5), EBUS-TBNA positivity at echelon-2 (HR = 6.7; 95%-CI: 1.31–31.2) and left-sided tumor location (HR = 4.0; 95%-CI: 1.24–13.2). There were significantly less combined ipsilateral upper (LN-stations 2 and 4) and lower (LN-station 7) mediastinal involvements (16.8% of patients) with EBUS-TBNA than with PET (38.9%, p < 0.0001, exact symmetry test). EBUS-TBNA detected a lobe specific heterogeneity between the odds ratios of LN-positivity in the upper versus lower mediastinum (p = 0.0021, Breslow-Day test), while PET did not (p = 0.19).

Conclusion

Frequent patterns of LN-metastatic spread could be defined by EBUS-TBNA and PET and discrepancies in the pattern were seen between both methods. EBUS-TBNA showed more lobe and tumor laterality specific patterns of LN-metastases than PET and skipped lymph node stations were rare. These systematic relations offer the opportunity to further refine multi-parameter risk of LN-involvement models for target volume delineation based on pattern of spread by EBUS-TBNA and PET.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01904-4.

Lymphatic invasion is a cause of local recurrence after wedge resection of primary lung cancer

OBJECTIVE

After securing a sufficient surgical margin at wedge resection and finding no pathologic evidence of residual tumor at the surgical margin, a considerable number of patients develop local recurrence. We investigated the correlation between sub-pleural lymphatic flow and local recurrence.

METHODS

We retrospectively reviewed the medical records of 144 non-small cell lung cancer patients who underwent wedge resection between January 2006 and December 2014 at our institution.

RESULTS

Postoperative recurrence was observed in 36 patients (25%). Of these, local recurrence was observed in 29 patients (80.5%). The proportion of all recurrence and local recurrence were significantly higher among patients with lymphatic vessel invasion (LVI) (p < 0.0001). Recurrence-free survival rate was significantly lower in patients with LVI (24.8%) than in patients without LVI (80.2%, p < 0.0001). Multivariate logistic regression analysis demonstrated LVI (odds ratio = 6.420, p = 0.0009) as a significant predictor of local recurrence.

CONCLUSIONS

Intratumoral lymphatic invasion represents a major cause of local recurrence. Although we should aim for radical surgery whenever possible, when limited surgery is the only option, postoperative adjuvant treatment may need to be considered for patients showing lymphatic invasion even at an early stage.

Development of the pulmonary pleura with special reference to the lung surface morphology: a study using human fetuses

In and after the third trimester, the lung surface is likely to become smooth to facilitate respiratory movements. However, there are no detailed descriptions as to when and how the lung surface becomes regular. According to our observations of 33 fetuses at 9–16 weeks of gestation (crown-rump length [CRL], 39–125 mm), the lung surface, especially its lateral (costal) surface, was comparatively rough due to rapid branching and outward growing of bronchioli at the pseudoglandular phase of lung development. The pulmonary pleura was thin and, beneath the surface mesothelium, no or little mesenchymal tissue was detectable. Veins and lymphatic vessels reached the lung surface until 9 weeks and 16 weeks, respectively. In contrast, in 8 fetuses at 26–34 weeks of gestation (CRL, 210–290 mm), the lung surface was almost smooth because, instead of bronchioli, the developing alveoli faced the external surfaces of the lung. Moreover, the submesothelial tissue became thick due to large numbers of dilated veins connected to deep intersegmental veins. CD34-positive, multilayered fibrous tissue was also evident beneath the mesothelium in these stages. The submesothelial tissue was much thicker at the basal and mediastinal surfaces compared to apical and costal surfaces. Overall, rather than by a mechanical stress from the thoracic wall and diaphragm, a smooth lung surface seemed to be established largely by the thick submesothelial tissue including veins and lymphatic vessels until 26 weeks.

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.

F-18-FDG-avid lymph node metastasis along preferential lymphatic drainage pathways from the tumor-bearing lung lobe on F-18-FDG PET/CT in patients with non-small-cell lung cancer

OBJECTIVE

F-18-FDG-avid lymph node (LN) metastasis may preferentially occur along the lymphatic drainage pathway (LDP) from the tumor-bearing lobe in patients with non-small cell lung cancer (NSCLC) on FDG PET/CT. This study evaluated whether the identification of metastatic LNs according to LDP-based visual image interpretation can improve LN staging on FDG PET/CT in these patients.

METHODS

FDG PET/CT study was performed in 265 patients with NSCLC. The presence and LN station of metastatic LNs were determined by surgery or the clinical course. In the LDP-based interpretation, FDG-avid LNs, which were located along the preferential LDP from each tumor-bearing lobe and visually more intense in FDG uptake compared with the remaining LNs straying away from the preferential LDP, were diagnosed as metastatic. The result was compared with the quantitative method using a cutoff value of 2.5 for the maximum standardized uptake value.

RESULTS

Of the total 1031 mediastinal and hilar LN stations with FDG-avid LNs in 265 patients, 179 stations in 66 patients were metastatic and the remaining 852 were benign. All the metastatic LN stations except for 2 stations showing skip metastasis were located along the main preferential LDP or another preferential LDP via a direct anatomic pathway from each tumor-bearing lung lobe. The specificity, accuracy, and PPV for identifying metastatic LN stations by LDP-based interpretation were 97.9, 95.7 and 89.5 %, respectively, which were significantly greater compared with those of 92.7, 90.8 and 70.3 % by the SUV-based method (P < 0.001).

CONCLUSIONS

The present study shows that FDG-avid LN metastasis preferentially occurs along the LDP from the tumor-bearing lobe in NSCLC patients. LDP-based visual image interpretation on FDG PET/CT can improve LN staging in these patients.

Optimization of lymph node dissection with VATS right upper lobectomy

Video-assisted thoracoscopic lobectomy (VATSL) has developed rapidly. As per the requirements of tumor staging and oncotherapy, the technique of VATS mediastinal lymph node dissection plays an important role. With our experience, lymph node dissection can be performed very well on the condition that surgical process and skills be optimized.

Conformal radiation therapy combined with XELOX chemotherapy for management of abdominal lymph node metastasis in patients with gastric cancer after surgery

AIM: To investigate the effect of conformal radiation therapy combined with XELOX (capecitabine plus oxaliplatin) chemotherapy in the treatment of abdominal lymph node metastasis in patients with gastric cancer after surgery.

METHODS: Forty patients who developed abdominal lymph node metastasis after surgery for gastric cancer were randomly divided into either a control group (n = 19) or a treatment group (n = 21). The treatment group was given conformal radiation therapy combined with chemotherapy with XELOX (xeloda + oxaliplatin), and the control group received XELOX chemotherapy only. Clinical efficacy, postoperative survival rate and adverse reactions were compared between the two groups. The levels of interleukin-2 (IL-2) and interleukin-6 (IL-6) in peripheral blood of all subjects were measured by ELISA preoperatively and postoperatively.

RESULTS: Total response rate was significantly higher in the treatment group than in the control group (82.0% vs 52.7%, χ² = 3.65, P < 0.05). The 1- and 2-year postoperative survival rates were also significantly higher in the treatment group than in the control group (61.9% vs 42.1%, 52.3% vs 21.1%, both P < 0.05). The incidence of adverse reactions (bone marrow suppression, gastrointestinal reactions, anemia, and liver function damage) showed no significant difference between the two groups (P > 0.05). Six months after the treatment, peripheral blood levels of IL-6 were decreased and those of IL-2 were increased in two groups, and the difference was significant (both P < 0.05).

CONCLUSION: Conformal radiation therapy combined with XELOX chemotherapy can significantly improve curative effect and postoperative survival in gastric cancer patients with postoperative abdominal lymph node metastasis, and is associated with tolerable side effects.