The presence of isolated tumor cells and micrometastases in the intrathoracic lymph nodes of patients with lung cancer is not associated with decreased survival

Systematic review and meta-analysis of the prognostic impact of lymph node micrometastasis and isolated tumour cells in patients with stage I-IIIA non-small cell lung cancer

Lymph node micrometastases could be one of the reasons for the high recurrence rate after complete surgical resection in stage I-IIIA non-small cell lung cancer (NSCLC). The standard evaluation of a single haematoxylin and eosin (H&E) slide of a paraffin-embedded section of a lymph node is insufficient for the detection of micrometastases, and there is a need for additional histopathological evaluation. The association of lymph node micrometastases with survival remains as yet unresolved. The aim of this systematic review and meta-analysis is to investigate if lymph node micrometastases and isolated tumour cells in patients with stage I-IIIA NSCLC, detected with multiple sectioning and/or immunohistochemistry (IHC) and/or reverse transcriptase polymerase chain reaction (RT-PCR), are associated with overall survival (OS) and disease-free survival (DFS) after surgical resection. We performed a meta-analysis of time-to-event outcomes based on 15 articles using ancillary techniques to detect micrometastases. We extracted the OS and DFS every 3-6 months after surgery, for patients with and without occult lymph node micrometastasis, from the survival curves published in each article. These data were used to reconstruct OS and DFS for 'micrometastasis' and 'no micrometastasis' groups. Based on all included studies that used IHC, serial sectioning, or RT-PCR, we found a 5-year OS of 55% (micrometastasis) vs. 75% (no micrometastasis), and a 5-year DFS of 53% (micrometastasis) vs. 75% (no micrometastasis). Patients with stage I-IIIA NSCLC with lymph node micrometastases detected by ancillary histopathological and molecular techniques have a significantly poorer OS and DFS compared to patients without lymph node micrometastases.

Molecular Nodal Restaging Based on CEACAM5, FGFR2b and PTPN11 Expression Adds No Relevant Clinical Information in Resected Non-Small Cell Lung Cancer

BACKGROUND

The relapse rate in non-small cell lung cancer (NSCLC) is high, even in localized disease, suggesting that the current approach to pathological staging is insufficiently sensitive to detect occult micrometastases present in resected lymph nodes. Therefore, we aimed to determine the prognostic value of the expression of embryonic molecular markers in histologically-negative lymph nodes of completely-resected NSCLC.

METHODS

76 completely-resected NSCLC patients were included: 60 pN0 and 16 pN1. Primary tumors and 347 lymph node were studied. CEACAM5, FGFR2b, and PTPN11 expression levels were evaluated through mRNA analysis using real-time RT-qPCR assay. Statistical analyses included the Kruskal-Wallis test, Kaplan Meier curves, and log-rank tests.

RESULTS

CEACAM5 expression levels were scored as high in of 90 lymph nodes (26%). The molecular-positive lymph nodes lead to the restaging of 37 (62%) pN0 patients as molecular N1 or N2 and 5 (31%) pN1 cases were reclassified as molecular-positive N2. Surprisingly, molecular-positive patients associated with a better OS (overall survival, p = 0,04). FGFR2b overexpression was observed in 41 (12%) lymph nodes leading to the restaging of 17 patients (22%). Again a trend was observed toward a better DFS (disease-free survival) in the restaged patients (p = 0,09). Accordingly, high expression levels of CEACAM5 or FGFR2b in the primary were related to better DFS (p = 0,06; p < 0,02, respectively).

CONCLUSION

Molecular nodal restaging based on expression levels of CEACAM5 and/or FGFR2b, does not add relevant clinical information to pathological staging of NSCLC likely related to the better prognosis of their overexpression in primary tumors.

Intraoperative diagnosis of lymph node metastasis during segmentectomy for non-small cell lung cancer by rapid immunohistochemistry using noncontact alternating current electric field mixing

Background

Although lobectomy is considered the standard surgery for any non‐small cell lung cancer (NSCLC), recent evidence indicates that for early NSCLCs segmentectomy may be equally effective. For segmentectomy to be oncologically safe, however, adequate intraoperative lymph node staging is essential. The aim of this study was to compare the results of a new rapid‐IHC system to the HE analysis for intraoperative nodal diagnosis in lung cancer patients considered for segmentectomy.

Methods

This retrospective study analyzed the pathological reports from NSCLC resections over a six‐year period between 2014 and 2020. Using a new device for rapid‐IHC, we applied a high‐voltage, low‐frequency alternating current (AC) field, which mixes the antipancytokeratin antibody as the voltage is switched on/off. Rapid‐IHC can provide a nodal diagnosis within 20 minutes.

Results

Frozen sections from 106 resected lymph nodes from 70 patients were intraoperatively evaluated for metastasis. Of those, five nodes were deemed positive based on both HE staining and rapid‐IHC. In addition, rapid‐IHC alone detected isolated tumor cells in one hilar lymph node. Three cStage IA patients with nodal metastasis detected with HE staining and rapid‐IHC received complete lobectomies. Five‐year relapse‐free survival and overall survival among patients receiving segmentectomy with rapid‐IHC were 88.77% and 88.79%, respectively.

Conclusions

Rapid‐IHC driven by AC mixing is simple, highly accurate, and preserves nodal tissue for subsequent tests. This system can be used effectively for intraoperative nodal diagnosis.

Rapid immunohistochemistry based on alternating‐current field mixing (completed within 20 minutes) is simple and highly accurate. This system will assist clinicians when making intraoperative diagnoses of lymph node metastasis and deciding upon the appropriate surgical procedure in segmentectomy for lung cancer.

Key points

Significant findings of the study

Rapid immunohistochemistry driven by alternating‐current field mixing (completed within 20 minutes intraoperatively) is simple, highly accurate, and preserves lymph node tissue for subsequent pathological examination, including molecular assessments.

What this study adds

Segmentectomy for lung cancer is oncologically safe, but only when there is adequate intraoperative node staging. Rapid immunohistochemistry will assist clinicians when making intraoperative nodal diagnoses.

Detection of disseminated tumor cells in lymph nodes from patients with early stage non-small cell lung cancer

BACKGROUND

The regional lymph node involvement is a major prognostic factor in patients with non-small cell lung cancer (NSCLC) undergoing surgical resection. Disease relapse is common, suggesting that early disseminated disease is already present in the regional lymph nodes at the time of surgery, and that the current nodal staging classification might be suboptimal. Early detection of disseminated tumor cells (DTCs) in lymph nodes could potentially enable identification of subcategories of patients with high risk of disease relapse.

METHOD

Lymph node samples were collected from 128 NSCLC patients at the time of surgery and the presence of DTCs determined by immunomagnetic selection (IMS) using the MOC31 antibody recognizing EpCAM. Results obtained with IMS were compared to the pathological staging obtained by histopathology. Associations between the presence of DTCs and clinicopathological variables and patient outcome were investigated.

RESULTS

DTCs were detected in 40 % of the lymph node samples by IMS. Their presence was significantly associated with pN status as assessed by histopathology, and samples from 83 % of the patients with lymph node metastases (pN1-2) had detectable DTCs. In the group of patients who were negative for lymph node metastases by standard histopathology (pN0) DTCs were detected in 32 %. The presence of DTCs was not associated with any other clinicopathological variables. Patients with IMS-positive samples showed decreased relapse free survival compared to patients with IMS-negative samples, but the difference was not statistically significant. The pN status was significantly associated with both relapse free and overall survival, but the presence of DTCs had no prognostic impact in the subcategory of patients with pN0 status.

CONCLUSION

Our findings do not support further development of lymph node DTC detection for clinical use in early stage NSCLC.

Lack of supportive evidence for the use of immunohistochemical staining to identify occult regional lymph node metastases in primary lung cancer

Immunohistochemical (IHC) staining for the identification of nodal occult metastases (OM), not detected by routine histological examination, has been proposed for improved staging, prognostication and decision of adjuvant treatment in surgically treated primary lung cancer. In a prospective study, we analysed 178 cases of primary lung cancer stage I-III (N0-N1) for OM by immunostaining lymph node tissue using a broad-spectrum anti-cytokeratin antibody. OM were found in 7 (4 %) of the 178 cases. Using Kaplan-Meier analysis, overall survival was not significantly different between cases with stage I and cases upstaged to stage II because of OM (n = 3), or between cases with stage II and cases upstaged to stage III (n = 4). Likewise, the presence of OM was not significantly correlated with overall survival in univariable or multivariable Cox proportional hazards regression models, also when disregarding OM <0.2 mm in size. Given the low frequency of OM and lack of significant impact on survival in our study, the justification for including IHC staining of lymph nodes in lung cancer in clinical practise does not appear convincing. Moreover, we report several potential pitfalls in the use of broad-spectrum cytokeratin IHC staining for OM detection, for example staining of intra-nodal mesothelial cells.

[The prognostic value of micrometastasis in non-small cell lung cancer]

肺癌是我国目前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）占肺癌的80%-85%。诊断时的分期是NSCLC主要的预后因子，也是治疗模式选择的重要依据。然而，完全性切除术后的Ⅰ期的NSCLC仍有25%-30%的复发率。这部分复发的患者可能早期就存在局部和（或）远处的隐匿性转移。因此，很多研究开始对NSCLC患者进行微转移的检测，并评估其预后价值。本文总结了近年来的相关研究，并就NSCLC的淋巴结微转移、骨髓微转移、胸膜腔微转移及外周血微转移的预后作用进行综述。

Histological evaluation of preoperative mediastinoscopy lymph node biopsies in non-small cell lung cancer

INTRODUCTION

Despite the advent of PET scanning and endoscopic minimally invasive methods of sampling mediastinal lymph nodes, surgical assessment, particularly by mediastinoscopy, remains an important tool for staging non-small cell lung cancer.

METHODS

We carried out a retrospective review of mediastinoscopic lymph node biopsies taken at The Royal Infirmary of Edinburgh between 1996 and 2006 and performed additional histological investigations on select cases.

RESULTS

In total, 89/802 (11%) patients had a negative mediastinoscopy but final resection stage of N2/N3. Within this group, 41/89 (46%) patients had positive resection lymph nodes in stations potentially accessible to biopsy at mediastinoscopy. Of these, 30 (34%) patients had had the metastatic station sampled at mediastinoscopy. Further histopathological examination (multiple levels and pancytokeratin immunohistochemistry) of these original biopsies detected micrometastases in two cases, one of which, in retrospect, had been missed on the original section at the time of reporting. Isolated tumour cells were detected by immunohistochemistry in another two cases.

CONCLUSIONS

Routine examination of additional levels and immunohistochemical staining of mediastinal lymph nodes biopsies is not required and would not improve the overall negative predictive value of the procedure.

Dilemmas in Lung Cancer Staging

The TNM staging system is the most important prognostic factor for lung cancer. The most encountered difficulties in pathologic staging of lung cancer include assessment of pleural invasion, synchronous tumor nodules, and lymph node sampling.

Lymph node micrometastases detected by carcinoembryonic antigen mRNA affect long-term survival and disease-free interval in early-stage lung cancer patients

The majority of stage I lung cancer patients undergo a complete resection of their tumor; however, they still harbor a considerable risk of mortality due to recurrences. A correlation between the presence of lymph node micrometastases and poor prognosis has been observed. The aim of this study was to correlate the lymph node molecular staging with the 5-year survival and disease-free interval following pulmonary lobectomy for non-small cell lung cancer (NSCLC). A quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for carcinoembryonic antigen (CEA) mRNA was performed on primary lung tumors and regional lymph nodes from 55 surgically resected NSCLC patients classified as clinical stage I. CEA mRNA was found to be present in all the primary tumors. RT-PCR revealed the presence of cancer cells in the lymph nodes of 20 patients (36.3%) and routine staining detected lymph node metastases in 11 patients. Significant differences in survival and disease-free intervals were observed in patients with lymph node micrometastases versus patients with negative lymph nodes (P=0.0026 and P=0.0044, respectively). Multivariate analyses confirmed that micrometastases were an independent predictor for worse prognosis (P=0.0098) and a short disease-free interval (P=0.0137). This study demonstrated strong correlations between the molecular detection of lymph node micrometastases and 5-year survival rates and disease-free interval in patients who underwent pulmonary lobectomy for early-stage lung cancer.

cT1aN0M0 lung adenocarcinoma treated with left S9+10 segmentectomy followed by completion lobectomy for a solitary metastasis (isolated tumor cells) in the neighboring segmental lymph node

A 47-year-old woman with a lung adenocarcinoma of 1.3 cm located in the left S9+10 was treated by S9+10 segmentectomy with sentinel node (SN) identification using radioisotopes. During segmentectomy, frozen section of the segmental nodes at S9+10 and S6, identified as SNs, did not show metastasis; however, postoperative immunohistochemical staining with cytokeratin revealed isolated tumor cells in the segmental node at S6. None of the other dissected nodes, including the hilar, interlobar, and mediastinal nodes, showed metastasis, even with immunohistochemical staining. Completion lobectomy was conducted 6 days after segmentectomy, and the resected specimens did not show further metastasis. The final pathological diagnosis was adenocarcinoma with pT1aN0(i+)M0 stage A. The present case was indicative of the importance of dissecting the segmental lymph node located not only at the tumor-bearing segment but also at the neighboring segment, especially the one located between the primary tumor and the lobar bronchi.

Evidence-Based Principles in Pathology: Existing Problem Areas and the Development of “Quality” Practice Patterns

Context.—Contrary to the intuitive impressions of many pathologists, several areas exist in laboratory medicine where evidence-based medicine (EBM) principles are not applied. These include aspects of both anatomic and clinical pathology. Some non-EBM practices are perpetuated by clinical “consumers” of laboratory services because of inadequate education, habit, or overreliance on empirical factors. Other faulty procedures are driven by pathologists themselves.

Objectives.—To consider (1) several selected problem areas representing non-EBM practices in laboratory medicine; such examples include ideas and techniques that concern metastatic malignancies, “targeted” oncologic therapy, general laboratory testing and data utilization, evaluation of selected coagulation defects, administration of blood products, and analysis of hepatic iron-overload syndromes; and (2) EBM principles as methods for remediation of deficiencies in hospital pathology, and implements for the construction of “quality” practices in our specialty.

Data Sources.—Current English literature relating to evidence-based principles in pathology and laboratory medicine, as well as the authors' experience.

Conclusions.—Evidence-based medicine holds the promise of optimizing laboratory services to produce “quality” practices in pathology. It will also be a key to restraining the overall cost of health care.