Evaluating the Genomic Yield of a Single Endobronchial Ultrasound-guided Transbronchial Needle Aspiration in Lung Cancer: Meeting the Challenge of Doing More With Less

Endobronchial ultrasound-guided transbronchial needle aspiration in patients with previously treated malignancies: diagnostic performance and predictive value

BACKGROUND

Endobronchial ultrasound-guided transbronchial needle aspiration is a minimally invasive and effective sampling approach for patients with mediastinal or hilar lymphadenopathy. Increased recognition of the ultrasonographic features revealed the value of its images in predicting mediastinal lymph node malignancy. However, its diagnostic validity and the predictive value of its ultrasonographic features have not been demonstrated well in patients after systemic anti-tumor therapy. This study aimed to evaluate the efficiency of endobronchial ultrasound-guided transbronchial needle aspiration in patients with suspicious lymph nodes after anti-tumor therapy.

METHODS

We retrospectively reviewed cases of endobronchial ultrasound-guided transbronchial needle aspiration performed between January 2019 and August 2021 at a single tertiary hospital center. Patients with suspected mediastinal or hilar lymph nodes within 5 years of systemic anti-tumor therapy were enrolled. Final diagnoses were determined by pathologic diagnoses of samples from transbronchial needle aspiration, surgery, or follow-up for at least 6 months. Ultrasonographic features were analyzed to assess the predictive value of malignant lymph nodes after treatment.

RESULTS

Overall, 168 lymph nodes of 138 patients were analyzed. Among 110 (65.5%) malignant lymph nodes, 75 originated from lung cancers; the other 35 were from other malignancies. No complications related to endobronchial ultrasound-guided transbronchial needle aspiration were observed. Of 58 negative results of transbronchial needle aspiration, 51 were proven to be true negatives; 7 were false. The overall sensitivity and the negative predictive value were 94.02% and 87.93%, respectively. Univariate and multivariate analysis revealed the absence of central hilar structure and short axis > 10 mm as independent predictive factors for malignancy.

CONCLUSIONS

Endobronchial ultrasound-guided transbronchial needle aspiration performs satisfactorily in diagnosing mediastinal and hilar lymphadenopathy even after anti-tumor treatment.

Is endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) reliable and safe procedure in geriatric patients?

BACKGROUND

Even though studies have indicated the usefulness and safety of endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA), elderly patient data are limited due to the small sample sizes.

AIM

We aimed to evaluate usage and safety of EBUS-TBNA in elderly population.

METHODS

This single-center retrospective study was conducted with patients who underwent an EBUS-TBNA procedure between September 2011 and December 2019. The patients were categorized into two groups: those aged 65 years or older (elderly group) and those younger than 65 years (younger group).

RESULTS

2444 patient data, 1069 of which were in the elderly group, were analyzed. The cytological examination of EBUS-TBNA identified specimen adequacy in 96.8% of patients. One hundred and thirty patients (5.3%) experienced complications, with similar complication rates recorded in both the elderly and younger groups (5.4% vs 5.2%, p: 0.836). Logistic regression analyses revealed that age, and presence of hypertension, diabetes mellitus, coronary artery disease and malignancy are associated significantly with complication-related EBUS-TBNA. For the lymph nodes with a final diagnosis of malignancy, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of EBUS-TBNA revealed a diagnostic performance in excess of 90% except for metastasis and lymphoma.

CONCLUSION

EBUS-TBNA can be considered a safe and effective technique in patients aged 65 years and over.

Evaluation of lung cancer biomarkers profile for the decision of targeted therapy in EBUS-TBNA cytological samples

BACKGROUND

Guidelines recommend performing biomarker tests for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), BRAF and ROS proto-oncogene-1(ROS1) genes and protein expression of programmed death ligand-1(PD-L1) in patients with non-small lung cell carcinoma (NSCLC). Studies reported that endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) can provide sufficient material for cancer biomarker analyses, but there are still concerns about the subject.

AIM

The purpose of the study was to assess the adequacy of EBUS-TBNA for testing lung cancer biomarkers.

METHODS

We retrospectively reviewed patients with NSCLC whose EBUS-TBNA was analysed for EGFR, ALK, ROS-1, BRAF and PD-L1 expression between December 2011 and December 2020.

RESULTS

A total of 394 patients were enrolled in the study. EGFR mutation and ALK fusion were the most common studied biomarkers. EBUS-TBNA adequacy rate for biomarker tests was found 99.0% for EGFR, 99.1 for ALK, 97.2% for ROS1, 100% for BRAF and 99.3% for PD-L1 testing. Multivariate analysis revealed the histological type, history of treatment for NSCL, size, or 18-fluorodeoxyglucose uptake of sampled lesion did not show any association with TBNA adequacy for biomarker testing.

CONCLUSION

EBUS-TBNA can provide adequate material for biomarker testing for EGFR, ALK, ROS-1, BRAF and PD-L1 expression.

What Is New in Biomarker Testing at Diagnosis of Advanced Non-Squamous Non-Small Cell Lung Carcinoma? Implications for Cytology and Liquid Biopsy

The discovery and clinical validation of biomarkers predictive of the response of non-squamous non-small-cell lung carcinomas (NS-NSCLC) to therapeutic strategies continue to provide new data. The evaluation of novel treatments is based on molecular analyses aimed at determining their efficacy. These tests are increasing in number, but the tissue specimens are smaller and smaller and/or can have few tumor cells. Indeed, in addition to tissue samples, complementary cytological and/or blood samples can also give access to these biomarkers. To date, it is recommended and necessary to look for the status of five genomic molecular biomarkers (EGFR, ALK, ROS1, BRAFV600, NTRK) and of a protein biomarker (PD-L1). However, the short- and more or less long-term emergence of new targeted treatments of genomic alterations on RET and MET, but also on others’ genomic alteration, notably on KRAS, HER2, NRG1, SMARCA4, and NUT, have made cellular and blood samples essential for molecular testing. The aim of this review is to present the interest in using cytological and/or liquid biopsies as complementary biological material, or as an alternative to tissue specimens, for detection at diagnosis of new predictive biomarkers of NS-NSCLC.

Integrating endobronchial ultrasound bronchoscopy with molecular testing of immunotherapy biomarkers in non-small cell lung cancer

Immunotherapy has transformed treatment of advanced non-small-cell lung cancer (NSCLC) patients leading to remarkable long-term survival benefit. However, only about 20% of advanced NSCLC patients typically respond to immune checkpoint inhibitors (ICIs) that target the PD-1/PD-L1 pathway. The only validated biomarker for ICI therapy is the PD-L1 immunohistochemistry (IHC) test, which is considered an imperfect assay due to several variables including availability and integrity of tumour tissue, variability in staining/scoring techniques and heterogeneity in PD-L1 protein expression within and across tumour biopsies. Herein, we discuss integrating minimally invasive EBUS bronchoscopy procedures with novel molecular approaches to improve accuracy and sensitivity of PD-L1 testing. EBUS guided bronchoscopy facilitates repeated sampling of tumour tissue to increase the probability of detecting PD-L1 positive tumours. Since intra-tumoural PD-L1 (CD274) copy number is reported to be less heterogeneous than PD-L1 protein detection, quantifying PD-L1 transcript levels may increase detection of PD-L1 positive tumours. PD-L1 transcript levels show excellent concordance with PD-L1 IHC scoring and multiplex digital droplet PCR (ddPCR) assays that quantify absolute PD-L1 transcript copy number have been developed. ddPCR can also be automated for high throughput detection of low abundant variants with excellent sensitivity and accuracy to improve the broader application of diagnostic cut-off values. Optimizing diagnostic workflows that integrate optimal EBUS bronchoscopy procedures with emerging molecular ICI biomarker assays may improve the selection criteria for ICI therapy benefit.

Next-Generation Sequencing with Liquid Biopsies from Treatment-Naïve Non-Small Cell Lung Carcinoma Patients

Recently, the liquid biopsy (LB), a non-invasive and easy to repeat approach, has started to compete with the tissue biopsy (TB) for detection of targets for administration of therapeutic strategies for patients with advanced stages of lung cancer at tumor progression. A LB at diagnosis of late stage non-small cell lung carcinoma (NSCLC) is also being performed. It may be asked if a LB can be complementary (according to the clinical presentation or systematics) or even an alternative to a TB for treatment-naïve advanced NSCLC patients. Nucleic acid analysis with a TB by next-generation sequencing (NGS) is gradually replacing targeted sequencing methods for assessment of genomic alterations in lung cancer patients with tumor progression, but also at baseline. However, LB is still not often used in daily practice for NGS. This review addresses different aspects relating to the use of LB for NGS at diagnosis in advanced NSCLC, including its advantages and limitations.

Feasibility of Performing Transvascular Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

BACKGROUND

Thoracic vascular structures often preclude transbronchial access to central lung parenchymal lesions and lymph nodes, thereby necessitating either a surgical or transvascular needle aspiration (TVNA) approach for diagnostic sampling. The aim of this study was to evaluate the safety and efficacy of endobronchial ultrasound (EBUS) TVNA in the diagnosis and staging of mediastinal tumors.

PATIENTS AND METHODS

We performed a retrospective analysis of 35 cases of EBUS-TVNA. Cases were reviewed in the Cerner electronic medical records between March 2013 and October 2018. Records were reviewed for patient comorbidities, smoking status, anticoagulation intake, procedural details, sample results, and postprocedural complications.

RESULTS

Thirty-five EBUS-TVNA procedures were reviewed. Twenty-nine of them were performed by traversing the main pulmonary artery or its branches. Three involved transvascular access through the azygous vein, 2 via the brachiocephalic artery and 1 through the superior vena cava. Only 4 patients (11.4%) experienced postprocedural complications, which included mild hemoptysis, moderate hemoptysis requiring epinephrine and saline infusion, acute exacerbation of chronic obstructive pulmonary disease, and a rapid ventricular rate on top of preexisting atrial fibrillation. The yield of TVNA for malignancy was 22 (95.6%) of 23 patients. Overall yield was 31 (88.6%) of 35, with a need for additional intervention in 4 (11.4%) of 35 patients. Mutational analysis was adequate when ordered.

CONCLUSION

In our single-center experience, the EBUS-TVNA procedure had a high diagnostic yield and was associated with low rates of postprocedural complications. Further trials are needed to assess its efficacy compared to more invasive procedures.

Collection and Handling of Thoracic Small Biopsy and Cytology Specimens for Ancillary Studies: Guideline From the College of American Pathologists in Collaboration With the American College of Chest Physicians, Association for Molecular Pathology, American Society of Cytopathology, American Thoracic Society, Pulmonary Pathology Society, Papanicolaou Society of Cytopathology, Society of Interventional Radiology, and Society of Thoracic Radiology

CONTEXT.—

The need for appropriate specimen use for ancillary testing has become more commonplace in the practice of pathology. This, coupled with improvements in technology, often provides less invasive methods of testing, but presents new challenges to appropriate specimen collection and handling of these small specimens, including thoracic small biopsy and cytology samples.

OBJECTIVE.—

To develop a clinical practice guideline including recommendations on how to obtain, handle, and process thoracic small biopsy and cytology tissue specimens for diagnostic testing and ancillary studies.

METHODS.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. Core needle biopsy, touch preparation, fine-needle aspiration, and effusion specimens with thoracic diseases including malignancy, granulomatous process/sarcoidosis, and infection (eg, tuberculosis) were deemed within scope. Ancillary studies included immunohistochemistry and immunocytochemistry, fluorescence in situ hybridization, mutational analysis, flow cytometry, cytogenetics, and microbiologic studies routinely performed in the clinical pathology laboratory. The use of rapid on-site evaluation was also covered.

RESULTS.—

Sixteen guideline statements were developed to assist clinicians and pathologists in collecting and processing thoracic small biopsy and cytology tissue samples.

CONCLUSIONS.—

Based on the systematic review and expert panel consensus, thoracic small specimens can be handled and processed to perform downstream testing (eg, molecular markers, immunohistochemical biomarkers), core needle and fine-needle techniques can provide appropriate cytologic and histologic specimens for ancillary studies, and rapid on-site cytologic evaluation remains helpful in appropriate triage, handling, and processing of specimens.

Novel multiplex droplet digital PCR assay for scoring PD-L1 in non-small cell lung cancer biopsy specimens

OBJECTIVES

Immune checkpoint inhibitors have become integrated into the clinical management of non-small cell lung cancer (NSCLC). Using RTqPCR, we have previously identified a gene expression panel that detected presence of malignant cells (MMP9:TIMP3 ratio) and quantified PD-L1 transcript levels in small biopsy specimens. However, RTqPCR has diagnostic limitations as it does not generate absolute copy number and is not readily multiplexed. To address this, we have developed a multiplex droplet digital PCR (ddPCR) assay.

MATERIALS AND METHODS

Biopsies obtained from NSCLC patients (n = 48 adenocarcinoma and n = 40 squamous cell carcinoma) and control lung biopsy specimens (n = 20) were analysed. Absolute MMP9, TIMP3 and PD-L1 transcript copy numbers were determined within a single assay by multiplex ddPCR using Taqman primers and the QX200 Droplet Digital PCR System.

RESULTS AND CONCLUSIONS

Using our optimised triplex ddPCR assay, the MMP9:TIMP3 ratio was significantly elevated in NSCLC biopsies and using a cut-off of >0.028, was 99% (95% CI; 80.5-94.5) sensitive and 80% specific for identifying malignant biopsies. The PD-L1:TIMP3 ratio significantly associated with PD-L1 tumour cell immunohistochemistry staining (r = 0.539, p < 0.0001) and was significantly higher in biopsies with >50% PD-L1 tumour cell staining (p < 0.0001). In summary, a major advantage of our workflow is that it can accurately quantify PD-L1 tumour levels and provide sufficient nucleic acid for screening additional targetable mutations such as EGFR, ALK and ROS1 from a single small biopsy, thereby potentially avoiding the need for re-biopsy. Future studies will need to determine diagnostic ddPCR values that are predictive of clinical response to PD-1/PD-L1 immunotherapy.

Validation of a Next-Generation Sequencing Assay Targeting RNA for the Multiplexed Detection of Fusion Transcripts and Oncogenic Isoforms

CONTEXT.—

Next-generation sequencing is a high-throughput method for detecting genetic abnormalities and providing prognostic and therapeutic information for patients with cancer. Oncogenic fusion transcripts are among the various classifications of genetic abnormalities present in tumors and are typically detected clinically with fluorescence in situ hybridization (FISH). However, FISH probes only exist for a limited number of targets, do not provide any information about fusion partners, cannot be multiplex, and have been shown to be limited in specificity for common targets such as ALK.

OBJECTIVE.—

To validate an anchored multiplex polymerase chain reaction-based panel for the detection of fusion transcripts in a university hospital-based clinical molecular diagnostics laboratory.

DESIGN.—

We used 109 unique clinical specimens to validate a custom panel targeting 104 exon boundaries from 17 genes involved in fusions in solid tumors. The panel can accept as little as 100 ng of total nucleic acid from PreservCyt-fixed tissue, and formalin-fixed, paraffin-embedded specimens with as little as 10% tumor nuclei.

RESULTS.—

Using FISH as the gold standard, this assay has a sensitivity of 88.46% and a specificity of 95.83% for the detection of fusion transcripts involving ALK, RET, and ROS1 in lung adenocarcinomas. Using a validated next-generation sequencing assay as the orthogonal gold standard for the detection of EGFR variant III (EGFRvIII) in glioblastomas, the assay is 92.31% sensitive and 100% specific.

CONCLUSIONS.—

This multiplexed assay is tumor and fusion partner agnostic and will provide clinical utility in therapy selection for patients with solid tumors.

Molecular testing strategies in non-small cell lung cancer: optimizing the diagnostic journey

Molecular testing identifies patients with advanced non-small cell lung cancer (NSCLC) who may benefit from targeted therapy or immunotherapy (i.e., immune checkpoint inhibitor treatment for patients with high tumor mutational burden (TMB), microsatellite instability-high or mismatch repair-deficient tumors). Current guidelines state that molecular testing should be conducted at the time of initial diagnosis and tumor progression on targeted therapy. In real-world clinical practice in the United States (US), molecular testing is often not conducted or happens late in the diagnostic journey, resulting in delayed or inappropriate treatment. Herein, we review the rationale for molecular testing in advanced NSCLC, along with best-practice guidelines based on published recommendations and our own clinical experience, including a case study. We propose three strategies to optimize molecular testing in newly diagnosed patients with advanced NSCLC: (I) pulmonologists, interventional radiologists, or thoracic surgeons order molecular tests as soon as advanced NSCLC with an adenocarcinoma component is suspected; (II) liquid biopsies conducted early in the diagnostic pathway; and (III) pathologist-directed reflex testing, as conducted in other areas of oncology. To help facilitate these strategies, we outline our recommendations for optimal sample collection techniques and stewardship. In summary, we believe that implementation of these individual strategies will allow clinicians to effectively leverage available treatment options for advanced NSCLC, reducing the time to optimal treatment and improving patient outcomes.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration for Diagnosis and Staging of Lung Cancer

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS TBNA) is fundamental to the diagnosis of lung cancer, as many patients present with more advanced stages of lung cancer, with enlarged hilar and mediastinal lymph nodes. It also represents a way to sample pulmonary masses directly to make the diagnosis, whereby no other accessible tissue is present and the mass sits adjacent to a large central airway. Very importantly also, EBUS TBNA is the widely accepted first procedure in lung cancer staging. A combined procedure of EUS TBNA can be performed to improve diagnostic accuracy.

Next-Generation Sequencing for Genotyping of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration Samples in Lung Cancer

BACKGROUND

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) can obtain a small amount of specimen. This study aims to evaluate the feasibility and robustness of using EBUS-EBNA samples to perform capture-based targeted next-generation sequencing (NGS).

METHODS

Tissue samples from patients with advanced non-small cell lung cancer were collected by EBUS-TBNA and were formalin-fixed paraffin-embedded. Three representative genes, EGFR, ALK, and ROS1, were examined by amplification refractory mutation system polymerase chain reaction, immunohistochemistry, and quantitative reverse transcription polymerase chain reaction. The remaining samples were processed with NGS assay with a 56-gene panel. Classic driver mutations detected by NGS were verified by conventional methods.

RESULTS

Of the 85 samples from patients with advanced non-small cell lung cancer, 77 were performed successfully with all assays. Forty-one mutations in EGFR, ALK, and ROS1 were detected in both conventional methods and NGS, representing a 100% concordance. In contrast, four EGFR mutations detected by NGS were not covered in the targeted regions of amplification refractory mutation system polymerase chain reaction, leading to a negative call in these patients. Altogether, NGS detected 12 additional variants, including six KRAS mutations, one BRAF mutation, one RET fusion, one MET amplification concurrent with EGFR L858R, one KRAS amplification together with EGFR 19del, and one ERBB2 amplification. The mean number of needle passes per lymph node was 5.2 in samples successfully applied in all assays.

CONCLUSIONS

NGS assay can be successfully conducted with limited tissue samples obtained from EBUS-TBNA. Compared with conventional methods, NGS assay provides more comprehensive information on genetic alterations in tumors, which greatly assists therapeutic decision making for advanced lung cancer.

What should be known prior to performing EUS exams? (Part II)

In “What should be known prior to performing EUS exams, Part I,” the authors discussed the need for clinical information and whether other imaging modalities are required before embarking EUS examinations. Herewith, we present part II which addresses some (technical) controversies how EUS is performed and discuss from different points of view providing the relevant evidence as available. (1) Does equipment design influence the complication rate? (2) Should we have a standardized screen orientation? (3) Radial EUS versus longitudinal (linear) EUS. (4) Should we search for incidental findings using EUS?

Endobronchial ultrasound-guided transbronchial needle aspiration with the flexible 19-gauge needle

INTRODUCTION AND OBJECTIVES

Endosonography has become standard of care in the diagnostic work-up of mediastinal lymphadenopathy and peribronchial lung lesions, but its success rate in some specific settings/conditions may be hampered by limited needle flexibility and size. We report on our initial experience with the 19G Flex needle, characterized by larger size and greater flexibility as compared with the currently available cytology needles.

METHODS

Retrospective review of prospectively collected data on the first 13 consecutive patients submitted to endosonography with the 19G Flex needle. Patients were included if they had: (a) suspicion of a histologically complex disease (ie, lymphoma); (b) suspicion of an advanced lung cancer possibly requiring extensive genotyping; (c) a lesion whose sampling with a 22G needle had failed because of lack of visibility when the needle was loaded into the scope.

RESULTS

The 13 patients enrolled had a mean age of 58.15 ± 17 years and a male to female ratio of 8:5. Target lesions (mean size 18.6 ± 6.4 mm) were lymphadenopathies (9 patients), lung lesions (3 patients) and a pleural nodule (1 patient). Histology core/s and a definite diagnosis (adenocarcinoma, 4 cases; lymphoma, 2; mesothelioma, 2, metastases from extrathoracic tumors, 2; non-small-cell lung cancer not otherwise specifiable, 1; small cell carcinoma, 1; sarcoidosis, 1) were obtained in 100% of patients. A single case of self-resolving bleeding was the only complication we observed.

CONCLUSIONS

Preliminary results obtained with the dedicated Flex 19G needle are promising, as sample size/quality is satisfactory and the needle influence on scope flexibility is minimal.