Comparison of Programmed Death Ligand-1 Immunohistochemical Staining Between Endobronchial Ultrasound Transbronchial Needle Aspiration and Resected Lung Cancer Specimens

Current status and progress of PD-L1 detection: guiding immunotherapy for non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths and represents a substantial disease burden worldwide. Immune checkpoint inhibitors combined with chemotherapy are the standard first-line therapy for advanced NSCLC without driver mutations. Programmed death-ligand 1 (PD-L1) is currently the only approved immunotherapy marker. PD-L1 detection methods are diverse and have developed rapidly in recent years, such as improved immunohistochemical detection methods, the application of liquid biopsy in PD-L1 detection, genetic testing, radionuclide imaging, and the use of machine learning methods to construct PD-L1 prediction models. This review focuses on the detection methods and challenges of PD-L1 from different sources, and discusses the influencing factors of PD-L1 detection and the value of combined biomarkers. Provide support for clinical screening of immunotherapy-advantage groups and formulation of personalized treatment decisions.

The efficacy outcomes in non-small cell lung cancer patients treated with PD axis inhibitor agents - a population-based study of the Vojvodina region

Background: By 2021, the FDA approved the use of the drugs pembrolizumab and atezolizumab in the first-line treatment of patients with high positivity of programmed death ligand-1 (PD-L1) in locally advanced and metastatic non-small-cell-lung cancer (NSCLC). This approval was the result of statistically significant evidence from international, multicentric clinical studies that all reported increasing progression-free survival (PFS) and overall survival (OS) in these patients. Methods: In our study, we reported the demographic and clinical characteristics of 79 patients diagnosed with NSCLC with expression of PD-L1 ≥50% from January 2019 to December 2022 at the Institute for Pulmonary Diseases of Vojvodina, who received pembrolizumab therapy as the first-line treatment. Patients were divided according to the histological type of lung cancer as adenocarcinoma (ADC) or squamous cell carcinoma (SCC) of the lung. In 52 of the 79 patients, PFS and in 32 of them overall survival (censored OS) was shown according to the histological type of tumor, the tumor proportion score (TPS) of PDL-1 expression, and the metastatic status within the Tumor Nodes Metastasis (TNM) disease classification. Independent factors of death outcome were shown by multivariable proportional hazard regression analysis. Results: The study included 79 patients diagnosed with NSCLC with an expression of PD-L1 ≥50%, 50 (63.3%) patients with ADC, and 29 (36.7%) patients with SCC, whose 55 (69.6%) PDL-1 expression was obtained from broncho biopsy (BB). The majority of patients, 49 (62%), had a TPS PD-L1 score of 51%-79%. Median, PFS for adenocarcinoma was 22 months and censored OS was 27 months, while for squamous cell carcinoma, median PFS was 12 months, and censored OS was 21 months. M1b disease stage, which was the most common in patients, had a PFS of 16 months and a censored OS of 18 months. Conclusion: Pembrolizumab monotherapy in patients with NSCLC in the fourth stage of the disease and with the positivity of the immune checkpoint protein TPS PD-L1 above 50% represents a safe therapy that allows a satisfactory period without disease progression and overall survival with acceptable treatment complications.

Programmed Death Ligand-1 and Tumor Mutation Burden Testing of Patients With Lung Cancer for Selection of Immune Checkpoint Inhibitor Therapies: Guideline From the College of American Pathologists, Association for Molecular Pathology, International Association for the Study of Lung Cancer, Pulmonary Pathology Society, and LUNGevity Foundation

CONTEXT.—

Rapid advancements in the understanding and manipulation of tumor-immune interactions have led to the approval of immune therapies for patients with non-small cell lung cancer. Certain immune checkpoint inhibitor therapies require the use of companion diagnostics, but methodologic variability has led to uncertainty around test selection and implementation in practice.

OBJECTIVE.—

To develop evidence-based guideline recommendations for the testing of immunotherapy/immunomodulatory biomarkers, including programmed death ligand-1 (PD-L1) and tumor mutation burden (TMB), in patients with lung cancer.

DESIGN.—

The College of American Pathologists convened a panel of experts in non-small cell lung cancer and biomarker testing to develop evidence-based recommendations in accordance with the standards for trustworthy clinical practice guidelines established by the National Academy of Medicine. A systematic literature review was conducted to address 8 key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, recommendations were created from the available evidence, certainty of that evidence, and key judgments as defined in the GRADE Evidence to Decision framework.

RESULTS.—

Six recommendation statements were developed.

CONCLUSIONS.—

This guideline summarizes the current understanding and hurdles associated with the use of PD-L1 expression and TMB testing for immune checkpoint inhibitor therapy selection in patients with advanced non-small cell lung cancer and presents evidence-based recommendations for PD-L1 and TMB testing in the clinical setting.

Endobronchial Ultrasound Guided Transbronchial Needle Aspiration and PD-L1 Yields

PURPOSE

Immunotherapy is a leading approach for treating advanced non-small cell lung cancer (NSCLC) by targeting the PD-1/PD-L1 checkpoint signaling pathway, particularly in tumors expressing high levels of PD-L1 (Jug et al. in J Am Soc Cytopathol 9:485-493, 2020; Perrotta et al. in Chest 158: 1230-1239, 2020). Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive method to obtain tissue for molecular studies, including PD-L1 analysis, in unresectable tumors (Genova et al. in Front Immunol 12: 799455, 2021; Wang et al. in Ann Oncol 29: 1417-1422, 2018). This study aimed to assess the adequacy of PD-L1 assessment in EBUS-TBNA cytology specimens.

METHODS

Data was collected retrospectively from patients who underwent EBUS-TBNA between 2017 and 2021 for suspected lung cancer biopsy. Samples positive for NSCLC were examined for PD-L1 expression. EBUS was performed by experienced practitioners, following institutional guidelines of a minimum of five aspirations from positively identified lesions. Sample adequacy for molecular testing was determined by the pathology department.

RESULTS

The analysis involved 387 NSCLC cases (149 squamous cell, 191 adenocarcinoma, 47 unspecified). Of the 263 EBUS-TBNA specimens tested for PD-L1, 237 (90.1%) were deemed adequate. While 84% adhered to the protocol, adherence did not yield better results. Significantly higher PD-L1 adequacy was observed in squamous cell carcinomas (93.2%) compared to adenocarcinoma (87.6%). The number of aspirations and sedation type did not correlate with PD-L1 adequacy in either cancer type, but lesion size and location had a significant impact in adenocarcinomas. Adenocarcinoma exhibited higher PD-L1 expression (68%) compared to squamous cell carcinoma (48%).

CONCLUSION

EBUS-TBNA offers high yields for assessing immunotherapy markers like PD-L1, with satisfactory adequacy regardless of NSCLC subtype, lesion size, or location.

Comparison of primary and metastatic site-related PD-L1 expression in predicting ORR in patients with advanced NSCLC who received ICB-based therapy

BACKGROUND

Whether the value of PD-L1 expression from metastatic sites to predict the efficacy of immune checkpoint blockade (ICB)-based treatment is equivalent to that from a primary tumor is uncertain. This study aimed to compare the utility of PD-L1 TPS from a primary lung tumor and metastatic sites to predict the overall response rate (ORR) of first-line ICB-based treatment.

METHODS

This study included 249 patients with advanced non-small cell lung cancer (NSCLC) who received first-line ICB-based treatment. All subjects underwent PD-L1 testing prior to ICB-based treatment and were divided into two cohorts corresponding to the different biopsy sites: lung primary site-sampled cohort (PT cohort, n = 167) and metastatic site-sampled cohort (MT cohort, n = 82).

RESULTS

There was no statistical significance in PD-L1 TPS distribution between the two cohorts (p = 0.742). PD-L1 TPS ≥50% was also related to high ORR compared with PD-L1 < 50% in the PT cohort (34.3% vs. 14.1%, p = 0.004). In contrast, ICB-based therapy could bring comparable ORR (35.1% vs. 33.3%, p = 0.871) in the MT cohort regardless of PD-L1 TPS status (≥50%, or <50%). As supported, when the cutoff value of TPS was selected as 50%, it was suggested that PT-related PD-L1 was the independent predictor of ORR (OR 2.870, 95% CI: 1.231-6.694, p = 0.015) rather than MT-related PD-L1 (OR 0.689, 95% CI: 0.236-2.013, p = 0.495). Furthermore, ROC proved that PT-related PD-L1 expression manifested a better AUC of 0.621 (p = 0.026) than that of MT-related PD-L1 (AUC = 0.565, p = 0.362).

CONCLUSION

Compared with PT-related PD-L1 expression, MT-related PD-L1 expression showed limited value in predicting ORR in patients with advanced NSCLC receiving ICB-based therapy. It was concluded that even patients with low MT-related PD-L1 expression could benefit from ICB-based therapy.

Accuracy of Cytologic vs Histologic Specimens for Assessment of Programmed Cell Death Ligand-1 Expression in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Programmed cell death ligand-1 (PD-L1) expression on tumor cells, evaluated by immunohistochemistry, guides the use of immunotherapy in advanced non-small cell lung cancer (NSCLC).

RESEARCH QUESTION

What is the sensitivity and specificity of PD-L1 testing performed in cytologic vs paired histologic specimens in patients with NSCLC?

STUDY DESIGN AND METHODS

The MEDLINE, Embase, Web of Science, and Cochrane Library databases were searched through June 1, 2021. The primary outcome was pooled sensitivity and specificity of PD-L1 testing performed on cytologic specimens compared with the reference standard of histologic specimens, analyzed at the PD-L1 expression cutoffs (tumor proportion score) ≥ 1% and ≥ 50%. Pooled sensitivity and specificity, and associated 95% CIs, were estimated using bivariate generalized linear mixed models.

RESULTS

Twenty-six articles were included, encompassing a total of 1,064 pairs of histology specimens and cytology cell blocks, and 267 pairs of histology specimens and direct smears. Among these, 946 paired specimens were acquired without interval treatment between the collection of histology and cytology samples. The pooled sensitivity and specificity of cytology specimens compared with paired histology specimens at the PD-L1 expression cutoff ≥ 1% were 0.84 (95% CI, 0.77-0.89) and 0.88 (95% CI, 0.82-0.93), respectively, whereas the pooled sensitivity and specificity at cutoff ≥ 50% were 0.78 (95% CI, 0.69-0.86) and 0.94 (95% CI, 0.91-0.96), respectively. When only paired specimens acquired without interval treatment were considered, the pooled sensitivity and specificity of cytology specimens at PD-L1 expression cutoff ≥ 1% were 0.84 (95% CI, 0.76-0.90) and 0.89 (95% CI, 0.82-0.94), respectively, whereas the pooled sensitivity and specificity at cutoff ≥ 50% were 0.80 (95% CI, 0.71-0.89) and 0.94 (95% CI, 0.91-0.96), respectively.

INTERPRETATION

Cytologic specimens provide an accurate assessment of PD-L1 expression in most patients with NSCLC, at both ≥ 1% and ≥ 50% cutoffs, when compared with histologic specimens.

TRIAL REGISTRATION

PROSPERO; No.: CRD42020153279; URL: https://www.crd.york.ac.uk/prospero/.

Performance of endobronchial ultrasound transbronchial needle aspiration as the first nodal staging procedure for the determination of programmed death ligand-1 expression in non-small cell lung cancer patients

PURPOSE

The determination of the programmed death ligand-1 (PD-L1) expression is part of the diagnostic algorithm for advanced non-small cell lung cancer (NSCLC) patients. We aimed to analyze the diagnostic performance of EBUS-TBNA performed as first-choice nodal staging procedure for the determination of PD-L1 expression in NSCLC patients.

METHODS

Longitudinal-prospective study including NSCLC patients diagnosed between January 2018 and October 2019, for whom a primary tumor biopsy sample and an EBUS-TBNA cytological malignant sample were available. Samples with fewer than 100 malignant cells were considered inadequate. PDL-1 IHC 22C3 pharmDx antibody was used. The percentage of tumor cells expressing PD-L1, setting 1% and 50% as cutoff points, was collected. The weighted kappa coefficient was used to assess the concordance of PD-L1 expression. The PD-L1 expression was compared in precision terms.

RESULTS

From a total of 43 patients, 53 pairs of samples were obtained, of which 23 (43.4%) were adequate and included for analysis. The weighted kappa coefficient for PD-L1 expression was 0.41 (95% CI 0.15-0.68) and 0.56 (95% CI 0.23-0.9) for cutoff values ≥ 1% and ≥ 50%, respectively. In advanced stages, the weighted kappa coefficient was 0.6 (95% CI 0.3-0.9) and 1 (95% CI 1-1) for PD-L1 expression cutoff values ≥ 1% and ≥ 50%, respectively. EBUS-TBNA showed a sensitivity, specificity, positive predictive value, and negative predictive value of 1 to detect PDL-1 expression ≥ 50% in advanced stages.

CONCLUSION

EBUS-TBNA performed as first nodal staging procedure in advanced NSCLC patients provides reliable specimens for the detection of PD-L1 expression ≥ 50% and could guide immunotherapy.

Invasive Diagnostic Procedures from Bronchoscopy to Surgical Biopsy-Optimization of Non-Small Cell Lung Cancer Samples for Molecular Testing

Background and Objectives: Treatment of advanced lung cancer (LC) has become increasingly personalized over the past decade due to an improved understanding of tumor molecular biology and antitumor immunity. The main task of a pulmonologist oncologist is to establish a tumor diagnosis and, ideally, to confirm the stage of the disease with the least invasive technique possible. Materials and Methods: The paper will summarize published reviews and original papers, as well as published clinical studies and case reports, which studied the role and compared the methods of invasive pulmonology diagnostics to obtain adequate tumor tissue samples for molecular analysis, thereby determining the most effective molecular treatments. Results: Bronchoscopy is often recommended as the initial diagnostic procedure for LC. If the tumor is endoscopically visible, the biopsy sample is susceptible to molecular testing, the same as tumor tissue samples obtained from surgical resection and mediastinoscopy. The use of new sampling methods, such as cryobiopsy for peripheral tumor lesions or cytoblock obtained by ultrasound-guided transbronchial needle aspiration (TBNA), enables obtaining adequate small biopsies and cytological samples for molecular testing, which have until recently been considered unsuitable for this type of analysis. During LC patients' treatment, resistance occurs due to changes in the mutational tumor status or pathohistological tumor type. Therefore, the repeated taking of liquid biopsies for molecular analysis or rebiopsy of tumor tissue for new pathohistological and molecular profiling has recently been mandated. Conclusions: In thoracic oncology, preference should be given to the least invasive diagnostic procedure providing a sample for histology rather than for cytology. However, there is increasing evidence that, when properly processed, cytology samples can be sufficient for both the cancer diagnosis and molecular analyses. A good knowledge of diagnostic procedures is essential for LC diagnosing and treatment in the personalized therapy era.

Clinical Applications of Endobronchial Ultrasound (EBUS) Scope: Challenges and Opportunities

Endobronchial Ultrasound (EBUS) has been widely used to stage lung tumors and to diagnose mediastinal diseases. In the last decade, this procedure has evolved in several technical aspects, with new tools available to optimize tissue sampling and to increase its diagnostic yield, like elastography, different types of needles and, most recently, miniforceps and cryobiopsy. Accordingly, the indications for the use of the EBUS scope into the airways to perform the Endobronchial Ultrasound-TransBronchial Needle Aspiration (EBUS-TBNA) has also extended beyond the endobronchial and thoracic boundaries to sample lesions from the liver, left adrenal gland and retroperitoneal lymph nodes via the gastroesophageal tract, performing the Endoscopic UltraSound with Bronchoscope-guided Fine Needle Aspiration (EUS-B-FNA). In this review, we summarize and critically discuss the main indication for the use of the EBUS scope, even the more uncommon, to underline its utility and versatility in clinical practice.

Handling and standardization of EBUS needle aspiration in NSCLC patients: The value of the cell block, a monoinstitutional experience

BACKGROUND

Lung cancer is the main cause of cancer-related death worldwide, and 85% of all lung tumors are non-small cell lung cancers (NSCLC). More than 60% of all lung tumors are diagnosed at an advanced stage, leading to poor prognosis. Given the growing demand for NSCLC profiling for selection of the most appropriate therapy, the acquisition of adequate tumor samples has become increasingly crucial, mostly in advanced NSCLC patients due to old age and/or comorbidities. Being a mini-invasive sampling technique, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) represents a valuable alternative to traditional transthoracic or surgical sampling in these patients, and perfoming cell block (CB) could be crucial to maximize the potential biological information. The aim of this study is to describe a monoinstitutional interprofessional experience in handling EBUS-TBNA and CB in 464 patients.

METHODS

We retrospectively collected all the consecutive CBs obtained from EBUS TBNA performed between 2014 and 2021 on the lung lesions or mediastinal lymph nodes. All the CBs were handled in a standardized method.

RESULTS

A total of 95.5% (448/464 samples) of adequacy for site and 92.6% (430/464) of adequacy for diagnosis were observed. Moreover, in the adenocarcinoma histotype, ALK, ROS1 and tumor proportion score (TPS) PD-L1 assessment by IHC was possible in 96% (140/146) of cases, and molecular profile was obtained in 93.8% (137/146) of cases. In the squamous cell carcinoma histotype, TPS PD-L1 assessment was possible in 81% (13/16) of cases. All four CB results obtained from carcinoma NOS were adequate for ALK, ROS1 and PD-L1 assessment and molecular profiling. All 39 metastatic samples from extra-pulmonary primary were adequate for immunohistochemical characterization and molecular profiling. Finally, reporting of the tumor sample adequacy to the clinicians took a median time of about 30 h (range: 24-80 h).

CONCLUSION

Careful cytological smear management together with the handling and standardization of CB obtained from EBUS-TBNA could represent an effective method to increase the adequacy of the tumor specimen for both diagnosis and molecular profile.

PD-L1 immunohistochemistry: Clones, cutoffs, and controversies

Cancer immunotherapy has become a major component of oncologic treatment for a growing number of malignancies. Of particular interest to pathology has been monoclonal antibody therapy targeting immune checkpoints, notably programmed cell death (PD-1) and programmed cell death ligand (PD-L1). Targeting of these checkpoints attempt to overcome tumor evasion of the immune system. While PD-L1 testing is currently implemented as a predictive biomarker in multiple indications with the PD-L1 axis blockade, PD-L1 immunohistochemistry has been a complex issue for the pathology laboratory as it requires an understanding of multiple clones, on multiple testing platforms for multiple different malignancies, each with variable scoring criteria and thresholds. This review attempts to summarize the important PD-L1 testing algorithms and test performance for the practicing pathologist who actively reviews PD-L1 immunohistochemistry.

Suitability of endobronchial ultrasound-guided transbronchial needle aspiration samples for programmed death ligand-1 testing in non-small cell lung cancer, the Bristol experience

Treatment for non-small cell lung cancer (NSCLC) is now personalised using molecular mutation testing. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) biopsy suitability for anaplastic lymphoma kinase (ALK) and epidermal growth factor receptor (EGFR) mutation testing is established. Less is currently known about EBUS-TBNA suitability for PD-L1 (programmed death ligand-1) testing. To assess EBUS-TBNA biopsy adequacy for ALK, EGFR and PD-L1 testing, we conducted a prospective study of 279 consecutive NSCLC patients referred to a tertiary EBUS-TBNA centre in South West England. One hundred eight-four (62.6%) patients were found to have adenocarcinoma, 83 (28.2%) had squamous cell carcinoma, and 27 (9.2%) were identified as NSCLC-not otherwise specified. EGFR testing was successful in 166 of 168 patients (98.8%), ALK testing in all 115 and PD-L1 testing in 43 of 49 patients (88.2%). Previous EGFR and ALK testing did not affect biopsy PD-L1 testing success. PD-L1 testing failures occurred in three of five (60.0%) of 22G needle biopsies, one of five (20.0%) of 21G needle biopsies and two of 39 (5.1%) of 19G needle biopsies, P = .016. EBUS-TBNA biopsies are mostly suitable for PD-L1 testing. Larger needle size may improve PD-L1 (but not EGFR and ALK) testing success but requires further study in a controlled trial.

Program death ligand-1 immunocytochemistry in lung cancer cytological samples: A systematic review

In this era of personalized medicine, targeted immunotherapies like immune checkpoint inhibitors (ICI) blocking the programmed death‐1 (PD‐1)/program death ligand‐1 (PD‐L1) axis have become an integral part of treating advanced stage non‐small cell lung carcinoma (NSCLC) and many other cancer types. Multiple monoclonal antibodies are available commercially to detect PD‐L1 expression in tumor cells by immunohistochemistry (IHC). As most clinical trials initially required tumor biopsy for PD‐L1 detection by IHC, many of the currently available PD‐1/PD‐L1 assays have been developed and validated on formalin fixed tissue specimens. The majority (>50%) of lung cancer cases do not have a surgical biopsy or resection specimen available for ancillary testing and instead must rely primarily on fine needle aspiration biopsy specimens for diagnosis, staging and ancillary tests. Review of the literature shows multiple studies exploring the feasibility of PD‐L1 IHC on cytological samples. In addition, there are studies addressing various aspects of IHC validation on cytology preparations including pre‐analytical (e.g., different fixatives), analytical (e.g., antibody clone, staining platforms, inter and intra‐observer agreement, cytology‐histology concordance) and post‐analytical (e.g., clinical outcome) issues. Although promising results in this field have emerged utilizing cytology samples, many important questions still need to be addressed. This review summarizes the literature of PD‐L1 IHC in lung cytology specimens and provides practical tips for optimizing analysis.

Feasibility of EBUS-TBNA for histopathological and molecular diagnostics of NSCLC-A retrospective single-center experience

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive bronchoscopic procedure, well established as a diagnostic modality of first choice for diagnosis and staging of non-small cell lung cancer (NSCLC). The therapeutic decisions for advanced NSCLC require comprehensive profiling of actionable mutations, which is currently considered to be an essential part of the diagnostic process. The purpose of this study was to evaluate the utility of EBUS-TBNA cytology specimen for histological subtyping, molecular profiling of NSCLC by massive parallel sequencing (MPS), as well as for PD-L1 analysis. A retrospective review of 806 EBUS bronchoscopies was performed, resulting in a cohort of 132 consecutive patients with EBUS-TBNA specimens showing NSCLC cells in lymph nodes. Data on patient demographics, radiology features of the suspected tumor and mediastinal engagement, lymph nodes sampled, the histopathological subtype of NSCLC, and performed molecular analysis were collected. The EBUS-TBNA specimen proved sufficient for subtyping NSCLC in 83% and analysis of treatment predictive biomarkers in 77% (MPS in 53%). The adequacy of the EBUS-TBNA specimen was 69% for EGFR gene mutation analysis, 49% for analysis of ALK rearrangement, 36% for ROS1 rearrangement, and 33% for analysis of PD-L1. The findings of our study confirm that EBUS-TBNA cytology aspirate is appropriate for diagnosis and subtyping of NSCLC and largely also for treatment predictive molecular testing, although more data is needed on the utility of EBUS cytology specimen for MPS and PD-L1 analysis.

Lung cancer staging, the established role of bronchoscopy

PURPOSE OF REVIEW

Lung cancer is the leading cause of cancer-related deaths worldwide. In the absence of distant metastases, accurate mediastinal nodal staging determines treatment approaches to achieve most favourable outcomes for patients. Mediastinal staging differentiates N0/N1 disease from N2/N3 in surgical candidates. Likewise, presence of nodal involvement in nonsurgical candidates who are being considered for stereotactic body radiation therapy is also critical. This review article seeks to discuss the current options available for mediastinal staging in nonsmall cell lung cancer (NSCLC), particularly the role of bronchoscopy.

RECENT FINDINGS

Although several techniques are available to stage the mediastinum, bronchoscopy with EBUS-TBNA with or without EUS-FNA appears to be superior in most clinical situations based on its ability to concomitantly diagnose and stage at once, safety, accessibility to the widest array of lymph node stations, cost and low risk of complications. However, training and experience are required to achieve consistent diagnostic accuracy with EBUS-TBNA.

SUMMARY

EBUS-TBNA with or without EUS-FNA is considered the modality of choice in the diagnosis and staging of NSCLC in both surgical and nonsurgical candidates.

Linear Endobronchial Ultrasound in the Era of Personalized Lung Cancer Diagnostics-A Technical Review

Major advances in molecular profiling for available targeted treatments and immunotherapy for lung cancer have significantly increased the complexity of tissue-based diagnostics. Endobronchial ultrasound-guided transbronchial needle aspirations (EBUS-TBNA) are commonly performed for diagnostic biopsies and lymph node staging. EBUS-TBNA has increasingly become one of the main sources of tumor cells for molecular analyses. As a result, there is a growing need for high quality EBUS-TBNA samples with adequate cellularity. This has increased the technical demands of the procedure and has created additional challenges, many of which are not addressed in the current EBUS guidelines. This review provides an overview of current evidence on the technical aspects of EBUS-TBNA in light of comprehensive sample processing for personalized lung cancer management. These include sonographic lymph node characterization, optimal needle choice, suction biopsy technique, and the role of rapid on-site evaluation. Attention to these technical details will be important to maximize the throughput of EBUS-TBNA biopsies for molecular testing.

Endobronchial ultrasound in diagnosing and staging of lung cancer by Acquire 22G TBNB versus regular 22G TBNA needles: study protocol of a randomised clinical trial

INTRODUCTION

Accurate diagnosis and staging of lung cancer is crucial because it directs treatment and prognosis. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and endoscopic ultrasound with bronchoscope fine-needle aspiration (EUS-B-FNA) are important in this process by sampling hilar/mediastinal lymph nodes and centrally located lung tumours. With the upcoming of immunotherapy and targeted therapies, assessment of programmed death ligand 1 (PD-L1) expression and molecular profiling has become important but is often impossible in cytological samples obtained through standard 22G TBNA needles. Recently, a three-pronged cutting edge 22G needle was developed that allows for transbronchial needle biopsy (TBNB). Our objective is to determine if EBUS/EUS-B-guided nodal/lung tumour sampling with Acquire 22G TBNB needles results in an improved suitability rate for the assessment of PD-L1 expression in comparison to standard 22G TBNA needles in patients with a final diagnosis of lung cancer.

METHODS AND ANALYSIS

This is an investigator-initiated, parallel group randomised clinical trial. Patients are recruited at respiratory medicine outpatient clinics of participating university and general hospitals in the Netherlands, Poland and Italy. In total 158 adult patients with (suspected) lung cancer are included if they have an indication for mediastinal/hilar lymph node or lung tumour sampling by EBUS-TBNA and/or EUS-B-FNA based on current clinical guidelines. Web-based randomisation between the two needles will be performed. Samples obtained from mediastinal/hilar lymph nodes and/or primary tumour will be processed for cytology smears and cell block analysis and reviewed by blinded reference pathologists. An intention-to-treat analysis will be applied. Patients with missing data will be excluded from analysis for that specific variable but included in the analysis of other variables. This study is financially supported by Boston Scientific.

ETHICS AND DISSEMINATION

The study was approved by the local Ethics Committee (Medisch Ethische Toetsingscommissie Amsterdam Medical Center (AMC)). Dissemination will involve publication in a peer-reviewed biomedical journal.

TRIAL REGISTRATION NUMBER

NL7701; Pre-results.

The detection value of PD-L1 expression in biopsy specimens and surgical resection specimens in non-small cell lung cancer: a meta-analysis

Background

The detection value of different types of specimens for programmed death ligand-1 (PD-L1) expression remains controversial. As such, the purpose of this meta-analysis was to compare the detection value of biopsy specimens and surgical resection specimens for PD-L1 expression in patients with non-small cell lung cancer (NSCLC).

Methods

PubMed and Web of Science were searched prior to December 2020 to identify studies that compared the detection value of biopsy specimens and surgical resection specimens for PD-L1 expression in NSCLC. Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 scale was used to evaluate the quality of the literature included. The detection value of different types of specimens for PD-L1 expression was then assessed. Besides, the relative risk (RR) with 95% CI were pooled using Review Manager 5.3 software and Stata 14.0 software.

Results

The meta-analysis involved 12 articles and included 877 patients. There was no significant difference in the detection rate of PD-L1 at the 1% cutoff between biopsy specimens and surgical resection specimens (RR =0.89, 95% CI: 0.70–1.12, P=0.33). However, there was a significant difference between two groups when the cutoff is 50% (RR =0.69, 95% CI: 0.58–0.83, P<0.01). In addition, a subgroup analysis of the type of biopsy specimens and the PD-L1 qualitative immunohistochemistry (IHC) assays showed that the detection rate of PD-L1 in small biopsies and using the SP142 antibody were lower than in surgical specimens and using other antibodies for both the 1% and 50% cut-offs (P<0.01).

Conclusions

Current evidence suggests that caution must be taken when using biopsy specimens from patients with advanced NSCLC to evaluate PD-L1 status eligible for immunotherapy, additional biopsy specimens sampling may be needed to minimize the risk of tumor misclassification. In addition, PD-L1 qualitative IHC assays and the type of biopsy specimens related to PD-L1 expression detection.

Feasibility and reliability of evaluate PD-L1 expression determination using small biopsy specimens in non-small cell lung cancer

BACKGROUND

Programmed cell death ligand-1 (PD-L1) is a useful biomarker in non-small cell lung cancer (NSCLC) patients who would probably benefit from immunotherapy. In most patients with advanced stage NSCLC, only small biopsy specimens were available for the evaluation of PD-L1 expression. In this study, we evaluated the feasibility and reliability of PD-L1 testing on small biopsy samples.

METHODS

Small specimens of advanced NSCLC patients obtained via endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), endobronchial biopsy (EBB), or computed tomography (CT)-guided core-needle biopsy were collected. Tumor cell count and tissue sufficiency for PD-L1 immunohistochemistry (IHC) were evaluated and compared. The clinical course of patients who received immunotherapy in the study population was also examined.

RESULTS

Tissue acquisitions for PD-L1 testing in three groups were all above 90%, with no statistically significant differences. The PD-L1 expressions levels were concordant in most patients with more than one sample (8/11). In the EBB group, PD-L1-positive patients had higher objective response rate (ORR) (53.2% vs. 26.9%, p = 0.048) and longer progression-free survival (PFS) (312 vs. 179 days, p = 0.035) than PD-L1 negative patients. In the core needle biopsy group, patients with positive PD-L1 expression also trended to have higher ORR and longer PFS. However, in the EBUS-TBNA group, both ORR and PFS were similar between patients with positive or negative PD-L1 expression.

CONCLUSIONS

This study showed that EBUS-TBNA, EBB, and core needle biopsy provides adequate samples for PD-L1 testing. The predictive value of PD-L1 expression on different small samples still warrants further studies.

Feasibility of comprehensive genotyping specimens from radial endobronchial ultrasonography and electromagnetic navigation bronchoscopy

Introduction

Mini-invasive bronchoscopic techniques (such as radial endobronchial ultrasonography (rEBUS) and electromagnetic navigation (EMN)) have been developed to reach the peripheral lung but result in small samples. The feasibility of an adequate molecular testing from these specimens has been very little studied.

Methods

We retrospectively reviewed EMN and rEBUS procedures performed in patients diagnosed with lung cancer in our institution in 2017 and 2018. We analysed the sensitivity for rEBUS and EMN and each sampling method, and the feasibility of a comprehensive molecular testing.

Results

In total, 317 rEBUS and 14 EMN were performed. Median sizes of tumours were 16 and 32 mm for EMN and rEBUS, respectively. Overall sensitivity for rEBUS and EMN was 84.3%. Cytology was found to be complementary with biopsies, with 13.3% of cancer diagnosed on cytology while biopsies were negative. Complication rate was 2.4% (pneumothorax 1.5%, mild haemoptysis 0.9%). Genotyping (immunohistochemistry for ROS1 and ALK followed by fluorescence in situ hybridisation if positive and hybrid capture next-generation sequencing covering 48 genes), when ordered (n=188), was feasible in 69.1% (EGFR 17.7%, KRAS 31.7%, BRAF 4.8%, ALK 1.2%, MET 3.1%, HER2 0.8%). PD-L1 (programmed death-ligand 1) expression, when ordered (n=232), could be analysed in 94% of cases. Overall, 56.9% (33 out of 58) of patients for whom genotyping was not feasible underwent a second sampling (12 pretreatment, 21 at progression), allowing for the detection of six actionable genotypes (five EGFR, one MET).

Conclusion

rEBUS and EMN are sensitive and safe procedures that result in limited samples, often not suitable for genotyping, highlighting the importance of integrating liquid biopsy in routine testing.

Radial EBUS and EMN bronchoscopies are safe and sensitive procedures for lung cancer diagnosis. Cytology is highly complementary with histology. These small samples are, however, not suitable for an exhaustive molecular testing in 30% of cases.https://bit.ly/3eZ7Xn0

PD-L1 Testing in Cytological Non-Small Cell Lung Cancer Specimens: A Comparison with Biopsies and Review of the Literature

INTRODUCTION

Programmed death-ligand 1 (PD-L1) expression is used for treatment prediction in non-small cell lung cancer (NSCLC). While cytology may be the only available material in the routine clinical setting, testing in clinical trials has mainly been based on biopsies.

METHODS

We included 2 retrospective cohorts of paired, concurrently sampled, cytological specimens and biopsies. Also, the literature on PD-L1 in paired cytological/histological samples was reviewed. Focus was on the cutoff levels ≥1 and ≥50% positive tumor cells.

RESULTS

Using a 3-tier scale, PD-L1 was concordant in 40/47 (85%) and 66/97 (68%) of the paired NSCLC cases in the 2 cohorts, with kappa 0.77 and 0.49, respectively. In the former cohort, all discordant cases had lower score in cytology. In both cohorts, concordance was lower in samples from different sites (e.g., biopsy from primary tumor and cytology from pleural effusion). Based on 25 published studies including about 1,700 paired cytology/histology cases, the median (range) concordance was 81-85% (62-100%) at cutoff 1% for a positive PD-L1 staining and 89% (67-100%) at cutoff 50%.

CONCLUSIONS

The overall concordance of PD-L1 between cytology and biopsies is rather good but with significant variation between laboratories, which calls for local quality assurance.

Selecting the optimal immunotherapy regimen in driver-negative metastatic NSCLC

The treatment landscape of driver-negative non-small-cell lung cancer (NSCLC) is rapidly evolving. Immune-checkpoint inhibitors, specifically those targeting PD-1 or PD-L1, have demonstrated durable efficacy in a subset of patients with NSCLC, and these agents have become the cornerstone of first-line therapy. Approved immunotherapeutic strategies for treatment-naive patients now include monotherapy, immunotherapy-exclusive regimens or chemotherapy-immunotherapy combinations. Decision making in this space is complex given the absence of head-to-head prospective comparisons, although a thorough analysis of long-term efficacy and safety data from pivotal clinical trials can provide insight into the optimal management of each subset of patients. Indeed, histological subtype and the extent of tumour cell PD-L1 expression are paramount to regimen selection, although other clinicopathological factors and patient preferences might also be relevant in certain scenarios. Finally, several emerging biomarkers and novel therapeutic strategies are currently under investigation, and these might further refine the current treatment paradigm. In this Review, we discuss the current treatment landscape and detail our approach to first-line immunotherapy regimen selection for patients with advanced-stage, driver-negative NSCLC.

Suitability of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration versus Paired Transbronchial Biopsy Specimens for Evaluating Programmed Death Ligand-1 Expression in Stage III and IV Lung Cancer: A Comparative Retrospective Study

Objectives: Cancer cells usually escape tumor-reactive T-cell responses using immune checkpoint proteins, such as programmed death protein-1 (PD-1) and its ligand, programmed death ligand-1 (PD-L1). These proteins can be blocked by immune checkpoint inhibitors (ICIs); the decision on ICI-based first-line treatment for advanced lung cancers depends on the PD-L1 levels in tumor specimens. Determining the PD-L1 expression conventionally requires histological specimens from resected tumors and core biopsy specimens. Non-small cell lung cancer (NSCLC) is usually diagnosed at stage III or IV; therefore, only small biopsy specimens, such as those obtained via endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) are available. However, the suitability of EBUS-TBNA specimens determining the PD-L1 expression levels in advanced lung cancers remains unclear.

Materials and Methods: Here, we investigated the concordance rate of PD-L1 expression between EBUS-TBNA and matched transbronchial biopsy (TBB) specimens. Using the 22C3 anti-PD-L1 antibody (immunohistochemistry), we determined the PD-L1 expression levels in paired specimens obtained from 69 patients (50 with advanced NSCLC and 19 with small cell lung cancer [SCLC]), as well as the efficacy of ICIs in these patients.

Results: The concordance rate of PD-L1 expression between the EBUS-TBNA and TBB specimens was 78.3%. The κ values referent to the PD-L1-positive expression rate between EBUS-TBNA and TBB specimens were 0.707 and 0.676 at cutoff limits of ≥1% and ≥50%, respectively. Among the 19 SCLC patients, 16 (84.2%) exhibited no PD-L1 expression in both EBUS-TBNA and TBB specimens. Notably, the progression-free survival of patients with ≥50% PD-L1 expression in the paired specimens who received ICI treatment was 8.3 months.

Conclusion: Collectively, our results validate the use of EBUS-TBNA specimens for the determination of the PD-L1 expression levels in the context of NSCLC and SCLC.

EBUS-TBNA Cytological Samples for Comprehensive Molecular Testing in Non-Small Cell Lung Cancer

Clinical guidelines promote the identification of several targetable biomarkers to drive treatment decisions in advanced non-small cell lung cancer (NSCLC), but half of all patients do not have a viable biopsy. Specimens from endobronchial-ultrasound transbronchial needle aspiration (EBUS-TBNA) are an alternative source of material for the initial diagnosis of NSCLC, however their usefulness for a complete molecular characterization remains controversial. EBUS-TBNA samples were prospectively tested for several biomarkers by next-generation sequencing (NGS), nCounter, and immunohistochemistry (PD-L1). The primary objectives were to assess the sensitivity of EBUS-TBNA samples for a comprehensive molecular characterization and to compare its performance to the reference standard of biopsy samples. Seventy-two EBUS-TBNA procedures were performed, and 42 NSCLC patients were diagnosed. Among all cytological samples, 92.9% were successfully genotyped by NGS, 95.2% by nCounter, and 100% by immunohistochemistry. There were 29 paired biopsy samples; 79.3% samples had enough tumor material for genomic genotyping, and 96.6% for PD-L1 immunohistochemistry. A good concordance was found between both sources of material: 88.9% for PD-L1, 100% for NGS and nCounter. EBUS-TBNA is a feasible alternative source of material for NSCLC genotyping and allows the identification of patient candidates for personalized therapies with high concordance when compared with biopsy.

Real-World Outcomes of Patients With Advanced Non-small Cell Lung Cancer Treated With Anti-PD1 Therapy on the Basis of PD-L1 Results in EBUS-TBNA vs Histological Specimens

BACKGROUND

Programmed death-ligand 1 (PD-L1) testing is feasible in most specimens acquired using endobronchial ultrasound-guided needle aspiration (EBUS-TBNA).

RESEARCH QUESTION

Are the outcomes of patients with advanced non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICI) on the basis of PD-L1 expression in EBUS-TBNA samples significantly different from those of patients who are treated on the basis of PD-L1 expression in histological samples?

STUDY DESIGN AND METHODS

Patients treated with pembrolizumab or nivolumab between June 2016 and 2019 were included. Patient characteristics, PD-L1 expression, line of treatment, response (Response Evaluation Criteria in Solid Tumors [RECIST] criteria), and vital status (May 14, 2020) were recorded. Progression-free survival (PFS) and overall survival (OS) were assessed, and hazard ratios (HR) estimated.

RESULTS

A total of 145 patients were treated with pembrolizumab or nivolumab on the basis of PD-L1 expression in EBUS-TBNA (31.7%) or histological (68.3%) samples. Most had metastatic disease, with a predominance of adenocarcinomas (64.1%). First-line pembrolizumab was administered to 61 patients with tumor proportion score ≥50% in EBUS-TBNA (n = 16) or histology samples (n = 45). Median OS and PFS of patients who received first-line pembrolizumab on the basis of PD-L1 results in EBUS-TBNA vs histology samples were not significantly different (OS 25.8 months vs not reached, respectively; HR, 0.82 [95% CI, 0.34-1.95], P = .651). Similarly, the median OS and PFS of patients who received subsequent lines of treatment on the basis of PD-L1 results in EBUS-TBNA vs histological samples were not significantly different (including after adjustment for PD-L1 expression).

INTERPRETATION

These findings suggest that PD-L1 results in EBUS-TBNA samples can guide ICI therapy, with treatment outcomes being comparable to those of patients in whom PD-L1 expression was assessed in histological specimens.

Endobronchial ultrasound-guided transbronchial needle aspiration in patients with previously treated lung cancer

PURPOSE

The sampling and accurate diagnosis of lymph nodes during the clinical history of lung cancer are essential for selecting the appropriate treatment strategies. This study aims to evaluate the feasibility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in patients with previously treated lung cancer.

METHODS

Patients who underwent EBUS-TBNA after treatment for lung cancer were retrospectively reviewed. We classified the patients into two groups; Group 1 (G1): Indicated to have a recurrence of new lesions after radical surgery or chemo/radiotherapy with a curative intent; and Group 2 (G2): Indicated to have residual tumor cells after undergoing primary treatment for chemo/radiotherapy or re-staging after induction therapy prior to surgery.

RESULTS

Seventy previously treated lung cancer cases (G1, n = 52; G2, n = 18) were enrolled. Thirty-two cases (61.5%) had recurrent disease in G1, and 9 cases (50.0%) had nodal metastasis in G2. The diagnostic accuracy was 95.2% in G1 and 88.9% in G2. Twenty-four cases were examined for epidermal growth factor receptor (EGFR) mutations, and 9 (37.5%) cases had mutations, including two cases with a T790M mutation. Furthermore, in one case, a re-biopsy revealed that the initial adenocarcinoma had transformed into small cell lung cancer.

CONCLUSION

Performing EBUS-TBNA during lung cancer treatment showed a high diagnostic yield. Samples obtained by EBUS-TBNA were helpful in determining when to perform repeat biomarker testing as well as for making pathological re-evaluations.

Implementation of PD-L1 22C3 IHC pharmDxTM in Cell Block Preparations of Lung Cancer: Concordance with Surgical Resections and Technical Validation of CytoLyt® Prefixation

BACKGROUND

Programmed death ligand-1 (PD-L1) assessed by immunohistochemistry (IHC) is used as biomarker for pembrolizumab therapy in advanced stage lung cancer patients. However, data permitting direct performance comparison between cytology and surgical specimen types are limited since both specimens from a single tumor site are infrequently available. In addition, alcohol fixation used with cytology specimens requires technical validation of the PD-L1 IHC assay before clinical use. We here report our experience with implementation of the PD-L1 22C3 IHC pharmDxTM assay for cytologic samples at a large tertiary cancer center.

STUDY DESIGN

Archival formalin-fixed (FF), paraffin-embedded cell blocks (CBs) and subsequent lung tumor resections (LTRs) from the same anatomical site were used for a direct comparison of PD-L1 tumor proportion scores (TPSs). TPS values were independently determined by one surgical lung pathologist and two cytopathologists blinded to the specimen pairs. An interim analysis was performed to facilitate the pooling of expertise among observers. After PD-L1 22C3 IHC pharmDxTM implementation for FF cytology specimens, dual-processed samples were used for a prospective technical validation of CytoLyt® prefixation (CF). Digital image analysis was performed for a subset of dual-processed specimens.

RESULTS

Eighty-one CBs and LTRs were included for comparison of the specimen types. PD-L1 assessment in CBs had an accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 88.9/72.8, 66.7/73.5, 95.2/72.3, 80.0/65.8, and 90.9/79.1% for the ≥50/≥1% cutoff, respectively. The intraclass correlation coefficient was 0.84 (95% confidence interval [CI]: 0.76, 0.90), and it improved after interim analysis (before: 0.79 and after: 0.92). The overall concordance between CF and FF for the categories defined by the ≥50/≥1% cutoff values was 90.4% (95% CI: 79.0, 96.8). Similar assay performance was confirmed by digital analysis.

CONCLUSIONS

PD-L1 22C3 IHC pharmDxTM shows good reliability if used with CB preparations. CF does not impact assay results significantly. Clinical validation with outcome data is needed, and digital methods of assessment should be further investigated.

Programmed Death Ligand 1 Testing of Endobronchial Ultrasound-guided Transbronchial Needle Aspiration Samples Acquired For the Diagnosis and Staging of Non-Small Cell Lung Cancer

RATIONALE

Immunotherapy has become an integral part of management in patients with advanced non-small cell lung cancer (NSCLC). Programmed death ligand 1 (PD-L1) expression in at least 50% of tumor cells on histologic samples has been correlated with improved efficacy of the immune checkpoint inhibitor pembrolizumab. A limited number of studies have examined the suitability of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimens for assessment of PD-L1 status.

OBJECTIVE

We sought to examine the feasibility and results of PD-L1 testing performed on EBUS-TBNA samples acquired for the diagnosis and staging of NSCLC.

MATERIALS AND METHODS

Patients were identified from a prospectively maintained pathology database. Baseline characteristics were tabulated. Hematoxylin and eosin slides were reviewed to categorize cellularity between <100, 100 to 500, and >500 viable tumor cells. Samples were tested using Dako's PD-L1 IHC 22C3 pharmDx kit, with a minimum of 100 viable tumor cells. For patients in whom additional tissue samples were available, the results of PD-L1 testing were compared.

RESULTS

PD-L1 testing was attempted on 120 EBUS-TBNA samples. The most common NSCLC subtype was adenocarcinoma (78%). Seventy-six specimens (63%) had a cellularity >500 tumor cells. Among 110 of 120 (92%) patients with an adequate endobronchial ultrasound (EBUS) sample, 53 of 110 (48.2%) had high PD-L1 expression, defined as a Tumor Proportion Score ≥50%. EBUS PD-L1 results were concordant with an available histologic sample in 14 of 18 patients (78%), with no false-negative results.

CONCLUSION

PD-L1 testing was feasible in the majority of EBUS-TBNA samples acquired for the diagnosis and staging of NSCLC. Comparison of EBUS results with histologic samples revealed moderate concordance, with no false-negative results.

Bronchoscopic tissue yield for advanced molecular testing: are we getting enough?

The treatment of advanced lung cancer has become increasingly personalized over the past decade as a result of the improved understanding of tumor molecular biology and anti-tumor immunity. An adequate tumor sample is central to targetable mutation analysis, and immunologic profiling. The majority of lung cancer patients currently present at an advanced disease stage, so that diagnosis and staging are largely based on small biopsy and cytology specimens. Flexible bronchoscopy techniques play a prominent role in the acquisition of these diagnostic specimens. This narrative review summarizes the available evidence with regards to the role of various conventional and advanced flexible bronchoscopy techniques in acquiring sufficient tissue for mutation analysis and programmed death-ligand 1 (PD-L1) testing.

Comparative analysis of programmed death ligand 1 expression in paired cytologic and histologic specimens of non-small cell lung cancer

BACKGROUND

In advanced non-small cell lung cancer (NSCLC), cytologic specimens from transbronchial needle aspiration (TBNA) or transthoracic needle aspiration are often the only cancer tissue material available for the analysis of programmed death ligand 1 (PD-L1) expression. This study was aimed at assessing the concordance of PD-L1 expression in histologic and cytologic samples and at evaluating interobserver agreement on specimens in this setting.

METHODS

One hundred and thirty-eight specimens from 60 patients with NSCLC were analyzed. Histologic specimens were represented by endoscopic samples obtained with forceps (biopsies), whereas cytologic specimens were from TBNA and bronchial lavage (BL). PD-L1 expression was quantified with the immunohistochemistry (IHC)-based Ventana SP263 assay. For cytologic specimens, IHC was performed on cell block sections. Two independent pathologists who were blinded to the clinical data evaluated partial or complete membrane IHC staining. Concordance between 2 methods and between 2 pathologists was evaluated with normal and weighted Cohen's κ coefficients, overall agreement, and Bland-Altman plots.

RESULTS

PD-L1 expression was quantified in 138 specimens from 60 patients. Concordance between cytologic and histologic approaches was moderate (κ = 0.56; weighted κ = 0.55). Also, concordance in the biopsy-TBNA and biopsy-BL subgroups was moderate (κ = 0.43 and κ = 0.47, respectively), whereas interobserver agreement was substantial (weighted κ = 0.72). A Bland-Altman plot showed an underestimation in PD-L1 values from cytologic samples in comparison with histologic ones.

CONCLUSIONS

The results demonstrate that in the absence of available histologic specimens, PD-L1 positivity in cytologic samples could be a reliable data for the oncologist to consider immune checkpoint inhibitor therapy. However, a comparison of cytologic and histologic samples has shown an underestimation of PD-L1 values in cytologic samples.

Convex probe endobronchial ultrasound: historical, contemporary, and cutting-edge applications

The use of convex-probe endobronchial ultrasound (CP-EBUS) has revolutionized bronchoscopy. It has provided the option of a relatively safe, minimally invasive approach for the assessment of various intrathoracic diseases. In current practice, its most dramatic impact has been on the diagnosing and staging of lung cancer. It has served as an invaluable tool that has replaced mediastinoscopy in a variety of clinical scenarios. Many pulmonologists and thoracic surgeons consider CP-EBUS the most significant milestone in bronchoscopy after the development of the flexible bronchoscope itself. In this review, we summarize the historical aspects, current indications, technical approach, and future direction of CP-EBUS.

EBUS-FNA cytologic-histologic correlation of PD-L1 immunohistochemistry in non-small cell lung cancer

INTRODUCTION

Immune checkpoint pathway markers induce immune tolerance to non-small cell lung cancer (NSCLC). Therapeutic antibodies targeting the programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway have demonstrated efficacy in tumors expressing relatively high PD-L1 levels. Minimally invasive endobronchial ultrasound-guided fine needle aspiration allows patients with inoperable tumors or comorbidities to attain a confirmatory diagnosis. The aims of the present study were to determine whether PD-L1 testing is equivalent to cytology and biopsy or resection specimens at different tumor proportion score cutoffs and for different NSCLC subtypes.

MATERIALS AND METHODS

Data were retrospectively collected for patients with paired NSCLC cytology and surgical resection specimens from May 4, 2007 to May 4, 2017. The Food and Drug Administration-approved Dako PD-L1 immunohistochemistry 22C3 pharmDx kit was used to measure PD-L1 on paired cytology cell block and biopsy or resection specimens, and the PD-L1 tumor proportion scores were recorded. Statistical analysis of categorical and continuous variables was performed using SAS, version 9.4.

RESULTS

A total of 53 paired cytology and resection samples (27 adenocarcinoma, 25 squamous cell carcinoma, and 1 unclassified) were analyzed. Supposing the resection specimen to reflect the true PD-L1 expression, the sensitivity, specificity, positive predictive value, negative predictive value, and overall agreement for the cytology method was 73.3%, 65.2%, 73.3%, 65.2%, and 69.8%, respectively. For high PD-L1 expression (≥50%), the cytology method demonstrated an overall agreement of 79.2%. The overall agreement between methods was 81.5% and 76% for cases of adenocarcinoma and squamous cell carcinoma, respectively.

CONCLUSIONS

NSCLC cytology samples from endobronchial ultrasound-guided fine needle aspiration are suitable for PD-L1 testing, especially using a high PD-L1 expression cutoff of ≥50% and for adenocarcinoma.

Diagnostic yield of endobronchial ultrasound-guided transbronchial needle aspiration to assess tumor-programmed cell death ligand-1 expression in mediastinal lymph nodes metastasized from non-small cell lung cancer

PURPOSE

We investigated the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) to evaluate programmed cell death ligand-1 (PD-L1) expression in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

A retrospective chart review of patients who underwent EBUS-TBNA between April 2017 and April 2019 was conducted. Among patients diagnosed with NSCLC, we investigated the rate of successful evaluation of tumor PD-L1 expression, compared the relevant factors between patients with evaluable and those with unevaluable PD-L1 expression, and examined the response to immune checkpoint inhibitors (ICIs) after EBUS-TBNA.

RESULTS

Of the 40 patients assessed, 32 (80%) had evaluable PD-L1 expression. Patients with evaluable PD-L1 expression were older than those with unevaluable PD-L1 expression (p = 0.017), and we noted a tendency for a larger diameter of the biopsied lymph node (p = 0.12). The response rate to ICIs was 100% in patients with a tumor proportion score (TPS) ≥ 50%, 33% in those with a TPS 1-49%, and 0% in those with a TPS < 1%.

CONCLUSION

The diagnostic yield of EBUS-TBNA to evaluate PD-L1 expression in advanced NSCLC appeared acceptable in association with relevant clinical outcomes after treatment with ICIs. A further prospective study with a larger sample size is required to confirm our findings.

Cytology for PD-L1 testing: A systematic review

Evaluation of tumoral programmed cell death ligand-1 (PD-L1) expression is standard practice for patients with advanced non-small-cell lung cancer (NSCLC) who may be candidates for treatment targeting the programmed cell death-1 (PD-1)/PD-L1 pathway. Currently, all of the commercially available immunohistochemistry assays have been validated for use with histology specimens although, in routine clinical practice, approximately 30-40 % of patients with advanced NSCLC have only cytology specimens available for diagnosis, staging, and biomarker analysis. This systematic review evaluated the success rate, concordance, and clinical utility of using cytology specimens to assess tumor PD-L1 expression levels compared with histology specimens from patients with advanced NSCLC. EMBASE and PubMed database searches identified 142 unique, relevant publications, of which 15 met the inclusion criteria for at least one analysis. In 709 specimens, across seven publications, the proportion of cytology specimens evaluable for PD-L1 testing was 92.0 %. Among nine studies eligible for concordance analysis between cytology and histology specimens at a PD-L1 tumor cell expression cutoff of ≥50 %, overall percentage agreement was 89.7 % (n = 428), 72.0 % for positive percentage agreement (n = 218), and 95.0 % for negative percentage agreement (n = 258); results using a tumor PD-L1 expression cutoff of ≥1 % were similar. Our analyses suggest that using cytology specimens to assess PD-L1 expression is feasible, with good levels of concordance between cytology and histology specimens using PD-L1 tumor cell expression cutoffs of ≥1 % and ≥50 %. In conclusion, there is no convincing evidence that cytology specimens are inadequate or inferior to histology specimens for assessing PD-L1 expression in patients with NSCLC.

PD-L1 CPS Scoring Accuracy in Small Biopsies and Aspirate Cell Blocks from Patients with Head and Neck Squamous Cell Carcinoma

To evaluate the performance characteristics of PD-L1 immunohistochemistry (IHC) combined positive scoring (CPS) in core biopsies and aspirate cell blocks from patients with head and neck squamous cell carcinoma (HNSqCCa). PD-L1 IHC using the SP263 antibody was performed on 20 paired cases which consisted of a small biopsy and an excisional specimen. The scores were compared at both the 1% and 20% cutpoints. Using the CPS result obtained from the resected specimen or excisional biopsy as the gold standard, PD-L1 IHC performed on the core biopsy or cell block identified 4 of 6 positive cases (66%) at the 20% cutpoint and 12 of 17 (70%) positive patients at the 1% cutpoint. False positive cases were uncommon at both cutpoints. CPS scoring should be used with caution in small biopsies from patients with HNSqCCa. A negative result should prompt consideration of an excisional biopsy and repeat testing.

Endobronchial ultrasound-guided intranodal forceps biopsy (EBUS-IFB)-technical review

Endobronchial ultrasound (EBUS) and transbronchial needle aspiration (TBNA) have changed the landscape of pulmonology. Mediastinal structures beyond the confines of airway walls are visualized in real-time with EBUS, leading to improved accuracy of tissue sampling and diagnostic yield. With the development of various needle sizes ranging from 25-G to 19-G, the sampling of lymph nodes is becoming easier and more commonplace. Yet, certain conditions such as sarcoidosis and lymphoma may still be difficult to diagnose via EBUS-TBNA. Furthermore, in the age of targeted therapy, there are more demands on EBUS-TBNA samples for molecular marker testing and next-generation sequencing. Here, we present a complementary methodology, EBUS-guided intranodal forceps biopsy (EBUS-IFB), for tissue acquisition that may help address these deficiencies. Specifically, we aim to propose indications, contraindications, outline approaches in performing IFB, and provide an overview of the data for this complementary technique.

Comparison of tumor cell numbers and 22C3 PD-L1 expression between cryobiopsy and transbronchial biopsy with endobronchial ultrasonography-guide sheath for lung cancer

Background

We previously reported cryobiopsy (Cryo) with endobronchial ultrasonography-guide sheath (EBUS-GS) for peripheral pulmonary lesions (PPLs) provides significantly larger tissues than transbronchial biopsy (TBB) and provides high quantity and quality DNA for gene analysis by next generation sequencing. However, the tumor cell yields and programmed death ligand 1 (PD-L1) expression between each approach have not been compared. Here, we assessed the tumor cell numbers and PD-L1 expression for Cryo with EBUS-GS for PPLs and TBB in patients with lung cancer.

Methods

Sixteen patients were enrolled in this prospective study from June to November 2017 at Tokyo Women’s Medical University Hospital. The number of tumor cells from a single biopsy, total number of tumor cells, average number of tumor cells, and 22C3 PD-L1 expression (≥ 50% and ≥ 1%) were compared between Cryo and TBB.

Results

The numbers of tumor cells from a single biopsy, total numbers of tumor cells, and average numbers of tumor cells obtained by Cryo were significantly larger than those obtained by TBB (Cryo [means ± standard errors of the means]: 1321 ± 303.7, 1981 ± 411.7, and 1406 ± 310.3; TBB: 208.8 ± 38.24, 1044 ± 189.0, and 208.8 ± 37.81; P < 0.0001, P = 0.0474, P = 0.0006, respectively). PD-L1 ≥ 50% and ≥ 1% patients for Cryo were 18.8 and 56.3%, respectively, whereas those for TBB were 12.5 and 37.5%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, concordance, and κ coefficient based on Cryo for TBB were 66.7, 100, 100, 92.9, 93.8%, and 0.7647, respectively, for PD-L1 ≥ 50%; and 44.4, 71.4, 66.7, 50, 56.3%, and 0.1515, respectively, for PD-L1 ≥ 1%.

Conclusion

Cryo with EBUS-GS may be a useful diagnostic approach for lung cancer, with advantages over TBB for gene analysis and whole exon sequencing. Particularly, it could contribute to patients taking pembrolizumab as first-line therapy when PD-L1 was negative by evaluating TBB specimens. It could also provide ample tissue for PD-L1 expression analysis in addition to accurate diagnosis and gene analysis.

The role of endobronchial ultrasound transbronchial needle aspiration for programmed death ligand 1 testing and next generation sequencing in advanced non-small cell lung cancer

Guidelines recommend testing for driver mutations and programmed death ligand 1 (PD-L1) expression at the time of initial diagnosis and during disease progression to help determine prognosis and initiate personalized therapy. In this article we review the updated literature and techniques of endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) in obtaining adequate tissue for molecular analysis by using next-generation sequencing (NGS) and for assessing PD-L1 expression through immunohistochemistry.

PD-L1 testing on the EBUS-FNA cytology specimens of non-small cell lung cancer

OBJECTIVES

The FDA approved PD-L1 tests for anti-PD-L1 immunotherapy are for surgical or histology specimens. It is not clear if cytology specimens could be used for PD-L1 testing to guide immunotherapy. In this study, we assess the suitability of EBUS-FNA cytology specimens for the testing of PD-L1.

MATERIALS AND METHODS

Consecutive patients with Non-small cell lung cancer (NSCLC) underwent EBUS procedure between January 1, 2017 and March 31, 2018 for PD-L1 testing were included. The cell blocks of EBUS-FNA cytology specimens were used for PD-L1 testing using Dako 22C3 phamDx antibody according to the Dako protocol. PD-L1 protein expression in tumor cells is determined by using Tumor Proportion Score (TPS).

RESULTS AND CONCLUSION

Of the 265 EBUS-FNA specimens from 262 patients sent for testing, 230 (86.8%) were adequate for PD-L1 testing. Of the 34 NSCLC patients with both histology and EBUS-FNA cytology specimens tested for PD-L1, the results from different specimen types had a concordance of 91.3%. The PD-L1 results from 16 paired specimens from the same anatomic site had 100% agreement. The rates of PD-L1 TPS ≥ 50% were significantly higher in the metastatic tumors in the lymph nodes than in the lung primary lesions. Therefore, EBUS-FNA cytology specimen is suitable for PD-L1 testing in patients with advanced NSCLC. The metastatic tumors in mediastinal lymph nodes appear to have higher PD-L1 expression than primary lesions.

Heterogeneity analysis of PD-L1 expression and copy number status in EBUS-TBNA biopsy specimens of non-small cell lung cancer: Comparative assessment of primary and metastatic sites

OBJECTIVES

Most patients with non-small cell lung cancer (NSCLC) are diagnosed at advanced stages where small biopsy specimens obtained through endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) are sometimes the only available samples for diagnosis. We aimed to determine whether EBUS-TBNA specimens are suitable for the evaluation of PD-L1 protein expression and copy number alterations (CNAs).

MATERIALS AND METHODS

PD-L1 protein expression and CNAs in 71 EBUS-TBNA specimens of NSCLC were assessed. Sixty-eight corresponding transbronchial biopsy (TBB) specimens from primary sites, thirteen resected primary tumors, and six resected metastases were comparatively analyzed. PD-L1 expression in tumor cells was assessed by immunohistochemistry (E1L3N). Positivity of ≥1% was used as the cutoff. PD-L1 CNAs were assessed with fluorescent in situ hybridization and were classified into three categories: amplification, polysomy, and disomy. Concordance between EBUS-TBNA and other specimens was calculated.

RESULTS

The cohort comprised 48 men (67.6%), 15 never-smokers (21.1%), and 39 adenocarcinomas (54.9%). The concordance of PD-L1 positivity between EBUS-TBNA and other specimens was moderate; κ = 0.63 for EBUS-TBNA vs. TBB, κ = 0.68 for EBUS-TBNA vs. resected primary tumors, and κ = 1.0 for EBUS-TBNA vs. resected metastases. The concordance of PD-L1 CNA status was comparable with that of PD-L1 expression: κ = 0.60 for EBUS-TBNA vs. TBB and κ = 0.74 for EBUS-TBNA vs. resected primary tumors. When PD-L1 copy number was assessed as a continuous variable, the correlation of PD-L1 CNAs was superior to that of PD-L1 expression. Intratumorally, PD-L1 copy number was less heterogeneous than protein expression in whole sections of resected tumors.

CONCLUSION

EBUS-TBNA specimens can be used to assess PD-L1 CNAs and protein expression. Although spatial heterogeneity should be considered for accurate interpretation, the evaluation of PD-L1 CNAs provides more reproducible results than that of protein expression levels especially with regard to intratumoral heterogeneity.

Reliability of PD-L1 assays using small tissue samples compared with surgical specimens

Programmed death ligand 1 (PD-L1) immunohistochemistry (IHC) assays are widely used for complementary or companion diagnostic purposes during treatment with immune checkpoint inhibitors. However, limited information is available on the clinical reliability of the PD-L1 IHC assay using small biopsy samples.Participants included 46 patients with nonsmall cell lung cancer who underwent PD-L1 testing using 3 PD-L1 IHC assays (22C3, SP142, and SP263) for both small biopsy samples and surgical specimens from November 2017 to June 2018. The PD-L1 IHC assay results were analyzed with cut-off values of 1%, 5%, 10%, and 50%. The PD-L1 IHC results obtained from the surgical specimens were regarded as the reference values.The 22C3, SP142, and SP263 PD-L1 IHC assays were performed in 26 (57%), 20 (43%), and 46 (100%) patients, respectively. Biopsy methods included radial probe endobronchial ultrasound using a guide sheath, endobronchial ultrasound-guided transbronchial needle aspiration, bronchoscopic biopsy, and percutaneous needle aspiration in 26 (57%), 4 (9%), 12 (25%), and 4 (9%) patients, respectively. The 22C3, SP142, and SP263 PD-L1 assays had concordance rates of 73-96, 65-80, and 72%-91%, respectively, compared with the reference values.PD-L1 testing with 3 commercial PD-L1 IHC assays using small biopsy samples is reliable in patients with nonsmall cell lung cancer.

Diff-Quik Cytology Smears from Endobronchial Ultrasound Transbronchial Needle Aspiration Lymph Node Specimens as a Source of DNA for Next-Generation Sequencing Instead of Cell Blocks

BACKGROUND

Next-generation sequencing (NGS) in lung cancer specimens from endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is usually performed on formalin-fixed paraffin-embedded cell block material.

OBJECTIVES

Since DNA can be damaged by this process, we investigated the potential of using DNA extracted from Diff-Quik cytology smears made for rapid on-site evaluation during EBUS-TBNA.

METHODS

In a prospective study, 67 patients undergoing diagnostic EBUS-TBNA were ana-lysed. We compared cell blocks and smears for DNA yields and sequencing (TruSeq Amplicon Cancer Panel) outcomes. Smears were also evaluated for tumour cell fraction and overall cellularity (cell count).

RESULTS

Primary lung cancer was diagnosed in 64 patients and metastatic malignancy in 3 patients. The DNA yield from smears was significantly higher than that obtained from matched cell blocks (mean 1,740 vs. 434 ng; p = 0.001). For 33 cases with matched smears and cell blocks the mutation profiles were similar. Smears with abundant malignant cells (using a cut-off of > 25% tumour cell fraction and > 1,000 cells) accurately predicted high (> 50 ng) DNA yield and therefore success in triaging samples to sequencing. In terms of tissue workflow, using only smears as source DNA for sequencing was an improvement in the use of only cell blocks (54/67 [80.6%] vs. 41/67 [61.2%]); however, the use of cell blocks when smears were not available or did not yield sufficient DNA further improved the success rate to 62/67 (92.5%) cases.

CONCLUSION

We recommend smears in laboratory workflows as the primary source of DNA for NGS following an EBUS procedure.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: Techniques and Challenges

Intrathoracic lymphadenopathy is a common problem encountered in clinical practice and is caused by a wide variety of diseases. Traditionally, the mediastinal lymph nodes were sampled using conventional transbronchial needle aspiration (TBNA), or surgical methods such as mediastinoscopy, and thoracotomy (open or video-assisted thoracoscopy). However, surgical modalities including mediastinoscopy are invasive, expensive, and not universally available. Moreover, they are associated with considerable morbidity and mortality. Conventional TBNA although minimally invasive has a low diagnostic yield. In the last decade, endobronchial ultrasound-guided TBNA (EBUS-TBNA) has emerged as the diagnostic procedure of choice in evaluating undiagnosed intrathoracic lymphadenopathy. EBUS-TBNA is also currently the preferred modality in the mediastinal staging of lung cancer. The procedure is minimally invasive, safe, and can be performed as a day-care procedure. In the era of personalized medicine in lung cancer, optimizing the procedure, sample collection, and processing are crucial, as more tissue is required for performing a wide array of molecular tests. Despite its widespread use and acceptance, the diagnostic sensitivity of EBUS-TBNA is still low. To maximize the yield, cytologists and physicians should be aware of the technical details of the procedure. Herein, we discuss the technique of performing EBUS-TBNA, its indications, contraindications, and the processing of the samples at our bronchoscopy suite. We also highlight the challenges faced by the cytologists and clinicians while processing EBUS aspirates.