Molecular testing on endobronchial ultrasound (EBUS) fine needle aspirates (FNA): Impact of triage

Cytopathology: From its humble beginnings to the birth of the cytopathology fellowship

Cytopathology or cytology as a field has grown remarkably in the 20th and 21st centuries with recent advances shaping the way we train our future colleagues and how we currently practice. This article explores the history of cytopathology tracing back as early as the 18th century with focus on the birth of the cytopathology fellowship in the United States.

Doing more with less: integrating small biopsies in cytology practice

Cytopathologists are at the forefront of specimen acquisition during many different procedures while providing rapid on site evaluation (ROSE). This has added pressure to cytopathologists as more and more ancillary testing is being requested on smaller amounts of tissue. By focusing on the most common organ sites: lung, head and neck, and pancreas, there is a discussion of what the cytopathologist needs to know to triage tissue successfully. Finally, there is a discussion of the logistical aspects of integrating small biopsies into everyday practice.

Supernatant fluid from endobronchial ultrasound-guided transbronchial needle aspiration for rapid next-generation sequencing

INTRODUCTION

There is an increasing demand to optimize the workflow and maximize tissue available for next-generation sequencing (NGS) for non-small cell carcinoma. We looked at transbronchial needle endobronchial ultrasound-guided bronchoscopy with transbronchial needle aspiration samples and evaluated the performance of supernatant (SN) fluid processed from a dedicated aspirate collected for NGS testing.

MATERIALS AND METHODS

Nineteen samples were collected and processed using a new workflow. Five aspirates were collected in formalin. One additional dedicated pass was collected fresh and centrifuged. The resulting cell pellet was added to formalin for cell block (CB) processing. DNA and RNA were extracted from concentrated SN for targeted testing using the Oncomine Precision Assay (Thermo Scientific, Waltham, MA). NGS results from the corresponding CB samples were used as "controls" for comparison.

RESULTS

Thirty-one mutations were detected in SN (Table 1). The most frequently mutated genes were TP53 (35%), EGFR (23%), KRAS (13%), CTNNB1 (6%), and ERBB2 (6%). There was 100% concordance between the mutations detected in SN and corresponding CBs with comparable variant allele frequencies. Turnaround time of NGS results was 1 day for SN compared to 4-10 days for CB.

CONCLUSIONS

We were able to demonstrate the usefulness of SN for reliable rapid molecular results. We successfully incorporated the workflow for tissue handling and processing among our clinical, cytopathology, and molecular teams. Molecular results were available at the same time as the cytologic diagnosis, allowing for timely reporting of a comprehensive diagnosis. This approach is particularly useful in patients with advanced disease requiring urgent management.

Expert opinion on NSCLC small specimen biomarker testing - Part 1: Tissue collection and management

Biomarker testing is crucial for treatment selection in advanced non-small cell lung cancer (NSCLC). However, the quantity of available tissue often presents a key constraint for patients with advanced disease, where minimally invasive tissue biopsy typically returns small samples. In Part 1 of this two-part series, we summarise evidence-based recommendations relating to small sample processing for patients with NSCLC. Generally, tissue biopsy techniques that deliver the greatest quantity and quality of tissue with the least risk to the patient should be selected. Rapid on-site evaluation can help to ensure sufficient sample quality and quantity. Sample processing should be managed according to biomarker testing requirements, because tissue fixation methodology influences downstream nucleic acid, protein and morphological analyses. Accordingly, 10% neutral buffered formalin is recommended as an appropriate fixative, and the duration of fixation is recommended not to exceed 24–48 h. Tissue sparing techniques, including the ‘one biopsy per block’ approach and small sample cutting protocols, can help preserve tissue. Cytological material (formalin-fixed paraffin-embedded [FFPE] cytology blocks and non-FFPE samples such as smears and touch preparations) can be an excellent source of nucleic acid, providing either primary or supplementary patient material to complete morphological and molecular diagnoses. Considerations on biomarker testing, reporting and quality assessment are discussed in Part 2.

Telecytology validation: is there a recipe for everybody?

INTRODUCTION

Telecytology offers a suitable solution to the cost and time efficiency questions on rapid onsite evaluation (ROSE). An increasing number of institutions are adopting new telecytology systems to meet the increasing ROSE requests, although there is no agreement on the details of how a telecytology validation study needs to be conducted. We propose a standardized approach for telecytology validation studies that could be done in a variety of practices.

MATERIALS AND METHODS

Consecutive cases from 6 months prior were chosen to reflect a case mix comparable to real life. A fellow assessed the slides at the ROSE site while 6 cytopathology faculty convened in a conference room with a television screen, and noted the adequacy, diagnostic category, and specific diagnoses. All participants were blinded to the original adequacy assessment and final diagnoses. For each case, evaluation time and the slides counts were noted.

RESULTS

Fine-needle aspiration specimens from 52 patients were included in the study. Of these, 13 cases were used in the first "test" session. The adequacy concordance rates ranged between 92.3% and 100%, with an overall concordance rate of 94.8%. The diagnostic category concordance rates ranged between 90.3% and 95.5%, with an overall concordance rate of 91.9%. The specific diagnosis concordance rates ranged between 84.6% and 92.9%, with an overall concordance rate of 88.1%.

CONCLUSIONS

Validation of telecytology requires a standardized approach just like any other new technology. In this study, we propose an efficient and accurate method for cytopathology departments of various case volumes to conduct telecytology validation studies.

Traveling with ROSE in EBUS-TBNA - Experience from a Tertiary Care Hospital in South India

Aims and Objectives

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a precise modality for tissue sampling of mediastinal and hilar lesions adjacent to the proximal airway. This study aims to determine the diagnostic efficacy, sensitivity, and specificity of rapid-on site evaluation (ROSE) in EBUS-TBNA.

Materials and Methods

This is a retrospective study that included 100 patients who underwent EBUS-TBNA of paratracheal and mediastinal lymph nodes in a tertiary care hospital in South India between March 2018 and March 2020. After the procedure, the diagnostic yield from the nodes sampled was transferred to slides that were stained with rapid hematoxylin and eosin (H and E), and then onsite evaluation was done. The tissue derived was also processed for histopathologic examination in all cases. ROSE was performed to assess sample adequacy and to arrive at a preliminary diagnosis. In patients suspected of tuberculosis, the sample was collected for GeneXpert evaluation as well.

Results

Of the 100 cases studied, 51 were males and 49 were females. The age distribution was between 3 and 78 years. Forty-seven cases were diagnosed as granulomatous lymphadenitis, 13 as metastatic malignancies, 33 as reactive lymphadenitis, 3 as atypical cells, and 1 case was diagnosed as a cystic lesion. The diagnostic yield was not adequate for evaluation in three cases. Diagnostic yield was obtained in the first two passes where the lymph nodes were more than 2 cm in size. More diagnostic passes were required in lymph nodes less than 2 cm and those located between and adjacent to major vessels. The onsite diagnosis was correlated with the final histopathologic diagnosis.

Conclusion

ROSE serves as a useful adjunct to reduce procedure time and enhance sample collection and triaging, and reduces the need for further invasive testing.

Technical aspects of the use of cytopathological specimens for diagnosis and predictive testing in malignant epithelial neoplasms of the lung

Lung cancer is a leading cause of cancer mortality worldwide but recent years have seen a rapidly rising proportion of cases of advanced non-small cell carcinoma amenable to increasingly targeted therapy, initially based on the differential response to systemic treatment of tumours of squamous or glandular differentiation. In two-thirds of the cases, where patients present with advanced disease, both primary pathological diagnosis and biomarker testing is based on small biopsies and cytopathological specimens. The framework of this article is an overview of the technical aspect of each stage of the specimen pathway with emphasis on maximising potential for success when using small cytology samples. It brings together the current literature addressing pre-analytical and analytical aspects of specimen acquisition, performing rapid onsite evaluation, and undertaking diagnostic and predictive testing using immunocytochemistry and molecular platforms. The advantages and drawbacks of performing analysis on cell block and non-cell block specimen preparations is discussed.

The role of rapid on site evaluation on touch imprint cytology and brushing during conventional bronchoscopy

BACKGROUND

The increase in immunohistochemical and molecular predictive tests in lung cancer requires new strategies for managing small samples taken during bronchoscopic procedures. The value of Rapid On Site Evaluation (ROSE) during conventional bronchoscopic procedures on endobronchial neoplasms in optimizing small biopsies and cytologlogical tissue specimens for diagnostic testing, and ancillary studies was evaluated.

METHOD

ROSE on touch imprint cytology (TIC) and brushing was performed on 690 consecutive cases of patients undergoing biopsies, using fiber optic bronchoscopy. Immunohistochemical assay for PD-L1, ALK, and ROS1 and molecular testing, via next generation technique for EGFR, KRAS, and BRAF, were performed.

RESULTS

The concordance between ROSE and final diagnoses was almost perfect for brushing (sensitivity: 0.84; specificity: 0.96), and less so for touch preparations (sensitivity: 0.77; specificity: 0.89). Immunohistochemical assay for PD-L1 was evaluated on 256 bioptic cases with only six unsuitable samples. Material available for immunohistochemistry for ALK was sufficient in 151 biopsies with no inadequate cases. ROS1 was evaluated in 132 biopsies, with only two unsuitable samples. Molecular analysis was performed on 128 biopsies, 29 TIC, and 17 brushing. Out of these, only ten were considered to be unsuitable.

CONCLUSIONS

ROSE is an effective procedure for monitoring the quality and quantity of material taken during conventional bronchoscopic procedures for evaluating the suitability of small samples that must undergo immunohistochemical and molecular assay.

Practical Considerations Relating to Routine Clinical Biomarker Testing for Non-small Cell Lung Cancer: Focus on Testing for RET Fusions

For patients with advanced non–small cell lung cancer, genomic profiling of tumors to identify potentially targetable alterations and thereby inform treatment selection is now part of standard care. While molecular analyses are primarily focused on actionable biomarkers associated with regulatory agency-approved therapies, there are a number of emerging biomarkers linked to investigational agents in advanced stages of clinical development will become approved agents. A particularly timely example is the reported data and US Food and Drug Administration approval of highly specific small molecule inhibitors of the proto-oncogene tyrosine-protein kinase receptor RET indicate that testing for tumor RET gene fusions in patients with NSCLC has become clinically important. As the number of biomarkers to be tested in NSCLC grows, it becomes increasingly important to optimize and prioritize the use of biopsy tissue, in order to both continue to allow accurate histopathological diagnosis and also to support concurrent genomic profiling to identify perhaps relatively uncommon genetic events. In order to provide practical expert consensus guidance to optimize processes facilitating genomic testing in NSCLC and to overcome barriers to access and implementation, a multidisciplinary advisory board was held in New York, on January 30, 2019. The panel comprised physicians involved in sample procurement (interventional radiologists and a thoracic surgeon), surgical pathologists specializing in the lung, molecular pathologists, and thoracic oncologists. Particular consideration was given to the key barriers faced by these experts in establishing institutional genomic screening programs for NSCLC. Potential solutions have been devised in the form of consensus opinions that might be used to help resolve such issues.

Lung cancer cytology and small biopsy specimens: diagnosis, predictive biomarker testing, acquisition, triage, and management

In the 21st century, there has been a dramatic shift in the management of advanced-stage lung carcinoma, and this has coincided with an increasing use of minimally invasive tissue acquisition methods. Both have had significant downstream effects on cytology and small biopsy specimens. Current treatments require morphologic, immunohistochemical, and/or genotypical subtyping of non-small cell lung carcinoma. To meet these objectives, standardized classification of cytology and small specimen diagnoses, immunohistochemical algorithms, and predictive biomarker testing guidelines have been developed. This review provides an overview of current classification, biomarker testing, methods of small specimen acquisition and triage, clinical management strategies, and emerging technologies.

Pulmonary small cell carcinoma: Review, common and uncommon differentials, genomics and management

Lung cancer is the leading cause of cancer-related death worldwide. It is divided into sub-categories based upon morphology, immunostaining pattern, biology, molecular profile, and/or treatment options. Up until the early 2000s when driver mutations with targeted therapies were identified in a subset of adenocarcinomas, the most critical distinction of lung carcinomas was driven by differences in treatment between small cell carcinoma (SCC) and nonsmall cell lung carcinoma (NSCLC). The distinction between SCC and NSCLC remains critical in the 21st century for management, especially for advanced stage cancer. In the vast majority of cases, morphological features are sufficient to separate SCC from other types of lung cancers. In some instances, however, cytomorphological features and immunohistochemical overlap with other tumors, limited sample availability, and/or crush artifact pose diagnostic challenges. The aim of this review is to highlight salient features of SCC and ancillary studies to distinguish it from common and uncommon potential mimickers, as well as provide updates in genomics and management.

Tumor Cell Representation by an Improvised Technique of Fine-Needle Aspiration Specimen Acquisition and Cell Block Preparation: Our Experience in Lung Cancer Cases in a Peripheral Center of Eastern India

Background

Being a minimally invasive diagnostic technique, Fine-Needle Aspiration Cytology (FNAC) has become the first-line test and corresponding aspirated material has become the target specimen for diagnosis and ancillary tests in lung carcinoma. Although the role of Cell Blocks (CBs) in diagnosis and in ancillary testing is well recognized in literature, limited attention has been paid to specimen procurement and triage in the preparation of CBs. In the present scenario, CBs are not consistently optimal because of its low cellularity.

Aims

This study is aimed to describe an improvised technique of specimen acquisition and cell block preparation in CT-guided FNACs of lung carcinoma cases in a resource-constrained center and to assess its efficacy for optimal representation of cellularity, morphology, and architecture.

Materials and Methods

Total 85 lung carcinoma cases undergoing CT-guided FNAC in our center from February 2017 to January 2018 were included in this study. 4 to 5 direct smears and subsequent CBs were made from material obtained by single pass. Cellularity of smears and corresponding cell blocks were assessed and categorized according to a scoring system (score 1 to 3 for number of cells <50, 50-100, >100, respectively). Preserved architecture and morphology were also assessed in smears and CBs.

Results

The evaluated samples showed a cellularity score 3 in 65.4%CBs and score 2 in 24.7% CBs. Overall, 90.1% cell blocks had acceptable cellularity. Cell morphology was preserved in all CBs of acceptable cellularity, except for two adenocarcinoma, one squamous cell carcinoma, and one small cell carcinoma blocks. Cellular architecture was also preserved in all CBs of acceptable cellularity.

Conclusions

This simple improvised technique of CB preparation optimized its cellularity, morphology, and architectural preservation, even after adequate cellular FNA smears.

Processing and Reporting of Cytology Specimens from Mediastinal Lymph Nodes Collected using Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: A State-of-the-Art Review

Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) is presently the preferred modality for sampling mediastinal lymph nodes. There is an unmet need for standardization of processing and reporting of cytology specimens obtained by EBUS-TBNA. The manuscript is a state-of-the-art review on the technical aspects of processing and reporting of EBUS-TBNA specimens. A literature search was conducted using the PubMed database, and the available evidence was discussed among the authors. The evidence suggests that at least one air-dried and one alcohol-fixed slide should be prepared from each lymph node pass. The remaining material should be utilized for microbiological analysis (in saline) and cell block preparation (10% formalin or other solutions). Wherever available, rapid-onsite evaluation should be performed to assess the adequacy of the sample and guide the need for additional material. The lymph node aspirate should also be collected in Roswell Park Memorial Institute solution in cases where lymphoma is under consideration. The use of liquid-based cytology provides good quality specimens that are free from blood and air-drying artifacts and can be used wherever available. Sample adequacy and the diagnostic category should be furnished separately in the cytology report.

Preanalytic Variables and Tissue Stewardship for Reliable Next-Generation Sequencing (NGS) Clinical Analysis

An enduring goal of personalized medicine in cancer is the ability to identify patients who are likely to respond to specific therapies. Our growing understanding of the biology and molecular signatures of individual tumor types has facilitated the identification of predictive biomarkers and has led to an increasing number of diagnostic tests to be performed, often as serial and distinct assays on limited tumor specimens. The biomarker diagnostics field has been revolutionized by next-generation sequencing (NGS), which provides a comprehensive overview of the genomic profile of a tumor. Many preanalytic variables can influence the accuracy and reliability of NGS results. Standardization of preanalytic variables is, however, complicated by the plethora of specimen acquisition and processing methods. Variables across the tissue journey, including specimen acquisition, specimen fixation, and sectioning, as well as postfixation processing, such as nucleic acid extraction, library preparation, and choice of sequencing methods, are critical for the reliability of NGS analysis; thus, standardization would be beneficial. In this article, each step in the tissue journey is outlined, with specific focus on preanalytic variables that can influence NGS results. Practical considerations for standardization of these variables are provided to facilitate accurate, reliable, and reproducible NGS-based molecular characterization of tumors, ultimately informing diagnosis and guiding treatment.

Transthoracic computed tomography-guided lung biopsy in the new era of personalized medicine

Computed tomography-guided lung biopsy is a valid and safe procedure for characterizing pulmonary nodules. In the past years, this technique has been mainly used to confirm the malignant nature of undetermined pulmonary lesions; however, today its role has been completely renewed. With the advent of target therapy and immunotherapy, it has arisen for lung cancer, in inoperable patients, the necessity to obtain adequate bioptical material to perform a correct molecular characterization of the lesion. Moreover, the possibility of acquired drug-resistance mechanisms makes it necessary in some cases to rebiopsy these lesions over time. For these reasons, it is likely that the request of computed tomography-guided lung biopsy will increase in the future, therefore every radiologist should be confident with its most important aspects.

The diagnosis of non-small cell lung cancer in the molecular era

Lung carcinoma is the leading cause of cancer mortality for both genders in the United States and throughout the world. Many of these tumors are being diagnosed with minimally invasive means resulting in small samples. There is a need to extract an increasing amount of therapeutic and prognostic information from progressively smaller samples. Collaboration among clinicians and pathologists is needed to produce a comprehensive final diagnosis in patients with lung cancer. This collaboration facilitates triage of small samples for ancillary studies including molecular testing. What follows represents a review of the current required testing for lung cancer specimens, an example of an algorithm currently employed at the Cleveland Clinic so that all required tests can be performed even on the smallest of specimens and suggestions on how pathologists may approach this new era of "doing more with less".

Telecytology implementation: Deployment of telecytology for rapid on-site evaluations at an Academic Medical Center

INTRODUCTION

There are limited publications that address technical and practical informatics considerations when implementing telecytology for rapid on-site evaluation (ROSE). Our aim was to share the experience of deploying telecytology for ROSE at our institution.

MATERIALS AND METHODS

Key informatics issues relevant to adopting telecytology for ROSE at our institution were appraised including workflow, information technology (IT), validation, training, and quality assurance (QA).

RESULTS

A dynamic telemicroscopy solution was selected that required trained cytotechnologists to attend on-site procedures for ROSE. For validation 60 cases were reviewed using the first camera at each facility, but only 20 cases to validate subsequent cameras. A concordance rate of >90% between ROSE interpretation performed digitally to original interpretations was required for clinical validation. After reviewing 440 cases from two comparable time periods before and after implementation, employing telecytology was shown to decrease cytopathologists' work time per ROSE case from an average of 20.95 min per case to 2.91 min per case (86% time savings). The non-diagnostic rate for traditional ROSE was 7.7% compared with 4.1% after the implementation of telecytology, and the deferral rate went from 43.6% for traditional ROSE to 44.1% with telecytology. Traditional ROSE diagnoses correlated with final diagnoses in 91.8% cases, compared to 95.5% with telecytology.

CONCLUSIONS

Challenges when implementing telecytology for ROSE included technical issues, workflow concerns, and incorporating trainees into daily practice. The end result of our implementation was the adoption of an innovative way to deliver a ROSE service that maximised efficiency for cytopathologists without compromising diagnostic performance.

An Automatable Method for Determining Adequacy of Thyroid Fine-Needle Aspiration Samples

CONTEXT.—

Thyroid nodules are a common clinical problem. Cytologic evaluation via fine-needle aspiration is often employed in the diagnostic workup, and rapid on-site assessment of adequacy can help ensure an adequate sample is obtained. However, rapid on-site assessment of adequacy only examines part of the sample, a part that may not then be available for ancillary testing. Moreover, the procedure is time-consuming and poorly reimbursed.

OBJECTIVE.—

To develop an automatable fluorescence-based image analysis system for assessing the adequacy of thyroid fine-needle aspirations that uses the entire aspirated sample.

DESIGN.—

There were 12 previously diagnosed cases that served as a training set, and 11 cases were used for validation of an image analysis algorithm. The samples were fluorescently stained and imaged using a fluorescent microscope. The images were assessed for adequacy by an image analysis algorithm. Following image analysis, a ThinPrep slide was prepared and blindly scored by a cytopathologist. The standard and computer-derived results were then compared.

RESULTS.—

The algorithm was optimized using the 12 cases in the training set and then applied to the 11 test cases. A total of 8 of 8 adequate samples in the test group were correctly scored as adequate, and 2 of 3 cases that were inadequate were correctly scored as inadequate by the algorithm. One case was erroneously designated as not adequate by the algorithm.

CONCLUSIONS.—

Our results demonstrate the feasibility of automating thyroid adequacy assessment using a fluorescent labeling technique followed by computer image analysis.

Translational research: Empowering the role of pathologists and cytopathologists

Research activity is in the core essence of pathology. Advancing our understanding of disease pathogenesis translates into better patient care. Because of their unique position, laboratorians are the best to accurately identify, annotate, and classify research specimens. They also are essential for the accurate interpretation of genomic testing. Currently, cytopathologists are moving to the center of patient care through active communication with clinicians and patients. There are certain research areas in which cytopathologists can be pioneers, such as image analysis, morphology research, and genotype-phenotype association studies integrating morphologic and molecular features. Health service utilization research is another domain in which cytopathologists can excel. Successful research is a journey that necessitates multiple steps. It also involves building expertise in how to overcome obstacles and handle challenges.

Updates in Lung Cancer Cytopathology

Lung cancer diagnosis and ancillary testing are increasingly relying on cytology and small biopsy specimens obtained via minimally invasive means. Paired with traditional immunohistochemical characterization of tumors, biomarker testing and comprehensive genomic profiling are becoming essential steps in the workup of lung cancer to identify targetable alterations and guide optimal therapy selection. Recent advances in immune checkpoint inhibitor therapy have led to an increasingly complex and unresolved landscape for tumor PD-L1 testing. The prevalence and importance of lung cancer cytology specimens are growing, with more required by the cytopathologist in directing the care of patients with lung cancer.

Endobronchial ultrasound-guided fine-needle aspiration for pulmonary carcinomas genotyping: experience with 398 cases including rapid EGFR/KRAS analysis in 43 cases

BACKGROUND

Endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) of mediastinal lymph nodes is a minimally invasive and efficient tool for both diagnosis and staging of lung cancer. EBUS-FNA also permits tumor genotyping. However this critical datum for the therapeutic management is often long to obtain for metastatic patients with short life expectancy.

METHODS

From May 2011 to December 2017, 398 lung cancer patients underwent a genetic analysis based on EBUS-FNA samples. EBUS-FNAs were performed with rapid on-site evaluation. Mutations were studied with Sanger or new generation sequencing. Forty-three cases were also tested with a fully automated real-time PCR rapid technique. ALK abnormalities were assessed by immunohistochemistry and/or in situ hybridization.

RESULTS

A genotypic result could be obtained in 316 cases (79.4%) and in 180 of the 198 more recent cases (90.9%). Genetic abnormalities were observed in 191 cases (48.0%). Using the rapid technique, EGFR/KRAS mutational status was obtained within a few hours following the histological diagnosis and on the same day of the EBUS-FNA by analyzing fresh specimens after intra-operative cytological diagnosis.

CONCLUSIONS

In term of molecular diagnosis, EBUS-FNA provides high-quality biological material similar to that of other clinical sampling methods. Furthermore, our study suggests that a rapid molecular diagnostic method could lead to a prompt and appropriate therapeutic management for many advanced stage patients.