Observer variability in histopathological reporting of non-small cell lung carcinoma on bronchial biopsy specimens

A Multicenter, Single-Arm, Prospective Trial Assessing the Diagnostic Yield of Electromagnetic Bronchoscopic and Transthoracic Navigation for Peripheral Pulmonary Nodules

Rationale: Strict adherence to procedural protocols and diagnostic definitions is critical to understand the efficacy of new technologies. Electromagnetic navigational bronchoscopy (ENB) for lung nodule biopsy has been used for decades without a solid understanding of its efficacy, but offers the opportunity for simultaneous tissue acquisition via electromagnetic navigational transthoracic biopsy (EMN-TTNA) and staging via endobronchial ultrasound (EBUS). Objective: To evaluate the diagnostic yield of EBUS, ENB, and EMN-TTNA during a single procedure using a strict a priori definition of diagnostic yield with central pathology adjudication. Methods: A prospective, single-arm trial was conducted at eight centers enrolling participants with pulmonary nodules (<3 cm; without computed tomography [CT]- and/or positron emission tomography-positive mediastinal lymph nodes) who underwent a staged procedure with same-day CT, EBUS, ENB, and EMN-TTNA. The procedure was staged such that, when a diagnosis had been achieved via rapid on-site pathologic evaluation, the procedure was ended and subsequent biopsy modalities were not attempted. A study finding was diagnostic if an independent pathology core laboratory confirmed malignancy or a definitive benign finding. The primary endpoint was the diagnostic yield of the combination of CT, EBUS, ENB, and EMN-TTNA. Measurements and Main Results: A total of 160 participants at 8 centers with a mean nodule size of 18 ± 6 mm were enrolled. The diagnostic yield of the combined procedure was 59% (94 of 160; 95% confidence interval [CI], 51-66%). Nodule regression was found on same-day CT in 2.5% of cases (4 of 160; 95% CI, 0.69-6.3%), and EBUS confirmed malignancy in 7.1% of cases (11 of 156; 95% CI, 3.6-12%). The yield of ENB alone was 49% (74 of 150; 95% CI, 41-58%), that of EMN-TTNA alone was 27% (8 of 30; 95% CI, 12-46%), and that of ENB plus EMN-TTNA was 53% (79 of 150; 95% CI, 44-61%). Complications included a pneumothorax rate of 10% and a 2% bleeding rate. When EMN-TTNA was performed, the pneumothorax rate was 30%. Conclusions: The diagnostic yield for ENB is 49%, which increases to 59% with the addition of same-day CT, EBUS, and EMN-TTNA, lower than in prior reports in the literature. The high complication rate and low diagnostic yield of EMN-TTNA does not support its routine use. Clinical trial registered with www.clinicaltrials.gov (NCT03338049).

A deep learning model for the classification of indeterminate lung carcinoma in biopsy whole slide images

The differentiation between major histological types of lung cancer, such as adenocarcinoma (ADC), squamous cell carcinoma (SCC), and small-cell lung cancer (SCLC) is of crucial importance for determining optimum cancer treatment. Hematoxylin and Eosin (H&E)-stained slides of small transbronchial lung biopsy (TBLB) are one of the primary sources for making a diagnosis; however, a subset of cases present a challenge for pathologists to diagnose from H&E-stained slides alone, and these either require further immunohistochemistry or are deferred to surgical resection for definitive diagnosis. We trained a deep learning model to classify H&E-stained Whole Slide Images of TBLB specimens into ADC, SCC, SCLC, and non-neoplastic using a training set of 579 WSIs. The trained model was capable of classifying an independent test set of 83 challenging indeterminate cases with a receiver operator curve area under the curve (AUC) of 0.99. We further evaluated the model on four independent test sets-one TBLB and three surgical, with combined total of 2407 WSIs-demonstrating highly promising results with AUCs ranging from 0.94 to 0.99.

Interpathologist Diagnostic Agreement for Non-Small Cell Lung Carcinomas Using Current and Recent Classifications

CONTEXT.—

Measurement of interpathologist diagnostic agreement (IPDA) should allow pathologists to improve current diagnostic criteria and disease classifications.

OBJECTIVES.—

To determine how IPDA for pathologists' diagnoses of non-small cell lung carcinoma (NSCLC) is affected by the addition of a set of mucin and immunohistochemical (IHC) stains to hematoxylin-eosin (H&E) alone, by recent NSCLC reclassifications, by simplification of these classifications, and by pathologists' practice location, pulmonary pathology expertise, practice duration, and lung carcinoma case exposure.

DESIGN.—

We used a Web-based survey to present core images of 54 NSCLC cases to 22 practicing pathologists for diagnosis, initially as H&E only, then as H&E plus mucin and 4 IHC stains. Each case was diagnosed according to published 2004, 2011, and 2015 NSCLC classifications. Cohen's kappa was calculated for the 231 pathologist pairs as a measure of IPDA.

RESULTS.—

Twenty-two pathologists diagnosed 54 NSCLC cases by using 4 published classifications. IPDA is significantly higher for H&E/mucin/IHC diagnoses than for H&E-only diagnoses. IPDA for H&E/mucin/IHC diagnoses is highest with the 2015 classification. IPDA is estimated higher after collapse of stated diagnoses into subhead or dichotomized classes. IPDA for H&E/mucin/IHC diagnoses with the 2015 World Health Organization classification is similar for community and academic pathologists, and is higher when pathologists have pulmonary pathology expertise, have more than 6 years of practice experience, or diagnose more than 100 new lung carcinoma cases per year.

CONCLUSIONS.—

Higher IPDA is associated with use of mucin and IHC stains, with the 2015 NSCLC classification, and with pathologists' pulmonary pathology expertise, practice duration, and frequency of lung carcinoma cases.

Second ESMO consensus conference on lung cancer: pathology and molecular biomarkers for non-small-cell lung cancer

To complement the existing treatment guidelines for all tumour types, ESMO organises consensus conferences to focus on specific issues in each type of tumour. The Second ESMO Consensus Conference on Lung Cancer was held on 11-12 May 2013 in Lugano. A total of 35 experts met to address several questions on management of patients with non-small-cell lung cancer (NSCLC) in each of four areas: pathology and molecular biomarkers, early stage disease, locally advanced disease and advanced (metastatic) disease. For each question, recommendations were made including reference to the grade of recommendation and level of evidence. This consensus paper focuses on recommendations for pathology and molecular biomarkers in relation to the diagnosis of lung cancer, primarily non-small-cell carcinomas.

Analysis of lncRNA expression profiles in non-small cell lung cancers (NSCLC) and their clinical subtypes

Lung cancer is one of the most common human cancers worldwide. Among all lung cancer cases, non-small cell lung cancer (NSCLC) accounts for approximately 85%. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts that have been shown to play important roles in tumourigenesis and tumor progression. To reveal novel tumor-related lncRNAs in NSCLC and their associations with clinical subtypes, we herein identified 2935 probe sets mapped to lncRNAs on Affymetrix HG-U133 Plus 2.0 array with an lncRNA classification pipeline. We found 47 lncRNAs differentially expressed between normal lung tissues and tumor samples and 19 lncRNAs differed in expression between SCC and AC, two subtypes of NSCLC, after analyses of the gene expression profiles of five datasets downloaded from the gene expression omnibus (GEO) with a leave one dataset out validation process. The different lncRNA expression profiles between NSCLC and normal tissue and between the subtypes of NSCLC may have potential implications in the pathogenesis of this cancer. lncRNAs screening may be beneficial in the diagnosis, subclassification, and the personalized treatment of NSCLC.

Prediction of lung cancer histological types by RT-qPCR gene expression in FFPE specimens

Lung cancer histologic diagnosis is clinically relevant because there are histology-specific treatment indications and contraindications. Histologic diagnosis can be challenging owing to tumor characteristics, and it has been shown to have less-than-ideal agreement among pathologists reviewing the same specimens. Microarray profiling studies using frozen specimens have shown that histologies exhibit different gene expression trends; however, frozen specimens are not amenable to routine clinical application. Herein, we developed a gene expression-based predictor of lung cancer histology for FFPE specimens, which are routinely available in clinical settings. Genes predictive of lung cancer histologies were derived from published cohorts that had been profiled by microarrays. Expression of these genes was measured by quantitative RT-PCR (RT-qPCR) in a cohort of patients with FFPE lung cancer. A histology expression predictor (HEP) was developed using RT-qPCR expression data for adenocarcinoma, carcinoid, small cell carcinoma, and squamous cell carcinoma. In cross-validation, the HEP exhibited mean accuracy of 84% and κ = 0.77. In separate independent validation sets, the HEP was compared with pathologist diagnoses on the same tumor block specimens, and the HEP yielded similar accuracy and precision as the pathologists. The HEP also exhibited good performance in specimens with low tumor cellularity. Therefore, RT-qPCR gene expression from FFPE specimens can be effectively used to predict lung cancer histology.

Clinical relevance of the new IASLC/ERS/ATS adenocarcinoma classification

In 2011, recommendations for a multidisciplinary classification of lung adenocarcinoma were published under the auspices of the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society. The review was considered necessary due to emerging data on the radiological features, genetics and therapeutic approaches to lung adenocarcinoma, all underpinned by expanding the knowledge of the pathology of this common tumour. The existing WHO classification of 2004 was not really fit for this multidisciplinary focus on the disease. This review describes the recommendations made on the reporting of surgically resected lung cancers according to their predominant pattern, and argues the case for replacing the term bronchioloalveolar carcinoma (WHO 1999 and 2004 definition) with adenocarcinoma in situ and for the introduction of minimally invasive adenocarcinoma. There is also a discussion of diagnosis of non-small-cell lung carcinomas in the small biopsy or cytology setting, a practice that was inadequately addressed in WHO 2004, yet this is much more relevant to most pathologists' daily practice because 85% or so of adenocarcinomas are never resected. Predictive immunohistochemistry, used correctly, can reduce non-specific diagnosis to less than 10% of the cases. Finally, there is an overview of the emerging data on therapeutically relevant lung adenocarcinoma genetics, considering targetable mutations that are now the focus of much activity. The clinical relevance of these changes is discussed.

NSCLC subtype prediction using cytologic fluid specimens from needle aspiration biopsies

This study evaluated the diagnostic usefulness of tumor marker concentrations in cytologic fluids (CF) for subtyping non-small cell lung cancer (NSCLC) and assessed the relationship between fluorine-18-fluorodeoxyglucose ((18)F-FDG) uptake with serum and CF tumor marker levels. This prospective study included 88 patients diagnosed with adenocarcinoma or squamous cell carcinoma (SCC). Cytokeratin-19 fragment (CYFRA 21-1), carcinoembryonic antigen (CEA), and squamous cell carcinoma antigen (SCCA) concentrations in the CF samples were correlated with serum tumor marker concentrations, (18)F-FDG uptake, and NSCLC subtype. Fifty-eight patients were diagnosed with adenocarcinoma. Multivariate analysis revealed higher CF and serum SCCA levels; smoking status predicted SCC from adenocarcinoma. CF SCCA showed the highest accuracy (83%) in distinguishing between SCC and adenocarcinoma. CF samples obtained during routine needle aspiration biopsy procedure contain tumor marker levels sufficient to distinguish between SCC and adenocarcinoma; CF SCCA had the highest diagnostic accuracy.

Pathology and personalized medicine in lung cancer

SUMMARY Personalized medicine for patients with non-small-cell lung cancer is a reality now and its use will only increase in the future. Pathology is key in supporting this approach to treatment decision-making, by performing the most complete and accurate histological subtyping of tumors possible, supported by predictive immunohistochemistry and the assessment of relevant biomarkers. The need for these extra diagnostic steps emphasizes the importance of maximizing tissue yields from biopsy procedures. Although multiplex approaches may allow simultaneous assessment of several biomarkers, there will remain a need for different types of test (e.g., immunohistochemistry, as well as mutation testing). Next-generation technologies for DNA sequencing are a great hope for extensive genetic analysis of single samples, provided various technical and logistical problems can be solved. All such laboratory activity must be supported by high-quality internal procedures and external quality-assurance schemes.

Challenges in Implementing Personalized Medicine for Lung Cancer within a National Healthcare System

The traditional approach to the treatment of advanced non-small cell lung cancer (NSCLC) relied on the uniform use of cytotoxic chemotherapy. Over the last eight years, this paradigm of care has been shifting towards the use of molecularly targeted agents. Epidermal growth factor receptor (EGFR) mutations have emerged as an important biomarker for these targeted agents and multiple studies have shown that tyrosine kinase inhibitors (TKI) that inhibit EGFR are superior to traditional chemotherapy in patients possessing an EGFR mutation. Nationally funded health care systems face a number of challenges in implementing these targeted therapies, most related to the need to test for biomarkers that predict likelihood of benefiting from the drug. These obstacles include the challenge of getting a large enough tissue sample, workload of involved specialists, reliability of subtyping in NSCLC, differences in biomarker tests, and the disconnect between the funding of drugs and the related biomarker test. In order to improve patient outcomes, in a national healthcare system, there is a need for governments to accept the changing paradigm, invest in technology and build capacity for molecular testing to facilitate the implementation of improved patient care.

Validation of interobserver agreement in lung cancer assessment: hematoxylin-eosin diagnostic reproducibility for non-small cell lung cancer: the 2004 World Health Organization classification and therapeutically relevant subsets

CONTEXT

Precise subtype diagnosis of non-small cell lung carcinoma is increasingly relevant, based on the availability of subtype-specific therapies, such as bevacizumab and pemetrexed, and based on the subtype-specific prevalence of activating epidermal growth factor receptor mutations.

OBJECTIVES

To establish a baseline measure of interobserver reproducibility for non-small cell lung carcinoma diagnoses with hematoxylin-eosin for the current 2004 World Health Organization classification, to estimate interobserver reproducibility for the therapeutically relevant squamous/nonsquamous subsets, and to examine characteristics that improve interobserver reproducibility.

DESIGN

Primary, resected lung cancer specimens were converted to digital (virtual) slides. Based on a single hematoxylin-eosin virtual slide, pathologists were asked to assign a diagnosis using the 2004 World Health Organization classification. Kappa statistics were calculated for each pathologist-pair for each slide and were summarized by classification scheme, pulmonary pathology expertise, diagnostic confidence, and neoplastic grade.

RESULTS

The 12 pulmonary pathology experts and the 12 community pathologists each independently diagnosed 48 to 96 single hematoxylin-eosin digital slides derived from 96 cases of non-small cell lung carcinoma resection. Overall agreement improved with simplification from the comprehensive 44 World Health Organization diagnoses (κ  =  0.25) to their 10 major header subtypes (κ  =  0.48) and improved again with simplification into the therapeutically relevant squamous/nonsquamous dichotomy (κ  =  0.55). Multivariate analysis showed that higher diagnostic agreement was associated with better differentiation, better slide quality, higher diagnostic confidence, similar years of pathology experience, and pulmonary pathology expertise.

CONCLUSIONS

These data define the baseline diagnostic agreement for hematoxylin-eosin diagnosis of non-small cell lung carcinoma, allowing future studies to test for improved diagnostic agreement with reflex ancillary tests.

Personalized medicine for lung cancer: new challenges for pathology

Recent advances in non-small-cell lung cancer (NSCLC) therapy mean the relatively simple discrimination between small-cell and 'non-small-cell' carcinoma is insufficient to determine the best treatment for individual patients. Safety, efficacy and prescribing requirements mandate more specific subtyping of NSCLC for several new drugs: practice made difficult by the tumour heterogeneity combined with the paucity of tissue in most diagnostic samples. Immunohistochemical approaches have emerged as accurate predictors of probable tumour histotype. P63 and/or cytokeratins 5 and 6 and thyroid transcription factor 1 (TTF1) are among the best predictors, respectively, of squamous and adenocarcinoma histology. Molecular characteristics may predict response to both newer molecular targeted agents and traditional cytotoxic agents. Specific mutations in the epidermal growth factor receptor (EGFR) gene as predictors of response to EGFR tyrosine kinase inhibitors (erlotinib, gefitinib) is the first example of markers which predict response to targeted agents. Actual drug targets [e.g. thymidilate synthase (TS) - pemetrexed] or markers of the tumour's ability to repair cytotoxic drug-induced damage [e.g. excision repair cross-complementation group 1 (ERCC1) - cisplatin] may well also complement NSCLC diagnosis. This extended diagnostic requirement from increasingly limited material provided by minimally invasive biopsy techniques poses major challenges for pathology.

[Sampling and search for the EGFR mutation: what's taking, when and how to test?]

Since the IPASS study, that has shown a benefit in term of progression-free survival in first line of treatment in non-small cell lung cancer (NSCLC) with activating EGFR mutations, and the restricted prescription of this treatment to the presence of these mutations, the determination of the mutational status has became necessary at the diagnosis. This research study of these mutations, present in about 10% of non-selected NSCLC, has to be preferred in case of clinical factors predictive of mutations (sex, race, tobacco status, adenocarcinoma), but don't have to be exclusive, the correlation between these clinical factors and the presence of the mutations being imperfect. Also, the research study of the EGFR mutations should be performed for patients non eligible for chemotherapy (PS>2). Molecular testing could be performed on biopsies, and also on cytology, knowing that there is a mismatch between the tumor and the metastasis for EGFR status. Samples should be prepared according to standardized protocols, avoiding fixation with Bouin. The gold-standard for molecular testing is still sequencing, but alternative targeted tests (allele-specific PCR...) seem to be more sensitive. Some immunohistochemistry tests are in development for EGFR mutations, but have to be validated on large prospective cohorts. At last, new tumoral sampling have to be performed in case of progression under gefitinib in first line, to look for acquired resistance EGFR mutations, or for other resistance molecular markers (Met amplification).

A systematic review of the interobserver variability for histology in the differentiation between squamous and nonsquamous non-small cell lung cancer

INTRODUCTION

The importance of identifying non-small cell lung cancer (NSCLC) histologic subtype has increased recently because of the development of target-specific chemotherapeutic agents. This systematic review was undertaken to examine the interobserver variability for histology in differentiating between subtypes of NSCLC, specifically the ability to differentiate squamous from nonsquamous histology.

METHODS

A systematic literature search was undertaken to identify studies that evaluated the reproducibility of histologic diagnosis by pathologists in their reporting of NSCLC subtypes. Studies were screened using a priori defined eligibility criteria. The National Health and Medical Research Council diagnostic levels of evidence were applied and quality assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. Data were extracted and reanalyzed to permit comparison of agreement in nonsquamous and squamous cell carcinoma by 2 × 2 tables. Percentage agreement and kappa statistics were calculated for each included study.

RESULTS

Out of 1480 articles identified through the literature search, six were eligible for inclusion. The percentage agreement for all subtypes of NSCLC in the included studies ranged from 67.1 to 89.6% (κ, 0.42-0.84). Based on the primary reanalysis of data (reanalysis 1), agreement between pathologists in differentiating nonsquamous and squamous histology ranged from 77.0 to 94.2% (κ = 0.48-0.88) indicating a moderate to high level of agreement.

CONCLUSION

The reasonably high agreement and kappa statistics for the included studies suggest that pathologists can reproducibly differentiate between nonsquamous and squamous NSCLC. This is clinically important in guiding oncologist decision making in choosing the most appropriate therapy for their patients.

Principles of staging as applied to nonsmall cell lung cancer

PURPOSE OF REVIEW

To review the principles of staging cancer as applied to nonsmall cell lung cancer.

RECENT FINDINGS

The current staging system is under review for update. It is timely to review the principles of staging cancer to see how the nonsmall cell lung cancer staging system can be improved. Staging systems should predict prognosis, and guide therapy and research. Based on newer data the next staging system will likely incorporate more categories for tumor size and metastatic disease. Nodal staging may need to distinguish between single station N2 disease and multiple N2 station involvement, as there is some evidence that those with bulky multiple station N2 disease do worse. Histology is increasingly used to guide therapy and there are data that it can affect prognosis.

SUMMARY

How we stage patients with nonsmall cell lung cancer is about to change. The most important changes are to tumor size classification and classification of metastatic disease. Better standardization of measurements for tumor staging may further improve the utility of staging.

Use and abuse of lung biopsy

The lung biopsy is widely recognized as a valuable tool for the diagnosis and management of diverse pulmonary disorders. The transbronchial lung biopsy, open lung biopsy, and video assisted thoracoscopic surgery biopsy are the principal tools that have been developed for obtaining lung tissue for histopathological examination. Whereas these various types of lung biopsies are highly sensitive and specific tests available for diagnosis, they may be fraught with potential problems. This review hopes to inform the reader of the indications and limitations of the lung biopsy.

The clinical value of lung imaging fluorescence endoscopy for detecting synchronous lung cancer

Some patients with non-small cell lung cancer (NSCLC) will also have a synchronous malignant lesion. The lung imaging fluorescence endoscopy (LIFE) has proven better than conventional white light bronchoscopy (WLB) for visualizing premalignant lesions or early stages of lung cancer. In this study, the additional value of LIFE in diagnosing synchronous lung cancers as well as the impact of these findings on definite therapy was analyzed. Seventy-two patients with recently diagnosed NSCLC or pulmonary lesions highly suspect of lung cancer were studied. Patients underwent WLB, followed by LIFE. Apart from the primary lesions, additional abnormal and suspicious lesions seen at WLB and LIFE were scored separately and biopsied. Sixty-nine patients had NSCLC and three patients had small cell lung carcinoma. Apart from the primary lesion, one up to six additional endobronchial lesions were visualized in 48 patients by WLB and/or LIFE. High-grade dysplastic lesions were detected in ten patients, three of whom were eligible for surgery of the primary tumor after completion of the investigations. Three other patients (4.3%) had synchronous cancers (NSCLC). In one patient, the lesion was visualized by LIFE and by WLB. The other two malignant lesions were detected only by LIFE. In these three latter patients, diagnostic work-up and definite treatment was changed, as a result of detection of synchronous lesions. In conclusion, LIFE has additional value in detecting synchronous malignant lesions in patients with primary lung cancer. The detection of these lesions changed diagnostic work-up and definite treatment plan. Therefore, LIFE should be used in the work-up of patients with primary lung cancer.

Preoperative histological classification of primary lung cancer: accuracy of diagnosis and use of the non-small cell category

AIMS

To compare the preoperative classification of lung carcinoma made on cytological and histological specimens with the postoperative classification made on the resected specimen. In addition, to find out how often the term "non-small cell lung cancer, not otherwise specified" (NSCLC) was used, and in such cases to note the final diagnosis.

METHODS

Between 1991 and 1995, 303 patients had a lung resection in Aberdeen for primary carcinoma. For each patient, the departmental records were examined for preoperative specimens (cytological and histological). A note was made of whether each specimen was positive or negative for malignancy and, if positive, what the cell type was. Where patients had more than one sample submitted, the most specific result was taken.

RESULTS

Fifty four per cent of patients had a correct specific preoperative diagnosis of malignancy, whereas 34% were labelled as NSCLC. Patients with squamous carcinoma were more likely to have a diagnosis of malignancy (88%) that was specifically correct (75%). Patients who had adenocarcinoma were less likely to have a preoperative diagnosis of malignancy (64%) that was specifically correct (35%). For those in whom a diagnosis of NSCLC was made, 55% turned out to have adenocarcinoma whereas 24% had squamous carcinoma.

CONCLUSIONS

By adhering strictly to criteria, a high accuracy of diagnosis can be achieved for squamous carcinoma, but the diagnosis of adenocarcinoma seems to be more of a challenge. NSCLC is a useful and appropriate classification, the use of which reduces the rate of inaccurate specific diagnosis. There are occasions when pathologists can provide a more accurate diagnosis by being less precise.