Cytology Reporting System for Lung Cancer from the Japan Lung Cancer Society and the Japanese Society of Clinical Cytology: An Extensive Study Containing More Benign Lesions

Clinical utility of rapid on-site evaluation of brush cytology during bronchoscopy using endobronchial ultrasound with a guide sheath

Previous studies have shown that rapid on-site evaluation (ROSE) improves the diagnostic yield of bronchoscopy using endobronchial ultrasound with a guide sheath (EBUS-GS) for peripheral pulmonary lesions (PPL). While ROSE of imprint cytology from forceps biopsy has been widely discussed, there are few reports on ROSE of brush cytology. This study investigated the utility of ROSE of brush cytology during bronchoscopy. We retrospectively analyzed data from 214 patients who underwent bronchoscopy with EBUS-GS for PPL. The patients in the ROSE group had significantly higher diagnostic sensitivity through the entire bronchoscopy process than in the non-ROSE group (96.8% vs. 83.3%, P = 0.002). The use of ROSE significantly increased the sensitivity of brush cytology with Papanicolaou staining (92.9% vs. 75.0%, P < 0.001). When ROSE was sequentially repeated on brushing specimens, initially negative ROSE results converted to positive in 79.5% of cases, and the proportion of specimens with high tumor cell counts increased from 42.1 to 69.0%. This study concludes that ROSE of brush cytology improves the diagnostic accuracy of bronchoscopy and enhances specimen quality through repeated brushing.

Evaluating the Risk of Malignancies of the Diagnostic Categories Proposed by the World Health Organization System for Reporting Lung Cytopathology: A 2-Year Single Institutional Experience

INTRODUCTION

The WHO System of Reporting Lung Cytopathology proposed a 5-tiered system in 2023. We report the risk of malignancies (ROMs) of bronchial washing/lavage and percutaneous fine-needle aspiration (FNA) specimens. We also evaluated the change of ROMs when image correlation is required.

METHODS

Lung cytology cases in 2021 and 2022 with histologic follow-up were included. CT reports were reviewed to identify cases with a solid nodule/tumor but benign cytological findings. These were reassigned from the "benign" to "non-diagnostic" category, and the ROMs were re-estimated.

RESULTS

A total of 1,031 bronchial washing/lavage and 206 FNAs were identified. The ROMs of bronchial washing/lavage were "non-diagnostic" 56.5% (13/23), "benign" 41.9% (320/764), "atypical" 71.7% (71/99), "suspicious for malignancy" 94.7% (72/76), and "malignant" 100% (70/70). The ROMs of FNAs were "non-diagnostic" 66% (33/50), "benign" 58.2% (39/67), "atypical" 70% (28/40), "suspicious for malignancy" 96.2% (25/26), and "malignant" 100% (70/70). When image finding was considered, cases initially assigned as "benign" were re-classified to "non-diagnostic" with decreases in ROMs for the "benign" category.

CONCLUSIONS

Malignancy risks associated with the WHO System of Reporting Lung Cytopathology diagnostic groups were reported. Image correlation for the "benign" category led to a decrease in case number and ROM.

Insufficient endobronchial ultrasound-guided transbronchial needle aspiration specimens. When and why? The analysis of criteria and reasons behind the insufficient specimens

BACKGROUND

The classification terminology systems for pulmonary cytology specimens have recently emerged. Inadequate samples, classified as "nondiagnostic," raise challenges in determining the threshold of cell numbers and the risk of malignancy (ROM).

METHODS

The study retrospectively reviewed 248 endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples: 46 insufficient samples, 60 low cellularity samples, and 142 adequate samples. Characteristics as cellularity, number of benign and malignant cells, and background features were assessed. Receiver operating characteristic curve analysis was performed to establish cell sufficiency thresholds for the diagnosis.

RESULTS

Out of the 248 samples analyzed, 108 were classified as benign, 94 as malignant, and 46 as insufficient. The study found that the cellularity thresholds for diagnosis in cell blocks and cytological samples were ≥50 cells and ≥100 cells, respectively. The thresholds for tumor cell counts were ≥1 - 10 cells for both types of cells, respectively. Considerably, some low cellularity samples were initially classified as insufficient despite meeting the diagnostic thresholds upon revision. The ROM varied across sample categories, with insufficient samples having a ROM of 10.9%, benign samples 15.7%, suspicious samples 92.0%, and malignant samples 100%.

CONCLUSION

Insufficient EBUS-TBNA samples raise challenges in diagnosis and management. This study identified the root cause of insufficient samples, including factors related to humans, diagnostic methods, sampling, and laboratory processing. By understanding the root causes, diagnostic recommendations can be developed to improve the diagnostic process. The findings emphasize the importance of standardized classification and terminology systems for clear communication among healthcare professionals and institutions, ultimately improving patient care and enabling quality assurance measures.

Retrospective application of WHO reporting system for lung cytopathology with assessment of risk of malignancy

INTRODUCTION

The recently introduced World Health Organization (WHO) Reporting System for Lung Cytopathology presents 5 diagnostic categories with corresponding risk of malignancy (ROM) and management protocols. This study uses the system to categorize our institutional respiratory tract cytology specimens, evaluating ROM and diagnostic accuracy for each category.

MATERIALS AND METHODS

In a retrospective analysis (May 2020 to August 2021), the following respiratory cytology specimens were classified based on the WHO categories: bronchoalveolar lavage (BAL), bronchial wash/bronchial brushings (BB/BW), endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), fine-needle aspiration cytology (FNAC), sputum, biopsy imprint (BI), and endotracheal wash. Exclusions comprised pleural effusions and EBUS-TBNA from mediastinal and hilar lymph nodes. Correlation of cytologic and histopathologic diagnoses was performed to assess ROM collectively and individually.

RESULTS

A total of 1518 respiratory samples (BAL [968], BW/BB [380], EBUS-TBNA [42], FNAC [32], sputum [80], BI [11] and endotracheal wash [5]) of 1410 patients were screened, of which 522 cases (34.3%) had histopathologic correlation. One hundred forty-one cases (9.3%) were Insufficient/Inadequate/Non-Diagnostic (ND), 1221 (80.4%) were Benign (B), 3 (0.2%) were Atypical (A), 32 (2.1%) were Suspicious for malignancy (SM) and 121 (8.0%) were Malignant (M). The estimated ROM for each category was 49.2% for ND, 13.3% for B, 66.6% for A, 81.5% for SM and 92.7% for M. FNAC and EBUS-TBNA exhibited the highest sensitivity (100%) compared with BW/BB (66.3%). Specificity ranged from 96.8% to 100% across the samples, while diagnostic accuracy varied from 58.8% to 100%.

CONCLUSIONS

Application of the WHO reporting system enhances standardized terminology, aiding clinicians in informed decision-making and improving patient care through accurate risk assessment of malignancy.

Risk of malignancy assessment of the different cytologic categories in respiratory cytology samples according to the new guidelines of the Papanicolaou Society of Cytopathology

BACKGROUND

Cytology is extremely important for diagnosis of lung carcinoma and the Papanicolaou Society of Cytopathology (PSC) had proposed a new classification system for respiratory cytology for better communication between physicians and better patient management. The objective of this study is to analyze our samples in accordance with this classification and to evaluate the diagnostic accuracy of various cytologic techniques and to assess the risk of malignancy.

METHODS

Eight hundred and twenty respiratory cytology specimens (FNA, BAL, washing, brushing, sputum) collected between 2019 and 2022 were classified according to the PSC system and the risk of malignancy was assessed for each category using follow-up surgical samples. Sensitivity, specificity, and accuracy rates were determined based on a categorial approach, according to a similar study.

RESULTS

The data of 820 respiratory cytology specimens from 576 patients were analyzed. 2.6% of these were non-diagnostic, 64.1% were NM, 5% were AC, 0.4% were N-B-LG, 4% were SM and 23.9% were ML. The risk of malignancy for each diagnostic category were: 42.8% for non-diagnostic, 31.2% for NM, 43.9% for AC, 87.9% for SM, 94.3% for ML. Sensitivity and specificity was calculated using only the malignant cases considered as positive tests and was 45.57% and 97.34% respectively.

CONCLUSION

Our results correlated with the PSC system, and it was considered useful in clinical practice. However, more studies should be performed to evaluate the usefulness of this system. The ROMs of each category and the impact of different techniques should be further studied.

The rationale for the development and publication of the World Health Organization reporting systems for cytopathology and a brief overview of the first editions of the lung and pancreaticobiliary systems

The International Academy of Cytology has joined with the International Agency for Research on Cancer and the World Health Organization (WHO) to develop international systems for reporting the cytopathology of lung, pancreas and biliary tract, lymph nodes, soft tissue, liver, breast, and kidney and adrenal gland. The WHO recently published the reporting systems for lung and pancreaticobiliary cytopathology. The objectives of this collaboration are to standardize the reporting of cytopathology; improve the quality of reporting by establishing the key diagnostic cytopathological features of entities and neoplasms; provide detailed best-practice guidelines in sampling techniques, specimen handling and processing, and the use of ancillary techniques; and facilitate communication between cytopathologists and clinicians to improve patient care. Each WHO system has defined specific categories and terminology for reporting cytopathology, and each category has an estimated risk of malignancy as far as the current literature allows and a suggested diagnostic management algorithm to assist clinicians. The WHO systems recognize that local medical and pathology infrastructure will vary, particularly in low-income and middle-income countries, and the WHO systems and their diagnostic management recommendations have been developed to allow them to be applied worldwide in all resource settings. The process of the selection of editors and authors and the writing and editing responsibilities has used the same model as that used for the fifth edition WHO Classification of Tumours, to which the WHO cytopathology systems are directly linked. This review provides the rationale and history of this joint International Academy of Cytology, International Agency for Research on Cancer, and WHO cytopathology project and a brief overview of the WHO reporting systems for lung and pancreaticobiliary cytopathology.

Grey zones in respiratory cytology: Atypical or suspicious for malignancy and neoplasms of unknown malignant potential

The purpose of pulmonary cytology is two-fold. First, to establish whether a pulmonary nodule is benign or malignant. Second, pulmonary cytology should classify the type of pathologic process present. When a pulmonary nodule is characterized as malignant, it is of high importance to further classify the malignancy as to type, with non-small cell carcinomas being sub-divided into adenocarcinomas, squamous cell carcinomas, and other types of non-small cell carcinoma. The World Health Organization Reporting System for Lung Cytopathology (WHORSLC) provides an important framework for reporting and classifying material obtained by cytologic techniques, including sputum analysis, bronchial brushings, bronchial washings, and fine-needle aspiration. The system contains five categories for specimen reporting. Clinicians prefer definitive diagnoses separating specimens into definitively benign or definitively malignant categories. The WHORSLC recognizes that it is not invariably possible for cytopathologists to separate specimens into definitively benign or definitively malignant categories. The five categories of the WHORSLC recognize the spectrum of cytologic changes running from clearly benign to clearly malignant, which cytopathologists must place into diagnostically useful and reproduceable categories. The intermediate categories of "atypical" and "suspicious for malignancy" provide structured categories with stringent definitions, estimated malignancy risks, and suggested management and follow-up recommendations. In this way, the categories "atypical" and "suspicious for malignancy" aid in maintaining the high diagnostic accuracy of the "benign" and "malignant" categories.

A brief review of the WHO reporting system for lung cytopathology

The International Academy of Cytology has joined with the International Agency for Research on Cancer to bring together a group of experts in lung cytopathology to develop a WHO Reporting System for Lung Cytopathology (WHO System). This System aims to improve and standardize the reporting of cytopathology, facilitate communication between cytopathologists and clinicians, and improve patient care. The WHO System describes 5 categories for reporting lung cytopathology: 'Insufficient/Inadequate/Nondiagnostic', 'Benign', 'Atypical', 'Suspicious for malignancy', and 'Malignant', each one with a clear descriptive term, a definition, a risk of malignancy, and a suggested management algorithm. The key diagnostic cytopathologic features of each of the lesions within each category have been established by consensus through an Expert Editorial Board, who are also the authors of this review and selected for each reporting system and chosen based on their expertise in the field and/or diversity of geographical representation. Many other co-authors from around the world also contributed. The assignment of writing and editing responsibilities used the same model as that used for the WHO Classification of Tumours (https://whobluebooks.iarc.fr/about/faq/). The WHO System provides the best practice application of ancillary testing, including immunocytochemistry and molecular pathology, and guides in sampling and processing techniques to optimize the handling and preparation of specimens. The WHO System was created by the authors to be applicable globally and is based on cytomorphology with possibilities for additional diagnostic management of the patient. The authors are aware that local medical and pathology resources would differ, especially in low- and middle-income countries. The WHO Tumour Classification for Thoracic Tumors, Fifth Edition, is directly accessible through the online WHO System.