Risk Stratification of Pleural Fluid Cytology Based on the International System for Reporting Serous Fluid Cytology in a Tertiary Care Centre

Abstract

<b><i>Background:</i></b> The International Academy of Cytology and the American Society of Cytopathology proposed the international system for reporting serous fluid cytology (TISRSFC) in 2019 to form uniform reporting terminologies for fluid cytology. This system defines a spectrum of diagnostic categories to be used in daily clinical practice. Fluid cytology is a widely accepted, cost-effective, minimally invasive earliest diagnostic method for the investigation that aids management decisions. The present study aims to reclassify pleural fluid cytology and calculate the risk of malignancy (ROM) for each diagnostic category. <b><i>Material and Methods:</i></b> It is a retrospective 2 years observational study comprising 690 pleural fluid specimens. Retrospective reviews were performed, and cases were reclassified into five categories as per TISRSFC. Immunohistochemistry was applied whenever needed. Cytological diagnosis was correlated with respective histopathology and/or clinical and/or radiological diagnosis. ROM was calculated for all diagnostic categories. <b><i>Results:</i></b> In the present study of 690 cases, 7.97% were non-diagnostic (ND), 84.1% cases were negative for malignancy (NFM), 0.87% were atypia of undetermined significance (AUS), 1.16% were suspicious for malignancy (SFM), and 5.94% were malignant (MAL). Cell blocks were prepared in 33 (4.8%) cases and immunohistochemistry was applied in 7 cases. The commonest site for pleural fluid metastasis was the lungs, accounting for 4.64% (32/690) cases. Further, ROM was calculated for all diagnostic categories as follows: (1) ND: 30.9%, (2) NFM: 12.9%, (3) AUS: 100%, (4) SFM: 100%, and (5) MAL: 90.2%. <b><i>Conclusion:</i></b> Cytological examination of pleural fluids is an accurate, prompt, and affordable technique. This standardized ISRSFC reporting system will maintain uniformity and reproducibility in reporting, leading to improved clinical decision-making of pleural fluids.

Risk of malignancy assessment of the International System for Reporting Serous Fluid Cytopathology: Experience in a community hospital setting and comparison with other studies

“…These heterogeneities might stem from a difference in served population-based characteristics, such as the prevalence of cancers, or different diagnostic concepts among institutions and individual pathologists even from the same country. [26][27][28] Furthermore, the follow-up approach to determining the ROM varied among different Jha 2021 15 Pergaris 2021 17 Xu 2021 11 Straccia 2022 12 Ahuja & Malviya 2022 16 Bharti 2022 9 Hou 2021 18b This was excluded from further pooled series because of a lack of data for some categories.…”

“…The frequency and ROM of ISRSFC categories from nine different studies are summarized in Table 3. [8][9][10][11][12][15][16][17][18] For pleural effusions, in total, eight studies reclassified specimens as ND, NFM, AUS, SFM, and MAL in ranges of 0.0%-8.0%, 42.0%-84.1%, 0.6%-7.8%, 1.2%-7.2%, and 5.9%-31.9%, respectively; with reported ROM ranges of 0.0%-87.5%, 2.1%-23.9%, 33.3%-100.0%, 64%-100.0%, If a discrepancy existed between repeated specimens that were collected from the same patient, the highest diagnostic category was counted.…”

“…and 90.2%-100.0% in ND, NFM, AUS, SFM, and MAL effusions, respectively. [8][9][10][11][12][15][16][17] In four studies of reclassified peritoneal effusions, the frequency of ND, NFM, AUS, SFM, and MAL effusions ranged from 0.7% to 1.4%, from 59.9% to 84.0%, from 1.6% to 4.2%, from 2.4% to 4.8%, and from 10.5% to 33%, respectively, with reported ROM ranges of 16.7%-100.0%, 4.8%-26.3%, 22.2%-62.5%, 83.3%-100.0%, and 100.0% only, respectively. 8,12,16,17 The I 2 index of heterogeneity for the summary ROM ranged from 66.0% to 89.0% and from 47.0% to 92.0% in pleural and peritoneal fluids, respectively (all p values < .01), indicating moderate to high-level heterogeneity in all categories of both pleural and peritoneal effusion studies.…”

“…We further compared the frequency distribution and ROM of each category between ISRSFC-suggested meta-analyses 19 and consequential reclassification studies series (including the current study; Table 4). [8][9][10][11][12][15][16][17] A univariate random effect model estimated the ROM ± standard error in pooled reclassification series. The overall frequency distribution of reclassification series was significantly different from the ISRSFC-determined analysis 19 in both pleural and peritoneal effusions (p values for the χ 2 test were < .001 for both).…”

“…In the design of a standardization, it is important to speak the same language across pathologists globally; however, revealing the dissimilarities between centers could help provide more realistic approaches to patient care. Although the value of this system has been reported from a few large academic centers or tertiary institutions, [8][9][10][11][12] the impact of the ISRSFC in community practice has not been fully explored. As reported in other cytopathology reporting systems, a significant difference in the ROM can exist between large academic cancer centers and community hospital-based practice.…”