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

Abstract

BACKGROUND:The International System for Reporting Serous Fluid Cytopathology (ISRSFC) was published recently to provide standard reporting terminology for serous fluid. To date, several ISRSFC reclassification studies have reported a wide range of diagnostic category frequency and the associated risk of malignancy (ROM). Herein, the authors applied the ISRSFC to report pleural and peritoneal effusions retrospectively in a community hospital setting. METHODS: With Internal Review Board approval, 446 peritoneal effusion specimens and 299 pleural fluid specimens from 576 patients in three community hospitals over a 12-month period were reviewed and reclassified according to the ISRSFC. RESULTS: After reclassification, in pleural effusions, 18 (5.0%) were nondiagnostic (ND), 273 (76.0%) were negative for malignancy (NFM), 18 (5.0%) were atypia of undetermined significance (AUS), 6 (1.7%) were suspicious for malignancy (SFM), and 44 (12.3%) were malignant (MAL). In peritoneal effusions, after reclassification, 11 (5.5%) were ND, 168 (77.1%) were NFM, 9 (4.1%) were AUS, 2 (0.9%) were SFM, and 27 (12.4%) were MAL. The calculated ROM was 0.0% for ND, 1.8% for NFM, 37.5% for AUS, 83.3% for SFM, and 100.0% for MAL in peritoneal effusions; and the ROM was 8.3% for ND, 1.2% for NFM, 44.4% for AUS, and 100.0% for both SFM and MAL in pleural effusions. Further analysis demonstrated notable heterogeneity among published ISRSFC reclassification studies, although the overall ROMs did not differ significantly from the ISRSFC-determined ROMs (all p values were > .05 for mean ROM comparisons). CONCLUSIONS: The findings suggested the necessity for each laboratory to perform its own ROM analysis based on its statistics for ISRSFC-tiered classification terminology.

Application of the International System for Reporting Serous Fluid Cytopathology (ISRSFC) in reporting serous effusion: A retrospective study

“…This is consistent with the results of previous studies. [9,17,21] The highest specificity and PPV were obtained when only M was considered positive, whereas the highest sensitivity was obtained when AUS, SFM, and M were considered positive. These findings are similar to those reported by Zhu et al [3] The highest diagnostic accuracy was observed when AUS and SFM were positive for pleural and peritoneal effusions, in agreement with Straccia et al, [9] but unlike Lobo et al [22] The false-positive and false-negative diagnostic rates highly depend on the investigator's experience.…”

“…[9,[15][16][17] The MAL category accounted for the majority of our samples, and the percentage of SFM cases was more significant than that in previous studies. [9,[18][19][20][21] This phenomenon stems from the fact that the source of serous effusion mainly comes from patients with tumors, and tumor conditions are the most common reason for fluid cytology. If a patient is diagnosed with SFM, physicians will consider it positive based on clinical symptoms and tumor history, thus depriving some SFM of the opportunity to be identified as MAL or NFM using adjunctive methods such as immunohistochemistry.…”

Review of the impact of the International System for Serous Fluid Cytopathology

“…There were 13 studies that included pleural effusions, 10 of which reported ROM evaluation (Table 2). 18,[20][21][22][24][25][26][29][30][31][32][33][34] The number of samples/patients ranged from 350 to 2454. The estimated ROM for each category was: ND, 0%-57.1%; NFM, Eleven studies provide data for peritoneal effusions, and ROM was assessed in seven of them (Table 3).…”

“…The estimated ROM for each category was: ND, 0%-57.1%; NFM, Eleven studies provide data for peritoneal effusions, and ROM was assessed in seven of them (Table 3). 18,[20][21][22][24][25][26]29,31,35,36 The number of samples/patients ranged from 217 to 2257 in studies with reported ROM. The estimated ROM for each category was: ND, 0%-100%; NFM, 1.8%-27.5%; AUS, 22.2%-62.5%; SFM, 80%-100%; MAL, 100%.…”

“…There were 13 studies that included pleural effusions, 10 of which reported ROM evaluation (Table 2). 18,20–22,24–26,29–34 The number of samples/patients ranged from 350 to 2454. The estimated ROM for each category was: ND, 0%‐57.1%; NFM, 1.8%‐29.8%; AUS, 33.3%‐62.3%; SFM, 76.2%‐99.3%; and MAL, 90.2%‐100%, excluding the study by Jha et al Notably, in the study by Jha et al 32 the ROM was reported to be considerably high for all categories: 87.5% for ND, 51.61% for NFM and 88.23 for AUS; these findings are discordant with those reported by the other investigators.…”