BackgroundPleural fluid cytology is an important diagnostic test used for the investigation of pleural effusions. There is considerable variability in the reported sensitivity for the diagnosis of malignant pleural effusions (MPE) in the literature.ObjectiveThe purpose of this review is to determine the diagnostic sensitivity of pleural fluid cytology for MPE, both overall and by tumour type, to better inform the decision-making process when investigating pleural effusions.Data sourcesA literature search of EMBASE and MEDLINE was performed by four reviewers. Articles satisfying inclusion criteria were evaluated for bias using the QUADAS-2 tool.Data extractionFor quantitative analysis, we performed a metaanalysis using a binary random-effects model to determine pooled sensitivity. Subgroup analysis was performed based on primary cancer site and meta-regression by year of publication.SynthesisThirty-six studies with 6057 patients with MPE were included in the meta-analysis. The overall diagnostic sensitivity of pleural fluid cytology for MPE was 58.2% (95% CI 52.5% to 63.9%; range 20.5%–86.0%). There was substantial heterogeneity present among studies (I2 95.5%). For primary thoracic malignancies, sensitivity was highest in lung adenocarcinoma (83.6%; 95% CI 77.7% to 89.6%) and lowest in lung squamous cell carcinoma (24.2%; 95% CI 17.0% to 31.5%) and mesothelioma (28.9%; 95% CI 16.2% to 41.5%). For malignancies with extrathoracic origin, sensitivity was high for ovarian cancer (85.2%; 95% CI 74.2% to 96.1%) and modest for breast cancer (65.3%; 95% CI 49.8% to 80.8%).ConclusionsPleural fluid cytology has an overall sensitivity of 58.2% for the diagnosis of MPE. Clinicians should be aware of the high variability in diagnostic sensitivity by primary tumour type as well as the potential reasons for false-negative cytology results.PROSPERO registration numberCRD42021231473.

No abstract

Sarcoidosis is a multisystem disease characterized by non-caseating granulomatous inflammation that most commonly involves the lungs. Endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) has become an invaluable tool in the assessment of patients with mediastinal and/or hilar lymphadenopathy. It has been hypothesized that use of the larger 19-gauge (G) needle with EBUS-TBNA improves diagnostic sensitivity in sarcoidosis. However, it is unclear whether the existing literature supports this supposition. METHODS:A literature search of EMBASE, MEDLINE, Cochrane Library, and Google Scholar was performed by two reviewers. Included articles were evaluated for bias using the QUADAS-2 tool. For quantitative analysis, we performed a meta-analysis using a binary random-effects model to determine pooled sensitivity. Subgroup analysis was performed based on needle size, use of ROSE, study design, and prevalence of sarcoidosis in study group. RESULTS:Sixty-five studies with a total of 4242 patients were included in the meta-analysis. Overall pooled sensitivity for diagnosis of sarcoidosis was 83.99% (95% CI 81.22 -86.53) among all studies. The 19G subgroup had a significantly higher sensitivity (93.73%; 95% CI 89.72% -97.74%; I2 0.00%; p<0.01) compared to 21G subgroup (78.52%; 95% CI 66.89% -90.15%; I2 93.05%), 22G subgroup (84.07%; 95% CI 80.90% -87.24%; I2 85.21%) or unspecified 21G/22G subgroup (78.85%; 95% CI 70.81% -86.90%; I2 84.47%). There were no significant differences with use of ROSE, prevalence of sarcoidosis or by study design. CONCLUSIONS:The use of 19G needles during EBUS-TBNA appears to improve diagnostic sensitivity for sarcoidosis compared to 21G and 22G needles.CLINICAL IMPLICATIONS: The use of 19G needles during EBUS-TBNA should be considered in patients with suspected sarcoidosis. Further primary studies in 19G needle use is recommended for any indication.