Critical analysis of the utility of initial pleural aspiration in the diagnosis and management of suspected malignant pleural effusion

Abstract

IntroductionCurrent guidelines recommend an initial pleural aspiration in the investigation and management of suspected malignant pleural effusions (MPEs) with the aim of establishing a diagnosis, identifying non-expansile lung (NEL) and, at times, providing a therapeutic procedure. A wealth of research has been published since the guidelines suggesting that results and outcomes from an aspiration may not always provide sufficient information to guide management. It is important to establish the validity of these findings in a ‘real world’ population.MethodsA retrospective analysis was conducted of all patients who underwent pleural fluid (PF) sampling, in a single centre, over 3 years to determine the utility of the initial aspiration.ResultsA diagnosis of MPE was confirmed in 230/998 (23%) cases, a further 95/998 (9.5%) were presumed to represent MPE. Transudative biochemistry was found in 3% of cases of confirmed MPE. Positive PF cytology was only sufficient to guide management in 45/140 (32%) cases. Evidence of pleural thickening on CT was associated with both negative cytology (χ2 1df=26.27, p<0.001) and insufficient samples (χ2 1df=10.39, p=0.001). In NEL 44.4% of patients did not require further procedures after pleurodesis compared with 72.7% of those with expansile lung (χ2 1df=5.49, p=0.019). In patients who required a combined diagnostic and therapeutic aspiration 106/113 (93.8%) required further pleural procedures.ConclusionsAn initial pleural aspiration does not achieve either definitive diagnosis or therapy in the majority of patients. A new pathway prioritising symptom management while reducing procedures should be considered.

Diagnostics in Pleural Disease

“…Diagnosing an MPE through PF poses some challenges. Historically, PF cytology yields were suggested to be 60%; however, more recent data would suggest that this is likely an overestimation [13,[47][48][49]. It is suggested that 50-75 mL should be sent as a minimum to maximise yield and a repeat fluid cytology may increase the yield by a further 26%, though this latter claim is based on a small retrospective series [50,51].…”

“…Simply demonstrating the presence of malignant cells is no longer sufficient; adequate cellular material is required to perform the necessary molecular diagnostics. It has been demonstrated that a positive PF cytology result is not enough to affect a change in management and strong cases have been made for alternative diagnostic pathways for these patients (see thoracoscopic biopsies) [48,49].…”

Seven-year retrospective analysis of pleural effusion cytologies and cytohistopathological correlation

“…The cytopathological evaluation results were divided into four groups as inconclusive, negative for malignancy, suspected malignancy, and malignant cytology [11,12]. Malignant pleural effusion was accepted as the presence of malignant cells in cytology [13].…”

Malignant pleural effusion: Updates in diagnosis, management and current challenges

“…Recent evidence suggests that the initial pleural aspiration may have limited utility in the diagnosis of MPE ( 10 ). The sensitivity of pleural fluid alone is low; even when malignant cells are detected, the sample may be insufficient to provide information to guide oncological treatment ( 10 , 11 ) (‘actionable histology’), and the fluid recurs in the majority of patients.…”

“…Recent evidence suggests that the initial pleural aspiration may have limited utility in the diagnosis of MPE ( 10 ). The sensitivity of pleural fluid alone is low; even when malignant cells are detected, the sample may be insufficient to provide information to guide oncological treatment ( 10 , 11 ) (‘actionable histology’), and the fluid recurs in the majority of patients. Following this first procedure, the patient therefore requires further procedures to achieve a diagnosis (pleural biopsy), and a further ‘definitive’ pleural fluid control procedure.…”