Pleural Diagnostic Work-Up

Pleural Diagnostic Work-Up

Investigating unilateral pleural effusions: the role of cytology

https://www.ncbi.nlm.nih.gov/pubmed/30262573

Clinical Trial

Reference: Arnold DT, De Fonseka D, Perry S, et al. Investigating unilateral pleural effusions: the role of cytology. Eur Respir J. 2018;52(5)

Background: Investigation of the cause of a unilateral pleural effusion is a common task for pulmonologists. Cytology evaluation is routinely requested after performing a thoracentesis, but the utility of cytology for diagnosing a malignant pleural effusion (MPE) varies depending on the underlying malignancy.

PICO:

Populations:

  • Consecutive patients referred to a single center pleural service with an undiagnosed unilateral pleural effusion

Intervention:

  • Diagnostic thoracentesis as part of normal clinical care with at least 40mL pleural fluid sent for cytology analysis in the majority of patients

Comparison:

  • The sensitivity of pleural fluid cytology for detecting different cancer types based on a final diagnosis in each patient 12 months after the initial thoracentesis, as determined by two consultants

Outcome:

  • Pleural fluid cytology has a higher sensitivity for diagnosing adenocarcinomas compared to other cancer types
  • There is significant variation in adenocarcinomas depending on the primarily malignancy
  • Sensitivity of pleural fluid cytology for the diagnosis of mesothelioma is low

Take Home: There is significant variation in the sensitivity of pleural fluid cytology depending on the underlying malignancy. The sensitivity of pleural fluid cytology is highest for adenocarcinoma and lowest for mesothelioma. The sensitivity does vary depending on the primary malignancy, even in patients with adenocarcinoma. This information should be considered when determining the best approach to the work-up of an undiagnosed unilateral pleural effusion.


 Sensitivity of Initial Thoracentesis for Malignant Pleural Effusion Stratified by Tumor Type in Patients with Strong Evidence of Metastatic Disease

https://pubmed.ncbi.nlm.nih.gov/30016797/

Retrospective 

Reference: Grosu HB, Kazzaz F, Vakil E, et al. Sensitivity of Initial Thoracentesis for Malignant Pleural Effusion Stratified by Tumor Type in Patients with Strong Evidence of Metastatic Disease. Respiration. 2018;96(4):363-369.

Summary: Thoracentesis with cytology evaluation of pleural fluid is commonly performed during the evaluation of pleural effusions, especially when malignancy is suspected. Prior to this study, there was limited data on the sensitivity of thoracentesis based on tumor type. This retrospective study evaluated 725 patients with 63% having pleural fluid cytology that was positive for malignancy. This study found the sensitivity of pleural fluid cytology from thoracentesis varies depending on the underlying solid tumor malignancy. The sensitivity was lowest in sarcomas, head and neck cancers and renal cell carcinoma and highest in breast and pancreatic cancer.


 Investigation of a unilateral pleural effusion in adults: British Thoracic Society Pleural Disease Guideline 2010

https://www.ncbi.nlm.nih.gov/pubmed/20696692

Guideline 

Reference: Hooper C, Lee YC, Maskell N. Investigation of a unilateral pleural effusion in adults: British Thoracic Society Pleural Disease Guideline 2010. Thorax. 2010;65 Suppl 2:ii4-17.

Summary: Pleural effusions are a common medical condition requiring further evaluation and management by clinicians. These guidelines summarize recommendations for the investigation of a unilateral pleural effusion. These guidelines include information regarding optimal imaging for the identification and drainage of a pleural effusion, lab testing that should be completed and analyzed once pleural fluid is drained via thoracentesis as well as further investigative measures that can be completed if a diagnosis is still uncertain after an initial thoracentesis. These guidelines also discuss pleural effusions specific to certain conditions.


 Prospective study to determine the volume of pleural fluid required to diagnose malignancy

https://pubmed.ncbi.nlm.nih.gov/19741064/

Clinical Trial 

Reference: Swiderek J, Morcos S, Donthireddy V, et al. Prospective study to determine the volume of pleural fluid required to diagnose malignancy. CHEST 2010; 137:68-73.

Background: This study was designed to determine the optimal volume of pleural fluid to diagnosed a MPE.

PICO:

Populations:

  • 102 patients with known or suspected MPE

Intervention:

  • 121 thoracenteses

Comparison:

  • Cytologic examination of pleural fluid removed during thoracentesis in 10mL, 60mL and 150mL aliquots

Outcome:

  • Malignancy diagnosed in 74.4% of patients
  • Increased sensitivity and negative predictive value for cytospin/direct smear with 60mL (P=0.0058 and P=0.045) and 150mL aliquots (P<0.001 and P=0.009) compared with 10mL
  • Increased sensitivity and negative predictive value for combined cytospin/direct smear and cell block preparations when comparing 10mL to 150mL aliquots (P=0.0099 and P=0.033)
  • No difference in specificity or positive predictive value for any aliquot

Take Home: The sensitivity for diagnosis of malignancy in pleural fluid is dependent on the amount of fluid drained during thoracentesis. Volumes greater than 10mL are preferable. Volumes of 60mL or greater may be adequate when using only direct smear/cytospin, whereas volumes of 150mL or greater may be necessary when using both direct smear/cytospin and cell block for making the diagnosis.