Predicting complications in malignant pleural effusions - a pilot study

Pleural effusion, where fluid builds up in the space around the lungs (the pleural cavity), can develop in a range of conditions, from mild heart problems to severe infections or cancer.  Malignant pleural effusions, where cancerous tissue is present in the cavity, affect around 50,000 people in the UK every year.   

Fibrinous strands, known as septations, can form in the fluid of malignant pleural effusions. In one study of 540 patients, 60% were found to be affected.  

Minor septations don’t stop fluid flowing freely within the effusion, but if they are extensive they can cause loculation. This is where fluid becomes contained in more than one collection or divided into multiple separate pockets.  

Loculation can lead to fluid not being completely removed when patients undergo a drainage procedure. Patients can then experience persistent breathlessness and limited lung re-expansion. It may also mean they can’t undergo other procedures, especially those which aim to seal the pleural space, like pleurodesis.  

It’s estimated that up to 15% of patients with malignant pleural infusions have enough septations to lead to these complications. 

Some cells release a substance called ‘soluble urokinase plasminogen activator receptor’ (suPAR) as part of their immune response. It is the immune response which also leads to fibrin being produced. suPAR can be detected in a range of bodily fluids, including pleural fluid. 

Aims

Four studies have looked at using pleural fluid suPAR as a potential biomarker. Building on this research, in our pilot study we will explore the potential of pleural fluid suPAR in detecting loculation, septation and pleurodesis success.  

We hope that this pilot work will lead to a larger study to investigate whether suPAR can be used to predict these complications in patients with malignant pleural effusion. 

Methods

We will use existing pleural fluid samples from 50 patients in the IPC-Plus study. We will test each sample twice for suPAR using commercially available kits. The suPAR levels in the samples will be matched to the IPC-Plus study data, which includes more information such as type of cancer, whether pleurodesis was successful and whether the patient survived.