Malignant Pleural Effusion (MPE) is a collection of fluid inside the chest caused by cancer. It is a common medical problem and often causes severe breathlessness. Patients with this condition generally have a very poor survival and so it is extremely important that they are given effective treatment as soon as possible to minimise the amount of time they have to spend in hospital.

Standard treatment for MPE involves an admission to hospital to drain the fluid and then attempt to prevent the fluid from returning by sticking the lung to the inside of the rib cage with medical talc powder which acts like glue. This is called talc pleurodesis (TP) but unfortunately it fails in about 30% of patients. This is usually because the lung has not fully re-expanded and has not made contact with the inside of the ribs. When this happens, the fluid can be effectively treated with a different type of drainage tube called an indwelling pleural catheter (IPC) which tunnels under the skin and is drained at home by the district nurses.

It is thought that pressure measurements taken from the fluid as it is drained may be able to show doctors whether or not the lung will re-expand before patients are committed to either TP or an IPC. In this research we wish to test if these measurements can be used to choose which is the best first treatment option (TP or IPC) for patients with MPE. We have called this 'EDIT management'. Since it is uncertain whether this new approach will work, patients will be randomised to have either standard treatment or EDIT management. We will compare the two groups to assess whether the patients who had EDIT management had to have fewer repeat procedures over the following 3 months.

Inclusion Criteria:

• Clinically confident diagnosis of malignant pleural effusion, defined as any of the following:

  1. Pleural effusion with histocytologically proven pleural malignancy OR
  2. Pleural effusion in the context of histocytologically proven malignancy elsewhere, without a clear alternative cause for fluid OR
  3. Pleural effusion with typical features of malignancy with pleural involvement on cross-sectional imaging (CT/MRI)

• Degree of breathlessness for which therapeutic pleural intervention would be offered

• Age >18 years

• Expected survival > 3 months

• Written Informed Consent

Exclusion Criteria:

• Females who are pregnant or lactating
• Clinical suspicion of non-expansile lung for which talc pleurodesis would not be offered
• Patient preference for 1st-line indwelling pleural catheter (IPC) insertion
• Previous ipsilateral failed talc pleurodesis
• Estimated pleural fluid volume ≤ 1 litre, as defined by thoracic ultrasound
• Any contraindication to chest drain or IPC insertion, including:

Irreversible coagulopathy Inaccessible pleural collection, including lack of suitable IPC tunnel site

- Any contraindication to MRI scanning, including:

Claustrophobia Cardiac pacemaker Ferrous metal implants or retained ferrous metal foreign body Previously documented reaction to Gadolinium-containing intravenous contrast agent Significant renal impairment (eGFR<30 ml/min)