The observational pilot study at the Churchill Hospital, funded by Oxford Respiratory Trials Unit, will assess the feasibility and efficacy of thoracic ultrasound (TUS) assessment in patients undergoing talc pleurodesis via intercostal chest drain (ICD) for recurrent symptomatic malignant pleural effusions (MPE). Participants will undergo TUS pre and post pleurodesis on up to four occasions. We hypothesise that a TUS scoring system will be able to predict short and long-term pleurodesis success earlier than current conventional medical practice allows. This study may ultimately allow the proposal of a treatment algorithm to manage patients with MPE in a more efficient manner.

Inclusion Criteria:

• The participant is willing and able to give informed consent for participation in the study.
• Adult male or female, aged 18 years or above.
• Diagnosed with a malignant pleural effusion requiring intercostal chest drain insertion and subsequent talc slurry pleurodesis for symptom relief and/or other therapeutic purposes as part of routine clinical care.

Exclusion Criteria:

• Age less than 18 years.
• Inability to provide informed consent
• Known hypersensitivity/allergy to medical talc, or other contraindication to the administration of intrapleural talc, as determined by the responsible clinician.
• Evidence of significant trapped lung that would prevent pleurodesis being performed, as determined by the clinician responsible for assessing the patient.
• Expected survival of less than one month due to underlying co-morbidities.

Adults undergoing drainage of a malignant pleural effusion and subsequent talc pleurodesis via an intercostal chest drain as part of their routine planned care.