The purpose of this study is to determine if an indwelling catheter is more effective than surgical pleurodosis in treating malignant pleural effusion. Who is it for? You may be eligible for this study if you are an adult who is suffering from symptomatic proven pleural malignancy or an otherwise unexplained pleural effusion. Study details Consenting participants will be randomised to one of two treatment arms: * Arm 1: Indwelling pleural catheter. A long term catheter is inserted under the skin in order to allow ongoing drainage of the pleural fluid. Participants will then be instructed to undergo a daily drainage regimen for 14 days at home. * Arm 2: Surgical pleurodesis. Participants under a key-hole surgery to remove fluid and facilitate lung re-expansion. Participants will then be followed up at discharge, 14 days, monthly for 6 months and then every 3 months up to one year post-procedure. These visits will include completion of Quality of Life questionnaires, a chest xray, an ultrasound (if thought necessary) and if you are at the lead site (Sir Charles Gairdner Hospital) a review of your Actigraphy logs up to 6 months after discharge. It is hoped this research will help to provide effective symptom control with minimal intervention for those with malignant pleural effusion.