A cancer-induced collection of fluid between the lung and chest wall (a malignant pleural effusion) affects more than 1,600 New Zealanders each year, causing disabling breathlessness. There is no agreement on the best way to manage malignant effusions. Conventional care involves inserting a chest tube, draining the fluid and inserting talc into the space - a talc pleurodesis. It is painful, with a success rate of about 70%. Failure necessitates further procedures. Indwelling pleural catheters present a new strategy, requiring only outpatient management, free from the side-effects of pleurodesis. This study will compare the efficacy and safety of indwelling pleural catheters with talc pleurodesis. It will look at the number of days in hospital, complications, and quality of life with each treatment. It has the potential to change the way patients with this condition are currently cared for, reducing time in hospital and improving quality of life.