Competing interests: None. Patient consent: Obtained. Ethics approval: The project was approved by the internal review board of CAISM/UNICAMP and was conducted in compliance with the current version of the selleck chem MG132 Declaration of Helsinki and with Resolution 196/96 of the Brazilian National Committee for Ethics in Research (CONEP) and its subsequent revisions. Provenance and peer review: Not commissioned; externally peer reviewed. Data sharing statement: Extra data can be accessed via the Dryad data repository at http://datadryad.org/ with the doi:10.5061/dryad.nr5j1.
Pleural effusions are a common complication of many cancers, with symptoms often requiring intervention. Data from 10 years ago

suggest that there are up to 175 000 new cases of malignant pleural effusion (MPE) in the USA per year and around 40 000 cases per year in the UK,1 although these figures may now be conservative as the global burden of malignancy continues to rise each year, and with it the incidence of MPE. Pleurodesis is the adherence of the visceral and parietal pleura, which causes an obliteration of the pleural space. Removing the pleural space reduces the possibility of pleural fluid build-up,

which means that induction of pleurodesis is considered the mainstay of treatment for recurrent MPE. Many substances have been shown to induce chemical pleurodesis, although by far the most commonly used one in Europe and North America is talc, which has been shown to be superior to alternatives such as tetracycline or bleomycin.2 Overall, pleurodesis success rates with talc are typically high, ranging from 81% to 100%,3 although this efficacy may vary considerably in real-world practice due to differences between clinicians and

individual centres. The traditional method to instil talc, the control arm in this study, requires a patient to be admitted to hospital for chest tube insertion and fluid drainage. Talc is administered as slurry and is made up with a physiologically inert fluid such as 0.9% saline. The chest tube is removed once subsequent drainage volumes become low, potentially indicating successful pleurodesis. An alternative to this approach is the application of sterile talc powder under Brefeldin_A direct vision at thoracoscopy (insufflation or poudrage). However, despite an increasing number of hospitals having access to medical thoracoscopy, it is still much less ubiquitous than Seldinger chest drain insertion, with the requirement for specialist training and the increased costs of the procedure being major limitations, along with the more complex nature of the procedure. The efficacy of talc poudrage at 1 month for pleurodesis has been documented in a number of studies. Published success rates tend to lie around 85%, although there is significant heterogeneity between study groups limiting reliability.