Chemical Pleurodesis for Malignant Pleural Effusion: How Far Have We Come in 80 Years?

sis, most likely because of the systemic absorption of small-size talc particles [2] . In a multicentre, open-label, prospective cohort study of 558 patients with MPE who underwent thoracoscopy and talc poudrage with 4 g of calibrated French large-particle talc, no patients developed ARDS, although oxygenation deteriorated in the first few days after talc pleurodesis [5] . Other agents that have been used for chemical pleurodesis over the years include bleomycin, tetracycline and doxycycline. A meta-analysis of 10 randomised studies found that non-recurrence of effusion was more likely with talc than other sclerosants, suggesting that there is little advantage of using other agents over largeparticle talc [6] . Only doxycycline has success and complication rates comparable to talc [7] . The search for the most effective and safe agent for chemical pleurodesis is ongoing. Many reports shave suggested that iodopovidone (povidone-iodine) may be as effective as talc, with a comparable complication rate, although others have suggested that its use may be associated with serious complications including renal failure, confusion, visual loss and even neonatal hyperthyroidism [8] . Neto et al. [9] previously reported a retrospective analysis of 61 pleurodesis procedures with iodopovidone performed in 54 patients. They observed a very high sucMalignant pleural effusion (MPE) is one of the most common causes of pleural exudates worldwide. Approximately 30–50% of all patients with metastatic malignancies will have pleural involvement at autopsy, and half of these will have pleural effusions, ranging from insignificant to massive [1] . Patients with a symptomatic MPE and an expected median survival of more than 3 months should be offered definitive palliative intervention, which may include chemical pleurodesis and/or the insertion of an indwelling pleural catheter (IPC). Globally, there is major heterogeneity in the therapeutic approach to MPE, mostly because of the paucity of high-quality evidence [2] . Chemical pleurodesis is achieved by the instillation of a sclerosant via a small-bore chest tube, IPC or during thoracoscopy. Amazingly, the most commonly used agent, talc, was first introduced as far back as 1935 [3] . In the largest randomised study on MPE of over 450 patients, the success rate of talc pleurodesis was approximately 75% at 1 month, but it was progressively reduced to approximately 50% at 6 months [4] . The same study found that talc poudrage was not superior to talk slurry, except in cases with lung and breast cancer [4] . Respiratory failure and acute respiratory distress syndrome (ARDS) have been associated with talc pleurodePublished online: October 21, 2015