The most common indication for diagnostic thoracoscopy is a patient with undiagnosed exudative pleural effusion. Because metastatic cancer is often suspected in these cases, the majority of patients are over 60 years. This in turn means that there is often associated comorbidity and a decreased performance status. Thoracoscopy, in general, should only be performed if the life expectancy is more than 3 months and the performance status is adequate (Karnofsky index at least 70 %, ECOG scale at least 3).

It is not easy to assess the optimal timing for thoracoscopic intervention in a patient with (suspected) malignant pleural effusion. The volume of an early detected effusion may be too small to cause dyspnea. In a palliative setting, most physicians tend to postpone treatment until symptoms are impairing the patient’s quality of life. Waiting too long without performing a thoracoscopic intervention in the setting of a malignant pleural effusion may be detrimental to the patient, as in the later stages of malignant pleural effusion the success rate achieved by pleurodesis is inferior; this is often explained by the incomplete re-expansion of the lung after removal of pleural fluid. Patients with a pleural effusion due to malignant disease benefit from early pleurodesis, as has been demonstrated recently (Steger et al. 2007). In their study, the most favorable outcome after talc pleurodesis was seen in women whose lungs were fully expandable, in patients whose Karnofsky index exceeded 60 %, in patients whose body mass index was greater than 25 kg/m², and in patients with benign disease.