INTRODUCTION
Approximately 15 percent of all patients with cancer develop malignant pleural effusions (MPEs) [1], with lung cancer and breast cancer accounting for 50 to 65 percent of MPEs [2]. MPEs can also complicate malignant mesothelioma, metastatic cancer (eg, from distant sites such as stomach or ovary), lymphoma, and other hematologic malignancies. The presence of an MPE usually portends a poor prognosis. More than 90 percent of patients with mesothelioma present with malignant effusion.The evaluation and management of MPE is discussed in this topic. Much of the content of this topic does not apply to patients with mesothelioma. Our approach is, in general, consistent with that outlined by the American Thoracic Society/Society of Thoracic Surgeons/Society of Thoracic Radiology (ATS/STS/STR), and the European Respiratory Society/European Association of Cardiothoracic Surgery (ERS/EACTS) [1,3]. The diagnosis of MPE and the management of refractory nonmalignant pleural effusions, are discussed in detail separately. (See "Pleural fluid analysis in adults with a pleural effusion" and "Management of nonmalignant pleural effusions in adults" and "Selection of modality for diagnosis and staging of patients with suspected non-small cell lung cancer", section on 'Pleural (T2, T3, M1a)'.)
DEFINITION (MALIGNANT/PARAMALIGNANT)
In MPEs, infiltration of cancer cells into pleural tissue is observed; pleural tissue invasion by malignant cells may be seen on pleural biopsy and may result in positive fluid cytology. The diagnosis of MPE is discussed separately. (See "Pleural fluid analysis in adults with a pleural effusion" and "Selection of modality for diagnosis and staging of patients with suspected non-small cell lung cancer", section on 'Pleural (T2, T3, M1a)'.)In contrast, paramalignant effusions result from tumor effects that indirectly act on the pleural space such as by bronchial obstruction, mediastinal lymph node infiltration, thromboembolism, or superior vena cava syndrome. In paramalignant pleural effusions, pleural fluid cytology and pleural biopsy are negative because cancer cells have not invaded pleural membranes. Paramalignant effusions are managed according to the underlying etiology.
TREATMENT GOALS
The presence of an MPE typically signifies advanced stage cancer and usually indicates that death will likely occur within an average of four to seven months, although rare exceptions of prolonged survival exist (eg, lymphoma). Thus, in general, the focus of MPE management is palliative and without survival benefit. Treatment should focus on patient-centered goals of therapy, which include sustained symptom relief, improvement in quality of life, acceptability of an intervention, affordability, and preference for less invasive procedures [4,5]. (See "Assessment and management of dyspnea in palliative care" and "Approach to symptom assessment in palliative care".)