Malignant Pleural Effusion
Management of Malignant Pleural Effusions
To treat or not to treat
Pleural effusions are generally markers of advanced, unresectable disease or disease progression. The median survival for patients with malignant pleural effusions is around 3 to 4 months.[4,5] Because a paramalignant effusion resulting from pneumonia or atelectasis may be present, the cytology should be confirmed before major treatment decisions are made. Once the cytology has been confirmed, the management strategy depends on the underlying primary malignancy and the number and type of previous therapies. For example, patients with newly diagnosed small cell carcinoma or malignant lymphoma are very likely to respond to systemic chemotherapy; however, patients who have already failed several lines of chemotherapy for gastric or ovarian cancer are unlikely to obtain significant palliation with systemic therapy.
About three-quarters of patients exhibit symptoms such as cough, dyspnea, and chest discomfort. Such patients may benefit from efforts to reduce the fluid burden, depending on their performance status, expected survival, and preference for risks versus benefits. The literature on the efficacy of treatment for pleural effusions is difficult to interpret because of the paucity of randomized trials, and the wide variability in the response criteria and the timing and duration of follow-up in uncontrolled trials.[6,7] Generally, the goal of therapy is palliation of symptoms. Measures of success may include complete drainage of the effusion, lung re-expansion, lack of fluid reaccumulation (i.e., duration of response), and subjective report of symptom relief. The choice of treatment depends on patient prognosis, functional status, and goals of care.
Thoracentesis involves percutaneous insertion of a needle for drainage of the effusion. Thoracentesis is not expected to permanently resolve the problem but rather to alleviate symptoms that are acute and severe. The use of thoracentesis is also appropriate as a therapeutic trial to determine whether fluid drainage is beneficial when the relationship between symptoms and effusion is unclear.
Most effusions will reaccumulate a few days after thoracentesis. The reaccumulation rate is approximately 98% by day 30. Repeated thoracenteses carry the potential risks of bleeding, infection, and pneumothorax. Other potential complications of thoracentesis include noncardiogenic pulmonary edema from rapid lung re-expansion (usually with the rapid removal of >1,500 cc) and pleural shock caused by an excessive vagal response to penetration of the parietal pleura. Any of these complications may be lethal, especially for the cancer patient with poor cardiopulmonary reserve.