In malignant pleural effusions there is decreased transport of hydrogen ions out of the pleural space, which can lead to a pH less than 7.30. When the pH of a malignant effusion is less than 7.30, there is a higher diagnostic yield on cytology, higher mortality, and worse response to pleurodesis.5,6
Once a patient is diagnosed with a malignant pleural effusion, it is important to discuss the potential treatment options, especially in those who are symptomatic.
Pleural effusions that are incidentally found do not need to be treated if patients are asymptomatic. Patients with metastatic cancer who are diagnosed with malignant pleural effusions, however, have a higher risk of mortality compared with those without effusions.7 Most studies have noted an approximate median survival between 3 and 12 months after diagnosis.8
In patients with metastatic disease, therapy targeted at the primary cancer can sometimes help resolve the effusions. Diuretics are, however, typically not helpful in managing malignant pleural effusions.
Patients can undergo intermittent thoracenteses to remove fluid and provide symptomatic relief, though the fluid can re-accumulate quickly, making frequent procedures challenging to coordinate and difficult for patients to undergo. If this occurs, some patients will choose to have a pleural catheter installed so that the fluid can be drained at home. The procedure and catheter do, however, come with the added risks of infection and bleeding.
Another option is performing chemical pleurodesis using a compound such as talc, which will cause a significant amount of inflammation leading to destruction of the pleural space and prevention of fluid re-accumulation.8 This procedure is typically not done in patients who have a poor short term prognosis.
Management of malignant pleural effusions should be tailored to the particular patient, depending on preference, prognosis, and variety of underlying disease.
- Light RW, Macgregor MI, Luchsinger PC, Ball WC Jr. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Intern Med. 1972;77(4):507-13.
- Heffner JE, Brown LK, Barbieri CA. Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Primary Study Investigators. Chest. 1997;111(4):970-80.
- Good JT Jr, Taryle DA, Sahn SA. The pathogenesis of low glucose, low pH malignant effusions. Am Rev Respir Dis. 1985;131(5):737-41.
- Sahn SA, Good JT Jr. Pleural fluid pH in malignant effusions. Diagnostic, prognostic and therapeutic implications. Ann Intern Med. 1988;108(3):345-9.
- Heffner JE, Nietert PJ, Barbieri C. Pleural fluid pH as a predictor of survival for patients with malignant pleural effusions. Chest. 2000;117(1):79-86.
- Heffner JE, Nietert PJ, Barbieri C. Pleural fluid pH as a predictor of pleurodesis failure: analysis of primary data. Chest. 2000;117(1):87-95.
- Morgensztern D, Waqar S, Subramanian J, Trinkaus K, Govindan R. Prognostic impact of malignant pleural effusion at presentation in patients with metastatic non-small cell lung cancer. J Thorac Oncol. 2012;7(10):1485-9.
- Maskell NA. Treatment options for malignant pleural effusions: patient preference does matter. JAMA. 2012;307(22):2432-3.