A malignant pleural effusion is a complication that occurs in 30% of lung cancers. It can also occur with other cancers, such as breast cancers and lymphomas. With lung cancer, a malignant pleural effusion may be the first sign of cancer, or it can occur as a late complication of advanced disease.
What Is a Malignant Pleural Effusion?A pleural effusion is defined as an abnormal amount of fluid in the space between the layers of tissue (the pleura) that line the lungs. If cancer cells are present in this fluid (the pleural cavity), it is called a malignant (cancerous) pleural effusion.
CausesAlmost any type of cancer can cause a pleural effusion if it is present in or spreads (metastasizes) to the chest area. The most common are those mentioned above.
SymptomsThe symptoms of a malignant pleural effusion can be very uncomfortable and may include shortness of breath, coughing, and chest pain.
DiagnosisIt is important to make an accurate diagnosis of a malignant pleural effusion, since the prognosis and treatment are much different than for non-malignant (benign) pleural effusions. It's important to note that even with cancer, up to 50% of pleural effusions are benign.
A malignant pleural effusion is often first suspected because of symptoms or findings seen on a chest x-ray or CT scan. If your doctor suspects a malignant pleural effusion, the next step is usually a thoracentesis, a procedure in which a needle is inserted into the pleural space to get a sample of the fluid. This fluid is then examined under a microscope (cytology exam of pleural fluid) to see if cancer cells are present.
If a thoracentesis cannot be done, or if the results are inconclusive, further procedures may need to be done to get an accurate diagnosis. In some cases, a thoracoscopy (a procedure in which a thorascope is inserted into the chest) may need to be done to obtain a biopsy to diagnose a malignant pleural effusion.
The goal in treating a malignant pleural effusion is palliative, that is, to improve quality of life and reduce symptoms but not to cure the cancer.
If it is very small, it can sometimes be left alone. Thoracentesis can be performed to remove the fluid, but it frequently returns. To prevent fluid from returning, a procedure called a pleurodesis may be done. In this procedure, a chemical such as talc is inserted between the 2 layers of the pleura so that they stick together, preventing fluid from accumulating. This is successful for 60 to 90% of people.
If a malignant pleural effusion persists, surgery may be done to drain the fluid into the abdomen, or a pleurectomy (a procedure that removes part of the pleura) may be performed. New treatments (such as medical pleuroscopy) are emerging to treat malignant pleural effusions as well. Chemotherapy may help with malignant pleural effusions due to small cell lung cancer, but it does not seem to help with those due to non-small cell lung cancer.
PrognosisSadly, the average life expectancy for lung cancer with a malignant pleural effusion is less than 6 months. The median survival time (the time at which 50% of people have died and 50% are still living) is 4 months.
CopingThe discomfort from a malignant pleural effusion can be considerable. Pair that with learning of the diagnosis and its poor prognosis, and the experience can be distressing for anyone -- particularly those who already have a malignant pleural effusion when they are first diagnosed with cancer. Ask questions. Ask for help from others, and allow them to give it. Consider joining a support group. Your emotions may span the spectrum from anger, to disbelief, to depression. That is normal. Seek out friends and loved ones who are willing to truly listen and support you.
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Heffner, J. and J. Klein. Recent advances in the diagnosis and management of malignant pleural effusions. Mayo Clinic Proceedings. 2008. 83(2):235-50.
Musani, A. Treatment options for malignant pleural effusion. Current Opinion in Pulmonary Medicine. 2009 May 11 (Epub ahead of print).
National Cancer Institute. Cardiopulmonary Syndromes. PDQ. Malignant Pleural Effusions. Updated 03/08/12. http://www.cancer.gov/cancertopics/pdq/supportivecare/cardiopulmonary/patient/page3
Spector, M. and J. Pollak. Management of Malignant Pleural Effusions. Seminars in Respiratory and Critical Care Medicine. 2008. 29(4):405-13.