A pleural effusion is a buildup of extra fluid in the pleural space, which is the space between the lungs and the chest wall. About half of people with cancer develop a pleural effusion. Cancer growing in the pleural space causes a malignant pleural effusion. More than 75% of people with a malignant pleural effusion have lymphoma or cancers of the breast, lung, or ovary. This condition is considered a sign of metastatic cancer, or cancer that has spread to other areas of the body. Although a malignant pleural effusion is treatable, it can be a serious, potentially life-threatening condition.
Relieving side effects–also called symptom management, palliative care , or supportive care–is an important part of cancer care and treatment. Talk with your health care team about any symptoms you experience, including any new symptoms or a change in symptoms.
People with a pleural effusion may experience the following symptoms:
- Shortness of breath 
- Dry cough
- Pain 
- Feeling of chest heaviness or tightness
- Inability to lie flat
- Inability to exercise
- Generally feeling unwell
The following tests may help diagnose a malignant pleural effusion, find the exact location of the pleural effusion, or plan treatment:
- A physical examination
- A chest x-ray, which is a picture of the inside of the body that shows the buildup of fluid
- Computed tomography (CT or CAT) , which is an imaging test that creates a three-dimensional picture of the inside of the body with an x-ray machine
- Ultrasound , an imaging test that uses sound waves to create a picture of the inside of the body
- Thoracentesis, which is the removal and analysis of fluid from the pleural cavity with a needle
A pleural effusion often requires treatment in a hospital or clinic. The most common treatment is to drain the malignant pleural fluid. This may be done in several ways:
- Thoracentesis (see above)
- Tube thoracostomy, which uses a tube inserted into the chest for about 24 hours to drain the fluid. This is usually followed by pleurodesis, which is a process that uses substances, such as talc, to try to get the edge of the lung to stick to the chest wall to decrease the chance of the fluid returning.
- The insertion of a small tube, called a catheter , placed temporarily into the pleural space that allows you or your family member to drain the fluid into a bottle as needed or directed.
- The insertion of a shunt, which is a device used to bypass or divert fluid from one place to another to drain excess fluid.
- Treatment of the cancer with chemotherapy  to prevent the effusion from returning.
Side Effects