Fluid Around the Lungs or Malignant Pleural Effusion

Approved by the Cancer.Net Editorial Board, 09/2014

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.

More Information

Side Effects

Advanced Cancer Care Planning

Additional Resource

National Cancer Institute: Malignant Pleural Effusion