Malignant Pleural Effusion

What happens in a malignant pleural effusion

Normally a thin film of fluid lets the lung slide smoothly against the chest wall. Cancer cells on the pleura increase fluid production and block the lymphatic channels that drain it. Fluid accumulates, sometimes several liters, collapsing part of the lung and pushing on the diaphragm.

It is a common complication of advanced cancer and, in many people, is the first sign that cancer has spread.

Causes

Not every effusion in a person with cancer is malignant. Heart failure, infection, blood clots or treatment side effects can also cause fluid, so testing is important. See pleural effusion for other causes.

Symptoms

• shortness of breath, first on exertion, then at rest
• a dry cough
• chest heaviness, discomfort or pain
• inability to lie flat
• reduced appetite and tiredness
• some people have no symptoms if the effusion is small

Diagnosis

1. Chest x-ray: shows fluid at the base of the lung.
2. Ultrasound: confirms fluid, guides safe drainage and can show pleural thickening or nodules.
3. CT scan: shows pleural tumors, the lung and the underlying cancer.
4. Thoracentesis: a needle removes fluid under local anesthetic. Fluid is tested for protein, LDH, cell counts and cancer cells (cytology). Cytology finds cancer in about 60% of malignant effusions.
5. Pleural biopsy: by CT-guided needle or thoracoscopy if the fluid test is negative but suspicion remains. Biopsies also allow tumor marker and mutation testing.

Treatment

The goals are to relieve breathlessness, prevent re-accumulation, minimize hospital time and support quality of life. Not everyone needs fluid removed: small effusions without symptoms can be watched.

Therapeutic thoracentesis

Draining fluid with a needle gives quick relief and shows whether breathlessness improves and whether the lung re-expands. Fluid usually returns within days to weeks, so most people need a longer-term solution.

Pleurodesis

Talc is introduced into the pleural space, either through a chest tube (talc slurry) or during thoracoscopy (talc poudrage), causing the lung lining to stick to the chest wall so fluid cannot collect. It requires a hospital stay of a few days and works best when the lung fully re-expands.

Indwelling pleural catheter (IPC)

A thin tube is tunneled under the skin and left in place, allowing fluid to be drained at home by the patient, family or nurses, often every 1 to 3 days. It is usually placed as an outpatient procedure, works even when the lung cannot fully re-expand (trapped lung), and can lead to spontaneous pleurodesis over time, allowing removal. IPCs and talc may be combined.

Treating the cancer

Chemotherapy, targeted therapy, immunotherapy or hormone therapy can reduce fluid production, particularly in breast cancer, lymphoma and some lung cancers.

Symptom relief

• a handheld fan directed at the face
• breathing and positioning techniques
• low-dose opioids, which relieve the sensation of breathlessness
• oxygen if levels are low
• palliative care support alongside cancer treatment

Complications

• re-accumulation of fluid
• infection of the pleural space or catheter site
• trapped lung (the lung cannot re-expand because of a thick layer of tumor or scar)
• pain from drainage or pleurodesis
• re-expansion pulmonary edema (rare, after removing large volumes quickly)

Outlook

A malignant pleural effusion usually indicates advanced cancer. Life expectancy varies widely, from weeks to more than a year, depending on the cancer type, response to treatment and general health. People with breast cancer, lymphoma or lung cancer with targetable mutations often live longer. Prompt management of the fluid can greatly improve comfort and allow time at home.

Frequently asked questions

What is a malignant pleural effusion?

It is fluid around the lung caused by cancer cells involving the pleura, the lining of the lung and chest wall. It most often occurs with lung or breast cancer and causes breathlessness, cough and chest discomfort.

How is a malignant pleural effusion treated?

The fluid is drained with a needle for quick relief. To stop it coming back, doctors may perform talc pleurodesis to seal the space, or place an indwelling pleural catheter so fluid can be drained at home. Treating the cancer can also reduce fluid.

What is the life expectancy with a malignant pleural effusion?

It varies widely depending on the type of cancer, how it responds to treatment and overall health. Some people live a few months, while others, particularly with breast cancer, lymphoma or lung cancer with targetable mutations, live a year or longer.

Does a pleural effusion always mean cancer?

No. Pleural effusions are commonly caused by heart failure, pneumonia, blood clots, kidney or liver disease. Even in people with cancer, some effusions have other causes, which is why the fluid is tested.

Can I go home with a pleural catheter?

Yes. An indwelling pleural catheter is designed for home use. You, a family member or a visiting nurse drain the fluid into a vacuum bottle every few days. Many people find it reduces hospital visits and gives them more control.