Malignant Pleural Effusion
Cancer-related fluid buildup around the lung
Quick Facts
- Type: Complication of cancer
- Location: Pleural space around the lung
- Main symptom: Breathlessness
- Common cancers: Lung, breast, lymphoma, others
Overview
A malignant pleural effusion is an abnormal buildup of fluid in the pleural space, the thin gap between the lung and the chest wall, caused by cancer. It is a type of pleural effusion in which cancer cells are present in the fluid or the cancer is otherwise responsible for the fluid forming.
The extra fluid stops the lung from expanding fully, which is why the most prominent symptom is shortness of breath. A malignant pleural effusion most often arises from lung cancer, breast cancer, lymphoma, or mesothelioma, though many cancers can cause it. While it usually indicates advanced disease, several effective treatments can relieve symptoms and improve comfort and quality of life.
The pleural space normally contains only a thin film of fluid that lets the lung glide smoothly as you breathe. When cancer disrupts the balance between fluid being produced and drained, large amounts can collect and compress the lung. Relieving that pressure, and stopping the fluid from rapidly returning, is the main goal of treatment alongside addressing the underlying cancer.
Symptoms
Symptoms develop as fluid accumulates and presses on the lung. Some effusions cause no symptoms and are found on imaging.
- Shortness of breath, especially with activity or when lying flat, which is the most common symptom
- A dull ache or feeling of heaviness in the chest
- A dry cough
- Reduced ability to exercise or carry out usual activities
- Fatigue and a general feeling of being unwell
Severe or sudden breathlessness, an inability to catch your breath at rest, or bluish lips need urgent medical attention.
Causes
A malignant pleural effusion forms when cancer affects the pleura or nearby structures, increasing fluid production or blocking its normal drainage. This can happen when cancer cells spread to the pleural lining or block the lymphatic channels that usually clear fluid.
The cancers that most commonly cause it include:
- Lung cancer
- Breast cancer
- Lymphoma
- Mesothelioma, a cancer of the pleural lining
- Cancers of the ovary, stomach, and other organs that spread to the chest
Risk Factors
- A known diagnosis of cancer, particularly lung or breast cancer
- Advanced or metastatic cancer
- Mesothelioma, often related to past asbestos exposure
- Lymphoma and some other blood cancers
Diagnosis
Doctors confirm the effusion and look for cancer cells to establish the cause:
- Chest X-ray and CT scan: To show the fluid and assess the lungs and chest.
- Ultrasound: To locate fluid and guide drainage safely.
- Thoracentesis: Removing a sample of fluid with a needle for laboratory analysis, including testing for cancer cells.
- Pleural biopsy or thoracoscopy: Taking tissue from the pleura when the diagnosis is unclear.
Finding cancer cells in the fluid confirms the effusion is malignant, though sometimes repeat sampling or biopsy is needed.
Treatment
Treatment focuses on relieving breathlessness, preventing the fluid from coming back, and treating the underlying cancer where possible.
- Thoracentesis: Draining the fluid with a needle to ease breathing quickly.
- Indwelling pleural catheter: A small tube left in place so fluid can be drained regularly at home.
- Pleurodesis: A procedure that seals the space between the lung and chest wall to stop fluid from re-accumulating.
- Treating the cancer: Chemotherapy, immunotherapy, hormonal therapy, or radiation aimed at the underlying cancer, depending on its type.
- Supportive care: Managing symptoms and supporting comfort and quality of life.
The choice between repeated drainage, a catheter, and pleurodesis depends on how quickly the fluid returns, how the lung re-expands, and a person's overall situation and wishes.
Managing the Condition
- Follow your care team's plan for draining fluid and managing the underlying cancer
- Learn how to use and care for an indwelling catheter if one is placed
- Report increasing breathlessness, fever, or redness around a catheter site, which may signal a problem
- Ask about palliative care services, which can greatly improve comfort and quality of life
When to See a Doctor
Contact your care team if you notice gradually worsening breathlessness, a persistent cough, or chest heaviness, especially if you have a known cancer diagnosis.
Seek emergency care for sudden or severe shortness of breath, breathlessness at rest, chest pain, bluish lips, or a high fever, as these may indicate a rapidly enlarging effusion or an infection that needs immediate attention.
Frequently Asked Questions
What causes a malignant pleural effusion?
It is caused by cancer affecting the pleura or nearby structures, which increases fluid production or blocks its drainage. Lung cancer, breast cancer, lymphoma, and mesothelioma are among the most common underlying cancers.
How is the fluid removed?
Fluid can be drained with a needle in a procedure called thoracentesis, which quickly eases breathing. If it keeps coming back, an indwelling catheter for home drainage or a sealing procedure called pleurodesis may be recommended.
Does a malignant effusion mean the cancer is advanced?
It usually indicates that the cancer has spread, but it does not mean treatment is no longer worthwhile. Many options can relieve breathlessness and improve comfort, and treating the underlying cancer can also help control the fluid.
What is pleurodesis?
Pleurodesis is a procedure that uses a medicine or other agent to seal the space between the lung and chest wall so that fluid can no longer build up there. It can provide lasting relief from recurrent effusions.
When is breathlessness an emergency?
Sudden or severe shortness of breath, breathlessness at rest, chest pain, or bluish lips require emergency care. These can indicate a large or rapidly worsening effusion or another serious problem that needs immediate treatment.
References
- National Cancer Institute (NCI). Cardiopulmonary syndromes and malignant effusions.
- Mayo Clinic. Pleural effusion.
- American Thoracic Society. Pleural effusion.
- MedlinePlus, U.S. National Library of Medicine. Pleural effusion.