Non-small cell lung cancer (NSCLC) is the most common type of lung cancer in the United States. About 84% of all lung cancer cases are NSCLC. It’s also usually less aggressive than small-cell lung cancer (SCLC).

Pleural effusion is a buildup of fluid around the lungs. Several lung conditions and even injuries to your chest can cause pleural effusion. When due to NSCLC, pleural effusion is associated with cancer spread and decreased survival odds.

But new research shows that, with aggressive treatment, people with NSCLC and pleural effusion might have a better outlook than was previously believed.

Pleural effusion is the buildup of fluid between the layers of membranes that line your lungs and the inside of your chest cavity. These membranes are called pleura. There’s always a small amount of fluid in the pleura that acts as a lubricant to help you take in and expel air.

Pleural effusion is when too much fluid builds up in the pleura. It’s also sometimes called “water on the lungs.”

Pleural effusion can lead to symptoms such as:

Doctors often check for pleural effusion during NSCLC diagnosis. Doctors can do a few different tests to check for pleural effusion. These tests include:

  • Chest X-ray: A chest X-ray can take images of the lungs to look for fluid buildup.
  • Chest CT scan or ultrasound: An imaging test such as a chest CT scan or ultrasound can create detailed images of the lungs.
  • Thoracentesis: Thoracentesis uses a needle between the ribs to remove a sample of fluid for examination in a lab.
  • Thoracoscopy: A thoracoscopy uses tiny cameras to allow doctors to see and treat the effusion at the same time. You’ll be under general anesthesia during the procedure.

Pleural effusion can be a sign that NSCLC has spread beyond the original tumor location. People whose NSCLC is at a higher stage are more likely to experience pleural effusion. In many cases, the presence of pleural effusion at diagnosis means the NSCLC has already advanced to stage 4.

But this isn’t always true. Pleural effusion can sometimes be the first symptom of lung cancer. It can also be due to complications of lung cancer.

To determine the exact stage of your cancer when pleural effusion is present, your doctor will need to identify the underlying cause of the pleural effusion.

If the underlying cause is NSCLC, meaning the pleural effusion contains cancer cells, the cancer is stage 4. If the underlying cause is something other than NSCLC, your stage will depend on factors such as tumor size and whether it has spread to your lymph nodes or surrounding tissues.

Doctors typically consider pleural effusion to be a sign of a poor outlook for people with NSCLC. But recent studies (1, 2) suggest that more aggressive treatment of NSCLC with pleural effusion can help improve the survival odds of people with otherwise minimal disease (when cancer hasn’t spread beyond the chest).

Your exact treatments will depend on other factors and when pleural effusion develops. Options generally include:

  • Thoracentesis: Doctors use this procedure both to diagnose and treat pleural effusion.
  • Tube thoracostomy: In a thoracostomy, doctors insert a tube into your chest for a day or more to drain fluid.
  • Catheter: Doctors can place a catheter into your chest to drain fluid. They may use this option when fluid drainage needs to be ongoing.
  • Shunt: A shunt is a surgically inserted tube doctors use to move fluid from one area of your body to another.
  • Chemotherapy: In some cases, treating NSCLC with chemotherapy is also the best treatment for pleural effusion.

Until recently, doctors didn’t consider people with NSCLC and pleural effusion as candidates for tumor removal surgeries.

But research has found that surgery can benefit some people with NSCLC and pleural effusion after receiving standard care. A 2019 study found that surgery improved the survival rate for people with minimal disease, meaning cancer that hasn’t spread beyond their chest.

More research on this topic is still needed, but initial results are promising.

Doctors typically consider pleural effusion a sign of advanced NSCLC, and the outlook can be challenging. Once NSCLC is in later stages, the 5-year survival rate is 8%.

But survival rates are based on old data. That figure represents data collected between 2011 and 2017. With advances in treatment, it’s likely that the current number is higher and will continue to rise.

If you have pleural effusion and NSCLC, your doctor might talk with you about palliative care. Palliative care can help you manage your NSCLC.

Palliative care isn’t the same as hospice, and it doesn’t mean your doctor expects you to die quickly. Palliative care is a program that provides you with extra medical, social, and mental health support while you manage your NSCLC.

If you have questions about pleural effusion and NSCLC, you can learn more by reading the answers to some commonly asked questions.

How common is pleural effusion in NSCLC?

About 8% to 15% of people with NSCLC have pleural effusion at the time of NSCLC diagnosis. About 40% to 50% of people with NSCLC will develop pleural effusion.

What increases my risk for pleural effusion?

The biggest risk factors for pleural effusion are also the biggest risk factors for NSCLC itself. These include smoking, exposure to secondhand smoke, and environmental factors. Other risk factors include contact with asbestos.

Is pleural effusion more common with some types of lung cancer?

Pleural effusion is more common in people with adenocarcinoma than in other types of NSCLC.

Pleural effusion is a buildup of fluid in the membranes between your lungs and chest wall. When pleural effusion occurs with NSCLC, it can indicate that cancer has spread and progressed to a late stage.

Doctors consider this a sign of a poor outlook for people with NSCLC and often eliminate surgery as a treatment option.

But if cancer hasn’t yet spread beyond your chest, new research suggests that more aggressive treatment may be possible. More research is needed to determine whether surgery can be an option for this subset of people with NSCLC and pleural effusion.

Talk with your doctor to learn more about options specific to you.