This page was reviewed under our medical and editorial policy by
Chukwuemeka Obiora, MD, Surgical Oncologist
This page was reviewed on April 7, 2023.
Paracentesis is a procedure used to remove excess fluid, or ascites, from the abdominal area. If you have cancer, ascites may develop because of pressure from tumors, causing discomfort.
You may need a paracentesis for advanced cancer, particularly if you have any of the following types:
A paracentesis is also called an abdominal tap or peritoneal tap.
A paracentesis doesn’t typically require a lot of preparation, but there are several steps you may wish to complete before the procedure.
Doctors typically perform a paracentesis in a hospital, outpatient clinic or their office. The procedure takes about 45 minutes.
For the procedure, you lie down in a bed with your head raised. Your abdomen area is exposed and cleaned, and a numbing medicine is applied. (The medicine may cause you to feel some stinging.) Next, a needle is inserted about an inch or two into the abdomen. The doctor may need to make a small cut to help with needle insertion.
The doctor then removes fluid with a syringe. It’s normal to feel lightheaded if the doctor is removing a lot of fluid, but let your care team know if you experience this feeling.
When the procedure is over, the incision site is bandaged. If a cut was made, the doctor may close it with one or two stitches. Then:
The benefit of a paracentesis is that it provides relief from any discomfort caused by ascites. However, it’s common for the fluid to return. You may need to have the procedure repeated in a few weeks, or have a special tube called a catheter placed so fluid can continuously drain out.
While a paracentesis for someone with cancer usually focuses on providing relief from fluid buildup, doctors also may choose to analyze the fluid. In this case, the fluid is sent to a laboratory to try to identify a cause for the buildup. Finding a cause is important because it could be related to an advancing cancer, heart disease, infection or other condition.
Although the risks of a paracentesis are low, they are still a possibility. Risks associated with a paracentesis include:
If you underwent a paracentesis to remove uncomfortable excess fluid related to a previously diagnosed cancer, your doctor may suggest additional ways to control the fluid and prevent it from building up again.
One way is by placing a catheter inside your body that attaches to a receptacle outside the body, allowing the fluid to drain without you having to return for another paracentesis.
Your doctor may also recommend chemotherapy, surgery, changes to your diet or the use of a diuretic.
If the doctor used a paracentesis to find out the cause of your excess fluid buildup, then the results may help show which other treatments, if any, you may need. Make sure to ask your care team any questions that you have along the way.