Ascites or Fluid in the Abdomen

Approved by the Cancer.Net Editorial Board, 06/2021

Ascites is the buildup of fluid in the abdomen. The peritoneum is a membrane that surrounds the organs inside the abdomen that makes ascitic fluid. This fluid is normal in the body, but cancer can cause the peritoneum to produce too much of this fluid. This is called "malignant ascites" and it is often a sign of advanced cancer.

What causes ascites?

Malignant ascites is caused by cancer that has spread to the lining of the organs inside your abdomen. It can also happen when cancer spreads to the liver. You are more likely to develop ascites if you have one of these cancers:

  • Breast cancer

  • Colon cancer

  • Gastrointestinal tract cancers, such as stomach and intestinal cancers

  • Ovarian cancer or fallopian tube cancer

  • Pancreatic cancer

  • Uterine cancer

What are symptoms of ascites?

Ascites often causes a lot of discomfort. People with ascites may have the following symptoms:

Tell your health care team if you experience any of the above symptoms. Relieving side effects is an important part of cancer care and treatment. This type of care is called palliative care or supportive care. It helps someone, with any type or stage of cancer, feel better.

How is ascites diagnosed?

Your doctor may use one or more of the following tests to locate, diagnose, or plan treatment for ascites:

  • Physical examination

  • X-ray, which is a picture of the inside of the body

  • Ultrasound

  • Computerized tomography (CT or CAT) scan, which creates a 3-dimensional picture of the inside of the body using x-rays.

  • Paracentesis, which is when a needle removes fluid from the abdomen for testing or to relieve symptoms.

How is ascites managed and treated?

The goal of treatment is to provide relief from uncomfortable symptoms. You may not need treatment if your ascites is not causing discomfort. Ascites treatment may have unpleasant side effects. Talk with your doctor about the benefits and risks of each option before deciding on a treatment plan. The treatment options for ascites include:

Changes to how you eat. For mild discomfort, eating less salt and drinking less water or other liquids may help. Salt helps your body hold onto water. Making diet changes can be a challenge for many people. Talk to your health care team about how to make these changes.

Diuretics. A diuretic is any substance that makes you urinate more often. This can help reduce the amount of fluid built up in your abdomen. Diuretics can be prescribed as medication. Most people do not experience side effects when taking a diuretic, but they can cause a loss of sleep, skin problems, fatigue, and low blood pressure.

Paracentesis. Paracentesis is a procedure to remove the fluid in the abdomen. It is used to diagnose the cause of ascites (see above), but it is also used to treat it. A doctor places a needle attached to a tube into the abdomen. The fluid drains through the needle and into the tube. Often, the fluid buildup will come back after a paracentesis procedure. Your health care team may decide to do another paracentesis procedure or they may decide to use a catheter.

Catheter. A catheter can be used to drain fluid. A catheter is a thin tube of plastic inserted into your pleural fluid. At home, you or your family member use the catheter to regularly drain the fluid into a bottle as instructed by your health care team. Occasionally, it may be recommended that a catheter be inserted inside the body to bypass or divert fluid from the abdomen into another part of the body. This is called a shunt or a peritoneovenous shunt.

Treating the cancer. Surgery or chemotherapy used to treat the cancer can sometimes also relieve ascites symptoms. This is because the cancerous cells stop making as much fluid.

Managing discomfort. Sometimes, problems caused by ascites keep coming back, even with treatment. Your health care team can help manage your discomfort by treating problems like swelling in the legs, constipation, nausea, and breathing problems.

Questions to ask the health care team

Consider asking your health care team these questions about ascites:

  • Is ascites a common side effect of the type of cancer I have?

  • What are the signs and symptoms of ascites that I should watch out for?

  • Will I need any tests to diagnose ascites?

  • What treatment options are available for the symptoms of ascites that I have? Which treatment do you recommend?

  • What is causing the ascites?

  • Who should I talk to about any discomfort or other side effects I am experiencing?

  • How can I get in touch with them during business hours and after hours?

Related Resources

Fluid Retention or Edema

Fear of Treatment-Related Side Effects

More Information

JAMA Oncology Patient Page: Ascites or Fluid in the Belly