Skip to main content

Managing Cancer Care


The abdomen (belly) is surrounded by a membrane (lining) called the peritoneum. The peritoneum normally produces fluid called peritoneal fluid. When this fluid builds up in the belly, it’s called ascites. It can make the belly hard and swollen (distended). Ascites caused by cancer is called malignant ascites.

What causes ascites?

In people with cancer, ascites can be caused by tumors in or around the abdomen. These tumors can trigger the peritoneum to create more ascitic fluid, leading to ascites.

Ascites is most common in these types of cancers because of their location near the peritoneum and abdomen:

  • Peritoneal
  • Liver
  • Pancreatic
  • Ovarian
  • Bladder
  • Gastric
  • Colon

However, most ascites is not caused by cancer. The most common cause of ascites is cirrhosis (liver disease). Cirrhosis and other liver problems can lead to scarring, which slows down the liver’s ability to filter blood. Over time, this can cause fluid to back up in the liver and abdomen.

What are the symptoms of ascites?

Many symptoms are usually caused by the extra fluid pressing on nearby areas. The most common sign of ascites is a swollen and hard belly. Other signs and symptoms are:

If your doctor thinks you might have ascites, they often will test the ascitic fluid. A diagnostic paracentesis is a procedure that uses a needle to collect a small amount of fluid. Cytology testing is usually done to confirm malignant ascites. This means that cancer cells can be seen in the fluid under a microscope.

Call 911 or go to the emergency department if you:

  • Have trouble breathing or chest pain
  • Notice swelling that is red, warm, or leaking fluid
  • Can’t eat for a day or more
  • Can’t urinate (pee)


Treatment for ascites

If ascites is caused by cancer, treating the cancer will often relieve the buildup of fluid. (To learn more about different types of cancer treatment, see Treatment Types.)

If ascites is still a problem or the cancer can’t be treated, a procedure called a therapeutic paracentesis might be done to improve the symptoms. A needle is placed into the abdomen to drain and remove the extra fluid. Some people can have several liters of fluid removed at one time. However, if the underlying cause isn’t treated, the fluid will return, usually within a few weeks.

Some people might choose to have a peritoneal drain or catheter placed. It’s a small tube that stays in the belly for as long as a person needs it. The drain is connected to a bag and drained at home every few days or as needed. This means the person doesn’t have to go to an appointment or have a needle placed every time they need fluid removed.

Tips for managing ascites

Ascites can be very uncomfortable. Here are some things you can do to manage it:

  • Limit or avoid salt, which can make you hold onto fluid and worsen swelling.
  • Avoid alcohol, which can cause swelling and affect the liver.
  • Ask your doctor before you take non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen. These medicines can cause swelling and damage the liver.

Talk to your doctor or cancer care team

If you have ascites, it’s important to talk to your doctor about new or worsening symptoms. Tell them if you have:

  • Swelling in your belly that is getting worse
  • Gain more than ten pounds in one week
  • Have fevers or signs of infection without a known cause

Ask your doctor or cancer care team what you should call right away for versus what can wait until office hours.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Bruera E & Dev R. Overview of managing common non-pain symptoms in palliative care. UpToDate. UpToDate Inc; 2023. Updated December 2021. Accessed December 18, 2023.

Runyon BA. Evaluation of adults with ascites. UpToDate. UpToDate Inc; 2023. Updated March 2022.  Accessed December 18, 2023.

Runyon BA. Malignancy-related ascites. UpToDate. UpToDate Inc; 2023. Updated October 2022. Accessed December 18, 2023.

Smith CC. Clinical manifestations and evaluation of edema in adults. UpToDate. UpToDate Inc; 2023. Updated July 2023. Accessed December 18, 2023.

Sterns RH. Pathophysiology and etiology of edema in adults. UpToDate. UpToDate Inc; 2023. Updated March 2022. Accessed December 18, 2023.

Last Revised: May 1, 2024

American Cancer Society Emails

Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.