What Type of Cancer Causes Fluid in the Abdomen?

Ascites (pronounced uh-site-ease) is a condition that affects the belly (abdomen). Fluid builds up inside the abdominal cavity, causing the belly to swell and feel hard. The most common causes of ascites are cancer and liver disease.

This condition may occur when cancer spreads to the abdomen. Specific types of cancer are more likely to spread to the abdomen and cause ascites. If cancer spreads to the abdomen and causes fluid to build up, it’s malignant or cancer ascites.

What Is Malignant Ascites?

A tissue called the peritoneum lines the inside of your abdomen and covers the organs in your belly. The peritoneum makes a liquid (called serous fluid) that fills the space between its two thin layers of tissue. Serous fluid cushions your internal organs and allows them to move freely.

Typically, your abdomen has about 50 to 100 milliliters of serous fluid. Malignant ascites occurs when cancer causes excess fluid to build up in your abdomen. When tumors grow in the belly, the peritoneum may make extra fluid.

Cancer in the abdomen may also cause:

  • Blockages in stomach lymph nodes that prevent fluid from draining.
  • Irritation to the peritoneum, increasing fluid production.

Ascites may also occur when tumors increase pressure inside the liver or cause liver damage. When the liver can’t filter blood as it should, veins may leak, and fluid builds up when it can’t move through the veins normally.

What type of cancer causes fluid in the abdomen?

Certain types of cancer are more likely to spread to the abdomen (peritoneum) or liver and cause malignant ascites.

Types of cancer that cause fluid in the abdomen include:

What stage of cancer causes fluid in the abdomen?

When cancer causes fluid to build up in the abdomen, it often means the cancer has spread (metastasized) from somewhere else. Metastatic cancer is late-stage cancer; most often, this is stage III or stage IV cancer.

What are the other causes of fluid in the abdomen?

Only about 10% of people who develop ascites have cancer. The most common cause of ascites is cirrhosis of the liver. Ascites can also happen in people with:

What are the symptoms of fluid in the abdomen?

Ascites causes several symptoms. Your belly may get bigger. You may feel bloated and heavy, and you may gain weight.

You may also have:

  • Appetite changes, indigestion, or a full feeling very quickly after eating.
  • Fatigue.
  • Nausea and vomiting.
  • Trouble breathing or shortness of breath.
  • Trouble making bowel movements, including constipation.
  • Swelling in your ankles or limbs (edema).

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How Do Doctors Diagnose Ascites?

Talk to your doctor if you experience ascites symptoms. Doctors diagnose ascites using:

Physical examination

Your doctor will look at your abdomen to check for swelling. They will put their hands on your belly to see if it feels hard and swollen.

Blood tests

Doctors may order blood tests to see if ascites is affecting how your organs function.

They may check:

  • Electrolytes, the minerals in your blood that help your muscles, nerves, and other body systems work properly.
  • Kidney function, or how well your kidneys filter your blood and produce urine.
  • Liver function, or how well your liver filters your blood and whether your liver has damage or disease.

Examination of fluid (paracentesis)

A doctor may use a needle to remove fluid from your abdomen. The term for this procedure is paracentesis. It tests the fluid to look for signs of infection and to determine if cancer cells are present.

Imaging tests

Your doctor may recommend imaging tests to determine the amount of fluid in your abdomen.

You may have:

Urine tests

Your doctor may want to test your urine to see if ascites is impacting your kidney function.

You may have:

  • Urinalysis. A doctor examines your urine sample to check for certain cells and substances that may indicate ascites or infection.
  • A 24-hour urine collection. Your doctor has you collect your urine over 24 hours. They check levels of proteins and other substances to see how well your kidneys function.

How Does a Doctor Treat Fluid in the Abdomen from Cancer?

When possible, your doctor will treat tumors that cause ascites. Reducing the size of tumors can help prevent fluid from building up in your belly. Cancer treatments may include surgery, chemotherapy, or radiation.

You may not need treatment if the ascites doesn’t make you uncomfortable. But if you don’t feel well, your doctor may offer treatment to help relieve your discomfort.

Treatments include medicines and other procedures to relieve fluid buildup.


Water pills (diuretics) are medicines that make you pee out more water. Urinating more often helps reduce the amount of liquid in your body.


During a paracentesis, a doctor removes fluid from your belly. They insert a needle with an attached flexible tube into your abdomen to drain the fluid.

If you don’t have too much fluid buildup, you may undergo a paracentesis at an outpatient center. If you develop excessive fluid in your peritoneum, you may need to do this in the hospital.

Can You Recover From Cancer Ascites?

Malignant ascites is a sign that cancer has progressed. Talk with your doctor about available cancer treatment options. Reducing tumor size and controlling the spread of cancer may help control ascites.

Living with Cancer Ascites

Palliative care is treatment that can help improve your quality of life when you have advanced cancer and malignant ascites. Talk to your doctor about whether this care is right for you. Your palliative care team can help you make decisions about treatment options.

Palliative care specialists offer:

  • Care to make you more comfortable.
  • Emotional support.
  • Pain management.

A social worker can connect you with others who have cancer ascites. Support groups and other supportive care can help you manage this condition.

American Cancer Society. Swelling. Link

American Society of Clinical Oncology. Ascites or Fluid in the Abdomen. Link

American Society of Clinical Oncology. Ovarian, Fallopian Tube, and Peritoneal Cancer: Stages and Grades. Link

Frontiers in Oncology. Malignant ascites in pancreatic cancer: Pathophysiology, diagnosis, molecular characterization, and therapeutic strategies. Link

JAMA Oncology Patient Page. Ascites, or Fluid in the Belly, in Patients With Cancer. Link

MedlinePlus. 24-hour urine protein. Link

MedlinePlus. Ascites. Link

MedlinePlus. Chronic Kidney Disease. Link

MedlinePlus. Electrolytes. Link

MedlinePlus. Liver Function Tests. Link

MedlinePlus. Urinalysis. Link

Merriam-Webster. Ascites. Link

National Cancer Institute. Cancer Staging. Link

StatPearls. Peritoneovenous Shunt. Link

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