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Cancer and its treatment may cause swelling which also can be called edema or ascites, depending on the area affected.
Swelling or edema is a build-up of fluid in the tissues. This can be caused by retaining salt and water because of certain medicines. It can also be a sign of heart, liver, or kidney damage or failure. Other causes might include surgery, infection, poor nutrition, tumor growth, or a blockage.
Swelling that happens because lymph nodes are blocked or removed causes lymph flow to be impaired. This is called lymphedema
Some medications, like diuretics, can help edema. Diuretics are often called water pills. They stimulate your kidneys to remove sodium and water from your body, so you'll urinate more often and get rid of extra fluid. But diuretics can have possible dangerous side effects. Talk to your doctor to learn more about this if you are prescribed diuretics for swelling or edema.
Ascites is excess fluid buildup in the belly (abdomen) because of pressure from tumors. It can make the belly hard and swollen (distended). Patients with ascites may also have nausea, vomiting, and fatigue. Sometimes the fluid also pushes on lungs which can cause difficulty breathing. Ascites is common in some cancers that have reached the advanced stages and spread in the abdominal area, including cancer of the ovary, liver, colon, stomach, or pancreas. Sometimes chemotherapy or surgery might help manage ascites. More often, a procedure is done to drain the fluid, called a paracentesis. A paracentesis gives temporary relief that may last days or weeks, but fluid often comes back. Sometimes a catheter (tube) is placed and left in the belly, allowing fluid to drain out as needed.
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 journalists, editors, and translators with extensive experience in medical writing.
Gradalski, T. A clinical note: Edema of advanced cancer: prevalence, etiology, and conservative management. A single hospice cross-sectional study. Journal of Pain and Symptom Management. 2019;57(2):311-318.
Gupta A, Sedhom R, Beg MS. Ascites or fluid in the belly, in patients with cancer. JAMA Oncology. 2019;doi:https://doi-org.proxy.lib.ohio-state.edu/10.1001/jamaoncol.2019.5409.
Marinos P, Sarnowski A, Moore A. The clinical management of abdominal ascites, spontaneous bacterial peritonitis and hepatorenal syndrome: are view of current guidelines and recommendations. European Journal of Gastroenterology & Hepatology. 2016;28(3):e10–e18.
National Comprehensive Cancer Network. Palliative Care. Version 2.2019. Accessed at www.nccn.org/professionals/physician_gls/pdf/palliative.pdf on September 19, 2019.
Last Revised: November 30, 2021
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