Causes of Fluid Buildup in Cancer Patients

Cancer and its treatment may cause a myriad of side effects and complications, including the buildup of fluid in certain areas of the body. Fluid buildup may have many different causes, and once the cause is established, treatment can occur. If an individual with cancer has concerns about preventing types of fluid buildup, it is best to discuss these concerns with a healthcare team to learn ways to reduce the risk of this complication.

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Ascites is a type of fluid buildup that occurs in the abdomen. According to, 15 to 50 percent of cancer patients will develop ascites at some point. Cancers that typically develop ascites include ovarian, breast, colon, stomach and pancreatic cancers. The causes are usually tumors in the abdomen and a lowered protein level in the blood. The lining of the stomach, called the peritoneum, is unable to absorb fluid because of tumor cells, and since protein attracts fluid, fluid flows out of the blood vessels into the abdomen. Ascites may also be caused by liver disease or congestive heart failure. When it is safe, paracentesis is performed to relieve the patient of the ascites. Paracentesis involves using a needle to go through the abdominal wall to drain the fluid from the abdomen.

Pleural Effusion

The lungs are contained within a space called the pleural cavity, and when an excess of fluid is in the pleural cavity, it is called a pleural effusion. Pleural effusion can make breathing difficult and uncomfortable, and when cancer cells are in the fluid, it is called malignant pleural effusion. The National Cancer Institute states that malignant effusions are commonly found in breast and lung cancers, leukemia and lymphoma. Effusions may also be caused by radiation or chemotherapy; these are called paramalignant effusions. Noncancerous pleural effusion may also occur in cancer patients due to changes in their bodies from congestive heart failure, pneumonia, pulmonary embolism or malnutrition, says the National Cancer Institute. Pleural effusion is treated in three main ways: paracentesis; thoracentesis, which closes the pleural sac to prevent fluid from building up in the space; and surgery.


Lymphedema is usually associated with breast cancer, but it may develop with other types of cancers. Lymphedema is the swelling that occurs in an arm or leg due to a blockage in the lymphatic system. The blockage prevents lymph fluid from flowing through the system and draining, causing buildup and swelling. Cancer typically causes secondary lymphedema from the removal of lymph nodes, radiation to lymph nodes, cancer cells themselves or infection. Lymphedema may be treated with massage, compression wrapping or garments and exercises. While lymphedema is not curable, the symptoms may be controlled.