What is ascites? How does it affect cancer patients?

Related conditions:
late-stage cancer or liver disease, associated with ovarian, endometrial, breast, gastrointestinal (stomach, colon, pancreatic) cancer

Definition:
Ascites is an abnormal accumulation of excess fluid in the abdominal (peritoneal) cavity that causes swelling or bloating. In late-stage cancer, tumor cells may be isolated from the fluid. Ascites can also occur with liver disease.

Risk factors: Ascites is not uncommon in cancer patients; 15 to 50 percent develop this condition at some time during their illness. Ascites is most common in patients with
ovarian cancer but may also be present in patients with uterine, breast, colon, stomach, and pancreatic cancers. Liver involvement with cancer can increase the problem with ascites. Noncancerous conditions that can result in ascites include hepatitis, kidney failure, heart failure, and constrictive pericarditis (inflammation of the sac around the heart).

Etiology and the disease process: A lining of tissue, the peritoneum, supports the organs in the abdomen and covers the peritoneal cavity. Normally a small amount of body fluid lubricates this cavity and is kept in correct proportion by a pressure gradient. The liver stores blood and fluid depending on the pressure in the venous and arterial blood system. Under normal conditions, the lymphatic system drains 80 percent of the peritoneal fluid, so minimal accumulation occurs. When pathological or disease conditions occur, the fluid accumulates and edema settles in the peritoneal cavity.

In malignant ascites, a tumor may obstruct the lymphatic system so that drainage cannot occur. Liver involvement can cause a backup of fluid into the peritoneal cavity. In severe cases of ascites, gallons of liquid can fill the peritoneal cavity, pressing on the diaphragm (the muscles that separate the chest from the abdomen and allow a person to breathe).

Ascites is not actually a disease but a symptom of some pathological condition within the body. Some of the conditions that can result in ascites include cirrhosis of the liver (80 percent of ascites cases), pancreatic ascites, chylous ascites (a symptom of lymphoma), and cancer. Renal and endocrine ascites occur in rare instances.

Incidence: Approximately 10 percent of all cases of ascites occur in cancer patients. As many as half of all cancer patients will experience ascites. About 30 percent of all ovarian cancer patients have ascites, with as many as 60 percent presenting with ascites at death. Most cases result from disease that starts in the peritoneum or spreads from other body organs (metastasis).

Symptoms: Mild ascites may not be noticeable or present any symptoms. As the disease progresses, the abdomen can become more distended and swollen to the point of discomfort and pain. The patient may experience a feeling of heaviness. The patient may have trouble sitting, walking, or moving around. Fluid buildup may cause indigestion, nausea, or vomiting. The patient may experience diminished appetite with weight loss and general fatigue. When the fluid becomes excessive, the patient may have weight gain and shortness of breath. Some patients complain of swelling in the legs and ankles or experience hemorrhoids. Changes may occur in the navel as fluid collects. The severity of symptoms depends on the progression of the disease.

Screening and diagnosis: Diagnosis is confirmed using a physical exam and patient history along with X rays, ultrasound, computed tomography, or paracentesis with fluid analysis (removing fluid through a thin needle into the abdomen). Simple measuring of abdominal girth can provide a baseline for continued assessment.

Treatment and therapy: Treatment is targeted to the symptoms and to improve quality of life. One approach is to reduce sodium and fluid intake to decrease fluid buildup. Another is the use of diuretic drugs that promote removal of fluid through the kidneys as urination. Caution must be taken in the use of diuretics as the patient may experience hypovolemia (a drop in circulating blood volume through large loss of blood or fluid) with a severe drop in blood pressure or a potassium imbalance that can threaten the regular beat of the heart.

If discomfort is severe, a therapeutic paracentesis can be performed by the health care provider. This procedure drains fluid from the abdomen through a thin needle inserted into the peritoneal cavity. This procedure is generally performed with a local anesthesia. Rarely, surgery to shunt the fluid away from the abdominal cavity (peritoneovenous shunt) or specific chemotherapy may help. Repeated paracentesis as can be tolerated by the patient may be the only effective approach long term.

Few alternative or complementary approaches are effective for ascites. Diet can be modified to minimize sodium intake. The patient should consume potassium-rich foods such as low-fat yogurt, cantaloupe, or baked potatoes to assist with proper heart function.

Prognosis, prevention, and outcomes: The prognosis for ascites depends on the underlying cause and intensity of the problem. Generally, unless the cause is corrected, the fluid will return after draining with paracentesis. In fact, rapid reduction through the draining of fluid can result in rapid reaccumulation of fluid. Removing more than five liters at one time can result in hypotension, shock, and death.

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