Cancer-Related Ascites and Drainage

Ascites is a build-up of fluid inside the abdomen. Macmillan defines it as "a build-up of fluid in the lining of the tummy (abdomen)." When cancer is the reason for it, the American Cancer Society calls it malignant ascites.

The lining in question is the peritoneum, a thin membrane that wraps the abdominal organs. It normally makes a small amount of slippery fluid so those organs can move against each other. Ascites is that system out of balance. Too much fluid is made, too little is carried away, or both.

This is common and it is uncomfortable. It also has a specific set of dangers, which is what the next section is for.

Go to an emergency department or call 911 for:

• New or worsening breathlessness at rest. MedlinePlus explains why this happens: "the fluid pushes up on the diaphragm, which in turn compresses the lower lungs."
• Severe belly pain, especially with fever. MedlinePlus lists spontaneous bacterial peritonitis — infection of the ascites fluid itself — among the complications of ascites.
• New confusion or unusual sleepiness. MedlinePlus also lists hepatic encephalopathy, a brain effect of liver failure, as a complication.
• Fainting, or dizziness that does not settle when you lie down, particularly in the day or two after a large drainage.

Call your cancer team the same day for:

• A temperature of 100.4°F (38°C) or higher. CDC's advice for people with cancer is exact: "Call your doctor immediately if you have a temperature of 100.4ºF (38ºC) or higher." CDC adds that "fever may be the only sign that you have an infection."
• Weight gain of more than ten pounds in a week, or a belly that is swelling faster than usual. The American Cancer Society names both.
• A drain that suddenly stops draining when fluid is clearly still there.
• Fluid that turns cloudy, milky, bloody or foul-smelling, when it had been clear or straw-colored.
• Redness, warmth, swelling or pus at the catheter site, or fluid leaking around it fast enough to soak through dressings.
• Not passing urine, or passing much less than usual. MedlinePlus's abdominal tap page lists lowered blood pressure after a large amount of fluid is removed, and kidney problems, among the uncommon risks of the procedure.

Do not wait for a portal message to be answered when someone is short of breath at rest or feverish.

Macmillan describes four routes to the same result.

Cancer cells on the peritoneum irritate the lining, and it responds by making more fluid than usual. Lymph nodes in the abdomen become blocked, so "the fluid cannot drain properly." Cancer in the liver raises pressure in the veins running through it. That pushes fluid out into the abdomen. A damaged liver also makes less blood protein, and fluid then leaks out of veins.

More than one of these can be running at once.

MedlinePlus adds that ascites "often results from high pressure in certain veins of the liver (portal hypertension)." Low albumin, a blood protein, also plays a part. This matters. Not all ascites in a person with cancer is malignant ascites. Heart failure, pancreatitis and cirrhosis cause it too, and the treatment differs. This is a fair thing to ask about directly.

The American Cancer Society reports it most often with cancers that sit in or near the abdomen. Its list: peritoneal, liver, pancreatic, ovarian, bladder, stomach and colon.

The American Cancer Society's leading sign is "a swollen and hard belly." Around that: abdominal discomfort, nausea, indigestion, heartburn, feeling full after a few mouthfuls, rapid weight gain, needing to pass urine more often, and breathlessness.

Macmillan adds tiredness, constipation and loss of appetite.

Feeling full quickly is the one people mention least and lose most weight from. Say it if it is happening.

An ultrasound or CT scan shows the fluid. What the fluid is takes a sample.

The American Cancer Society describes a diagnostic paracentesis: a needle draws off a small amount, and cytology — the study of cells under a microscope — looks for cancer cells. MedlinePlus notes the same test can identify infection, and lists cirrhosis, heart failure, kidney disease and pancreatic disease among other explanations it can turn up.

MedlinePlus describes the procedure step by step. The site is cleaned and hair clipped if needed. You get a local numbing medicine. "The tap needle is inserted 1 to 2 inches (2.5 to 5 cm) into the abdomen."

How it feels: "You may feel a slight sting from the numbing medicine, or pressure as the needle is inserted."

When the point is to relieve symptoms rather than to diagnose, the same route is used to take off liters at a time. MedlinePlus says a tap "may also be done to remove a large amount of fluid to reduce belly pain or shortness of breath."

Macmillan describes how that day usually runs. A small cut is made under local anaesthetic. A tube goes in, guided by ultrasound. Most people come in as a day case and are usually at the hospital "for at least 6 hours," though some stay overnight. Draining happens "over a few hours," and the pace depends on how much fluid there is and on your blood pressure.

Tell your team beforehand about allergies, all medicines including herbal ones, any bleeding problems, and if pregnancy is possible. MedlinePlus lists all four. The risks it names are a needle puncturing bowel, bladder or a blood vessel, along with infection, lowered blood pressure after a large amount of fluid is removed, and kidney problems. It describes all of these as uncommon.

Repeat taps get tiring. For ascites that refills, a catheter can stay in.

Macmillan describes long-term drains that remain in place, kept closed between sessions and covered with a dressing. The American Cancer Society describes the same thing as a permanent small tube used to drain at home every few days.

A peritoneal port is a variation. RadiologyInfo, from the Radiological Society of North America, describes it as "a small reservoir or chamber that is surgically placed under the skin to provide a painless way of withdrawing excess fluid from or delivering anti-cancer drugs into the abdominal or peritoneal cavity over a period of weeks, months or even years." An interventional radiologist places it using x-ray or ultrasound. You are usually sedated for it. "The catheter is inserted through the skin and into the abdominal cavity. A few inches away, a second incision is made where the peritoneal port is placed in a small pocket under the skin. One end of the catheter is then connected to the port through a tunnel just under the skin."

That tunnel is the point. It puts distance between the outside world and the abdominal cavity. RadiologyInfo puts the infection risk at "less than one in 1,000." It also notes that late infections, including peritonitis, can still happen. Site care in the first week matters most: RadiologyInfo says "it is especially important to keep the port site clean and dry," with sponge bathing rather than soaking.

Macmillan also mentions a peritoneovenous shunt, tubing placed surgically to move fluid from the abdomen into a vein in the neck.

Diuretics, also called water tablets, help some people. They work best when the liver is involved. Macmillan names spironolactone. You will need regular blood tests to watch kidney function. Do not change the dose yourself.

MedlinePlus recommends "lowering salt in your diet (no more than 1,500 mg/day of sodium)" and "avoiding alcohol." The American Cancer Society adds one more: ask your doctor before taking NSAIDs such as ibuprofen.

Treating the cancer itself can also reduce the fluid. Macmillan notes that chemotherapy sometimes improves ascites by acting on the cause.

• MedlinePlus — Ascites
• MedlinePlus — Abdominal tap
• American Cancer Society — Ascites
• Macmillan Cancer Support — Ascites and cancer
• RadiologyInfo.org (RSNA/ACR) — Peritoneal Ports
• CDC — Watch Out for Fever (Preventing Infections in Cancer Patients)