Malignant Bowel Obstruction

This page is for people with advanced cancer, and their families, who are worried about a blocked bowel. It covers the warning signs, what causes a blockage, how it is treated, and the decisions that can come with it.

NCI's instruction is short and firm. If you think you have a bowel obstruction, contact your doctor right away. Bowel obstructions can be life-threatening and require immediate medical attention.

MedlinePlus lists the same warning signs. They are not being able to pass stool or gas, a swollen abdomen that does not go away, vomiting that keeps happening, and unexplained abdominal pain that does not go away.

• Call your cancer team or palliative care team right away, at any hour. Do not send a portal message and wait.
• Go to an emergency department if you cannot reach them, cannot be seen in person quickly, or the pain and vomiting are severe or getting worse.
• Call 911 or go to the nearest emergency department for collapse, sudden confusion, being hard to wake, or trouble breathing. MedlinePlus says to call 911 for sudden confusion.

These are the signs NCI lists:

• Abdominal pain or cramps.
• Swelling in the abdomen.
• Constipation.
• Diarrhea.
• Nausea or vomiting.
• Problems passing gas.
• Loss of appetite.

No clinician has reviewed this page yet. Your palliative care or oncology team's instructions come first.

It looks like a mistake. It is not.

NCI's health professional page describes overflow diarrhea as a rare sign of a complete obstruction. So loose stool does not rule an obstruction out.

This is the difference between this page and the other emergency pages on this site. A blockage often builds over days.

NCI describes it as a progression. When an obstruction starts, the intestines may be only partly blocked, causing a few mild symptoms. As it worsens, the symptoms come more often and get more severe.

Then it names the picture of a complete blockage: frequent vomiting, extreme bloating, and intense abdominal pain.

That slow build is a chance and a trap. A chance, because reporting the mild version early gives more options. A trap, because mild symptoms are easy to explain away as constipation, or as the chemotherapy, or as a bad week.

Worth writing down before you call: when you last passed stool, when you last passed gas, how many times you have vomited and what it looked like, whether the belly is bigger, and what the pain does.

Constipation and an obstruction feel similar from the inside, and the home remedies for one are not right for the other.

NCI's guidance for constipation in cancer is to use only medicines and treatments for constipation that your doctor recommends. That is the whole of it. This is a decision for the team to make.

NCI is more specific still about the two things people reach for last. It says not to use suppositories or enemas unless your doctor recommends them. It explains that in some people with cancer they may lead to bleeding, infection or other harmful side effects.

There is also a cause worth knowing. MedlinePlus lists certain medicines, especially narcotics, among the causes of paralytic ileus. That is when the bowel does not work properly even though nothing physically blocks it. Opioids are narcotics, so your pain medicine and a bowel problem can be connected. That is a specific thing to raise with your team.

NCI splits the causes.

Cancer treatment can do it. Surgery on the abdomen or pelvis can leave adhesions, scar tissue that can bind the intestines together. Radiation to the abdomen can damage the intestines and cause inflammation.

Cancer itself can do it. NCI says cancers that form in the abdomen, such as colon, ovarian, pancreatic or stomach cancer, are more likely than other types to cause a blockage. It says advanced cancer is the most common cause of a malignant bowel obstruction.

Which of these it is changes what can be offered, which is why the team will ask about old operations and old radiation fields.

NCI says a bowel obstruction is treated in the hospital, and that a complete blockage will probably need surgery while a partial one may clear with other treatments.

• Bowel rest. Resting the bowel by avoiding food and drink, or sticking to a liquid diet that is easy on the intestines. NCI says this can help your body clear the blockage. Fluids are usually given into a vein.
• Nasogastric tube. Passed through the nose into the stomach to remove fluid and gas. MedlinePlus lists it as a way to decompress the bowel.
• Stent. A tube placed in the intestine to open the blocked area. NCI's health professional page notes that self-expandable stents used to decompress a complete, acute malignant obstruction have been found to reduce unnecessary surgery.
• Surgery. One option among several, and not right for everyone. NCI says that for a blockage caused by cancer, surgery will include removing the tumor that is causing it. The goal can be to clear the obstruction or simply to relieve symptoms. Your team will go over the risks and benefits with you.
• Gastrostomy tube. A tube through the abdominal wall into the stomach that lets fluid and air drain out into a bag. NCI's health professional page says it can be used when surgery is not possible.
• Antibiotics. NCI says antibiotics can help prevent tissue damage, organ failure or death from sepsis, which can follow a tear in the intestine.
• Antinausea and pain medicines. NCI's health professional page says octreotide reduces gastrointestinal secretions. It describes it as useful for pain and nausea that other medicines do not control when surgery is not possible.

Diagnosis is usually a CT scan, which NCI says finds both the cause and the exact location. An abdominal x-ray can show where the blockage is but is less sensitive. Blood tests and urinalysis check for dehydration and infection.

This is the part that makes malignant bowel obstruction different from every other emergency here.

NCI puts it in plain words. For a malignant bowel obstruction, it says to talk to your health care team about the available treatments and your goals of care. In most cases, treatment relieves symptoms and improves quality of life but may not help you live longer from the cancer. It adds that you and your family may need to make difficult decisions at this time.

That is not a reason to do nothing. Relief of vomiting and pain is worth having on its own terms. Ask your team which non-surgical options could ease symptoms.

But it does mean the honest question is not only "can this be cleared?" It is also "what am I trading, and for what?" Ask which option the team would choose for someone in your position, and why.

A suspected blockage always needs a call right away. A complication raises the stakes further.

NCI describes a tear in the intestine letting fluid leak into the abdomen and causing sepsis. CDC lists these sepsis signs: confusion or disorientation, shortness of breath, a high heart rate or weak pulse, fever, shivering or feeling very cold, extreme pain or discomfort, and clammy or sweaty skin.

• Call 911 or go to the nearest emergency department if any of these appear on top of a suspected blockage. Do not call the clinic first.

Preparing for an Emergency Department Visit With Cancer, and Sepsis During Cancer Treatment.

• National Cancer Institute — Bowel Obstruction and Cancer Treatment
• National Cancer Institute — Constipation and Cancer Treatment
• National Cancer Institute — Gastrointestinal Complications (PDQ) Health Professional Version
• MedlinePlus — Intestinal obstruction
• MedlinePlus — Confusion
• CDC — About Sepsis