Bowel Obstruction and Cancer Treatment – Side Effects

What is bowel obstruction?

A bowel (intestinal) obstruction is a serious condition that occurs when the small or large intestine becomes blocked. The blockage stops food and stool (poop) from moving through the intestines. The intestine may be partly or completely blocked and can sometimes be blocked in two places. Bowel obstructions can be life-threatening and require immediate medical attention.

A bowel obstruction may occur soon after cancer treatment ends or many months or years later. Bowel obstruction is most common in people with advanced cancer. 

What causes bowel obstruction in people with cancer?

Bowel obstruction in people with cancer may be caused by:

• Cancer treatment. Some types of cancer treatment can cause bowel obstruction:
  • Surgery on the abdomen or pelvis may lead to scar tissue, also called adhesions, that form after surgery. Adhesions can cause the intestines to bind together, creating a blockage.
  • Radiation therapy directed at the abdomen can damage the intestines, leading to scar tissue, inflammation, radiation enteritis, and irritation that can block the bowel.

• Cancer itself. Cancers that form in the abdomen, such as colon, ovarian, pancreatic, or stomach cancer, are more likely than other cancer types to cause a bowel obstruction. A bowel obstruction caused by cancer itself is called a malignant bowel obstruction. Cancer can cause a bowel obstruction in different ways:
  • A tumor that forms in or presses on the bowels can cause a bowel obstruction. A tumor can also cause a bowel obstruction if it grows in an area that affects the nerves that control the movement of food through the intestines.
  • Advanced cancer can cause a bowel obstruction when cancer spreads to the bowels from another place in the body. Advanced cancer is the most common cause of malignant bowel obstruction. 

Other causes of bowel obstruction not related to cancer or cancer treatment include a twist in the intestine, a hernia, irritable (inflammatory) bowel syndrome, diverticulitis, some medicines, long-term constipation, and other conditions.

What are the signs and symptoms of bowel obstruction?

Signs and symptoms of a bowel obstruction include:

• abdominal pain or cramps
• swelling in the abdomen
• constipation
• diarrhea
• nausea or vomiting
• problems passing gas
• loss of appetite

When an obstruction starts, the intestines may be partly blocked, causing a few mild symptoms. As the obstruction gets worse, your symptoms may happen more often and become more severe. You may have frequent vomiting, extreme bloating, and intense abdominal pain. These are signs of a complete obstruction, in which stool and gas are mostly or totally blocked from leaving the body.

How is bowel obstruction diagnosed?

Finding the cause of a bowel obstruction and the place where the intestine is blocked is important so your doctor can recommend treatment. Your doctor will ask about your symptoms and do a physical exam. They may also use the following tests and procedures to diagnose a bowel obstruction and suggest treatment options:

• CT scan (CAT scan) uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body from different angles. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This scan helps doctors find the cause and exact location of the obstruction. It is also called computed tomography, computerized tomography, or computerized axial tomography. 
• Abdominal x-ray is an x-ray of the organs inside the abdomen. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. It can also show the location of the obstruction, but it is not as sensitive as a CT scan.
• Blood tests, such as a complete blood count and electrolyte panel, show if you are dehydrated or have an electrolyte imbalance or infection. These problems may be caused by a bowel obstruction.
• Urinalysis checks the color of urine and its contents, such as sugar, protein, red blood cells, and white blood cells. A urinalysis shows your fluid levels, signs of infection, and other problems that may be caused by a bowel obstruction.

Treating a bowel obstruction

If you have a bowel obstruction, you will need to be treated in a hospital. Treatment for a bowel obstruction depends on what caused the blockage and whether the intestines are partly or completely blocked. If you have a complete blockage, you will probably need surgery. Partial obstructions may clear up with nonsurgical treatments.

Treatment for a bowel obstruction may include:

• Bowel rest. This is when you avoid eating and drinking to keep the obstruction from getting worse. Bowel rest or a liquid diet that is easy on your intestines can help your body clear the blockage. You may also receive fluid replacement therapy (IV fluids) to help the fluids and electrolytes in your body return to normal.
• Nasogastric tube. This tube is inserted through the nose and esophagus into the stomach to relieve pressure caused by a bowel obstruction by removing fluid and gas from the digestive system. A nasogastric tube helps control nausea, vomiting, and pain related to the obstruction and may help your body clear the blockage.
• Stent. This is a tube placed in the intestine to open the blocked area. Stents relieve bowel obstruction symptoms by temporarily opening the bowels to let food, waste, and gas pass through the body. Stents are most often used to treat bowel obstructions caused by cancer, but they may also be used for obstructions with other causes.
• Surgery. If a bowel obstruction does not go away with other treatments or if you have a complete blockage, you may need surgery to remove the obstruction. For an obstruction caused by cancer, surgery will include removing the tumor that is causing the blockage. Your doctor will talk with you about your overall health and potential risks and benefits of surgery to help you decide if surgery is right for you. 
• Gastrostomy tube. A tube that helps release fluid and air from the stomach to relieve symptoms caused by the obstruction. A tube is inserted through the wall of the abdomen directly into the stomach. The gastrostomy tube can be attached to a drainage bag with a valve. When the valve is open, fluid and air can leave the stomach. Gastrostomy tubes are most often used to treat bowel obstructions caused by cancer.
• Antibiotics. Sometimes a bowel obstruction causes a tear in the intestines that lets fluids leak into the abdomen. These fluids can cause your body to have an extreme immune response to an infection (sepsis). Antibiotics can help prevent tissue damage, organ failure, or death from sepsis.
• Antinausea and pain medicines. These can treat or control nausea, vomiting, and pain caused by a bowel obstruction.

Considerations for treating a malignant bowel obstruction

If you have a bowel obstruction caused by cancer (also called malignant bowel obstruction), talk to your health care team about available treatments and your goals of care. In most cases, treatments for malignant bowel obstructions relieve symptoms and improve quality of life but may not help you live longer from cancer. You and your family may need to make difficult decisions about your care at this time. If you choose care meant to relieve symptoms over more aggressive treatments, you can learn more about Choices for Care When Treatment May Not Be an Option.

Talking with your doctor about bowel obstruction

If you think you have a bowel obstruction, contact your doctor right away. They can help you decide on a treatment that is right for you.

Questions to ask your provider about bowel obstruction:

• What is causing the bowel obstruction?
• What treatments are available to me?
• What are possible complications of treatments I may receive for bowel obstruction?
• What foods should I eat or avoid? 
• How much liquid should I drink each day?
• What symptoms or problems should I call you about?
• Will I be at risk of future bowel obstructions?

Getting support if you have a bowel obstruction

Side effects like bowel obstruction can be hard to deal with, both physically and emotionally. It’s important to ask for support from your health care team. They can help you prepare for and make it through difficult times. Learn more about ways to cope with cancer, including ways to adjust to daily life during cancer treatment. 

For family members and friends who are caring for someone with cancer, you may find these suggestions for caregivers to be helpful. 

How a caregiver can help

• Help the person you are caring for eat and drink the foods and liquids their doctor has recommended. Many people treated for a bowel obstruction will need to be on a liquid diet while they recover.
• Provide the person you are caring for with a heating pad for their belly that can help relieve pain and cramping.
• Talk with the person you are caring for about their goals of care, especially if they have a malignant bowel obstruction, to help them decide on a treatment that is right for them.
• Carefully review follow-up care with the person’s doctor to learn what to expect after treatment and how you can help.