What Is Radiation Enteritis?

Radiation enteritis is a condition that can occur in the intestines after having treatment with radiation therapy, a common cancer treatment. The symptoms of radiation enteritis can include diarrhea, nausea, vomiting, and crampy abdominal pain.

In many cases, radiation enteritis will go away after the radiation treatment ends. However, in some cases, it may continue for longer and cause complications.

Radiation Enteritis Symptoms

The word enteritis comes from "enteron," meaning intestine, and the suffix “itis,” meaning inflammation. The radiation treatments that might be used for cancer can cause the intestines to become inflamed. This inflammation (redness, swelling) that happens in the intestines causes digestive symptoms. 

Some of the signs and symptoms of radiation enteritis can include:

• Abdominal pain
• Diarrhea
• Weight loss

Causes

Radiation enteritis is caused by radiation treatment used for cancer. Some reasons a person may be more at risk for having inflammation in the digestive system after radiation treatment are:

• Radiation dose: The dose of radiation used can affect the risk of radiation enteritis. Higher doses will carry more risk than lower doses. The dose prescribed should be enough to treat the cancer but not so much that it can increase the risk of inflammation.
  
• Treated area: The larger the area that receives the radiation, the higher the risk of radiation enteritis. One study of cervical cancer patients showed that limiting the area of the abdomen treated with radiation helped reduce the risk of symptoms in the intestines.
  
• Use of chemotherapy: Chemotherapy (medicine to kill cancer cells) is another treatment that may be used for cancer. When chemotherapy and radiation treatment are used at the same time, the risk of radiation enteritis is likely to increase.
  
• Surgery: Having radiation treatment after surgery might also increase inflammation in the digestive system.
  
• Other factors: Conditions that may increase the risk include inflammatory bowel disease, lupus, diabetes, hypertension (chronic high blood pressure), or scleroderma. Smoking cigarettes might also mean the risk of inflammation is higher.

Diagnosis

It can take time to get a diagnosis because radiation enteritis isn’t well understood. The symptoms are not specific and could be caused by other conditions. Testing may be necessary to arrive at a diagnosis. Additional tests may also be needed to rule out the progression of cancer.

Some of the tests that might be done to see if there is inflammation in the intestine include:

• Capsule endoscopy: Also called pill cam, you swallow a capsule-encased micro-camera to take images of the digestive tract.
• Computed tomography (CT) scan with oral contrast: You swallow a compound that will enhance imaging. A series of X-rays are taken to provide detailed images.
• Colonoscopy: A flexible tube with a camera and tools is passed through the anus to view the colon.
• Magnetic resonance imaging (MRI) with oral contrast: After swallowing a compound that will enhance imaging, powerful magnets are used to take detailed images.

Treatment

Most of the treatments are used to lessen the symptoms of radiation enteritis.

Diarrhea might be treated with medications, including:

• Biliary acid chelators such as Questran (cholestyramine)
• Antibiotics such as Xifaxan (rifaximin) or Flagyl (metronidazole) to treat any overgrowth of bacteria

For those who are having trouble absorbing nutrients from food or with getting enough calories, nutritional therapy might be used. This can include some nutritional supplements and parenteral nutrition, receiving nutrition through an intravenous (IV) line.

In severe cases, there could be a complication of a bowel obstruction. This occurs when the bowels are blocked up and food isn’t moving through or being digested. This might be treated with steroids, fluids, and/or nutrition through an IV. Nasogastric (NG) tube insertion may be done to decrease pressure on the bowel.

In some cases of obstruction, resection surgery is needed. This involves removing part of the intestine and the healthy ends of tissue.

Resection surgery to remove a section of inflamed intestine might also be used for chronic radiation enteritis and when medical treatment is not helpful. The symptoms of radiation enteritis can sometimes come on years after treatment or, unfortunately, go on for years. In some cases, surgery might help in improving the quality of life.

Hyperbaric oxygen is another possible treatment. In this procedure, you lie in a chamber in which there is increased pressure. Studies have been mixed on its use, but it may be helpful for specific people. However, hyperbaric chambers are not common and might be expensive, so accessing this treatment can be difficult for many. 

Prognosis

Most people with radiation enteritis recover after radiation therapy is completed. Radiation enteritis is still not well understood but treatments are improving. The prognosis for patients is also getting better. Patients will want to get diagnosed and treated early after symptoms start, which can lead to a good outcome. 

Coping

In the past, it was thought that there was not much help for the symptoms of radiation enteritis. However, the symptoms can negatively and substantially impact quality of life. Patients may need to be insistent about asking for a specialist and receiving treatment.

Getting a referral to a gastroenterologist with experience in treating radiation enteritis may be helpful. A gastroenterologist treats diseases and conditions of the digestive system.

Summary

Radiation enteritis is an inflammation of the intestines. It is caused by radiation treatment, which might be used to treat cancer. The inflamed intestines can lead to diarrhea, pain, weight loss, or certain complications. Treatment is usually done with medications to decrease symptoms and, uncommonly, with surgery.

A Word From Verywell

Being diagnosed with cancer is difficult enough, but the treatments can sometimes lead to complications. Radiation treatment could cause symptoms like diarrhea and pain that can be distressing and make it hard to leave the house and work or go to school. 

It might seem as though these symptoms are not significant compared to the larger goal of putting cancer in remission. Having a good quality of life is essential, and there are ways to lower the effect that radiation has on the body and treat any inflammation it causes.

Patients and caregivers may need to advocate strongly for a diagnosis and treatment. Asking questions, firmly demanding answers, and not giving up are all helpful in being heard and getting a treatment plan in place.