Radiation therapy stops the growth of rapidly dividing cells, such as cancer cells. Since normal cells in the lining of the bowel also divide rapidly, radiation treatment can stop those cells from growing, making it difficult for bowel tissue to repair itself. As bowel cells die and are not replaced, gastrointestinal problems develop over the next few days and weeks.
Symptoms of acute enteritis usually get better 2 to 3 weeks after treatment ends.
Patients with chronic enteritis may have the following symptoms:
Less common symptoms of chronic enteritis are bowel obstruction, holes in the bowel, and heavy rectal bleeding.
Symptoms usually appear 6 to 18 months after radiation therapy ends. Before determining that chronic radiation enteritis is causing these symptoms, recurrent tumors need to be ruled out. The radiation history of the patient is important in making the correct diagnosis.
Patients will be given a physical exam and be asked questions about the following:
Treatment of acute enteritis includes treating the diarrhea, loss of fluids, poor absorption, and stomach or rectal pain. These symptoms usually get better with medications, changes in diet, and rest. If symptoms become worse even with this treatment, then cancer treatment may have to be stopped, at least temporarily.
Medications that may be prescribed include antidiarrheals to stop diarrhea, opioids to relieve pain, and steroid foams to relieve rectal inflammation and irritation. If patients with pancreatic cancer have diarrhea during radiation therapy, they may need pancreatic enzyme replacement, because not having enough of these enzymes can cause diarrhea.
Nutrition also plays a role in acute enteritis. Intestines damaged by radiation therapy may not make enough or any of certain enzymes needed for digestion, especially lactase. Lactase is needed for the digestion of milk and milk products. A lactose-free, low-fat, and low-fiber diet may help to control symptoms of acute enteritis.
Treatment of the symptoms of chronic radiation enteritis is the same as treatment of acute radiation enteritis. Surgery is used to treat severe damage. Fewer than 2% of affected patients will need surgery to control their symptoms.
Two types of surgery may be used:
The patient's general health and the amount of damaged tissue are considered before surgery is attempted, however, because wound healing is often slow and long-term tubefeeding may be needed. Even after surgery, many patients still have symptoms.
To lower the risk that chronic radiation enteritis will occur, different treatment methods are used to reduce the area that is exposed to radiation. Patients may be positioned to protect as much of the small bowel as possible from the radiation treatment, or may be asked to have a full bladder during treatment to help push the small bowel out of the way. The amount of radiation may be adjusted to deliver lower amounts more evenly or higher amounts to specific areas. If a patient has surgery, clips may be placed at the tumor site to help show the area to be irradiated.