As cancer patients live longer, clinicians are being called on with greater frequency to manage the side effects and complications of cancer therapy. One such complication is radiation enteritis. This complication of radiation therapy can occur after radiation to the abdomen or pelvis.
Early symptoms of radiation enteritis are due to mucosal edema and ulceration, and include abdominal pain, nausea, vomiting, and a sensation of needing to move the bowels, tenesmus, or both. Late symptoms that are more related to radiation-induced scarring and narrowing of the bowel include small-caliber stools, rectal burning, and mucoid stools. The intensity of pain is mild to moderate and includes cramping. The onset of the early symptoms of radiation enteritis can begin within 1 week to 10 days after the completion of radiation therapy, and the late symptoms can occur months to years later. A variety of factors can predispose the patient to the development of radiation enteritis, including preexisting systemic disease such as diabetes and treatment-related factors. Recent studies suggest that genetic tissue specific hypoxia-inducible factor alpha may modify the acute gastrointestinal tissue response to radiation
Risk Factors Associated With Chronic Radiation Enteritis
(Modified from Theis VS, Sripadam R, Ramani V, et al. Chronic radiation enteritis. Clin Oncol. 2010;2:70–83.)
|Patient Factors||Treatment Factors|
|Reduced body mass index||Volume of small bowel in radiotherapy field|
|Comorbidities (e.g., diabetes mellitus, hypertension, inflammatory bowel disease)||Radiotherapy dose and fractionation|
|Previous intestinal surgery||Concomitant chemotherapy use|
Hypoxia-inducible factor alpha effect
Signs and Symptoms
Physical examination of a patient with radiation enteritis reveals diffuse abdominal tenderness and hyperactive bowel sounds. Mild abdominal distention may be present. Signs of acute peritoneal irritation suggestive of perforated viscus, such as rebound tenderness, are absent. The patient may exhibit frequent mucoid stools, diarrhea, and vomiting. The patient appears systemically ill, but not septic.
Colonoscopy provides definitive evidence of radiation enteritis, while helping to exclude other causes of abdominal pain that may mimic this clinical syndrome. Capsule endoscopy may also aid in the diagnosis. Based on the patient’s clinical presentation, additional tests, including complete blood cell count, erythrocyte sedimentation rate, and stool and blood cultures for infectious enteritis, may be indicated. Computed tomography (CT) of the abdomen with oral and intravenous contrast material is indicated if occult mass or abscess is suspected. Magnetic resonance imaging (MRI) of the abdomen also helps confirm the diagnosis of radiation enteritis.
A history of previous radiation therapy is necessary to consider the diagnosis of radiation enteritis. The very problem that necessitated radiation therapy in the first place—malignancy—can recur, however, and produce clinical symptoms indistinguishable from those of radiation enteritis. Given the immunocompromised state of most patients who have received radiation therapy, the possibility of infectious enteritis or intra-abdominal abscess always must be included in the differential diagnosis. Other causes of abdominal pain, including diverticulitis, bowel obstruction, and appendicitis, also may occur in conjunction with radiation enteritis.
Symptom management is the primary thrust of the treatment of radiation enteritis. Careful attention to the patient’s fluid and metabolic status during the acute phases of the disease is crucial to avoid complications. Psyllium helps the patient with diarrhea and with mucoid stools, and may decrease the sensations of needing to move the bowels frequently. Anticholinergics such as dicyclomine and antiperistaltics such as loperamide can help decrease diarrhea. Zinc oxide ointment and sitz baths with aluminum acetate soaks help ease the symptoms of tenesmus and rectal pain. Steroid and sucralfate enemas have also been reported to provide symptomatic relief in difficult cases of radiation enteritis.
Complications and Pitfalls
The potential for complications after radiation therapy is high. Spontaneous bowel perforation, stenosis, fistula formation, bleeding, and malabsorption occur with sufficient frequency to complicate the management of this painful condition. As mentioned, the potential for recurrence of tumor and infectious complications is ever present.CLINICAL PEARLS
Treatment of the symptoms associated with radiation enteritis should be part of the overall management of a patient with cancer. The recognition and treatment of symptoms other than pain are often delayed while the clinician focuses on pain control, further compounding the patient’s suffering. Vigilance for life-threatening complications of radiation enteritis, including bowel perforation, is mandatory to avoid disaster.