Radiation Enteritis
Etiology
Acute Radiation Enteritis
Diagnosis
Assessment
Medical management
The role of nutrition
Chronic Radiation Enteritis
Diagnosis
Treatment
Prevention
Etiology
Almost all patients undergoing radiation to the abdomen, pelvis, or rectum will
show signs of acute enteritis. Injuries clinically evident during the first
course of radiation and up to 8 weeks later are considered acute.[1] Chronic
radiation enteritis may present months to years after the completion of therapy,
or it may begin as acute enteritis and persist after the cessation of
treatment. Only 5% to 15% of persons treated with radiation to the abdomen
will develop chronic problems.[2]
Factors that influence the occurrence and severity of
radiation enteritis include the following:
- Dose and fractionation.
- Tumor size and extent.
- Volume of normal bowel treated.
- Concomitant chemotherapy.
- Radiation intracavitary implants.
- Individual patient variables (e.g., previous abdominal or pelvic surgery,
hypertension, diabetes mellitus, pelvic inflammatory disease, inadequate
nutrition).[3,4]
In general, the higher the daily and total dose delivered to the normal bowel
and the greater the volume of normal bowel treated, the greater the risk of
radiation enteritis. In addition, the individual patient variables
listed above can decrease vascular flow to the bowel wall and impair bowel
motility, increasing the chance of radiation injury.
Acute Radiation Enteritis
Diagnosis
Radiation therapy exerts a cytotoxic effect mainly on rapidly proliferating
epithelial cells, like those lining the large and small bowel. Crypt cell wall
necrosis can be observed 12 to 24 hours after a daily dose of 1.5 to 3 Gy.
Progressive loss of cells, villous atrophy, and cystic crypt dilation occur in
the ensuing days and weeks. Patients suffering from acute enteritis may
complain of nausea, vomiting, abdominal cramping, tenesmus, and watery
diarrhea. With diarrhea, the digestive and absorptive functions of the
gastrointestinal (GI) tract are altered or lost, resulting in malabsorption of fat,
lactose, bile salts, and vitamin B12. Symptoms of proctitis—including mucoid
rectal discharge, rectal pain, and rectal bleeding (if mucosal ulceration is
present)—may result from radiation damage to the anus or rectum.
Acute enteritis symptoms usually resolve 2 to 3 weeks after
the completion of treatment, and the mucosa may appear nearly normal.[5]
Assessment
Patient examination and assessment of radiation enteritis should include the
following:[6]
- The usual pattern of elimination.
- The pattern of diarrhea, including the following:
- Onset.
- Duration.
- Frequency, amount, and character of stools.
- Presence of other symptoms such as flatus, cramping, nausea,
abdominal distension, tenesmus, bleeding, and rectal excoriation.
- The nutritional status of the patient, including the following:
- Height and weight.
- Usual eating habits, any change in eating habits, and amount of
residue in diet.
- Signs of dehydration such as poor skin turgor, serum electrolyte
imbalance, increased weakness, or fatigue.
- Present level of stress, coping patterns, and impact of signs and symptoms
of enteritis on usual lifestyle patterns.
Medical management
Medical management includes treating diarrhea, dehydration, malabsorption, and
abdominal or rectal discomfort. Symptoms usually resolve with medications,
dietary changes, and rest. If symptoms become severe despite these measures,
a treatment break may be warranted.
Medications may include the following:
- Kaopectate, an antidiarrheal agent. Dose: 30 cc to 60 cc by mouth after each loose
bowel movement.
- Lomotil (diphenoxylate hydrochloride with atropine sulfate). Usual dose: One or two tablets by mouth every 4 hours as needed. Dose can be adjusted to
individual patients and patterns of diarrhea. For example, one
patient may achieve control of diarrhea with one tablet 3 times a day, while
another may require two tablets every 4 hours. Patients are not to take more than eight
tablets of Lomotil within a 24-hour period.
- Paregoric, an antidiarrheal agent. Usual dose: 1 teaspoon by mouth 4 times a day as needed
for diarrhea. Paregoric may also be alternated with Lomotil.
- Cholestyramine, a bile salt sequestering agent. Dose: one package by mouth after
each meal and at bedtime.
- Donnatal, an anticholinergic antispasmodic agent to alleviate bowel
cramping. Dose: One or two tablets every 4 hours as needed.
- Imodium (loperamide hydrochloride), a synthetic antidiarrheal agent.
Recommended initial dose: two capsules (4 mg) by mouth every 4 hours, followed by one
capsule (2 mg) by mouth after each unformed stool. Daily total dose should not
exceed 16 mg (eight capsules).
In addition to these medications, opioids may offer relief from abdominal pain. If proctitis is present, a steroid foam given rectally may
offer relief from symptoms. Finally, if patients with pancreatic cancer are
experiencing diarrhea during radiation therapy, they should be evaluated for
oral pancreatic enzyme replacement, as deficiencies in these
enzymes alone can cause diarrhea.
The role of nutrition
Damage to the intestinal villi from radiation therapy results in a reduction
or loss of enzymes, one of the most important of these being lactase. Lactase
is essential in the digestion of milk and milk products. Although there is no
evidence that a lactose-restricted diet will prevent radiation enteritis, a
diet that is lactose free, low fat, and low residue can be an effective
modality in symptom management.[7]
Foods to avoid
- Milk and milk products. Exceptions are buttermilk and yogurt, which are
often tolerated because lactose is altered by the presence of
lactobacillus. Processed cheese may also be tolerated because the lactose
is removed with the whey when it is separated from the cheese curd.
Milkshake supplements such as Ensure are lactose free and may be used.
- Whole-bran bread and cereal.
- Nuts, seeds, and coconuts.
- Fried, greasy, or fatty foods.
- Fresh and dried fruit and some fruit juices such as prune juice.
- Raw vegetables.
- Rich pastries.
- Popcorn, potato chips, and pretzels.
- Strong spices and herbs.
- Chocolate, coffee, tea, and soft drinks with caffeine.
- Alcohol and tobacco.
Foods to encourage
- Fish, poultry, and meat that is cooked, broiled, or roasted.
- Bananas, applesauce, peeled apples, and apple and grape juices.
- White bread and toast.
- Macaroni and noodles.
- Baked, boiled, or mashed potatoes.
- Cooked vegetables that are mild, such as asparagus tips, green and waxed
beans, carrots, spinach, and squash.
- Mild processed cheese, eggs, smooth peanut butter, buttermilk, and yogurt.
Helpful hints
- Ingest food at room temperature.[6]
- Drink 3,000 cc of fluid per day. Carbonated beverages should be allowed to
lose carbonation before being ingested.
- Add nutmeg to food, which will help decrease mobility of GI tract.
- Start a low-residue diet on day 1 of radiation therapy treatment.
Chronic Radiation Enteritis
Diagnosis
Only 5% to 15% of the patients who receive abdominal or pelvic irradiation will
develop chronic radiation enteritis. Signs and symptoms include colicky
abdominal pain, bloody diarrhea, tenesmus, steatorrhea, weight loss, and nausea
and vomiting. Less common are bowel obstruction, fistulas, bowel perforation,
and massive rectal bleeding.[8] The initial signs and symptoms occur 6
to 18 months after radiation therapy. Radiologic findings include
submucosal thickening, single or multiple stenoses, adhesions, and sinus or
fistula formation.[9] Microscopic findings include villi that are fibrotic or
may be lost altogether. Ulceration is common, varying from simple loss of
epithelial layers to ulcers that may penetrate to different depths of the
intestinal wall, even to the serosa. Lymphatic tissue is often atrophic or
absent. The submucosa is severely diseased. Arterioles and small arteries
show profound changes, with hyalinization of the entire wall thickness. The
muscularis is often distorted or focally replaced by fibrosis.
The diagnosis of chronic radiation enteritis may be difficult to make.
Clinically and radiologically recurrent tumor needs to be ruled out. Because of
the possible latency of the illness, it is essential that the physician obtain
a detailed history of the patient's radiation therapy course. It is
often advisable to include the radiation therapy physician in the continued
management of the patient's care.
Treatment
Medical management of the patient's symptoms (which are similar to symptoms of acute
radiation enteritis) is indicated, with surgical management reserved for severe
damage.[7] Fewer than 2% of the 5% to 15% of patients who received abdominal or
pelvic radiation will require surgical intervention.[10]
The timing and choice of surgical techniques remains somewhat controversial. A
lower operative mortality (21% vs. 10%) and incidence of anatomic dehiscence
(36% vs. 6%) have been reported with intestinal bypass than with resection.[11,12] Those who favor resection point out that the removal of diseased bowel
decreases the mortality rate for resection and is comparable to the bypass
procedure.[11] All agree that simple lysis of adhesions is inadequate and that
fistulas require bypass.
Surgery should be undertaken only after careful assessment of the patient's
clinical condition and extent of radiation damage because wound healing is
often delayed, necessitating prolonged parenteral feeding after surgery. Even
after apparently successful operations, symptoms may persist in a significant
proportion of patients.[13]
Prevention
Treatment techniques that can minimize the risk of severe radiation enteritis
include the following:
- Radiation therapy techniques:
- The use of a three- or four-field technique (as opposed to a two-field
technique) to minimize the amount of small bowel exposed to treatment.
- The treatment of the patient in a physical position that will aid in
removing as much small bowel from the treatment field as possible for example, treating a patient with a full bladder each day to aid
in pushing the small bowel up and out of the pelvis when pelvic radiation is given).
- Daily treatment of all fields, resulting in a lower integral
dose and more homogenous dose distribution.
- Use of computerized radiation dosimetry to best design the treatment
plan and the use of high-energy treatment machines such as linear
accelerators that deliver a high dose-to-tumor volume while sparing
the normal structures.[14]
- Surgery. Placing clips in high-risk areas to better define the
location or former location of the tumor and aid in radiation treatment
planning.
- Modification of treatment sequencing. An area for exploration is the
sequencing of radiation, chemotherapy, and surgery and its influence on the
severity of enteritis.
References
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O'Brien PH, Jenrette JM 3rd, Garvin AJ: Radiation enteritis. Am Surg 53 (9): 501-4, 1987.
[PUBMED Abstract]
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Yeoh EK, Horowitz M: Radiation enteritis. Surg Gynecol Obstet 165 (4): 373-9, 1987.
[PUBMED Abstract]
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Gallagher MJ, Brereton HD, Rostock RA, et al.: A prospective study of treatment techniques to minimize the volume of pelvic small bowel with reduction of acute and late effects associated with pelvic irradiation. Int J Radiat Oncol Biol Phys 12 (9): 1565-73, 1986.
[PUBMED Abstract]
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Haddad GK, Grodsinsky C, Allen H: The spectrum of radiation enteritis. Surgical considerations. Dis Colon Rectum 26 (9): 590-4, 1983.
[PUBMED Abstract]
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Alimentary tract. In: Fajardo LF: Pathology of Radiation Injury. New York: Masson Publishers, 1982, pp 47-76.
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Yasko JM: Care of the Client Receiving External Radiation Therapy. Reston, Va: Reston Publishing Company, Inc., 1982.
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Stryker JA, Bartholomew M: Failure of lactose-restricted diets to prevent radiation-induced diarrhea in patients undergoing whole pelvis irradiation. Int J Radiat Oncol Biol Phys 12 (5): 789-92, 1986.
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Kinsella TJ, Bloomer WD: Tolerance of the intestine to radiation therapy. Surg Gynecol Obstet 151 (2): 273-84, 1980.
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Mendelson RM, Nolan DJ: The radiological features of chronic radiation enteritis. Clin Radiol 36 (2): 141-8, 1985.
[PUBMED Abstract]
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Galland RB, Spencer J: Surgical management of radiation enteritis. Surgery 99 (2): 133-9, 1986.
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Lillemoe KD, Brigham RA, Harmon JW, et al.: Surgical management of small-bowel radiation enteritis. Arch Surg 118 (8): 905-7, 1983.
[PUBMED Abstract]
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Wobbes T, Verschueren RC, Lubbers EJ, et al.: Surgical aspects of radiation enteritis of the small bowel. Dis Colon Rectum 27 (2): 89-92, 1984.
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Wellwood JM, Jackson BT: The intestinal complications of radiotherapy. Br J Surg 60 (10): 814-8, 1973.
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Minsky BD, Cohen AM: Minimizing the toxicity of pelvic radiation therapy in rectal cancer. Oncology (Huntingt) 2 (8): 21-5, 28-9, 1988.
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