Assessing and treating 
radiotherapy-associated 
diarrhea

 

ASSESSING PATIENTS


When treatment-related diarrhea is suspected, assessment includes determining the clinical grade of diarrhea; obtaining patient medical, medication, and dietary histories (including herbal supplements such as saw palmetto, ginseng, milk thistle, plantago seed, or aloe, which can cause diarrhea¹); laboratory analysis of stools (including fecal leukocyte testing, C difficile toxins A and B tests, and bacterial cultures); dehydration assessment; and physical examination.³ Diarrhea does not preclude bowel obstruction or fecal impactation; when these are suspected, diagnostic abdominal imaging should be ordered.³ Possible neutropenic enterocolitis is also assessed with abdominal CT.³


The National Cancer Institute (NCI) grades diarrhea severity on a scale of 0 to 5 (0 represents an absence of diarrhea, 5 represents death).^1,5 Treatment-related diarrhea is sometimes categorized more simply as complicated or uncomplicated, but these designations are typically limited to chemotherapy-induced diarrhea. Grade 1-2 diarrhea with no cramping, nausea, or vomiting; fever; or neutropenia is classified as uncomplicated, whereas grade 3-4 diarrhea with moderate-to-severe cramping, nausea or vomiting, fever, neutropenia, sepsis, bleeding, dehydration, or diminished performance status is classified as complicated.³ 



MANAGING RADIOTHERAPY-ASSOCIATED DIARRHEA


The primary goals of intervention are to rehydrate and stabilize the patient, and to control the diarrhea with medication and dietary modification.^1,3,6,7 Milk and milk products should be avoided because lactose malabsorption caused by lactase deficiency frequently accompanies intestinal mucosal damage.³ Animal fats, spicy foods, caffeine, alcohol, and certain herbal supplements (listed above) should also be avoided.¹ The BRAT diet (banana, rice, applesauce, and toast) can reduce stool frequency.¹


The clinical evidence-based treatment for radiotherapy-associated diarrhea is sparse compared with that for chemotherapy-associated diarrhea.⁸ Aspirin may be helpful with radiotherapy-associated diarrhea.⁷ Mild or uncomplicated cases are treated with oral rehydration and antidiarrheal medication with opioids.^1,3,8 Loperamide [Imodium, generics] is the gold standard, administered as an initial dose of 4 mg followed by 2 mg every 2 hours, or noncamphorated deodorized tincture of opium, administered as 10 mg/mL morphine, 10-15 drops in water every 3 to 4 hours.^1,3,8 Tincture of opium is generally considered a second-line medication for diarrhea control.^1,3 


Patients should be asked to report fever, dizziness upon standing, and the number of stools. After the diarrhea wanes, patients should be instructed to continue avoiding dairy products and other diarrhea-causing foods, including caffeinated drinks, and begin to eat solid foods in small-serving-size meals up to 6 times a day.^1,3 Patients can be provided with a simple list of acceptable and prohibited foods and drinks. The critical importance of hydration should be emphasized; patients should be instructed to drink 3 to 4 liters of fluid daily, including water, broth, decaffeinated teas or soft drinks, sports drinks, and clear juices.¹ 


If diarrhea persists, prophylactic antibiotic therapy should be considered.³ If diarrhea persists for more than 24 hours, intestinal infection should be suspected and appropriate tests obtained, rehydration and electrolyte replacement continued as needed, and opioid therapy discontinued; hospitalization should be considered.^1,3


As with tincture of opium, octreotide (Sandostatin, generics), with dose escalation as needed from an initial dose of 100 to 150 mcg, is a second-line antidiarrheal treatment for low-grade (grade 1-2) diarrhea.³ Octreotide appears to be effective for treating grade 2-3 loperamide-refractory radiotherapy-associated diarrhea among rectal cancer patients who had been treated with concomitant fluorouracil chemoradiotherapy.⁸ Subcutaneous octreotide (100 mcg 3 times daily) appears to be superior to diphenoxylate (Lomotil, Lonox; 10 mg daily), an opioid antidiarrheal, in patients with grade 2-3 diarrhea who are undergoing radiotherapy only.⁸


From the February 01, 2013 Issue of Oncology Nurse Advisor