The efficacy of octreotide in the therapy of acute radiation-induced diarrhea: a randomized controlled study.

Abstract Purpose: Although the somatostatin analog octreotide is currently used in the treatment of chemotherapy-induced diarrhea and secretory diarrhea associated with various disorders, its role in the management of radiation enteritis is not well defined. We performed a randomized study that compared octreotide acetate with diphenoxylate hydrochloride plus atropine sulfate, the drug commonly used as therapy for acute radiation-induced diarrhea (ARID). Methods and Materials: Sixty-one patients with Grade 2 (four to six stools per day) or Grade 3 (≥ seven stools per day, National Cancer Institute Common Toxicity Criteria) diarrhea associated with pelvic radiotherapy were assigned randomly to receive octreotide s.c., 100 μg three times daily ( n = 33) or diphenoxylate and atropine orally, 2.5 mg four times daily ( n = 28). Radiotherapy was delivered to all patients in a conventional manner, with high-energy photons in a total dose ≥45 Gy, which exceeds the tolerance of intestine. Overall, there was no significant difference in patient characteristics or radiotherapy applied between the two arms. Patients were evaluated daily for the primary study end point, resolution of diarrhea, as well as for interruption of pelvic radiotherapy. Results: Within 3 days, ARID completely resolved in 20 patients in the octreotide arm (2 within the first day, 11 within the second day, and 7 within the third day) vs. only 4 (all within the second day of therapy) in the diphenoxylate arm ( p = 0.002). On the diphenoxylate arm, 15/28 patients were required to discontinue pelvic radiotherapy; on the octreotide arm, 6/33 patients were required to discontinue pelvic radiotherapy for an average of 1.89 ± 0.5 and 0.45 ± 0.2 days, respectively ( p = 0.003). No side effects were observed in either arm. Three patients on the diphenoxylate arm and only 1 on the octreotide arm required further treatment for parenteral replenishment of fluids and electrolytes or other antidiarrheal treatments. Conclusion: Octreotide seems to be more effective than conventional therapy with diphenoxylate and atropine in controlling ARID and eliminating the need for radiotherapy interruptions.