Purpose: To assess the effectiveness of depot octreotide for the prevention of diarrhea during pelvic radiation therapy.

Patients and Methods: Patients receiving pelvic radiation therapy (planned minimum dose, 45 Gy; 1.7 to 2.1 Gy daily) were eligible for the study. From May 10, 2002, through October 14, 2005, 125 patients were randomly allocated in a double-blind fashion to receive octreotide (100 µg, administered subcutaneously on day 1, followed by depot octreotide, 20 mg, administered intramuscularly on days 2 and 29; n = 62) or to receive a placebo (n = 63).

Results: Grade 0, 1, 2, and 3 diarrhea were observed in 18%, 31%, 31%, and 21% of patients in the octreotide arm, respectively, and in 25%, 32%, 22%, and 21% of patients in the placebo arm, respectively (P = .64). Grade 0, 1, 2, and 3 abdominal cramps were observed in 32%, 45%, 21%, and 2% of patients receiving octreotide, respectively, and in 51%, 24%, 21%, and 5% of patients receiving the placebo, respectively (P = .053). Some patient-reported symptoms were worse in the octreotide group, including nocturnal bowel movements (70% v 45%; P = .004), clustering of bowel movements (90% v 69%; P = .004), and bleeding with bowel movements (57% v 35%; P = .01).

Conclusion: As administered in this study, octreotide did not decrease diarrhea during pelvic radiation therapy. Some gastrointestinal symptoms were worse in patients treated with octreotide. Octreotide is not indicated for prevention of diarrhea during pelvic radiation therapy.