Phase III double-blind study of depot octreotide versus placebo in the prevention of acute diarrhea during pelvic radiation therapy: Results of North Central Cancer Treatment Group protocol N00CA

Abstract

8506 Background: A randomized study (Int J Rad Oncol Biol Phys 54:195–202, 2002) demonstrated a beneficial effect for octreotide in the treatment of diarrhea in patients receiving pelvic radiation therapy. This North Central Cancer Treatment Group study was undertaken to determine the effectiveness of depot octreotide in the prevention of diarrhea during pelvic radiation therapy. Methods: Patients receiving pelvic radiation therapy, with a planned minimum dose of 45 Gy at 1.70–2.1 Gy per day, were eligible for this study. The study was designed for a Wilcoxon test, with 112 evaluable patients, to have 85% power to detect a further one grade decrease in diarrhea over and above that experienced by patients treated with placebo. Between June 13, 2002 and October 28, 2005, 120 evaluable patients were randomly allocated, in double blind fashion, to receive octreotide (62 patients) or placebo (58 patients), prior to the fourth radiation therapy fraction. Octreotide dosing: Octreotide, 100 micrograms subcutaneously on day 1 followed by depot octreotide, 20 milligrams intramuscularly on days 2 and 29. Results: Grade 0, 1, 2 and 3 diarrhea was observed in 17%, 32%, 26% and 26% of patients treated with octreotide and 18%, 34%, 22%, and 26% of patients treated with placebo (P=0.86). Grade 0, 1, 2 and 3 tenesmus was observed in 55%, 30%, 11% and 4% of patients treated with octreotide and 76%, 16%, 4%, and 4% of patients treated with placebo (P=0.04). No other statistically significant differences in toxicity were observed. Conclusions: Octreotide, as administered in this study, did not decrease diarrhea during pelvic radiation therapy. [Table: see text]