Martenson, J.A., Halyard, M.Y., Sloan, J.A., Proulx, G.M., Miller, R.C., Deming, R.L., … Atherton, P.J. (2008). Phase III, double-blind study of depot octreotide versus placebo in the prevention of acute diarrhea in patients receiving pelvic radiation therapy: Results of north central cancer treatment group N00CA. Journal of Clinical Oncology, 26, 5248-5253.

To determine the effectiveness of octreotide in reducing treatment-related diarrhea during radiation therapy to the pelvis

Patients were randomized to receive octreotide acetate or placebo. Patients in the treatment group were given 100 µg subcutaneous octreotide acetate on day 1 followed by 20 mg intramuscular octreotide acetate on days 2 and 29. Patients in the control group received placebo by the same routes on the same days.

• The study reported on 125 patients.
• Patients had histologic proof of cancer in the pelvis without distant metastases and were receiving radiation therapy, either as definitive treatment or adjuvantly.                           

This was a multisite, collaborative trial of North Central Cancer Treatment Group.

Patients were undergoing the active treatment phase of care.

This was a double-blinded, randomized control trial.

A Bowel Function Questionnaire and a Uniscale Quality of Life (QOL) measure were used.

No statistically significant differences were found between groups. Octreotide did not reduce the severity or incidence of diarrhea during pelvic radiation therapy. Abdominal cramps were worse in patients on the octreotide arm, but the difference was not statistically significant (p = 0.053). Patients receiving octreotide experienced significantly more problems with nocturnal bowel movements (70% versus 45%, p = 0.004), clustering (90% versus 69%, p = 0.004), and blood with bowel movements (57% versus 35%, p = 0.01).

Octreotide did not result in improvement in diarrhea in this population and was associated with more problems. Octreotide did not have an effect on the severity or incidence of diarrhea during pelvic radiation therapy. Some gastroinstestinal (GI) symptoms were worse in patients receiving octreotide compared to placebo.

• The subjects in the treatment groups were different. More patients in the control group had histories of rectal surgery or primary rectal cancer.
• Not all patients completed the day 29 dose of study medication. Only 49 (79%) of 62 of patients in the placebo arm and 43 (69%) of 62 of patients in the octreotide arm received a second dose.
• No intention-to-treat analysis was conducted.

More clinical research is needed to evaluate the effective prevention of diarrhea during pelvic radiation therapy. Long-acting octreotide (LAO) should not be used outside of a controlled clinical trial setting.