Octreotide in Preventing Diarrhea in Patients Who Are Undergoing Radiation Therapy to the Pelvis

RATIONALE: Octreotide may be effective in preventing or controlling diarrhea in patients who are undergoing radiation therapy to the pelvis. It is not yet known whether octreotide is effective for diarrhea. PURPOSE: Randomized phase III trial to determine the effectiveness of octreotide in preventing diarrhea in patients who are undergoing radiation therapy to the pelvis.

OBJECTIVES: * Determine the effectiveness of octreotide in reducing acute treatment-related diarrhea in patients receiving external-beam radiotherapy to the pelvis. * Determine the effectiveness of this drug in reducing chronic treatment-related bowel dysfunction in these patients. * Determine the toxicity of this drug in these patients. * Assess the importance that these patients attach to various measures of bowel function. OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to prior anterior resection of the rectum (yes vs no), total planned cumulative dose of radiotherapy, including boost fields (4,500-5,350 cGy vs 5,351-6,000 cGy vs more than 6,000 cGy), use of concurrent fluorouracil (none vs bolus vs continuous infusion), use of concurrent leucovorin calcium (yes vs no), use of concurrent cisplatin (yes vs no), superior border of initial field (at or inferior to the L4-5 interspace vs superior to the L4-5 interspace), planned intracavitary brachytherapy (yes vs no), and primary site of disease (rectal cancer vs prostate cancer vs gynecological cancer vs other). Beginning no later than the fourth day of radiotherapy, patients are randomized to one of two treatment arms. * Arm I: Patients receive short-acting octreotide subcutaneously (SC) on day 1 and long-acting octreotide intramuscularly (IM) on days 2 and 29. * Arm II: Patients receive placebo SC on day 1 and IM on days 2 and 29. In both arms, treatment continues in the absence of unacceptable toxicity or the development of severe diarrhea. Patients complete a bowel function questionnaire at baseline, weekly during radiotherapy, and then weekly for 4 weeks and at 1 and 2 years after completion of radiotherapy. Patients are followed weekly for 4 weeks and then at 1 and 2 years.