[Prevention of radiation-induced diarrhea by smectite. Results of a double-blind randomized, placebo-controlled multicenter study]

Strahlenther Onkol. 2000 Apr;176(4):173-9. doi: 10.1007/s000660050053.
[Article in German]


Purpose: Diarrhea and abdominal pain are well-known side effects abdominal or pelvic of radiation therapy that may lead to interruption of treatment in serious cases. In recent trials the silicate smectite has proven a promising drug in the prophylaxis of these adverse events. The presented trial aimed at the verification of earlier studies and the evaluation of a dose-effect relationship.

Patients and methods: Between April 1994 and May 1995, a total of 176 patients obtaining radiotherapy of the pelvis or the abdomen were evaluated in a double-blind, randomized placebo-controlled investigation regarding the prophylactic effect of smectite (= Colina) against radiotherapy-induced diarrhea. During the whole period of radiotherapy 85 patients obtained 2 x 6 g smectite daily and 91 patients received 2 x 6 g placebo. The primary end point of the analysis was the time to the first appearance of diarrhea (> or = 3 pappy stools).

Results: All 176 patients were evaluated according to an intent-to-treat analysis. There was no significant difference between the prophylactic effects of smectite and placebo. For an explorative post-hoc analysis the total study group was split up into 2 subgroups, one with an irradiated small bowel volume < or = 837.5 ml, the other with a small bowel volume > 837.5 ml (median); the analysis indicated that the first subgroup showed a benefit for the smectite-treated patients in contrast to the placebo treatment (32 vs. 18 calendar days to the first appearance of diarrhea). This benefit was statistically not significant.

Conclusion: Prophylactic application of smectite during irradiation of the pelvis and the abdomen can delay the development of radiotherapy-induced diarrhea, a statistical significance could not be verified neither in the total study group nor in the post-hoc subgroup analysis.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial
  • English Abstract
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Abdomen / radiation effects*
  • Aged
  • Data Interpretation, Statistical
  • Diarrhea / etiology
  • Diarrhea / prevention & control*
  • Double-Blind Method
  • Female
  • Gastrointestinal Agents / administration & dosage
  • Gastrointestinal Agents / therapeutic use*
  • Humans
  • Lymphoma / radiotherapy
  • Male
  • Middle Aged
  • Pelvis / radiation effects*
  • Placebos
  • Prostatic Neoplasms / radiotherapy
  • Radiotherapy / adverse effects*
  • Radiotherapy Dosage
  • Rectal Neoplasms / radiotherapy
  • Silicates*
  • Time Factors
  • Uterine Cervical Neoplasms / radiotherapy
  • Uterine Neoplasms / radiotherapy


  • Gastrointestinal Agents
  • Placebos
  • Silicates
  • Smectite