Decreasing the Adverse Effects in Pelvic Radiation Therapy: A Randomized Controlled Trial Evaluating the Use of Probiotics.

Purpose: The aim of this randomized controlled trial was to evaluate the potential benefit from 2 probiotic bacteria of the species against radiation therapy-induced comorbidities.

Methods And Materials: Women (>18 years of age) scheduled for radiation therapy because of gynecologic cancer were randomly allocated to consume placebo or either low-dose probiotics (1 × 10 colony-forming unit/capsule twice daily) or high-dose probiotics (5 × 10 colony-forming unit/capsule twice daily). The intervention started approximately 1 week before the onset of radiation therapy and continued until 2 weeks after completion. During this period the participants were daily filling in a study diary documenting the incidence and severity of symptoms, intake of concomitant medication, and stool consistency. The primary endpoint was the probiotic effect on the mean number of loose stools during radiation therapy.

Results: Of the 97 randomized women, 75 provided data for the analysis of the results. The mean number of loose stools (sum of Bristol stool type 6 and 7) was not significantly reduced in the probiotic groups, but there was a significant reduction in the mean number of days with >1 loose stool with 15.04 ± 8.92 days in the placebo and 8.65 ± 5.93 days in the high-dose probiotics group ( = .014). The benefit was even more pronounced in the 2 weeks following the end of radiation therapy ( = .005). Moreover, intake of the probiotics resulted in a reduced severity of the symptoms grinding abdominal pain ( = .041) and defecation urgency ( = .08) and a reduced percentage of days with these symptoms ( = .023 and  = .042, respectively), compared with placebo. There were no differences regarding reported adverse events.

Conclusions: Intake of the 2 probiotic bacteria was beneficial and reduced many measures or symptoms of the radiation-induced toxicity in women treated for gynecologic cancer.