The Effects of Probiotic-Prebiotic Use on Acute Inflammatory Parameters in Patients Receiving Pelvic Radiotherapy: A Prospective Multicenter Study.

This is the first prospective clinical study to evaluate the impact of prebiotic and probiotic use on acute radiation-induced pelvic side effects and associated changes in serum cytokine levels in patients with pelvic malignancies. This multicenter prospective study included 80 patients with pelvic cancers treated at two centers between 2021 and 2023. Patients were divided into three groups: probiotic + prebiotic, prebiotic only, and nonsupplemented. Serum cytokine levels (tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6) and radiation-related side effect scores were assessed at the beginning of pelvic radiotherapy (RT) and again at the fifth week. Based on data normality, the Wilcoxon signed-rank test was used for statistical analysis. According to side effect scores, in the prebiotic-only group, a modest yet statistically significant increase in fecal incontinence (FI; =0.040) and blood and mucus in the stool (BMS; =0.049) was observed. Conversely, the probiotic + prebiotic group showed a significant increase in dysuria (=0.001) and impotence (=0.016). IL-6 levels significantly increased in the prebiotic-only group (=0.035), while TNF-α levels rose significantly in the group without any nutritional support (=0.025). No significant increase in cytokine levels or intestinal side effects was observed in the combined probiotic + prebiotic group (  > 0.05 for all comparisons). The absence of a rise in cytokine levels and intestinal toxicity in the probiotic + prebiotic group suggests that probiotics may play a role in mitigating radiation-induced intestinal side effects and inflammatory responses.