The Effects of synbiotics supplementation on reducing Chemotherapy-induced side effects in women with Breast Cancer: A Randomized Placebo-Controlled Double-Blind Clinical Trial

background The prevalence of breast cancer and its mortality rate are increasing rapidly among women worldwide. on other hand, the courses of chemotherapy as the main treatment for these patients are too much exhaustive and annoying. this study was designed to evaluate the effects of synbiotics (probiotics + prebiotics) supplementation as a safe and inexpensive adjuvant treatment in reducing common chemotherapy side effects in women with breast cancer. Methods The current study was carried out on 67 women with definitive breast cancer diagnosis who were hospitalized to receive one-day chemotherapy sessions and met inclusion criteria. Patients were randomly allocated to the intervention or control group to receive synbiotics or placebo, respectively. Twice a day oral consumption of synbiotics supplements for 8 weeks. The primary outcome was the changes in severity or experience of chemotherapy complication, analyzed by intention to treat (ITT). Using 7 validated questionnaires, chemotherapy complications in initiation, 4 weeks and 8 weeks after intervention were assessed. Dietary intake was measured by 24-h dietary recall at beginning, 4th and 8th weeks. We used version 24 of SPSS software for statistical analysis. P-value < 0.05 was considered as statistically significant. Results Sixty seven breast cancer patients completed the study. After 8 weeks of intervention and adjusting confounders, the severity of chemotherapy complications including, fatigue (P < 0/001) and unnormal defecation (P = 0.005) decreased significantly in the synbiotic group compared to the placebo group. Also, nausea/vomiting (P = 0.015), and anorexia (P < 0.001) were decreased in the end of the study compared to the first visit, but it was not statistically significant compared to the placebo group. conclusions Synbiotics supplementation during chemotherapy can potentially reduce the severity of fatigue and abnormal defecation. It can also be promising in reducing anorexia and nausea/vomiting. Trial Registration this study was registered in the Iranian Registry of Clinical Trials (IRCT) (registered code: IRCT20091114002709N56) (date of registration: 5/5/2021). direct link to the trial page: https://www.irct.ir/trial/54559