Carlson, LindaDeleemans, Julie2022-05-042022-05-042022-04Deleemans, J. (2022). The Chemo-Gut Project: investigating the effects of cancer treatment on gut microbiota, gastrointestinal and psychosocial health in cancer survivors (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/114604Introduction: Cancer treatments such as chemotherapy adversely affect the gut microbiota, gastrointestinal (GI) and psychosocial health. However, it is unknown whether changes in the gut microbiota persist in the long-term, and if this may be related to GI and psychosocial symptoms. This work investigated the longer-term effects of cancer treatments on the gut microbiota, psychosocial and GI symptoms, and explored potential prebiotic and probiotic treatment options. Methods: A cross-sectional survey study with 317 cancer survivors examined characteristics of GI, physical and mental health outcomes, whether GI symptoms were associated with mental and physical health, and relationships between type of cancer treatment and these outcomes. A cross-sectional pilot study with 17 cancer survivors and 18 healthy volunteers investigated relationships between cancer treatment-related factors, gut microbiota, GI and psychosocial symptoms. A systematic review then evaluated the current literature on prebiotic and probiotic interventions used to treat GI and/or psychosocial symptoms in cancer patients and survivors. Results: Survivors in the survey study reported persistent GI symptoms, and 52% rated their GI symptom severity as moderate to extreme. Survivors reported poorer mental and physical health compared to PROMIS normative scores, and higher GI symptom severity was associated with worse mental and physical health. Survivors in the pilot study had more GI symptoms, poorer psychosocial health, and significantly greater abundance of Selenomondales, Veilloneliaceae, and Intestinibacter. In survivors, Lachnospiraceae, Ruminococcaceae and Intestinibacter correlated with psychosocial symptoms. Survivors ≤6 months post-treatment had lower alpha diversity than survivors >6 months post-treatment and healthy controls. Our systematic review found that probiotics were associated with improvements in several GI symptoms, especially diarrhea. However, improvements in anxiety, depression, fatigue, and QOL were only found in cancer survivors who received probiotic intervention. Conclusion: GI symptoms may persist for years after anti-cancer therapies have ended, and are associated with poorer physical and psychosocial health. In the first 6 months after cancer treatment gut microbiota alpha diversity is lowest, and specific bacteria may impact survivors’ psychosocial symptoms. Probiotics may help to alleviate some GI and psychosocial symptoms. Interventions combining dietary treatment with psychosocial interventions may be crucial for optimizing patient outcomes.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Gut MicrobiotaPsychosocialOncologyGastrointestinal healthCancer survivorshipPatient Reported OutcomesMedicine and SurgeryOncologydoctoral thesis10.11575/PRISM/39724