The Chemo-Gut Probiotic Trial for Cancer Survivors

Background: Survivors of cancer experience chronic gastrointestinal (GI) and psychosocial health symptoms, and reduced gut microbial diversity. This may compromise survivors' long-term health and overall wellbeing. No studies have investigated probiotics for managing both GI and psychosocial symptoms together, or the composition of the gut microbiota in post-treatment cancer survivors. Aims: To investigate the effects of a probiotic vs. placebo on (i) abdominal pain and depressive symptoms (primary outcomes); (ii) (a) GI (i.e. gas/bloating, diarrhea, constipation) and psychosocial (i.e. anxiety, cognitive function, fatigue) symptoms, and general health; and (b) gut microbiota composition; (iii) relationships between bacteria, GI and psychosocial symptoms. Methods: This double-blinded, placebo-controlled, 2-arm, randomized trial will recruit N=66 participants allocated to the probiotic or placebo group for a 12-week trial. Adult survivors diagnosed with a solid tumour or blood cancer who have completed chemotherapy within the last 5 years, and show elevated GI or psychosocial symptoms will be included. The probiotic capsule contains Lactobacillus and Bifidobacterium strains, ingested orally once daily. Stool samples will be collected at baseline and week-12 and analyzed using GA-Map dysbiosis test and 16S rRNA gene sequencing. GI and psychosocial surveys will be completed at baseline, weeks 6 and 12. Descriptive statistics, frequencies, paired samples t-tests, linear mixed models, and Spearman's correlations analyses will be used. Implications: This study explores a novel, microbiota-based treatment for chronic GI and psychosocial symptoms in cancer survivors. These findings and commitment to patient-centred knowledge translation via creating patient materials (e.g. infographics, personal results summary) will enable patients to make informed decisions about their health.