Assessing mental health, cognitive function and quality of life of breast cancer patients: exploring associations with gut microbiota in an observational study. Assessing mental health, cognitive function and quality of life of breast cancer patients: exploring associations with gut microbiota in an observational study

Introduction: Breast cancer (BC) patients face several physical and psychological problems, such as anxiety, depression, and cognitive dysfunction. The disease and treatments can also impact the microbiota, leading to cognitive and psychological issues and, consequently, affecting quality-of-life (QoL). This study aimed to correlate the initial gut microbiota of newly diagnosed HR+ (Hormone Receptor)/HER2- BC patients with their mental health, cognitive function, and QoL at baseline and after 3 months of neoadjuvant chemotherapy (NAC). Materials and Methods: This is a prospective, longitudinal, observational, exploratory study. Newly diagnosed HR+/HER2- BC patients undergoing NAC were recruited upon diagnosis. At baseline (before NAC), general and lifestyle information, adherence to the Mediterranean diet, biochemical analysis, gut microbiota profile, the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire Core-30 (EORTC QLQ-C30), the Montreal Cognitive Assessment (MoCA) and the Hospital Anxiety and Depression Scale (HADS), were collected. The EORTC QLQ-C30, MoCA, and HADS were repeated 3 months later. Results: Most women showed mild cognitive impairment at baseline, and there was no clear trend of improvement or deterioration at 3 months. Participants had borderline anxiety at baseline, which improved to a normal range, while depression remained stable. QoL declined for most women, with over 70% experiencing problems at 3 months. The association of these parameters with microbiota profile suggested that women with poorer cognitive function over time had lower alpha-diversity and microbial richness. Women with improved scores in the depression subscale of the HADS appear to have higher alpha-diversity and lower richness. Contrarily, alpha-diversity was lower and richness was higher for improved anxiety and global QoL scores. The results also suggest that changes in the abundance of various genera and phyla may be linked to the evolution of scores for the 3 questionnaires. Conclusion: Our study suggests a link between the microbiota profile at diagnosis and the psychological symptoms that develop at 3 months of BC treatment. These findings shed light on potential strategies for positively modulating the microbiota to help enhance the body's resilience, particularly mental health, throughout the disease and treatments.