Combination of gut microbiota, proinflammatory cytokine, and ¹⁸F-FDG PET as potential indicators for predicting breast cancer recurrence

Breast cancer occurs at a younger age compared to western countries in South Korea. Despite advancements in treatment methods such as targeted therapy and immunotherapy, the increasing number of patients underscores the importance of improving disease-free survival (DFS). In this study, we evaluated the associations between gut microbiota composition, inflammatory cytokine levels, and breast cancer recurrence in preoperative patients. Additionally, we developed a composite prognostic index by integrating these factors with PET/CT indices and clinical prognostic factors. This study showed that Prevotella abundance was significantly higher in the DFS group than in the recurrence group, and higher Prevotella abundance was associated with lower levels of the inflammatory cytokine IL-1β. Survival analysis revealed that patients with low Prevotella abundance and high IL-1β levels had a higher risk of breast cancer recurrence. PET markers, such as SUV_tumor, SUV_VAT, and SUV_spleen, were also found to be significant prognostic indicators, with lower values associated with better survival outcomes. An integrated predictive model combining gut microbiota composition, cytokine levels, PET indices, and clinical factors demonstrated superior accuracy (AUC: 0.9025) in predicting breast cancer recurrence compared to individual components.