Abstract: Inflammatory markers in peripheral blood, such as neutrophil-lymphocyte ratio and platelet-lymphocyte ratio, can reflect the reactive hyperplasia of inflammatory cells in tumors. The metabolic parameters of ¹⁸F-FDG PET/CT are also correlated with the reactive hyperplasia of inflammatory cells in tumors. However, only a few reports exist on the relationship between tumor metabolic parameters and peripheral blood inflammatory markers. Therefore, this review starts from three aspects: tumor peripheral blood inflammatory markers, inflammatory cell reactive hyperplasia in tumors, and ¹⁸F-FDG PET/CT metabolic parameters. The correlation between ¹⁸F-FDG PET/CT metabolic parameters and peripheral blood inflammatory markers is reviewed.