This study aimed to evaluate early-to-intermediate, within-treatment changes in inflammatory biomarkers (CRP, NLR, PLR) and examine their associations with sociodemographic, clinical, and anthropometric variables among women with stage I-III non-metastatic breast cancer receiving outpatient chemotherapy, measured immediately before the first (C1) and third (C3) cycles.<h4>Material and methods</h4>Prospective single-arm cohort of women with stage I-III breast cancer receiving outpatient chemotherapy at a single center. This evidence concerns the gene CRP and breast cancer.