Supplementary Figure S4 from Cell-free DNA Concentration as a Biomarker of Response and Recurrence in HER2-Negative Breast Cancer Receiving Neoadjuvant Chemotherapy

Relationship of cfDNA concentration and circulating tumor DNA (ctDNA) with residual cancer burden (RCB) index. A. CfDNA (ng/mL, log10-transformed) and B. ctDNA concentrations (mean tumor molecules per mL of plasma, MTM/ml, log10-transformed) were measured in the plasma of patients with hormone receptor-positive HER2-negative (HR+HER2-) and triple-negative breast cancer (TNBC). The RCB index is a continuous measure of residual cancer in the breast and axillary lymph nodes after neoadjuvant chemotherapy, with an RCB index of zero equivalent to a pathologic complete response. The blue line represents the regression line, and the gray shading shows the 95% confidence interval. Pearson’s correlation test was used to calculate the correlation coefficient and the p-value. Blood was collected at pretreatment (T0), 3 weeks after treatment initiation (T1), 12 weeks after treatment initiation between paclitaxel-based treatment and anthracycline regimens (T2), and after neoadjuvant chemotherapy before surgery (T3).