Association Between Neutrophil-Lymphocyte Ratio and Oncotype Dx Recurrence Score in Early-Stage Hormonal Receptor-Positive, HER2-Negative, Node-Negative Breast Cancer

Purpose: The correlation between the preoperative neutrophil-to-lymphocyte ratio (NLR) and Oncotype DX (R) (ODX) recurrence score (RS) has not yet been established. We aimed to investigate the association between NLR and ODX RS in patients with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) early-stage breast cancer (BC). Patients and Methods: This retrospective study included consecutive patients with HR +/HER2-, node-negative primary BC who underwent surgical tumor resection from 2011 to 2019. Receiver operating characteristic curve analysis was used to obtain an optimal NLR cutoff value. Logistic regression analyses were used to estimate associations between various parameters and ODX RS. Furthermore, the factors significantly associated with the ODX RS in multivariable analysis were incorporated in a separate model and estimated using logistic regression. Results: A total of 160 patients were enrolled. The optimal preoperative NLR cutoff was 2.15. Multivariable analysis revealed that NLR and tumor grade (G1/G2 vs G3) were independent predictive factors of high RS cutoff (>= 26). Moreover, including the two variables yielded a stronger association; patients with low NLR and low-grade tumors were unlikely to have high RS (>= 26; odds ratio [OR] = 0.03, 95% confidence interval [CI]: 0.006-0.154; p < 0.001). Conversely, the presence of any of the following factors made patients unlikely to have low RS (<16; OR = 0.34, 95% CI: 0.16-0.73; p = 0.006): high NLR, high grade, or high Ki-67 levels (>20). Conclusion: NLR is a promising independent predictor of RS. Furthermore, in addition to tumor grade and Ki-67 level, they together are also a potential indicator of high and low RS. However, further studies are required to validate this hypothesis.