Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) as predictive biomarkers of pathologic complete response (pCR) in neoadjuvant breast cancer: an Irish Clinical Oncology Group study (ICORG 16-20)

Abstract

Background: Over the past few years, the rapidly advancing field of cancer immunology has provided solid evidence that the systemic inflammatory response, usually measured by surrogate blood-based parameters, such as neutrophil or platelet count, has an important role in the progression of several solid tumors. In this study, we investigate the association between pre neoadjuvant therapy NLR and PLR, and pCR in breast cancer Methods:We performed a retrospective review of patients with non-metastatic breast cancer treated with neoadjuvant therapy followed by surgery in seven cancer centers across Ireland. Blood cell counts were obtained within one week before the start of neoadjuvant therapy. The NLR and PLR were defined as the absolute neutrophil count and the absolute platelet count, respectively, divided by the absolute lymphocyte count. pCR was defined as the absence of residual invasive cancer in the complete resected breast specimen and all sampled regional lymph nodes following completion of neoadjuvant systemic therapy. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-offs for high vs low NLR and PLR. The relationships between pCR and NLR group (high/low) or PLR group (high/low) were investigated using the chi-squared test and binary logistic regression Results: A total of 304 breast cancer patients were included in the study. The median age was 54. 28% (n = 85) of patients had pCR. Applying the ROC mentioned above, we determined cutoff values of 2.05 and 138.19 for the NLR and PLR respectively, to be optimal to discriminate between high and low groups. In the non-pCR group, 64.8% (n = 142) had a NLR >2.05 compared to 51.8% (n = 44) in the pCR group. Patients with high NLR were less likely to achieve pCR compared to patients with low NLR (p = .036, OR = 1.72, 95% CI: 1.03 to 2.86 ). In the non-pCR group, 58.9% (n = 129) had a PLR >138.19 compared to 44.7% (n = 38) in the pCR group. Patients with high PLR were less likely to achieve pCR compared to those with low PLR (p = .026, OR: 1.77, 95% CI: 1.07 to 2.94) Conclusions: High NLR and PLR are independently associated with poor response to neoadjuvant therapy in breast cancer.