Combination of peripheral neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio is predictive of pathological complete response after neoadjuvant chemotherapy in breast cancer patients

The immune system seems to play a fundamental role in breast cancer responsiveness to chemotherapy. We investigated two peripheral indicators of immunity/inflammation, i.e. neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR), in order to reveal a possible relationship with pathological complete response (pCR) in patients with early or locally advanced breast cancer treated with neoadjuvant chemotherapy (NACT). We retrospectively analyzed 373 consecutive patients affected by breast cancer and candidates to NACT. The complete blood cell count before starting NACT was evaluated to calculate NLR and PLR. ROC curve analysis determined threshold values of 2.42 and 104.47 as best cut-off values for NLR and PLR, respectively. The relationships between NLR/PLR and pCR, along with other clinical-pathological characteristics, were evaluated by Pearson's χ 2 or Fisher's exact test as appropriate. Univariate and multivariate analyses were performed using a logistic regression model. NLR and PLR were not significantly associated with pCR if analyzed separately. However, when combining NLR and PLR, patients with a NLR^low/PLR^low profile achieved a significantly higher rate of pCR compared to those with NLR^high and/or PLR^high (OR 2.29, 95% CI 1.22–4.27, p 0.009). Importantly, the predictive value of NLR^low/PLR^low was independent from common prognostic factors such as grading, Ki67, and molecular subtypes. The combination of NLR and PLR may reflect patients' immunogenic phenotype. Low levels of both NLR and PLR may thus indicate a status of immune system activation that may predict pCR in breast cancer patients treated with NACT.