Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as predictors of outcomes in inflammatory breast cancer

Background: Inflammatory breast cancer (IBC) is uncommon, aggressive and associated with poor survival outcomes. The lack of prognostic biomarkers and therapeutic targets specific to IBC is an added challenge for clinical practice and research. Inflammatory biomarkers such as neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios (NLR and PLR) demonstrated independent prognostic impact for survival in breast cancer. In our study, these biomarkers were investigated in a cohort of patients with nonmetastatic IBC. Methods: A retrospective cohort of 102 IBC patients with nonmetastatic disease was conducted at the Mohammed VI University Hospital (Oujda, Morocco) between January 2010 and December 2014. NLR and PLR were obtained from blood cell count at baseline before neoadjuvant chemotherapy (NACT) from patients' medical records. The receiver operating characteristic was used to find the optimal cut-off. Correlation between these blood-based biomarkers and response to NACT was analyzed by Chi-squared and Fisher's exact test. Their prognostic value for predicting disease-free survival (DFS) and overall survival (OS) was performed based on Cox regression models. Results: Totally, 102 patients with IBC were included in the analysis. Pathologic complete response (pCR) after NACT, defined by the absence of an invasive tumor in the breast tissues and nodes after surgery (ypT0 ypN0), was observed in eight patients (7.8%). NACT response was found to be associated with menopausal status (p = 0.039) and nodal status (p < 0.001). Patients with a low NLR had a higher pCR rate as compared with the high-NLR group (p = 0.043). However, the pCR rate was not significantly associated with age (p = 0.122), tumor side (p = 0.403), BMI (p = 0.615), histological grade (p = 0.059), hormone receptors status (p = 0.206), human epidermal growth factor receptor 2 (p = 0.491) and PLR (p = 0.096). Pre-treatment blood-based NLR of 2.28 was used as the cut-off value to discriminate between high and low NLR according to the receiver operating characteristic curves. Similarly, a value of 178 was used as the cut off for PLR. Patients with low-NLR had a significantly better 5-year DFS (p < 0.001) and OS (p < 0.001) than the high-NLR group. Moreover, low-PLR was significantly associated with higher DFS (p = 0.001) and OS (p = 0.003). The NLR showed a significant prognostic impact for DFS (HR: 2.57; 95% CI: 1.43-4.61; p = 0.01) and for OS (HR: 2.92; 95% CI: 1.70-5.02; p < 0.001). Similarly, a meaningful association between PLR and 5-year DFS (HR: 1.95; 95% CI: 1.10-3.46; p = 0.021) and OS (HR: 1.82; 95% CI: 1.06-3.14; p = 0.03) was noticed. Conclusions: High NLR and PLR were found associated with reduced DFS and OS in nonmetastatic IBC. Further studies are awaited to confirm these findings.