The Relation between Neutrophil to Lymphocyte Ratio and Pathological Complete Response in Breast Cancer Patients Receiving Neoadjuvant Treatment.

Background: The neutrophil-to-lymphocyte ratio (NLR) has emerged as a potential predictive biomarker for pathological complete response (pCR) in breast cancer patients receiving neoadjuvant chemotherapy (NACT). As an indicator of inflammation and immune response, its prognostic value remains unclear. This study evaluates the association between pre-treatment NLR and pCR. Methods: This prospective observational study was conducted at the Medical Oncology Department of Maadi Military Hospital on breast cancer patients eligible for NACT. Patients were categorized into low (≤2.2) and high (>2.2) NLR groups. Clinical assessments, laboratory tests, and pathological evaluations were performed, with pCR assessed using CRS criteria. Results: Hypertension was significantly associated with pCR (p = 0.008), while the absence of comorbidities was linked to a lower likelihood of response (p = 0.017). A lower pre-treatment NLR was a strong predictor of pCR (p < 0.001), whereas post-treatment NLR showed no significant association (p = 0.541). Multivariate analysis confirmed that comorbidities (OR = 3.76, p = 0.017) and triple-negative breast cancer (OR = 4.03, p = 0.029) were significant predictors of pCR, while post-NLR exhibited a near-significant inverse correlation (OR = -6.52, p = 0.067). Conclusion: Our findings suggest that lower pre-NLR is strongly associated with better pCR rates in breast cancer patients undergoing NACT. Unexpectedly, comorbidities, particularly hypertension were also linked to a higher likelihood of achieving pCR. These results highlight the role of inflammatory markers in treatment response. Further research is warranted to validate pre-NLR as a biomarker and explore the impact of comorbidities on neoadjuvant therapy outcomes.