Pretreatment neutrophil to lymphocyte ratio as a predictor of pathological complete response to neoadjuvant immunotherapy in early breast cancer.

e12545 Background: Neoadjuvant immunotherapy has been increasingly used in early breast cancer, while lack of accessible predictive biomarkers of response remains an open question. High pretreatment neutrophil to lymphocyte ratio (NLR) was associated with worse prognosis and treatment responses to neoadjuvant chemotherapy in multiple cancers including breast cancer. However, it remains unclear whether NLR was associated with response to neoadjuvant immunotherapy in early breast cancer. Methods: We retrospectively analyzed 89 early breast cancer patients who received neoadjuvant chemotherapy in combination with at least 4 cycles of immunotherapy and subsequent breast surgery in Sun Yat-sen University Cancer Center. Pretreatment NLR was calculated, and Miller-Payne grade 5 in primary tumor site was considered pathological complete response (pCR) to neoadjuvant therapy. Univariate and multivariate analyses were used to evaluate the associations between clinicopathological markers and pCR. Results: 49.4% (44/89) of the patients achieved pCR. Compared to non-pCR patients, pCR patients had significantly lower pretreatment NLR (1.93 vs 2.87, p<0.001) and lower percentage of pretreatment cT3/T4 stage (11.4% vs 37.7%, p=0.006), and received more cycles of neoadjuvant immunotherapy (6.5 vs 6.0, p<0.05). More pCR patients received TCb based neoadjuvant therapy (86.4% vs 51.1%, p<0.001). In multivariate analysis, the pretreatment NLR (p=0.002) and cT3/T4 (p=0.010, as compared to cT1/T2) were independent predictive factors for pCR. Conclusions: Lower pretreatment NLR was associated with higher possibility of achieving pCR in early breast cancer treated with neoadjuvant immunotherapy. [Table: see text]