Assessment of stromal tumor-infiltrating lymphocytes in neoadjuvant chemotherapy for invasive breast carcinoma: Predictive insights across molecular subtypes.

BACKGROUND AND AIMS: Breast cancer, a leading cause of female mortality, has prompted the widespread adoption of Neoadjuvant chemotherapy (NAC) for its potential to minimize metastasis risk and downstaging tumors. Tumor Infiltrating Lymphocytes (TILs) have emerged as key immunological biomarkers, particularly in breast cancer research. This study focuses on evaluating Stromal TILs (sTILs) in pre-NAC core needle biopsies of Invasive Breast Carcinoma, No Special Type (IBC, NST) and correlating it with NAC response. MATERIALS AND METHODS: A retrospective study spanning three years (October 2020 to September 2023) was conducted in a tertiary care hospital, involving 73 patients meeting specific inclusion criteria. Pathological assessments, including hormone receptor status, molecular subtyping, and TILs evaluation, were performed. Logistic regression and statistical analyses were conducted to determine associations between TILs, clinicopathological parameters, and complete response. RESULTS: The study demonstrated excellent discriminatory power of TILs (>10 %) in predicting complete response. Univariate and multivariate logistic regression underscored the independent predictive value of TILs, emphasizing their significance across diverse molecular subtypes. CONCLUSION: This study provides crucial insights into immune response assessment, particularly sTILs, in optimizing breast cancer treatment strategies and patient outcomes during NAC, contributing to the evolving landscape of personalized emphasising oncology.