Objective: This study aims to investigate the correlation between the CD8+ tumor-infiltrating lymphocytes (TILs) expression and the efficacy of neoadjuvant therapy (NAT) in breast cancer, while previous studies have reported inconsistent findings regarding the predictive value of CD8+ TILs. Methods: Data from 94 breast cancer patients who underwent NAT between January 2017 and June 2019 were retrospectively analyzed. Preoperative CD8+ TILs expression was evaluated through immunohistochemistry, and its association with clinical and pathological responses to NAT was assessed. Results: Univariate analysis indicated that tumor stage, axillary lymph node status, and intratumoral CD8+ TILs were correlated with clinical complete response (cCR). Multivariate analysis identified intratumoral CD8+ TILs as an independent predictor of cCR (OR 3.038; p=0.02). Patients achieving pathological complete response (pCR) exhibited significantly higher intratumoral CD8+ TILs expression compared to those without (p=0.04). Univariate analysis also linked estrogen receptor (ER), progesterone receptor (PR), HER2 status, and intratumoral CD8+ TILs to pCR, with multivariate analysis confirming intratumoral CD8+ TILs as an independent predictor (OR 4.036; p=0.02). Conclusion: Our findings suggest that intratumoral CD8+ TILs are an independent predictor of the efficacy of neoadjuvant therapy in breast cancer. In the future, incorporating intratumoral CD8+ TILs into existing clinicopathological predictive models and combining their assessment with other immune biomarkers may enable the development of more robust predictive tools, thereby providing a solid foundation for truly individualized and precision-based neoadjuvant treatment in breast cancer. Keywords: Breast cancer, Neoadjuvant therapy, Efficacy prediction, Tumor-infiltrating lymphocytes, CD8+ TILs
Feng et al. (Sun,) studied this question.