Role of Tumor-Infiltrating Lymphocytes in Predicting Pathologic Complete Response in HER2-Positive Breast Cancer: An IMRAD-Based Analysis

Resumen

Background: Tumor-infiltrating lymphocytes (TILs) have emerged as a promising biomarker reflecting the host immune response in breast cancer, particularly in HER2-positive subtypes. Their role in predicting pathologic complete response (pCR) following neoadjuvant therapy remains an area of growing clinical interest.

Objective: To evaluate the predictive value of TILs for pCR in patients with HER2-positive breast cancer undergoing neoadjuvant therapy.

Methods: A comprehensive review and synthesis of existing clinical studies assessing stromal TIL levels and their association with pCR in HER2-positive breast cancer patients treated with chemotherapy and HER2-targeted therapy were conducted. Relevant studies were identified through systematic database searches, and findings were analyzed to determine correlations between TIL density and treatment outcomes.

Results: Multiple studies demonstrated a strong positive association between higher TIL levels and increased rates of pCR. Patients with elevated stromal TILs showed improved responsiveness to trastuzumab-based regimens. Quantitative increases in TILs were consistently associated with higher pCR rates, suggesting a dose-response relationship. Additionally, TILs were linked with improved long-term outcomes, including disease-free survival.

Conclusion: TILs represent a robust predictive biomarker for pCR in HER2-positive breast cancer. Their integration into clinical decision-making could enhance patient stratification and guide personalized therapeutic strategies.