Prognostic Value Of Tumor Infiltrating Lymphocytes Among HER-2+ Breast Cancer Patients Receiving Trastuzumab-Based Adjuvant Therapy

Abstract

Background: Tumor Infiltrating Lymphocytes (TILs) have prognostic value on HER2 positive breast cancer (BC). The absence of standardized method for evaluating TILs causes variations in results of previous studies. This study is performed to evaluate the prognostic value of TILs in HER2 positive BC treated with trastuzumab-based adjuvant therapy using standardized method recommended by the International TILs Working Group.
 Aim: To analyze the prognostic value of TILs in HER2 positive BC patients receiving trastuzumab-based adjuvant therapy at Dr. Sardjito General Hospital, Yogyakarta and to analyze proportion differences between high TILs (≥30%) and low TILs (<30%).
 Methods: This is a retropective cohort study on HER2 positive, stage 1-3 BC patients who received trastuzumab-based adjuvant therapy. Histopathology slides from 6 hospitals/laboratoriums were analyzed by two pathologists.
 Results: 73 data were available for analysis. TILs stroma <30% was 65,8% and most patients received combination of anthracyclines, taxanes and trastuzumab (67,1%). There was no difference of overall survival between high and low TILs (p log rank: 0,331).
 Conclusion: HER2 positive BC with high TILs did not show better overall survival compared to those with low TILs. The proportion of HER2 positive breast cancer with high TILs was lower than those with low TILs.