Tumor Infiltrating Lymphocytes Predicting Long-Term Outcomes in HER2-Negative Breast Cancer Patients with Visceral Metastases

Background: Tumor-infiltrating lymphocytes (TILs) were found to be associated with a better clinical outcome in specific subtypes of breast cancer. Aim: To study the association between TILs and the prognosis of Egyptian patients with HER2-negative breast cancer metastatic to the viscera. Methods: This prospective study included 100 patients with HER2-negative metastatic breast cancer. Intratumoral TILs, stromal TILs, and CD4 and CD8 were examined in the pathological specimens and their relationship with survival and response to treatment was studied. Results: At a median follow-up period of 43 months, the median overall survival was 44.7 months (95%CI: 39.2-50.2) and the 5-year overall survival rate was 28%. A high level of CD8+ve TILs was associated with significantly longer overall survival (p<0.001) and progression-free survival (p=0.043). There was no significant correlation between intratumoral TILs, stromal TILs, or CD4+ve and overall survival. Conclusions: A higher level of CD8+ve TILs is associated with better overall as well as progression-free survival in HER2-negative breast cancer with visceral metastases.