Changes in Tumor-infiltrating Lymphocytes After Neoadjuvant Chemotherapy and Clinical Significance in Triple Negative Breast Cancer

Abstract

Background/aim: Neoadjuvant chemotherapy (NAC) can affect tumors and the tumor microenvironment. As changes in tumor-infiltrating lymphocytes (TILs) after NAC and the resulting clinical significance have not been clearly defined, we evaluated both in triple negative breast cancer (TNBC).

Materials and methods: TIL level was histologically analyzed in pre-NAC biopsy and post-NAC operation specimens from 104 TNBC cases with residual invasive carcinoma after NAC.

Results: Forty-three cases (41.3%) showed decreases in TIL level, whereas 29 cases (27.9%) showed increases and no significant changes were found in 32 cases (30.8%). A decrease or increase in TIL levels corresponded to a better disease-free survival (DFS) as compared to unchanged levels. In multivariate analysis, a change in TIL level was an independent prognostic factor for DFS.

Conclusion: We identified a prognostic significance of TIL changes after NAC. Assessment of TILs before and after NAC can provide valuable prognostic information for TNBC patients.

Keywords: Breast cancer; neoadjuvant chemotherapy; tumor-infiltrating lymphocyte.