Relationship between the change in tumour-infiltrating lymphocyte level and residual tumour after neoadjuvant chemotherapy in patients with locally advanced breast cancer

Abstract

To evaluate the tumour-infiltrating lymphocyte (TIL) rates in breast tissue before and after neoadjuvant chemotherapy (NAC) and their impact on survival, eighty-four patients with locally advanced breast cancer (LABC) were assessed. Pre- and post-NAC TIL levels were determined using biopsy and surgical specimens, respectively. The median TIL rate was significantly different before (17.5%) and after (5%) NAC. Pre- and postoperative Ki-67 index, molecular subtype, pre- and post-NAC TIL concentration, and preoperative residual-cancer-burden TIL were significantly associated with pathological complete response (pCR). Specifically, higher pre-NAC TIL levels were associated with higher pCR rates. Postoperative Ki-67 index and pCR, and postoperative Ki-67 index were significant predictors of disease-free (DFS) and overall survival, respectively. The independent prognostic factors for DFS were postoperative Ki-67 score (hazard ratio [HR]: 6.16; p = 0.012), post-NAC TIL score (HR: 0.42; P = 0.041), and pCR (HR: 0.10; P = 0.038). Our study confirms that higher pre-NAC and lower postoperative TIL levels may be surrogate factors for longer DFS, and postoperative TIL rate may predict post-NAC pCR in patients with LABC.

Keywords:

• Breast cancer
• neoadjuvant chemotherapy
• tumour-infiltrating lymphocyte
• pathological response
• breast surgery
• disease-free survival

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data supporting the findings of this study are not openly available. Further inquiries should be directed to the corresponding author.