Locally advanced breast cancer: Tumor-infiltrating lymphocytes as a predictive factor of response to neoadjuvant chemotherapy

Abstract

Objective: To evaluate the pathologic response after neoadjuvant chemotherapy in patients with breast cancer according to the stromal tumor-infiltrating lymphocytes (TILs) as well as the evaluation of overall and disease-free survival according to TILs.

Methods: A six years (2008-2013) review was done including patients with locally advanced breast cancer that received neoadjuvant therapy and then surgery. An evaluation of the percentage of TILs was done in the pretreatment biopsies and a correlation analysis and survival curves were done.

Results: 187 patients were evaluated. The pathological complete response (pCR) in patients with TILs ≥30% was 58.5%, and in patients with TILs < 30% was 11% (p <0.001). An Odds Ratio of 8.85 was obtained in patients with TILs ≥30% to achieve a pCR. This relationship was seen in patients with HER2-enriched and triple-negative subtypes. No correlation between TILs and survival was obtained (OS: log-rank; p = 0.834; DFS: log-rank; p = 0.937).

Conclusions: The study of TILs is important because they represent an additional tool to predict the response to neoadjuvant treatment mostly in HER2-enriched and triple-negative subtypes of breast cancer.

Keywords: Breast cancer; Neoadjuvant treatment; Predictive factor; Stromal tumor infiltrating lymphocytes; TILs.