ONCOmmunity

Impact of adjuvant chemotherapy and radiotherapy on tumour-infiltrating lymphocytes and PD-L1 expression in metastatic breast cancer.

By: Shu Yazaki, Roberto Salgado, Tatsunori Shimoi, Masayuki Yoshida, Sho Shiino, Tomoya Kaneda, Yuki Kojima, Hitomi Sumiyoshi-Okuma, Tadaaki Nishikawa, Kazuki Sudo, Emi Noguchi, Takeshi Murata, Shin Takayama, Akihiko Suto, Yuichiro Ohe, Kan Yonemori

Department of Medical Oncology, National Cancer Center Hospital, Tokyo, Japan.
2022-6-19; doi: 10.1038/s41416-022-02072-2

Abstract

Background

Chemotherapy and radiotherapy were postulated to induce an inflamed tumour microenvironment. We aimed to evaluate the effects of adjuvant chemotherapy/radiotherapy on tumour-infiltrating lymphocytes (TILs) and programmed death-ligand 1 (PD-L1) expression in metastatic breast cancer.

Methods

We identified paired primary and metastatic tumours in 85 patients with breast cancer. Stromal TILs were assessed according to international guidelines. PD-L1 expression was evaluated using the VENTANA SP142 assay.

Results

TILs were significantly lower in metastatic tumours than in primary tumours (12.2 vs. 8.3%, p = 0.049). PD-L1 positivity was similar between primary and metastatic tumours (21.2 vs. 14.1%, p = 0.23). TILs were significantly lower in patients who received adjuvant chemotherapy than in those who did not (-9.07 vs. 1.19%, p = 0.01). However, radiotherapy had no significant effect on TILs (p = 0.44). Decreased TILs predicted worse post-recurrence survival (hazard ratio, 2.94; 95% confidence interval [CI]: 1.41-6.13, p = 0.003), while increased TILs was associated with a better prognosis (HR, 0.12; 95% CI: 0.02-0.08, p = 0.04).

Conclusions

TILs decreased in metastatic tumours, particularly in patients who relapsed after adjuvant chemotherapy. Changes in TILs from primary to metastatic sites could be a prognostic factor after recurrence.