Impact of adjuvant chemotherapy and radiotherapy on tumour-infiltrating lymphocytes and PD-L1 expression in metastatic breast cancer
Menée à partir d'échantillons de tumeurs primitives et de métastases provenant de 85 patientes atteintes d'un cancer du sein, cette étude évalue l'effet d'une chimiothérapie adjuvante et d'une radiothérapie sur l'infiltration lymphocytaire des tumeurs primitives et des métastases ainsi que sur le niveau d'expression de PD-L1
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.
British Journal of Cancer , article en libre accès, 2022