Predictive and prognostic value of stromal tumour-infiltrating lymphocytes before and after neoadjuvant therapy in triple negative and HER2-positive breast cancer

Abstract

AimLymphocyte predominant breast cancer (BC) is associated with higher pathological complete response (pCR) rate after neoadjuvant therapy (NAT) and favorable outcome in triple negative breast cancer (TNBC) and HER2+ BC. The predictive and prognostic impact of stromal tumour-infiltrating lymphocytes (TILs) after NAT and the change of TILs before (pre-) and after (post-) NAT are not well studied. We aimed to assess the predictive and prognostic value of pre- and post-NAT TILs, as well as their pharmacodynamics modulation and their change for TNBC and HER2+ BC. Materials and methodsTwo-hundred and nine consecutive patients (n = 80 TNBC, n = 129 HER2+ BC) who received NAT between 2001 and 2009 in a single institution were included. We evaluated the association between pre-NAT TILs and pCR, and the association between pre- and post-NAT TILs, as well as their immunodynamics change with relapse-free survival (RFS) for patients with residual disease (RD). ResultsLow pre-NAT TILs compared to int/high were significantly associated with lower pCR rate (TNBC: 4.0% vs 43.6%; HER2+ BC: 26.0% vs 51.9%). The median follow-up period was 98 months. In TNBC with RD, low pre-NAT TILs showed significant association with shorter RFS (HR = 3.844 [1.190–12.421], p = 0.024) in multivariate analysis. Low post-NAT TILs showed borderline significant association with shorter RFS (HR = 2.836 [0.951–8.457], p = 0.061). The change in TILs was not associated with RFS. In HER2+ BC, low pre-NAT TILs were not associated with RFS. ConclusionIn TN and HER2+ BCs, low pre-NAT TILs tumours had a low likelihood of achieving pCR. In TNBC with RD, both low pre- and post-NAT TILs were associated with shorter RFS. These results suggest that TILs information should be taken into account when additional therapies may be given in the post-neoadjuvant setting.