Abstract P2-08-47: Evaluation of stromal tumor-infiltrating lymphocytes (sTIL) and tertiary lymphoid structures (TLS) in early breast cancer patients with triple negative breast cancer(TNBC) included in a prospective study of neoadjuvant chemotherapy (NAC) with Epirubicin and cyclophosphamide (EC) and carboplatin-paclitaxel (PC) (BSMO 2014-01)
Authors: Fontaine C , Van den Eynden G , de Wind R , Boisson A , Renard V , Van den Bulck H , Vuylsteke P , Glorieux P , Dopchie C , Decoster L , De Grève J , Awada A , Wildiers H , Willard-Gallo K 
Published: May 2019

Background: BSMO 2014-01 is a completed prospective phase 2 study evaluating the efficacy of neoadjuvant EC and PC. One of the secondary endpoints was the correlation of sTIL with response, pCR and survival. We also assessed the relationship between sTIL and TLS in the diagnostic biopsies.

Methods: Stromal TIL (sTIL) were evaluated on H&E stained tumor biopsies before the start of the NAC according to the criteria described by Salgado et al(1). Scores were defined as "low" or "high" if lymphocytic infiltration in the stroma around the tumor was ≤ 10% or &gt; 10%. TLS are ectopic lymph node-like structures recently identified in breast cancer. TLS were counted using a dual IHC stain for CD3 (T cells) and CD20 (B cells) and categorized as "little" if the TLS occupied &lt; 10% or "moderate to abundant" if they occupied ≥ 10% of the adjacent tissue. The correlation between sTIL and pathologic parameters was analyzed using the chi-square test; DFS and OS between the groups was estimated by using the log-rank test.

Results: So far we could quantify the number of sTIL in 38 out of 63 TNBC pts treated with neoadjuvant EC-PC. Twenty eight pts had a high sTIL score and 10 pts had a low sTIL score. The high-sTIL group (19/28) achieved a numerical higher pathologic complete remission (pCR) rate than the low-sTIL group (5/10) (p=0.3); both groups had a comparable disease free survival of 28.6 mths and 26.7 mths respectively (p=0.7). The overall survival was similar:29 mths and 27.8 mths respectively (p=0.8). Stromal TLS were identified in 10 out 23 samples available for this analysis and we could demonstrate a positive correlation between high levels of sTIL and high levels of moderate to abundant TLS(CD3) in the adjacent tissue in six out of the ten samples in which TLS were present (p=0.1).

Conclusion: These preliminary results could not confirm the results published by Denkert et al earlier this year(2). A trend for correlation of the presence of high sTIL with moderate to abundant levels of TLS was found. Analysis on the remaining samples of all patients included in the study and correlation with outcome is ongoing and these completed results will be presented.

(1)Assessing Tumor-infiltrating lymphocytes in solid tumors. Hendry S, Salgado R et al. Adv Anat Pathol 2017; 235-251.

(2)Tumour-infiltrating lymphocytes and prognosis in different subtypes of breast cancer. Denkert C et al. Lancet Oncol 2018; 40-50.

Citation Format: Fontaine C, Van den Eynden G, de Wind R, Boisson A, Renard V, Van den Bulck H, Vuylsteke P, Glorieux P, Dopchie C, Decoster L, De Grève J, Awada A, Wildiers H, Willard-Gallo K. Evaluation of stromal tumor-infiltrating lymphocytes (sTIL) and tertiary lymphoid structures (TLS) in early breast cancer patients with triple negative breast cancer(TNBC) included in a prospective study of neoadjuvant chemotherapy (NAC) with Epirubicin and cyclophosphamide (EC) and carboplatin-paclitaxel (PC) (BSMO 2014-01) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-47.