Abstract PS6-31: Correlations between tumor-infiltrating lymphocytes, CD3, CD8 cells, and Immunoscore®, with pathological CR and time to progression in triple-negative breast cancer patients undergoing neoadjuvant chemotherapy

Abstract

Abstract Background High levels of stromal tumor-infiltrating lymphocytes (TILs) have been associated with better prognosis in early triple-negative breast cancer (TNBC). The Immunoscore® (IS) is a prognostic tool, which categorizes the densities of spatially positioned CD3 and CD8 cells in both invasive margins (IM) and the center of the tumor (CT), yielding a five-tiered classification (0-4). High IS values have been reported to predict improved outcomes in colorectal cancer. Methods The cohort consisted of 53 TNBC patients (pts) who previously received neoadjuvant anthracycline- and taxane-based chemotherapy. Quantitative analysis of the immune cells was carried out using computer-assisted image analysis in different tumor locations for CD3 and CD8 T-cell markers. Additionally, we measured stromal TILs according to the International TILs Working Group. Pre-treatment tumor samples were immune-stained for CD3 and CD8 T-cell markers and stromal TILs. The relationship between various clinical-pathological factors, and immune factors, was analyzed by Chi2 and Fischer exact test. The log-rank test and the Kaplan Meyer methods were used to estimate relapse-free survival. Results The median age of the pts was 50 years (27-84 years). Tumor sizes were categorized as T1 = 9 pts (17%), T2 = 41 pts (77%) and T3 = 3 pts (6%). Pts with positive glands = 19 (36%) pts and pts without gland involvement = 34 (64%). Stage grouping included stage 1 = 5 (9%), stage IIA = 33 (63%) pts, stage IIB = 9 (17%) pts, stage III = 6 (11%) pts. The median Ki-67 was 45% (range 5 - 90%). The median density of CD3 CT cells = 1190mm² (range 34 - 4614), CD3 IM = 1855mm² (range 57 - 6190), CD8 CT 508mm² (range 17 - 2486) and CD8 IM 805mm² (range 90 - 3156). The median percentage of stromal TILs was 5% (0 - 60%). Pts with an IS of 0 = 4 pts (8%), IS 1 = 3 (5%), IS 2 = 20 pts (38%), IS 3 = 24 pts (45%) and IS 4 = 2 pts (4%). The pathological complete response (pCR) rate of the entire cohort was 62%. A positive correlation was found between TILs and CD3 CT (R = 0.641, p < 0.0000), CD8 CT (R = 0.5623, p < 0.0000), CD3 IM (R = 0.6099, p < 0.0000), and CD8 IM. (R = 0.5010, p < 0.0010). TILs correlated with IS (R = 0,3603, p < 0.0087). There was no correlation between TILs and Ki-67 (R = 0.1497, p < 0.2943). On univariate analysis, factors associated with higher pCR included nodal status (positive = 42,11% vs. negative = 73,53% (p<0,02362) and Ki67 <40%= 33,33% vs. ≥40% = 76,47% (p<0,00235). A high density of CD3 (> than 1100mm2) and CD8 (> than 400mm2) positive T-cells in the CT was associated with higher pCR (CD3 CT: 30% vs. 70%, p=0.00489 and CD8 CT: 30% vs. 70%, p=0.03344). Analysis of CD3 (> than 1200mm2) (CD3 IM: 12% vs 88%, p=0.0.02367) and CD8 in the IM (> than 550mm2) was also significant for an association with pCR (CD8 IM: 23% vs. 77%, p=0.03). High IS (3+4= 73%) vs. intermediate (2=55%) vs. low (0+1=43%) showed a numerical difference that did not, however, reach a statistical significance with pCR (p=0.111). Analysis of TILs ≥ 20% showed a pCR of 76% compared to pts with TILs < 20% with a pCR of 54% (p < 0.12295). A Ki67 ≥40% was associated with a pCR of 76% compared to pts with Ki67 < 40% with a pCR 33% (p < 0.00235). The median time to progression (TTP) of the pts not attaining a pCR was 1600 days compared to those who did attain a pCR with a median PFS not reached yet, but exceeding 1800 days. The TTP of pts with Ki67 < 40% was 1700 days, while the pts with Ki67 ≥40% was not been reached (p < 0.03). At 1800 days, 95% of pts with CD3 > 1100mm2 did not relapse, compared to 75% pts with CD3 ≤ 1100 (p < 0.03). Conclusions This exploratory study shows that analyzing CD3 and CD8 cells in the center of the tumor and invasive margin might be more useful than examining TILs in TNBC pts. Further prospective, well-designed, adequately powered studies are required to confirm these findings. Citation Format: Bernardo Leon Rapoport, Jérôme Galon, Simon Nayler, Aurelie Fugon, Isabelle Boquet, Marine Martel, B Mlecnik, Carol Ann Benn, Teresa Smit, Liezl Heyman, Farhana Moosa, Ronald Anderson. Correlations between tumor-infiltrating lymphocytes, CD3, CD8 cells, and Immunoscore®, with pathological CR and time to progression in triple-negative breast cancer patients undergoing neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-31.