Abstract P3-08-12: An open source, automated tumor infiltrating lymphocyte algorithm for prognosis in triple-negative breast cancer

Background: The presence of high TILs (tumor infiltrating lymphocytes) have been shown to be predictive of response to chemotherapy and is also a prognostic factor associated with better outcome in breast cancer, especially in early stage triple-negative (TNBC) and HER2-positive breast cancers. TIL assessment, while now more standardized due to the efforts of Salgado and the International TIL Working Group (https://www.tilsinbreastcancer.org/), are still a subjective test with variability in evaluation that has prevented broad adoption. Given the advances in application of artificial intelligence to pathology images, we believe the next step for TILs is to make them automated and objective and to identify a standardized and meaning TIL cut-point. The aim of this study is to build an open source, HE N=87, Set C; N=183, and Set D; N=83) in both tissue microarray (TMA) and whole tissue section (WTS) format. Results: Using an optimal cut point (30%) derived from TNBC cohort training set A, patients with high eTILs% displayed an overall survival benefit (HR 0.4, p=0.0150). This algorithm was then applied in other three TNBC validation sets (Set B: HR=0.42, p=0.0033; Set C: HR=0.42, p=0.0127; Set D in TMA format: HR=0.39, p=0.0089). For Set D, we also tested WTS format which showed HR=0.23, (p=0.0155). The validation sets were combined to assess independence from clinical status in a multi-variable analysis where eTILs% was independently associated with improved overall survival (HR=0.35, p Citation Format: Yalai Bai, Balazs Acs, Jon Zugazagoitia, Sandra Martinez-Morilla, Fahad Shabbir Ahmed, David L. Rimm. An open source, automated tumor infiltrating lymphocyte algorithm for prognosis in triple-negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-12.