Abstract PS6-46: Correlation of Tumor-infiltrating lymphocytes with clinicopathological features and treatment outcomes in non-metastatic breast cancer patients
Authors: Hegazy Neamat Elsayed , Motal Haitham Mohsen Abdel , Tayel Hanan Yehia , Ismail Abdelsalam A 
Published: February 2021

Background Breast cancer is the second most common cancer in the world and most frequent among women. Tumor-infiltrating lymphocytes (TILs) can impact tumor progression and response to therapies. Here we aimed to study TILS using the International Immunooncology Biomarkers Working Group guidelines and correlating the TILS with clinicopathological characteristics, disease free and overall survival in non-metastatic breast cancer patients. Methods Non metastatic breast cancer patients (N = 86) who presented to our department between (2013 - 2015) were retrospectively evaluated. The assessment of TILS distribution was based on the TILS International Working Group 2014 recommendations. The eligible patients were reviewed retrospectively regarding the demographic status and clinical parameters and primary treatment information were extracted from the medical records. For all of the available patients, disease-free survival (DFS) and overall survival (OS) were calculated. Results In the study the majority of the patients were 45 years of age or less. The TILS percentage was measured using image analysis. All samples had a range of 1-100%, with a mean 22%. There was 9.3% of the patients having lymphocyte predominant breast cancer (≥50%), while 90.3% had TILS percentage of &lt;50%. Dividing the patients into low (0-20%), intermediate (20-&lt;50%) and high (50-100%). TILS percentage gave us 62.7%, 27.9% and 9.3% of the patients respectively. The distribution of TILS according to age showed a trend towards decreasing TILS with increasing age, and this was not statistically significant. The majority of tumors in the study were T2 (60.5%) followed by T1 (15.1%).. T1 and T2 tumors had significantly higher TILS percentages compared to T3 and T4, mean 24.94% versus mean 13.37% respectively. Using the t-test this showed a p&lt;0.006. The majority of patients in the study were N1 at 62.8% followed by an equal percentage of 17.4% as both N0 and N2. Patients who were N0 had a significantly higher TILS percentage when compared with N1 and N2, mean 33.07% versus mean 20.0% respectively. This was statistically significant using the t-test with a p&lt;0.032 (table 1). Also in this study, there were 74.4% tumors of the luminal subtype, 11.6% of the Her-2 enriched subtype and 12.8% of the triple negative subtype. Although there was no statistically significant correlation between any molecular subtype and TILS, there was a tendency for Her-2 enriched tumors and triple negative tumors to have a higher percentage of TILS in comparison with luminal subtypes as seen in table 1.

We noticed that there is a subgroup of patients with exceptionally high TILS, (called LPBC with TILS ≥50%) had a beneficial response to treatment and confers additional survival benefit; every incremental increase of 10% also resulted in benefit to treatment and delayed relapse. High level of TILS associated with delayed relapse and a survival benefit. Conclusions We demonstrated that increasing TILS confer a relapse free benefit of breast cancer patient, regardless of the tumor subtype, indicating that TILS represent an breast cancer the patients. Keywords Tumor-infiltrating lymphocyte, Breast cancer, outcome of management

Table 1:FinalNTumor infiltrating lymphocytes (TILS %)Min. - Max.Mean ± SD.MedianERNegative (0)212.0 - 100.027.33 ± 28.9318.0Weak (1+)63.0 - 40.019.67 ± 16.2917.0Moderate (2++)135.0 - 62.024.38± 20.6317.0Strong (3+++)451.0 - 87.019.78 ± 17.9217.0N/A15.0PRNegative (0)282.0 - 100.024.86 ± 26.1916.50Weak (1+)36.0 - 12.08.33 ± 3.217.0Moderate (2++)171.0 - 87.022.12 ± 22.1017.0Strong (3+++)371.0 - 62.021.68 ± 17.5518.0N/A15.0HER-2Negative (0)441.0 - 100.022.84 ± 22.9717.50Weak (1+)16.0Moderate (2++)114.0 - 87.025.09 ± 23.7625.0Strong (3+++)232.0 - 65.018.70 ± 17.1312.0N/A74.0 - 53.026.71 ± 22.1225.0BC subtypesLuminal A401.0 - 62.021.28 ± 17.9217.50Luminal B242.0 - 87.019.75 ± 18.9013.50Her2 Enriched104.0 - 65.023.20 ± 21.3616.50Triple -ve112.0 - 100.031.09 ± 35.0819.0N/A15.0

Citation Format: Neamat Elsayed Hegazy, Haitham Mohsen Abdel Motal, Hanan Yehia Tayel, Abdelsalam A Ismail. Correlation of Tumor-infiltrating lymphocytes with clinicopathological features and treatment outcomes in non-metastatic breast cancer patients [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 PS6-46.