Abstract P2-08-04: Prognostic impact of tumor-infiltrating lymphocytes (TIL's) and stromal-infiltrating lymphocytes (SIL's) in triple negative breast cancer
Authors: Sherwell-Cabello S , Maffuz-Aziz A , Bautista-Piña V , Labastida-Almendaro S , Camacho-Ramírez DA , Ríos-Luna NP , Rodríguez-Cuevas S 
Published: May 2016

Background. Immune response seems to improve outcome in women with Triple-Negative Breast Cancer (TNBC). Recent data suggests that the presence of Tumor-Infiltrating Lymphocytes (TIL's) is an independent factor associated with favorable prognosis. In this study, we evaluate the prognostic impact of both the TIL's and SIL's in patients with TNBC.

Methods. Data on women diagnosed with triple negative breast cancer between 2005 and 2013, was collected by retrospectively reviewing at Breast Disease Institute, FUCAM. The rate of intratumoral and/or stromal lymphocytes was evaluated in all histopathologic biopsies according to Denkert et al. Lymphocyte infiltrate was assessed in hematoxylin and eosin-stained sections. TIL's were reported as the percentage of tumor epithelial nests containing infiltrating lymphocytes, while SIL's as the percentage of stroma area with lymphocytic infiltrate without contact with tumor cells. The five-year disease-free survival (DFS) and overall survival (OS) were compared between groups with the presence or absence of Tumor-Infiltrating Lymphocytes or Stromal-Infiltrating Lymphocytes. Demographic and clinical characteristics were assessed, and the variables with a statistically significant difference between groups were analyzed in a multivariate analysis.

Results. A total of 172 patients with Triple-Negative breast cancer treated this institution were included with a mean age of 49.8 years. A complete absence of tumor lymphocytes was found in 88 patients while the presence of intratumoral, stromal or both was found in 84 (48.8%). A mean follow-up of 46.12 months showed significantly higher rates of both disease-free survival and overall survival in women with SIL's and TIL's (p = 0.014 and 0.042 respectively) in locally advanced stages (LAS), regardless the rate of infiltrating lymphocytes found.

5-year Overall Survival in Locally Advanced Stages Overall SurvivalpNegative48.7 ± 7.8 SIL´s74.2 ± 6.60.014TIL ´s69.2 ± 7.30.042Table 1. Statistical significance was defined as p &lt; 0.05.

In these patients, Stromal Lymphocytes are strongly correlated with a better prognosis compared with Intratumoral Lymphocytes.

Multivariate analysisVariables with statistical significanceβ ValuepSIL´s4.8460.028TIL ´s2.8500.091Table 2. Multivariate analysis. Statistical significance was defined as p = 0.10

Non-significant differences were found in early stages (p = 0.255).

Conclusion. Immunity seems to play a key role regarding the outcome in women with Triple-Negative Breast Cancer. We show that the presence of SIL's or TIL's are strongly associated with higher rates of disease-free and overall survival in LAS, especially when stromal lymphocytes are found. Independent to the rate of lymphocytic infiltrate, its presence has a statistical significance. Because it is a feasible, reproducible and inexpensive test that can be used as a prognostic predictor, we recommend assessing both SIL's and TIL's histopathologic biopsies of patients with TNBC.

Citation Format: Sherwell-Cabello S, Maffuz-Aziz A, Bautista-Piña V, Labastida-Almendaro S, Camacho-Ramírez DA, Ríos-Luna NP, Rodríguez-Cuevas S. Prognostic impact of tumor-infiltrating lymphocytes (TIL's) and stromal-infiltrating lymphocytes (SIL's) in triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-04.