Abstract P3-04-20: Predicting therapeutic effect by on tumor invasion lymphocytes (TILs) in endocrine therapy for stage IV breast cancer
Authors: Kashiwagi S , Asano Y , Goto W , Takada K , Takashima T , Morisaki T , Noda S , Onoda N , Ohsawa M , Hirakawa K , Ohira M 
Published: March 2017

Background: Breast cancer with distant metastasis at first presentation (stage IV disease) is often encountered in the outpatient department. With recent advances in multimodal therapies for breast cancer, long-term survival can now be expected even in stage IV breast cancer with distant metastasis. However, a goal in treating metastatic disease is prolongation of survival while maintaining good quality of life (QOL). Endocrine therapy is suitable for this purpose.The tumor immune environment not only modulates the effects of immunotherapy, but also the effects of other anticancer drugs and treatment outcomes. These immune responses can be evaluated with tumor-infiltrating lymphocytes (TILs), which has frequently been verified clinically. In the present study, we hypothesized that TILs would be useful as predictive marker of the therapeutic effect in endocrine therapy as well. In this study, the prediction of the therapeutic effect by TILs in endocrine therapy for stage IV breast cancer was clinically verified.

Materials and Methods:Data from 40 patients who underwent endocrine therapy as the initial drug therapy for stage IV breast cancer were used. The correlation between TILs evaluated according to the standard method, and prognosis, including the efficacy of endocrine therapy, was investigated retrospectively. Patients with 350% lymphocytic infiltration were considered to have lymphocyte-predominant breast cancer (LPBC).

Results:Among all 40 patients, TIL levels were high in 13 (32.5%) and low in 27 (67.5%) patients. Nine patients (22.5%) had LPBC, and 31 patients (77.5%) had non-LPBC. Investigation of the clinical pathological features of patients showed no significant differences between the high TIL and low TIL groups. There were also no significant differences between LPBC and non-LPBC patients. An analysis of outcomes comparing the high TIL and low TIL groups showed no prolongation in progression-free survival (PFS) (p=0.171, log-rank), time to treatment failure (TTF)(p=0.054), or overall survival (OS) (p=0.641). LPBC patients had significant prolongations of PFS (p=0.005), TTF (p=0.001), and OS (p=0.027) compared to non-LPBC patients. On receiver operating characteristic (ROC) curve analyses, results were better with LPBC (AUC: 0.700) than with TILs (AUC: 0.606).

Conclusion: The present findings suggest that a high level of lymphocytic infiltration in the tumor stroma may serve as a predictor of the therapeutic effect of endocrine therapy for patients with stage IV ER-positive breast cancer.

Citation Format: Kashiwagi S, Asano Y, Goto W, Takada K, Takashima T, Morisaki T, Noda S, Onoda N, Ohsawa M, Hirakawa K, Ohira M. Predicting therapeutic effect by on tumor invasion lymphocytes (TILs) in endocrine therapy for stage IV breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-20.