Abstract P2-05-05: Prediction of survival after neoadjuvant chemotherapy for breast cancer by evaluation of tumor-infiltrating lymphocytes (TILs) and residual cancer burden (RCB)
Authors: Asano Y , Kashiwagi S , Goto W , Takada K , Takashima T , Morisaki T , Noda S , Onoda N , Ohsawa M , Hirakawa K , Ohira M 
Published: March 2017

Background: The tumor immune environment not only modulates the effects of immunotherapy, but also the effects of other anticancer drugs and treatment outcomes. Thus, the importance of inhibiting and improving the tumor immune microenvironment is now recognized. These immune responses can be evaluated with tumor-infiltrating lymphocytes (TILs), which has frequently been verified clinically. On the other hand, residual cancer burden (RCB) evaluation has been shown to be a useful predictor of survival after neoadjuvant chemotherapy (NAC). In this study, RCB and TILs evaluations were combined to produce an indicator that we have termed “RCB-TILs”, and its clinical application to NAC for breast cancer was verified by subtype-stratified analysis.

Materials and Methods:A total of 177 patients with resectable early-stage breast cancer were treated with NAC.The correlation between TILs evaluated according to the standard method, and prognosis, including the efficacy of NAC, was investigated retrospectively. The RCB was calculated using the Residual Cancer Burden Calculator on the website of the MD Anderson Cancer Center. The RCB and TILs evaluations were combined to create the “RCB-TILs”. Patients who were RCB-positive and had high TILs were considered RCB-TILs-positive, and all other combinations were RCB-TILs-negative.

Results: Univariable analysis of patients with high TILs found that this contributed significantly to prolonging DFS in all patients (p = 0.022, hazard ratio = 0.420), TNBC patients (p = 0.004, hazard ratio = 0.177), and HER2BC patients (p = 0.026, hazard ratio = 0.123). For HRBC patients, however, high TILs did not contribute to survival (p = 0.990, hazard ratio = 0.992). Being RCB-TILs-positive, however, contributed significantly to prolonging DFS in all patients (p &lt; 0.001, hazard ratio = 0.181), TNBC patients (p &lt; 0.001, hazard ratio = 0.099), HER2BC patients (p = 0.026, hazard ratio = 0.123), and HRBC patients (p = 0.039, hazard ratio = 0.258). On multivariable analysis, being RCB-TILs-positive was an independent factor for recurrence after NAC in all patients (p &lt; 0.001, hazard ratio = 0.048), TNBC patients (p = 0.018, hazard ratio = 0.041), HER2BC patients (p = 0.036, hazard ratio = 0.134), and HRBC patients (p = 0.002, hazard ratio = 0.081).

Conclusion: The results of the present study suggest that RCB-TILs is a significant predictor for breast cancer recurrence after NAC and may be a more sensitive indicator than TILs alone.

Citation Format: Asano Y, Kashiwagi S, Goto W, Takada K, Takashima T, Morisaki T, Noda S, Onoda N, Ohsawa M, Hirakawa K, Ohira M. Prediction of survival after neoadjuvant chemotherapy for breast cancer by evaluation of tumor-infiltrating lymphocytes (TILs) and residual cancer burden (RCB) [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 P2-05-05.