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Abstract P1-19-08: Prognostic factors of human epidermal growth factor 2 (HER2) positive breast cancer patients with brain metastasis in the context of all available new therapies

Background: Patients with advanced human epidermal growth factor 2 (HER2)-positive breast cancer are at the highest risk developing breast cancer brain metastases (BCBM), which are associated with significant morbidity and mortality. The advent of HER2-directed therapy resulted in greatly improved survival outcomes and have been widely used. In this context of a better controlled systemic disease, brain metastases are emerging as a new challenge for the oncologist. The aim of this study was to determine the clinicopathologic factors associated with the prognosis of patients with HER2 positive BCBM, in the scenario of new therapies. Methods: A retrospective review of clinical data from patients who have developed HER2 positive BCBM from March 2005 to January 2018 at AC Camargo Cancer Center. Patients characteristics were collected, and overall survival (OS) , time to first HER2 positive BCBM and OS after HER2 positive BCBM were estimated by the Kaplan-Meier method. Associations between OS after BCBM and clinical variables were assessed by Cox proportional hazards regression models. Results Among 80 patients with HER2-positiveBCBM median age was 51 years (range, 24–81 years). Of the patients, 55 patients (69%) had ER-positive/HER2-positive breast cancer, and 25 (31%) had ERnegative/ HER2-positive breast cancer. The median brain metastasis-free survival period from primary breast cancer was 33.5 months .The median survival after developing brain metastasis was 28 .5 months. Patients with more than 3 brain metastases had significantly shorter overall survival(p=0,01). ). Nineteen patients (24%) underwent surgical treatment of metastasis in the brain and there was no associated with survival duration(p= 0,33). Patients treated with radiotherapy 71 (88%) had significantly better survival (p= 0,013), if the patient received stereotactic radiosurgery (53.5%) compared to total brain radiotherapy received ( 46,5%) was not associated with duration of survival (p= 0,24). . Treatment with other HER2-targeting agents after BCMB had significantly increased survival (p=0,022), including trastuzumab 53 (67%), pertuzumab 21 (26%), trastuzumab emtansine (TDM1 )= 35 (43%) and lapatinib 37 ( 46%). . In multivariate analysis, the presence of more than 3 brain metastases (p=0,005) was the sole independent prognostic factors. Conclusions: Our study indicates that HER2-positive patients with more than three brain metastases had a poor prognosis and that regardless of the use of new therapies. The role of new therapies in the management of patients with brain metastases is often not clearly defined. The best treatment strategy is not yet known and the study of prognostic factors may help to choose a better treatment sequence. Citation Format: Medeiros de Melo JC, da Costa AA, de Castro DG, Gomes AA, Guimaraes AP, Sanches SM, Diniz AC, Ribeiro AR. Prognostic factors of human epidermal growth factor 2 (HER2) positive breast cancer patients with brain metastasis in the context of all available new therapies [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-19-08.