The role of systemic treatment after whole brain radiotherapy (WBRT) in breast cancer patients with brain metastases: Differences depending on biological subtype

Abstract

1027 Background: The aim of the study was to analyze the efficacy of systemic treatment (chemotherapy [chth], endocrine therapy, targeted therapy) performed after WBRT in patients (pts) with breast cancer and brain metastases. Methods: The group of 222 consecutive breast cancer pts with brain metastases treated in one institution in the years 2003–2006 was divided into four biological subgroups based on ER, PR, and HER-2 receptors’ expression: HER-2(+++)ER/PR(-); HER-2(+++)ER/PR(+); ER(-)PR(-)HER-2(-); and ER/PR(+)HER-2(-). WBRT was performed in 219 (99%) pts. Systemic therapy after WBRT was continued in 160 (72%) pts. Clinically, patients with triple-negative breast cancer were more often in poor performance status (KPS<60%) than the others (51% vs. 28%, respectively). Survivals from brain metastases without and with systemic treatment were compared in four mentioned biological subgroups. Results: Median survival from brain metastases in the entire group was 7.5 months. In the group of ER/PR(+)HER-2(-) median survival without and with systemic therapy was 3 and 14 months, respectively (p = 0.007). In the group of HER-2(+++)ER/PR(+) median survival without further treatment, after chth and after chth with trastuzumab was 2, 8, and 13 months, respectively (p = 0.000) and in the group of HER-2(+++)ER/PR(-) median survival without further treatment, after chth and after chth with trastuzumab was 4, 8, and 10 months, respectively (p = 0.004). In triple-negative breast cancer patients median survival without and with chemotherapy was 3 and 4 months, respectively (p = 0.75). Conclusions: Systemic treatment (chth, endocrine therapy, targeted therapy) continued after WBRT in breast cancer pts with brain metastases prolongs survival in three of four biological subgroups. In the group of HER-2-positive breast cancer pts, trastuzumab added to chth had independent positive impact on survival. No benefit was observed in the subgroup of triple-negative breast cancer pts; it would be the result of refractory disease and the fact, that more pts were in poor performance status. No significant financial relationships to disclose.