Prognostic factors of survival in the trastuzumab era among women with breast cancer and brain metastases who receive whole brain radiotherapy: a single-institution review

Abstract

Background: The objective of this study was to review the outcome of women with breast cancer with known receptor status who were treated with whole brain radiotherapy for brain metastases and to determine factors that impact survival.

Methods: A total of 223 women with breast cancer and brain metastases, who received whole brain radiotherapy, were identified. All women with HER-2-positive disease had received trastuzumab. Kaplan-Meier product limit method was used to determine overall survival (OS) estimates. Cox proportional hazards models were then fitted to explore the association of OS with various patient and tumor characteristics.

Results: Median age at brain metastases diagnosis was 50 years. Sixty-seven (30.2%) patients had hormone receptor-positive/HER-2-negative disease, 101 (45.50%) had HER-2-positive disease, and 54 (24.3%) had triple receptor-negative disease. Median OS from brain metastases was 6 months, with 1-year survival of 30% (95% confidence interval [CI], 23%-36%). Women with hormone receptor-positive/HER-2-negative, HER-2-positive, and triple-negative tumors had median survivals of 5, 9, and 5 months, respectively (P = .0069). In the multivariate model, women with HER-2-positive disease had a significantly decreased risk of death compared with women with hormone receptor-positive/HER-2-negative disease (hazard ratio, 0.63; 95%CI, 0.42-0.94; P = .02). The risk of death among women with triple-negative disease compared with hormone receptor-positive/HER-2-negative disease was not significantly different (P = .54). Lower recursive partitioning analysis class and > or = 30-gray brain radiation dose were also significantly associated with a decreased risk of death.

Conclusions: Breast tumor subtype has a significant prognostic role among women with breast cancer and brain metastases. In addition, in the trastuzumab era factors such as recursive partitioning analysis and adequate radiation dose continue to be important prognostic factors.

Figure 1

Kaplan-Meier (K-M) curves for survival after a diagnosis of central nervous system metastases (met) are shown stratified by (A) HER-2 status, (B) breast cancer subtype, (C) radiation dose, and (D) recursive partitioning analysis (RPA). brainfu indicates brain function; GY, grays.