Journal Article

New brain metastases after whole-brain radiotherapy of initial brain metastases in breast cancer patients: the significance of molecular subtypes (KROG 16-12)

Kim Dae Yong, Shin, Kyung Hwan, Kim, Suzy, Hee-Jun, Kim, Kim In Ah, Jung Wonguen, Choi, Doo Ho, Choi, Byung Ock, Sea-Won, Lee, Kim, Jee Hyun, Kim Kyubo, Yoon, Won Sup, Oh, Yoon Kyeong, Im Seock-Ah, Chung Woong-Ki, Park, Yeon Hee, Kim, Jin Hee, Cha Jihye, Kwon Jeanny, Su, Kim Kyung, Kim, Jae Sik, Kim Yong Bae, Kim, Tae Hyun, Chang, Jee Suk, Kang, Ki Mun

2021

Overview

PurposeTo identify the risk factors leading to new brain metastases (BM) following brain-directed treatment for initial BM resulting from breast cancer (BC).MethodsIn this multi-institutional study, 538 BC patients with available follow-up imaging after brain-directed treatment for initial BM were analyzed. Tumor molecular subtypes were classified as follows: hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2−, n = 136), HER2-positive (HER2+, n = 253), or triple-negative BC (TNBC, n = 149).ResultsIn 37.4% of patients, new BM emerged at a median of 10.5 months after brain-directed treatment for initial BM. The 1-year actuarial rate of new BM for HR+/HER2−, HER2+, and TNBC were 51.9%, 44.0%, and 69.6%, respectively (p = 0.008). Initial whole-brain radiotherapy (WBRT) reduced new BM rates (22.5% reduction at 1 year, p < 0.001) according to molecular subtype (HR+/HER2−, 42% reduction at 1 year, p < 0.001; HER2+, 18.5%, p = 0.004; TNBC, 16.9%, p = 0.071). Multivariate analysis revealed an increased risk of new BM for the following factors: shorter intervals between primary BC diagnoses and BM (p = 0.031); TNBC (relative to HR+/HER2−) (p = 0.016); presence of extracranial metastases (p = 0.019); number of BM (>4) (p < 0.001); and BM in both tentorial regions (p = 0.045). Anti-HER2 therapy in HER2+ patients (p = 0.013) and initial use of WBRT (p < 0.001) significantly lowered new BM development.ConclusionsTumor molecular subtypes were associated with both rates of new BM development and the effectiveness of initial WBRT. Anti-HER2 therapy in HER2+ patients significantly lowered new BM occurrence.

• Publisher: Springer Nature B.V
• Subject: Brain cancer / Breast cancer / Cancer research / Epidermal growth factor / ErbB-2 protein / Metastases / Metastasis / Multivariate analysis / Neuroimaging / Radiation therapy / Risk factors