04.01.2021 | Clinical trial
New brain metastases after whole-brain radiotherapy of initial brain metastases in breast cancer patients: the significance of molecular subtypes (KROG 16-12)
verfasst von:
Jae Sik Kim, Kyubo Kim, Wonguen Jung, Kyung Hwan Shin, Seock-Ah Im, Hee-Jun Kim, Yong Bae Kim, Jee Suk Chang, Jee Hyun Kim, Doo Ho Choi, Yeon Hee Park, Dae Yong Kim, Tae Hyun Kim, Byung Ock Choi, Sea-Won Lee, Suzy Kim, Jeanny Kwon, Ki Mun Kang, Woong-Ki Chung, Kyung Su Kim, Won Sup Yoon, Jin Hee Kim, Jihye Cha, Yoon Kyeong Oh, In Ah Kim
Erschienen in:
Breast Cancer Research and Treatment
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Ausgabe 2/2021
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Abstract
Purpose
To identify the risk factors leading to new brain metastases (BM) following brain-directed treatment for initial BM resulting from breast cancer (BC).
Methods
In 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).
Results
In 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.
Conclusions
Tumor 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.