Novel prognostic classification predicts overall survival of patients receiving salvage whole-brain radiotherapy for recurrent brain metastasis from breast cancer: A recursive partitioning analysis (KROG 16-12)
Jae Sik Kim,
Kyubo Kim,
Wonguen Jung,
Kyung Hwan Shin,
Seock-Ah Im,
Yong Bae Kim,
Jee Suk Chang,
Doo Ho Choi,
Haeyoung Kim,
Yeon Hee Park,
Dae Yong Kim,
Tae Hyun Kim,
Jeanny Kwon,
Ki Mun Kang,
Woong-Ki Chung,
Kyung Su Kim,
In Ah Kim
Affiliations
Jae Sik Kim
Department of Radiation Oncology, Seoul National University College of Medicine, South Korea
Kyubo Kim
Department of Radiation Oncology, Ewha Womans University College of Medicine, South Korea
Wonguen Jung
Department of Radiation Oncology, Ewha Womans University College of Medicine, South Korea
Kyung Hwan Shin
Department of Radiation Oncology, Seoul National University College of Medicine, South Korea
Seock-Ah Im
Department of Internal Medicine, Seoul National University College of Medicine, South Korea
Yong Bae Kim
Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, South Korea
Jee Suk Chang
Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, South Korea
Doo Ho Choi
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, South Korea
Haeyoung Kim
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, South Korea
Yeon Hee Park
Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, South Korea
Dae Yong Kim
Proton Therapy Center, National Cancer Center, South Korea
Tae Hyun Kim
Proton Therapy Center, National Cancer Center, South Korea
Jeanny Kwon
Department of Radiation Oncology, Chungnam National University College of Medicine, South Korea
Ki Mun Kang
Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Changwon Hospital, South Korea
Woong-Ki Chung
Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, South Korea
Kyung Su Kim
Department of Radiation Oncology, Dongnam Institute of Radiological and Medical Sciences, South Korea; Department of Radiation Oncology, Ewha Womans University College of Medicine, South Korea
In Ah Kim
Department of Radiation Oncology, Seoul National University College of Medicine, South Korea; Department of Radiation Oncology, Seoul National University Bundang Hospital, South Korea; Corresponding author. Department of Radiation Oncology, Seoul National University Bundang Hospital, Gumi-ro 173, 82 Beon-gil, Bundang gu, Seongnam, 13620, Republic of Korea.
Background: To investigate outcomes of salvage whole-brain radiotherapy (WBRT) for recurrent brain metastases (BM) from breast cancer (BC), to identify prognostic factors of overall survival (OS), and to propose a novel prognostic classification for OS in these patients. Materials and methods: We identified 54 patients who had received salvage WBRT as the second brain-focused treatment for recurrent BM from BC (2000–2014). The median follow-up duration was 4.9 months. A recursive partitioning analysis (RPA) was conducted to develop a model to predict OS at the time of salvage WBRT. Results: The median OS was 6.8 months. OS according to BC-specific graded prognostic assessment (breast-GPA), modified breast-GPA, and updated breast-GPA did not represent our cohort. In the multivariate analysis, a long time before salvage WBRT (≥16 months), control of primary BC or extracranial metastases, systemic treatment after salvage WBRT, and administration of a biologically effective dose for an α/β of 10 Gy (BED10) of salvage WBRT >37.5 Gy showed superior OS. We proposed three RPA classes based on the control of both primary BC and extracranial metastasis and BED10 of salvage WBRT: class I, class II, and class III. In this model, patients with class I experienced the best OS (34.6 months; class II, 5.0 months; class III, 2.4 months; P < 0.001). Conclusions: In our RPA classification according to the control of both primary BC and extracranial metastasis and the dose of salvage WBRT, significant differences in OS were observed. The subsequent use of a systemic treatment showed better OS.
